Scientific Name(s): Centella asiatica (L.) Urban. Family: Apiaceae (carrots)
Common Name(s): Gotu kola (Chinese), Indian Pennywort (English), Brahmi (Hindi), Manduukaparani (Ayurveda), Tsubokusa (Japan), hydrocotyle , talepetrako , spadeleaf , Asiatic pennywort
Uses of Gotu Kola
Gotu kola has been traditionally used as treatment for a variety of conditions and as an aphrodisiac. There is potential efficacy in treating wounds, varicose veins, skin disorders, venous insufficiency, and to enhance memory, although there is little clinical information to support these claims.
Gotu Kola Dosing
Dosages of gotu kola in crude form range from 1.5 to 4 g/day. Various extracts standardized to asiaticoside content also are available and have been studied in clinical trials in venous insufficiency and wound healing at doses of 30 to 90 mg/day. Wound-healing studies have involved topical application of a hydrogel ointment containing a titrated extract of C. asiatica (TECA). Commercial manufacturers have numerous dosage regimens listed for gotu kola.
Avoid use if hypersensitive to any of the ingredients of C. asiatica or gotu kola.
Avoid use during pregnancy and lactation, because gotu kola may have emmenagogue effects.
Gotu Kola Interactions
None well documented.
Gotu Kola Adverse Reactions
Contact dermatitis is documented in some clinical trials.
Three cases of hepatotoxicity have been reported with patients using C. asiatica for 20 to 60 days.
C. asiatica is a perennial herbaceous creeping plant in the genus Centella (Apiceae). 1 , 2 The plant is also known as gotu kola and grows abundantly in shady, moist, or marshy areas. It is distributed widely in many parts of the world, including India, Sri Lanka, Madagascar, South Africa, Australia, China, and Japan. 1 , 3 , 4
Gotu kola has a long history of therapeutic uses in numerous medicinal systems dating back many centuries. 1 In India, the plant has been used to treat dermatitis, diabetes, cough, cataracts and other eye conditions, and to improve memory. In Europe, an infusion of the aerial parts of the plant was used to purify the blood and treat wounds, ulcers, dermatitis, and hypertension. A similar infusion has been used in Indonesia and Brazil to help improve memory. In Malaysia, the plant was used to treat respiratory ailments, such as bronchitis and asthma, and gastric complaints, including dysentery, kidney trouble, urethritis, and dropsy (edema). In Malaya, an infusion from this plant is sold as a tonic and cold beverage to treat liver ailments, tuberculosis, and blood in the urine. In the past, people in Japan valued the plant for its diuretic and detoxicant properties. 1 , 3 , 4 Sri Lankans noticed that elephants, known for their longevity, ate the leaves of the plant. Thus, the leaves were believed to promote long life, with a suggested “dosage” of a few leaves each day. 5 In South China, the plant is used as a dietary supplement to promote health and immune system function. 6
The plant species is native to China, India, Sri Lanka, and Indonesia, and is being introduced to other countries. 1
Gotu kola should not be confused with the dried seed of Cola nitida (Vent.) Schott. and Endl. (also known as kolanuts, kola, or cola), the plant used in cola beverages. C. nitida contains caffeine and is a stimulant. Gotu kola has no caffeine and has sedative properties. 5
The triterpenoids are the major components responsible for the medicinal activity of the plant. 1 , 6 However, the plant species also contains more than 70 constituents, including polyacetylenes, flavonoids, flavones, sterols, and lipids. 7 , 8 , 9 Below-ground parts of the plant contain small amounts of at least 14 different polyacetylenes. 10 A phytochemical study revealed the presence of amino acids, flavonols, fatty acids, alkaloids, sterols, saccharides, and inorganic salts. 11 A study of powdered gotu kola by microscopic and chemical identification methods has also been conducted. 12 The active constituents of the plant are the same components found in many drugs and cosmetic preparations. 13
Many studies focus on the triterpenoids asiaticoside, centelloside, madecassoside, and asiatic acid. 13 Asiaticoside has anxiolytic, 14 anti-inflammatory, antioxidant, antiulcer, and wound-healing properties. 15 Asiaticoside and madecassoside may be effective in treating arthritis. 16 Asiatic acid induces apoptosis and cell cycle arrest in several types of cancer in rats. 17
The pharmacokinetics of the total triterpene fraction of gotu kola have been studied after single and multiple administration to healthy volunteers. 18 Using a high-pressure liquid chromatography procedure for detection of asiatic acid, researchers found that after chronic treatment at 2 doses, the peak plasma concentration, area under the curve, and half-life were higher than those observed after the corresponding single-dose administration. Pharmacokinetic studies have also been completed in animals. 19
Gotu Kola Uses and Pharmacology
Numerous animal and clinical studies investigate the plant's therapeutic potential in treating infections, and as an antidepressant, analgesic, sedative, and wound-healing agent.Anxiety
Traditionally, gotu kola has been used in Ayurvedic and Chinese medicine to relieve anxiety and promote relaxation. A study conducted in rats compared the impact of different phytochemicals in gotu kola with placebo. During one portion of the study protocol, rats were given a commercial product from Madagascar that contained high levels of triterpene or placebo (ie, distilled water). The gotu kola groups received either 200 or 500 mg/kg of each product. Anxiolytic effects were noted in multiple measures assessed in both groups receiving high doses of gotu kola products; however, anxiolytic effects were not noted in either group at the lower dose. No differences were noted between the 2 commercial products. In another portion of this study, a hexane extract, ethyl acetate extract, and methanol extract were compared. Improvements in measures of behavior were noted in rats receiving ethyl acetate and methanol extracts. Rats receiving the hexane extract did not appear to have any improvement in behavioral symptoms. These findings are consistent with the fact that the asiaticoside concentration is lowest in the hexane extract and highest in the methanol extract. In a third portion of this study, dose-dependent assessments using pure asiaticoside found changes in behavioral and anxiety measures compared with controls. However, no differences between rats receiving asiaticoside and those receiving placebo were noted in locomotor activity, suggesting that gotu kola does not cause sedation in rats. 20 Additional rat behavioral model studies document the anxiolytic activity of asiaticoside. 21Clinical data
To determine gotu kolas effects on anxiety in humans, 40 healthy volunteers were randomly assigned to receive a single oral dose of gotu kola 12 g (n = 20) or placebo (n = 20). The acoustic startle response was reduced 60 and 90 minutes after the administration of a single dose of gotu kola, which may suggest a potential anxiolytic effect. No effects were noted on self-rated mood, heart rate, or blood pressure. 22Chemotherapy and radiation-induced toxicity
The cancer chemotherapeutic agents adriamycin and doxorubicin produce dose-dependent toxicity in the heart, limiting the total cumulative dose allowable. This effect is in part caused by oxidative damage to membrane lipids. Mitochondrial dysfunction is believed to also play a role in doxorubicin-associated cardiotoxicity. Thus, agents with potential antioxidant activity, such as C. asiatica , may protect against oxidative damage resulting from doxorubicin administration. C. asiatica antioxidant properties are believed to result from its phenolic compounds. The antioxidant activity of the plant may also be beneficial in reducing radiation-induced toxicity.Animal data
A study was conducted in adult male albino rats. The rats were divided into the following 4 groups: group 1 received placebo; group 2 received doxorubicin 2.5 mg/kg in 6 equal injections over 2 weeks; group 3 received an extract of C. asiatica (200 mg/kg); and group 4 received both doxorubicin and the extract of C. asiatica . The extract was given 1 week prior to doxorubicin and for 2 weeks during doxorubicin administration. At the end of this study, cardiac enzyme markers were significantly lower in rats treated with doxorubicin compared with placebo ( P < 0.05). However, the rats in group 4, who received pretreatment and simultaneous administration of C. asiatica and doxorubicin, did not have a significant change in cardiac enzyme markers ( P < 0.05). The same was also true for mitochondrial enzymes and respiratory marker enzymes in the respective groups. Additionally, morphological changes, such as severe swelling of the mitochondria and nucleus, were noted in the rats in group 2. However, rats receiving doxorubicin in combination with C. asiatica appeared to have normal morphology and mitochondrial ultrastructure. C. asiatica was concluded to be potentially effective in reducing the dose-dependent effect of cardiotoxicity associated with doxorubicin therapy because of its antioxidant properties. 23
Taste aversion and weight loss can be undesired results of radiation therapy. Male rats were exposed to low-dose, whole-body gamma radiation and received an aqueous extract of C. asiatica 100 mg/kg or ondansetron 1 mg/kg. Rats treated with ondansetron had more protection against conditioned taste aversion on the first postirradiation day. However, both ondansetron and C. asiatica appeared equally effective on the second postirradiation day. Additionally, rats receiving C. asiatica continued to experience a decline in conditioned taste aversion up to 5 days postirradition. This pattern was unlike that in rats treated with ondansetron. The aqueous extract also inhibited radiation-induced weight loss. Thus, it was concluded that C. asiatica offers a potential option in the prevention of radiation-induced taste aversion and weight loss. 24 , 25 An in vitro and in vivo study documents that C. asiatica also protected DNA and membranes against gamma radiation in mice. 26Hypertension
C. asiatica has been used to improve circulation in patients with venous hypertension and microangiopathy. The efficacy of centellase from C. asiatica in the treatment of venous hypertension has been evaluated using a combined microcirculatory model. 27 The researchers conducted a single-blind, placebo-controlled, randomized study of the effects of the total triterpenoid fraction (centellase) in 89 patients with venous hypertension microangiopathy. The hypotensive effects of centellase differed from placebo in activity on all the microcirculatory parameters investigated. No adverse reactions were noted.
Another study was conducted in 62 patients divided into 4 groups: group 1 consisted of patients with venous hypertension (ie, ambulatory venous pressure more than 42 mm Hg) who received total triterpene fraction of C. asiatica (TTFCA) 60 mg 3 times daily; group 2 consisted of patients with venous hypertension who received TTFCA 30 mg 3 times daily; group 3 consisted of patients with venous hypertension who received placebo; and group 4 consisted of healthy patients who received TTFCA 60 mg 3 times daily. Patients received treatment for 4 weeks. Various measures of venous hypertension, including ankle edema, ankle circumference, and capillary filtration rate, improved in groups 1 and 2 after 4 weeks of therapy. No change was noted in the placebo group or in the healthy group. 28
In a similar study, patients with venous hypertension (ambulatory venous pressure more than 42 mm Hg) were divided into 3 groups: group 1 received TTFCA 60 mg 3 times daily; group 2 received 30 mg 3 times daily; and group 3 received placebo. A fourth group of healthy patients served as a comparator group and received TTFCA 60 mg 3 times daily. Patients received treatment for a period of 4 weeks. Measures of venous hypertension (capillary filtration rate, ankle edema, and ankle circumference) were improved in patients receiving treatment with TTFCA, and the effects were greater in patients receiving higher-dose TTFCA (60 mg 3 times daily). Symptoms were also improved in subjects receiving TTFCA. 29
In a study involving 40 patients with severe venous hypertension, ankle swelling, and/or lipodermatosclerosis, patients were randomized to receive 8 weeks of treatment with either TTFCA 60 mg orally twice daily or placebo. At the end of this study, there was a decrease in flux at rest and rate of ankle swelling in patients receiving TTFCA compared with placebo ( P < 0.05). In addition, symptoms improved as a result of decreased capillary filtration in patients receiving TTFCA ( P < 0.05). The conclusion was that TTFCA was effective in improving venous microangiopathy. 30Infection
In vitro data
An in vitro study in India was performed to determine the antibacterial effects of an extract of C. asiatica against enteric pathogens as an antidiarrheal product. Microorganisms studied included strains of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , Vibrio cholerae , and Shigella . Antibacterial activity was noted with all concentrations of the extract (100, 200, 300, and 400 mg/mL); however, inhibitory effects were most prominent with the 400 mg/mL concentration. Bactericidal effects against the Shigella species, one of the V. cholerae species, and S. aureus were noted within 2 hours. Thus, this preliminary study suggests the potential effects of C. asiatica extract as an option for the treatment of diarrhea. 31 An in vitro study using a disc diffusion method documented that C. asiatica also has activity against methicillin-resistant S. aureus . 32
A topical form of C. asiatica had repellant activity against malarial vector Anopheles stephensi in studies conducted in mosquito cages. This mosquito is responsible for nearly 50% of malarial cases in West Asian countries. 33 , 34 , 35Memory and Mood
In vitro and animal data
To assess the effects of C. asiatica on brain function and neuronal maturation following birth, an aqueous extract of C. asiatica was given orally to mice in weight-based doses during the postpartum period. Multiple behavioral tests were conducted, including the radial arm maze test involving the selection of food used to test spatial memory. Three-month-old mice receiving C. asiatica showed a dose-dependent increase in performance of the radial arm maze, demonstrating that C. asiatica can improve cognitive function in young mice. Higher doses were associated with more correct entries compared with lower doses. However, mice receiving lower doses completed the radial arm maze more rapidly than those receiving higher doses, which may be explained by the depressant effects seen with higher-dose C. asiatica . 36
A small study was conducted in 7-day-old Wistar rats to assess the effects of C. asiatica fresh leaf juice on learning and memory during the neonatal period. Rats were divided into treatment groups of 2-, 4-, and 6-week duration. From these groups, rats were further divided into treatment arms consisting of normal controls, saline controls, and rats receiving C. asiatica , which was further subdivided into doses of 2, 4, and 6 mL/kg. Overall, the learning measures of rats receiving the low dose of C. asiatica 2 mL/kg for 2 weeks did not differ from those of normal control rats. Additionally, rats receiving higher doses for the short duration improved their learning behaviors. Rats receiving all doses of C. asiatica for 4 or 6 weeks demonstrated improvement in learning behaviors. Memory retention also improved in rats receiving all 3 doses of the extract for all 3 time periods. It was concluded that administration of C. asiatica to neonatal rats can improve learning and memory. 37
An in vitro study documents a 50% inhibition of acetylcholinesterase activity at concentrations of 100 to 150 mcg/mL with C. asiatica . Acetylcholinesterase inhibitors are used to treat the cognitive decline in Alzheimer disease. 38 In an animal model, a C. asiatica extract decreased amyloid beta plaque formation that is associated with the neurodegenerative changes in Alzheimer disease. 39 The mechanism of action may be associated with the plant's antioxidant activity, as well as its effect on certain signaling pathways (ie, ERK/RSK signaling pathway). 40 Several animal studies also document that treatment with C. asiatica increases dendritic length (intersections) and branches of neurons of amygdala, which enhances learning and memory 41 , 42 , 43 , 44 and may also provide an antianxiolytic effect. 42
The tail suspension test is a well-established screening model for antidepressants. 14 Asiaticoside reduced the immobility time in a mouse model. The antidepressant-like effect may be related to regulation of alpha-2-adrenergic receptors. Another mechanism of action may involve altering the activity of the hypothalamic-pituitary-adrenal axis and increasing the levels of monoamine neurotransmitters. 45Clinical data
In an 8-week randomized, placebo-controlled, double-blind pilot study of 28 patients, C. asiatica extract enhanced spatial and numeric working memory and attention, and improved mood. Patients were administered 250, 500, or 750 mg of C. asiatica in capsule form or placebo. The most important changes occurred in patients treated with 750 mg/day. The underlying mechanism may involve C. asiatica modulating dopamine and norepinephrine in the prefrontal cortex, and acetylcholine and serotonin in the hippocampus, leading to improved numeric and spatial memory. 46Psoriasis
C. asiatica has shown promise in the treatment of psoriasis. When creams containing oil and water extracts of the leaves were administered each morning to 7 psoriatic patients, 5 patients displayed complete clearance of lesions within 3 to 7 weeks. One patient experienced clearance of most lesions, and one demonstrated improvement without clearance. Another patient demonstrated a mild recurrence 4 months after treatment. Although this study was not controlled, a placebo effect was considered unlikely. Experience indicated that the creams were nontoxic and cosmetically acceptable, making them suitable for long-term use. 5
A double-blind, randomized, placebo-controlled, clinical study of 25 patients documented that application of an herbal gel extract containing C. asiatica increased skin firmness and elasticity. The gel is used in China, India, and the Mediterranean area. 47 These results were also supported by additional studies. 48 , 49
Other studies with various topical herbal extracts containing C. asiatica report beneficial skin effects in cold and dry weather conditions, 50 with chronically sun-damaged skin, 51 and in skin hydration. 42Venous insufficiency
A double-blind, placebo-controlled study of 94 patients with venous insufficiency of the lower limbs indicated that TECA produced clinical improvement in this condition. The patients received 12 or 60 mg/day for 8 weeks. Improvement occurred in subjective measures of sensation of heaviness and pain in the legs, edema, overall patient assessment of efficacy, and in the objective measure of vein distensibility. The researchers concluded that TECA stimulated collagen synthesis in the vein wall, thus increasing tonicity and reducing its capacity to distend. In contrast, patients receiving placebo exhibited an increase in vein distensibility. Although there was no statistically significant difference between the 2 TECA dosage groups, data trends suggested that the effect of TECA was dose-related. 52
A study was conducted to assess the role of C. asiatica in the prevention of edema and changes in circulation measures for patients traveling on an airline flight of at least 3 hours. Patients between 30 and 50 years of age with mild to moderate venous insufficiency and varicose veins were randomized to receive TTFCA 60 mg 3 times daily beginning 2 days before the flight, the day of the flight, and 1 day following the flight, or to receive no treatment. Those receiving TTFCA had less edema, while those in the control group continued to experience an increase in edema and worsening of other measures of circulation. These findings were consistent in those patients on flights of up to 10 hours duration. It was concluded that TTFCA presents an option for patients who are prone to edema, particularly on long flights. 53Wound healing
The wound-healing effect of the glycoside madecassoside may involve several mechanisms, including antioxidant activity and effects on collagen synthesis and angiogenesis. 54 Asiaticoside appears to stimulate would healing by inducing type 1 collagen synthesis 55 and promoting angiogenesis. 56Animal data
Experiments with rats have established that wounds heal by a process involving dilation followed by contraction. However, TECA 100 mg/kg accelerated healing time. 57 A study using rats and mice found that topically applied TECA rapidly penetrated to subcutaneous tissues and abdominal muscle in high concentrations and had a greater effect on wound healing than oral administration. Asiatic acid was absorbed later than madecassic acid. The topical preparations of TECA were also able to penetrate to the plasma and deeper tissues. 58
Topical application of asiaticoside 0.2% solution to guinea pig punch wounds resulted in a 57% increase in tensile strength, an increase in collagen content, and improved epithelialization. Oral doses of the asiaticoside 1 mg/kg solution also appeared to promote wound healing in guinea pigs. 59
In another study, the effects of C. asiatica were assessed in rats receiving dexamethasone, a glucocorticoid known to suppress wound healing. Wistar albino rats were divided into 4 groups: group 1 contained rats with wounds treated with normal saline; group 2 contained rats with wounds treated with an ethanolic extract of C. asiatica ; group 3 contained rats with wounds treated solely with dexamethasone; and group 4 contained wounded rats that received C. asiatica extract and dexamethasone. Three different wound models were studied, including dead space, incision, and excision wounds. The type of wound dictated the duration of therapy with C. asiatica (ie, daily for 10 days of therapy for dead space and incision wounds, and daily until the day of epithelization for rats with excision wounds). Rats treated with C. asiatica experienced an increase in wound-breaking strength, weight, and dry tissue weight, and hydroxyproline content, suggesting an increase in collagen content. Those treated with dexamethasone only (group 3) experienced a worsening of these parameters. However, rats in group 4 receiving dexamethasone and C. asiatica experienced an increase in these parameters. It was concluded that an ethanolic extract of C. asiatica promoted wound healing in rats because of the antioxidant properties of C. asiatica . 60
Because of the potential role in enhancing wound healing, the antioxidant effect of C. asiatica was studied in the wound-healing process in rats. A topical solution of asiaticoside 0.2% was applied twice daily for 7 days to cutaneous wounds in rats. The newly formed tissue had increased levels of antioxidants. However, antioxidant levels did not appear to differ from controls after 14 days of topical asiaticoside application. 61Clinical data
C. asiatica extracts promote wound healing in humans. There are 4 phases of wound healing: an initial period of vasoconstriction and hemostasis, followed by an inflammatory phase, a proliferative phase, and remodeling. C. asiatica appears to be effective in the proliferative phase through promotion of the production of type 1 collagen. 62 Other mechanisms by which C. asiatica may be beneficial in wound healing include a reduction in the inflammatory response and production of myofibroblasts. 63
Cell culture experiments have shown that the total triterpenoid fraction of the extracts at a concentration of 25 mcg/mL does not affect cell proliferation, total cell protein synthesis, or the biosynthesis of proteoglycans in human skin fibroblasts. However, the fraction does increase the collagen content of cell layer fibronectin, which may explain the action in wound healing. 64
TECA has been used as a scarring agent to stimulate wound healing in patients with chronic lesions, such as cutaneous ulcers, surgical wounds, fistulas, and gynecologic lesions. A clinical study evaluated TECA for treating bladder lesions in 102 patients with bilharzial infections. Injections of TECA 2%, usually administered intramuscularly for 1 to 3 months, produced cure or improvement in 75% of the cases, as determined from symptoms and urinary and cystoscopic findings. Healing occurred with little scar formation, avoiding much of the loss of bladder capacity that can result from bilharzial infections. 65
Though studies are lacking, the use of gotu kola in combination with other herbal products, such as horse chestnut, butcher's broom, witch hazel, or stone root, has been considered to improve the healing time of hemorrhoids due to gotu kola's ability to increase tensile strength and collagen content in the wound-healing process, as well as its ability to enhance microcirculation. 66Other pharmacologic activity
Reduction of fertility in female mice was found with 2 compounds from the crude extract of gotu kola: isothankuniside and BK compound (methyl 5-hydroxy-3,6-dioxo-23 [or 24]-nor-urs-12-ene-28-oate). No appreciable effects were reported with the crude extract. Mice treated with isothankuniside in 1 and 2 mg doses resulted in 15% to 35% more sterile matings when administered for the first 3 days of each week for 21 days. BK compound administered over the same treatment period was even more effective. 67 Because this was a preliminary screening study, the mechanism for this effect was not investigated.Cancer
Centella extract may be effective in killing cultured cancer tumor cells. 68 The extract, a 5:1 concentrate extracted with methanol, was effective at a level of 100 mcg/mL. In addition, no toxic effects were detected in normal human lymphocytes. A preliminary French study showed TECA produced histologic improvement in 5 of 12 patients with chronic hepatic disorders. 69 The triterpene asiaticoside from C. asiatica may induce apoptosis and enhance the anticancer activity of vincristine in several cancer cell lines. 70 Another in vitro study documented that asiatic acid isolated from C. asiatica -induced apoptosis and inhibited colon cancer cell growth by interfering with the mitochondrial membrane potential in a concentration and time-dependent manner. 71Cholesterol
Rats fed C. asiatica powder had significantly ( P < 0.05) lower serum low-density lipoprotein and triglycerides and higher high-density lipoprotein when compared with controls. However, cholesterol levels of rats fed either C. asiatica extract or powder were higher compared with controls. 72 An in vivo rabbit study documented that madecassoside protected against myocardial ischemia reperfusion injury, 73 possibly through antioxidant, antilipid, anti-inflammation, and antiapoptosis activity. 74Diabetes
In a small study involving fasted rabbits, C. asiatica 2 and 4 g/kg were administered to assess its effects on blood glucose. Extract administration resulted in a 26% mean deviation in blood glucose levels for rabbits receiving 2 g/kg and 35% mean deviation for those receiving 4 g/kg ( P < 0.05). 75Diabetic microangiopathy
A study was conducted in 50 patients with diabetic microangiopathy to assess the effects of C. asiatica . Thirty patients received oral TTFCA 60 mg twice daily for 6 months, 10 patients received placebo, and 10 patients received no treatment. Measures of microcirculation improved in patients receiving C. asiatica after 6 months of treatment. No changes were noted in patients receiving placebo or in those receiving no treatment. It was concluded that TTFCA has a potential role in improving microcirculation in patients with diabetic microangiopathy. 76Ethanol-induced gastric ulceration
An extract of C. asiatica was given orally to rats prior to ethanol administration in doses of 0.05, 0.25, or 0.5 g/kg. Premedication with C. asiatica resulted in a 58% to 82% dose-dependent reduction in the formation of gastric lesions. These results were believed to be the result of strengthening of the gastric mucosa and a reduction in free radicals. 77Joint disease
Asiaticoside reduced articular cartilage degeneration and inflammatory cell infiltration in mice with collagen-induced arthritis. The underlying mechanism may involve inhibiting lymphocyte proliferation and reducing cyclooxygenase-2 and cytokine expression. 78 , 79 Madecassoside also provides a protective effect in joint destruction by potentially regulating abnormal humoral and cellular immunity. 80 The results of an in vitro and in vivo study demonstrated that a standardized C. asiatica fraction inhibited zymosan-induced cartilage damage by potentially inhibiting nitric oxide production. 81 Nitric oxide plays a role in cartilage degradation in osteoarthritis.Varicose veins
The effect of gotu kola extract on mucopolysaccharide metabolism was studied in subjects with varicose veins. 82 The total triterpene fraction of the plant (60 mg/day for 3 months) elevated the basal levels of uronic acids and lysosomal enzymes, indicating an increased mucopolysaccharide turnover in varicose vein patients. These results confirm the regulatory properties of C. asiatica extract on the metabolism in the connective tissue of the vascular wall.
Dosages of gotu kola in crude form range from 1.5 to 4 g/day. Various extracts standardized to asiaticoside content are available and have been studied in clinical trials for potential treatment of venous insufficiency and wound healing at dosages of 30 to 90 mg/day. Wound-healing studies have involved topical application of a hydrogel ointment containing TECA. 83 , 84
Gotu kola is available in numerous dosage forms including capsules, creams, powders, liquids, 85 and teas. Commercial manufacturers have numerous dosage regimens listed for gotu kola.
Avoid use during pregnancy and lactation, because gotu kola may have emmenagogue effects. 86
Theoretically, gotu kola may interact with this drug class. The median effective dose of phenytoin, valproate, and gabapentin were found to be 13, 104, and 310 mg/kg body weight, respectively. However, during the presence of a C. asiatica ethyl acetate fraction the corresponding values were 5, 29, and 79 mg/kg body weight, respectively. 87 In an in vitro experiment, 1 mg/mL extracts from C. asiatica stimulated glutamic acid decarboxylase activity by more than 40%. 88Erectile dysfunction medications
An herbal product containing C. asiatica enhanced erectile function in rats. Some activities of the herbal product were comparable with sildenafil. 89Famotidine
Antiulcer activity of C. asiatica in rats was comparable with famotidine and sodium valproate. 90Sucralfate
A 600 mg/kg dose of C. asiatica given to rats twice daily for 5 days protected against induced gastric ulceration. The effects were comparable with sucralfate 250 mg/kg by mouth once a day for 5 days. C. asiatica increased gastric juice mucin secretion and mucosal cell glycoproteins, and decreased cell shedding, which leads to an increase in the mucosal barrier. 91
Contact dermatitis has been reported in some patients using preparations of fresh or dried parts of the plant. 92 Patients who received subcutaneous injections rather than intramuscular injections experienced pain at the injection site, with blackish discoloration of the subcutaneous tissues.
Relatively large doses of the extract had a sedative effect in small animals; this property is attributed to 2 saponin glycosides, brahmoside, and brahminoside. 93
Avoid use if hypersensitivity occurs with any of the ingredients of C. asiatica or gotu kola.
Three cases of hepatotoxicity have been reported with patients using C. asiatica for 20 to 60 days. After the product was discontinued, improvement was noted. Two patients were unintentionally rechallenged with C. asiatica , which resulted in recurrent liver damage. Hepatotoxicity from apoptosis and alteration in the cell membrane due to the active constituents pentacyclic triterpenic saponosides is suspected. 93
Several studies examined the protective effect of C. asiatica against several toxins, including lead, 94 , 95 arsenic, 96 and cyproterone acetate (genotoxic- and tumor-promoting agent). 97 Other studies reviewed the neuroprotective role of the plant species against neurotoxins. 98 , 99
Bibliography1. Zheng CJ, Qin LP. Chemical components of Centella asiatica and their bioactivities. Zhong Xi Yi Jie He Xue Bao . 2007;5(3):348-351.
2. Centella asiatica (L.) Urban. USDA, NRCS. 2007. The PLANTS Database ( http://plants.usda.gov , 14 June 2007). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
3. Satake T, Kamiya K, An Y, Oishi Nee Taka T, Yamamoto J. The anti-thrombotic active constituents from Centella asiatica . Biol Pharm Bull . 2007;30(5):935-940.
4. Centella asiatica . Altern Med Rev . 2007;12(1):69-72.
5. Natarajan S , Paily PP . Effect of topical Hydrocotyle asiatica in psoriasis . Indian J Dermatol . 1973;18(4):82-85.
6. Li H, Gong X, Zhang L, et al. Madecassoside attenuates inflammatory response on collagen-induced arthritis in DBA/1 mice. Phytomedicine . 2009;16(6-7):538-546.
7. Yu QL , Duan HQ , Takaishi Y , et al. A novel triterpene from Centella asiatica . Molecules . 2006;11(9):661-665.
8. Subban R, Veerakumar A, Manimaran R, Hashim KM, Balachandran I. Two new flavonoids from Centella asiatica (Linn.). J Nat Med . 2008;62(3):369-373.
9. Rafamantanana MH, Rozet E, Raoelison GE, et al. An improved HPLC-UV method for the simultaneous quantification of triterpenic glycosides and aglycones in leaves of Centella asiatica (L.) Urb (APIACEAE). J Chromatogr B Analyt Technol Biomed Life Sci . 2009;877(23):2396-2402.
10. Schulte KE , Rücker G , Bary EA . Polyacetylenes from Hydrocotyle asiatica L [in German]. Arch Pharm (Weinheim) . 1973;306(3):197-209.
11. Castellani C , Marai A , Vacchi P . The Centella asiatica [in Italian]. Boll Chim Farm . 1981;120:570-605.
12. Sappakun N , Ungwitayatom J . Thai crude drugs: preparation and specifications. Part 13. Centella asiatica (L.) . Warasan Phesatchasat . 1982;9:53-58.
13. Randriamampionona D, Diallo B, Rakotoniriana F, et al. Comparative analysis of active constituents in Centella asiatica samples from Madagascar: application for ex situ conservation and clonal propagation. Fitoterapia . 2007;78(7-8):482-489.
14. Liang X, Yan Ni Huang, Si Wei Chen, et al. Antidepressant-like effect of asiaticoside in mice. Pharmacol Biochem Behav . 2008;89(3):444-449.
15. Kimura Y, Sumiyoshi M, Samukawa K, Satake N, Sakanaka M. Facilitating action of asiaticoside at low doses on burn wound repair and its mechanism. Eur J Pharmacol . 2008;584(2-3):415-423.
16. Liu M, Dai Y, Yao X, et al. Anti-rheumatoid arthritic effect of madecassoside on type II collagen-induced arthritis in mice. Int Immunopharmacol . 2008;8(11):1561-1566.
17. Barbosa NR, Pittella F, Gattaz WF. Centella asiatica water extract inhibits iPLA2 and cPLA2 activities in rat cerebellum. Phytomedicine . 2008;15(10):896-900.
18. Grimaldi R , De Ponti F , D'Angelo L , et al. Pharmacokinetics of the total triterpenic fraction of Centella asiatica after single and multiple administrations to healthy volunteers. A new assay for asiatic acid . J Ethnopharmacol . 1990;28(2):235-241.
19. Zheng XC, Wang SH. Determination of asiatic acid in beagle dog plasma after oral administration of Centella asiatica extract by precolumn derivatization RP-HPLC. J Chromatogr B Analyt Technol Biomed Life Sci . 2009;877(5-6):477-481.
20. Wijeweera P , Arnason JT , Koszycki D , Merali Z . Evaluation of anxiolytic properties of Gotukola—( Centella asiatica ) extracts and asiaticoside in rat behavioral models . Phytomedicine . 2006;13(9-10):668-676.
21. Wijeweera P, Arnason JT, Koszycki D, Merali Z. Evaluation of anxiolytic properties of Gotukola—( Centella asiatica ) extracts and asiaticoside in rat behavioral models. Phytomedicine . 2006;13(9-10):668-676.
22. Bradwejn J , Zhou Y , Koszycki D , Shlik J . A double-blind, placebo-controlled study on the effects of Gotu Kola ( Centella asiatica ) on acoustic startle response in healthy subjects . J Clin Psychopharmacol . 2000;20(6):680-684.
23. Gnanapragasam A , Yogeeta S , Subhashini R , Ebenezar KK , Sathish V , Devaki T . Adriamycin induced myocardial failure in rats: protective role of Centella asiatica . Mol Cell Biochem . 2007;294(1-2):55-63.
24. Shobi V , Goel HC . Protection against radiation-induced conditioned taste aversion by Centella asiatica . Physiol Behav . 2001;73(1-2):19-23.
25. C Jagetia G. Radioprotective potential of plants and herbs against the effects of ionizing radiation. J Clin Biochem Nutr . 2007;40(2):74-81.
26. Joy J, Nair CK. Protection of DNA and membranes from gamma-radiation induced damages by Centella asiatica . J Pharm Pharmacol . 2009;61(7):941-947.
27. Belcaro G , Laurora G, Cesarone MR, et al. Efficacy of centellase in the treatment of venous hypertension evaluated by a combined microcirculatory model . Curr Ther Res Clin Exp . 1989;46(6):1015-1026.
28. Belcaro GV , Rulo A , Grimaldi R . Capillary filtration and ankle edema in patients with venous hypertension treated with TTFCA . Angiology . 1990;41(1):12-18.
29. De Sanctis MT , Belcaro G , Incandela L , et al. Treatment of edema and increased capillary filtration in venous hypertension with total triterpenic fraction of Centella asiatica : a clinical, prospective, placebo-controlled, randomized, dose-ranging trial . Angiology . 2001;52(suppl 2):S55-S59.
30. Cesarone MR , Belcaro G , De Sanctis MT , et al. Effects of the total triterpenic fraction of Centella asiatica in venous hypertensive microangiopathy: a prospective, placebo-controlled, randomized trial . Angiology . 2001;52(suppl 2):S15-S18.
31. Mamtha B , Kavitha K , Srinivasan KK , Shivananda PG . An in vitro study of the effect of Centella asiatica [Indian pennywort] on enteric pathogens . Indian J Pharmacol . 2004;36(1):41.
32. Zaidan MR, Noor Rain A, Badrul AR, Adlin A, Norazah A, Zakiah I. In vitro screening of five local medicinal plants for antibacterial activity using disc diffusion method. Trop Biomed . 2005;22(2):165-170.
33. Rajkumar S, Jebanesan A. Repellent activity of selected plant essential oils against the malarial fever mosquito Anopheles stephensi . Trop Biomed . 2007;24(2):71-75.
34. Rahuman AA, Venkatesan P, Gopalakrishnan G. Mosquito larvicidal activity of oleic and linoleic acids isolated from Citrullus colocynthis (Linn.) Schrad. Parasitol Res . 2008;103(6):1383-1390.
35. Senthilkumar N, Varma P, Gurusubramanian G. Larvicidal and adulticidal activities of some medicinal plants against the malarial vector, Anopheles stephensi (Liston). Parasitol Res . 2009;104(2):237-244.
36. Rao SB , Chetana M , Uma Devi P . Centella asiatica treatment during postnatal period enhances learning and memory in mice . Physiol Behav . 2005;86(4):449-457.
37. Mohandas KG, Muddanna S, Gurumadhra S. Centella asiatica (linn) induced behavioural changes during growth spurt period in neonatal rats . Neuroanatomy . 2005;4:18-23.
38. Mukherjee PK, Kumar V, Houghton PJ. Screening of Indian medicinal plants for acetylcholinesterase inhibitory activity. Phytother Res . 2007;21(12):1142-1145.
39. Dhanasekaran M, Holcomb LA, Hitt AR, et al. Centella asiatica extract selectively decreases amyloid beta levels in hippocampus of Alzheimer's disease animal model. Phytother Res . 2009;23(1):14-19.
40. Xu Y, Cao Z, Khan I, Luo Y. Gotu kola ( Centella Asiatica ) extract enhances phosphorylation of cyclic AMP response element binding protein in neuroblastoma cells expressing amyloid beta peptide. J Alzheimers Dis . 2008;13(3):341-349.
41. Rao SB, Chetana M, Uma Devi P. Centella asiatica treatment during postnatal period enhances learning and memory in mice. Physiol Behav . 2005;86(4):449-457.
42. Mohandas Rao KG, Muddanna Rao S, Gurumadhva Rao S. Enhancement of amygdaloid neuronal dendritic arborization by fresh leaf juice of Centella asiatica (Linn) during growth spurt period in rats. Evid Based Complement Alternat Med . 2009;6(2):203-210.
43. Mohandas Rao KG, Muddanna Rao S, Gurumadhva Rao S. Centella asiatica (L.) leaf extract treatment during the growth spurt period enhances hippocampal CA3 neuronal dendritic arborization in rats. Evid Based Complement Alternat Med . 2006;3(3):349-357.
44. Gadahad MR, Rao M, Rao G. Enhancement of hippocampal CA3 neuronal dendritic arborization by Centella asiatica (Linn) fresh leaf extract treatment in adult rats. J Chin Med Assoc . 2008;71(1):6-13.
45. Chen Y, Han T, Rui Y, Yin M, Qin L, Zheng H. Effects of total triterpenes of Centella asiatica on the corticosterone levels in serum and contents of monoamine in depression rat brain [in Chinese]. Zhong Yao Cai . 2005;28(6):492-496.
46. Wattanathorn J, Mator L, Muchimapura S, et al. Positive modulation of cognition and mood in the healthy elderly volunteer following the administration of Centella asiatica . J Ethnopharmacol . 20085;116(2):325-332.
47. Sommerfeld B. Randomised, placebo-controlled, double-blind, split-face study on the clinical efficacy of Tricutan on skin firmness. Phytomedicine . 2007;14(11):711-715.
48. Martelli L, Berardesca E, Martelli M. Topical formulation of a new plant extract complex with refirming properties. Clinical and non-invasive evaluation in a double blind trial. Int J Cosmet Sci . 2000;22(3):201-206.
49. Ahshawat MS, Saraf S, Saraf S. Preparation and characterization of herbal creams for improvement of skin viscoelastic properties. Int J Cosmet Sci . 2008;30(3):183-193.
50. Klövekorn W, Tepe A, Danesch U. A randomized, double-blind, vehicle-controlled, half-side comparison with a herbal ointment containing Mahonia aquifolium , Viola tricolor and Centella asiatica for the treatment of mild-to-moderate atopic dermatitis. Int J Clin Pharmacol Ther . 2007;45(11):583-591.
51. Haftek M, Mac-Mary S, Le Bitoux MA, et al. Clinical, biometric and structural evaluation of the long-term effects of a topical treatment with ascorbic acid and madecassoside in photoaged human skin. Exp Dermatol . 2008;17(11):946-952.
52. Pointel JP , Boccalon H , Cloarec M , Ledevehat C , Joubert M . Titrated extract of Centella asiatica (TECA) in the treatment of venous insufficiency of the lower limbs . Angiology . 1987;38(1 pt 1):46-50.
53. Cesarone MR , Incandela L , De Sanctis MT , et al. Flight microangiopathy in medium- to long-distance flights: prevention of edema and microcirculation alterations with total triterpenic fraction of Centella asiatica . Angiology . 2001;52(suppl 2):S33-S37.
54. Liu M, Dai Y, Li Y, et al. Madecassoside isolated from Centella asiatica herbs facilitates burn wound healing in mice. Planta Med . 2008;74(8):809-815.
55. Lee J, Jung E, Kim Y, et al. Asiaticoside induces human collagen I synthesis through TGFbeta receptor I kinase (TbetaRI kinase)-independent Smad signaling. Planta Med . 2006;72(4):324-328.
56. Kimura Y, Sumiyoshi M, Samukawa K, Satake N, Sakanaka M. Facilitating action of asiaticoside at low doses on burn wound repair and its mechanism. Eur J Pharmacol . 2008;584(2-3):415-423.
57. Poizot A , Dumez D . Modification of the kinetics of healing after iterative exeresis in the rat. Action of a triterpenoid and its derivatives on the duration of healing [in French]. C R Acad Sci Hebd Seances Acad Sci D . 1978;286(10):789-792.
58. Viala A , Cano JP , Durand A , et al. Animal study of the transcutaneous movement of the tritium-labelled active principles of Centella asiatica L. extract after administration in impregnated gauze or unguent [in French]. Therapie . 1977;32(5):573-583.
59. Shukla A , Rasik AM , Jain GK , Shankar R , Kulshrestha DK , Dhawan BN . In vitro and in vivo wound healing activity of asiaticoside isolated from Centella asiatica . J Ethnopharmacol . 1999;65(1):1-11.
60. Shetty BS , Udupa SL , Udupa AL , Somayaji SN . Effect of Centella asiatica L (Umbelliferae) on normal and dexamethasone-suppressed wound healing in Wistar Albino rats . Int J Low Extrem Wounds . 2006;5(3):137-143.
61. Shukla A , Rasik AM , Dhawan BN . Asiaticoside-induced elevation of antioxidant levels in healing wounds . Phytother Res . 1999;13(1):50-54.
62. MacKay D , Miller AL . Nutritional support for wound healing . Altern Med Rev . 2003;8(4):359-377.
63. Widgerow AD , Chait LA , Stals R , Stals PJ . New innovations in scar management . Aesthetic Plast Surg . 2000;24(3):227-234.
64. Tenni R , Zanaboni G , De Agostini MP , Rossi A , Bendotti C , Cetta G . Effect of the triterpenoid fraction of Centella asiatica on macromolecules of the connective matrix in human skin fibroblast cultures . Ital J Biochem . 1988;37(2):69-77.
65. Fam A . Use of titrated extract of Centella asiatica (TECA) in bilharzial bladder lesions . Int Surg . 1973;58(7):451-452.
66. Abascal K , Yarnell E . Botanical treatments for hemorrhoids . Altern Complement Ther . 2005;11(6):285-289.
67. Dutta T , Basu UP . Crude extract of Centella asiatica and products derived from its glycosides as oral antifertility agents . Indian J Exp Biol . 1968;6(3):181-182.
68. Babu TD , Kuttan G , Padikkala J . Cytotoxic and anti-tumour properties of certain taxa of Umbelliferae with special reference to Centella asiatica (L.) Urban . J Ethnopharmacol . 1995;48(1):53-57.
69. Darnis F , Orcel L , de Saint-Maur PP , Mamou P . Use of a titrated extract of Centella asiatica in chronic hepatic disorders (author's transl) [in French]. Sem Hop . 1979;55(37-38):1749-1750.
70. Huang YH, Zhang SH, Zhen RX, Xu XD, Zhen YS. Asiaticoside inducing apoptosis of tumor cells and enhancing anti-tumor activity of vincristine [in Chinese]. Ai Zheng . 2004;23(12):1599-1604.
71. Tang XL, Yang XY, Jung HJ, et al. Asiatic acid induces colon cancer cell growth inhibition and apoptosis through mitochondrial death cascade. Biol Pharm Bull . 2009;32(8):1399-1405.
72. Hussin M, Hamid AA, Mohamad S, Saari N, Bakar F, Dek SP. Modulation of lipid metabolism by Centella asiatica in oxidative stress rats. J Food Sci . 2009;74(2):H72-H78.
73. Li GG, Bian GX, Ren JP, Wen LQ, Zhang M, Lü QJ. Protective effect of madecassoside against reperfusion injury after regional ischemia in rabbit heart in vivo [in Chinese]. Yao Xue Xue Bao . 2007;42(5):475-480.
74. Bian GX, Li GG, Yang Y, et al. Madecassoside reduces ischemia-reperfusion injury on regional ischemia induced heart infarction in rat. Biol Pharm Bull . 2008;31(3):458-463.
75. Mutayabarwa CK , Sayi JG , Dande M . Hypoglycaemic activity of Centella asiatica (L) Urb . East Cent Afri J Pharm Sci . 2003;6(2):30-35.
76. Cesarone MR , Incandela L , De Sanctis MT , et al. Evaluation of treatment of diabetic microangiopathy with total triterpenic fraction of Centella asiatica : a clinical prospective randomized trial with a microcirculatory model . Angiology . 2001;52(suppl 2):S49-S54.
77. Cheng CL , Koo MW . Effects of Centella asiatica on ethanol induced gastric mucosal lesions in rats . Life Sci . 2000;67(21):2647-5263.
78. Li HZ, Wan JY, Zhang L, Zhou QX, Luo FL, Zhang Z. Inhibitiory action of asiaiticoside on collagen-induced arthritis in mice [in Chinese]. Yao Xue Xue Bao . 2007;42(7):698-703.
79. Yun KJ, Kim JY, Kim JB, et al. Inhibition of LPS-induced NO and PGE2 production by asiatic acid via NF-kappa B inactivation in RAW 264.7 macrophages: possible involvement of the IKK and MAPK pathways. Int Immunopharmacol . 2008;8(3):431-441.
80. Liu M, Dai Y, Yao X, et al. Anti-rheumatoid arthritic effect of madecassoside on type II collagen-induced arthritis in mice. Int Immunopharmacol . 2008;8(11):1561-1566.
81. Hartog A, Smit HF, van der Kraan PM, Hoijer MA, Garssen J. In vitro and in vivo modulation of cartilage degradation by a standardized Centella asiatica fraction. Exp Biol Med (Maywood) . 2009;234(6):617-623.
82. Arpaia MR , Ferrone R , Amitrano M , Nappo C , Leonardo G , del Guercio R . Effects of Centella asiatica extract on mucopolysaccharide metabolism in subjects with varicose veins . Int J Clin Pharmacol Res . 1990;10(4):229-233.
83. Brinkhaus B , Lindner M , Schuppan D , Hahn EG . Chemical, pharmacological and clinical profile of the East Asian medical plant Centella asiatica . Phytomedicine . 2000;7(5):427-448.
84. Hong SS , Kim JH , Li H , Shim CK . Advanced formulation and pharmacological activity of hydrogel of the titrated extract of C. asiatica . Arch Pharm Res . 2005;28(4):502-508.
85. Wongfhun P, Gordon M, Apichartsrangkoon A. Flavor characterization of fresh and processed pennywort ( Centella asiatica L.) juices. Food Chem . 2009;119(1):69-74. doi:10.1016/j.foodchem.2009.05.072 .
86. Ernst E . Herbal medicinal products during pregnancy: are they safe? BJOG . 2002;109(3):227-235.
87. Vattanajun A, Watanabe H, Tantisira MH, Tantisira B. Isobolographically additive anticonvulsant activity between Centella asiatica 's ethyl acetate fraction and some antiepileptic drugs. J Med Assoc Thai . 2005;(88 suppl 3):S131-S140.
88. Awad R, Levac D, Cybulska P, Merali Z, Trudeau VL, Arnason JT. Effects of traditionally used anxiolytic botanicals on enzymes of the gamma-aminobutyric acid (GABA) system. Can J Physiol Pharmacol . 2007;85(9):933-942.
89. Qinna N, Taha H, Matalka KZ, Badwan AA. A new herbal combination, Etana, for enhancing erectile function: an efficacy and safety study in animals. Int J Impot Res . 2009;21(5):315-320.
90. Chatterjee TK, Chakraborty A, Pathak M, Sengupta GC. Effects of plant extract Centella asiatica (Linn.) on cold restraint stress ulcer in rats. Indian J Exp Biol . 1992;30(10):889-891.
91. Sairam K, Rao CV, Goel RK. Effect of Centella asiatica Linn on physical and chemical factors induced gastric ulceration and secretion in rats. Indian J Exp Biol . 2001;39(2):137-142.
92. Eun HC , Lee AY . Contact dermatitis due to madecassol . Contact Dermatitis . 1985;13(5):310-313.
93. Jorge OA , Jorge AD . Hepatotoxicity associated with the ingestion of Centella asiatica [in English and Spanish]. Rev Esp Enferm Dig . 2005;97(2):115-124.
94. Saxena G, Flora SJ. Changes in brain biogenic amines and haem biosynthesis and their response to combined administration of succimers and Centella asiatica in lead poisoned rats. J Pharm Pharmacol . 2006;58(4):547-159.
95. Ponnusamy K, Mohan M, Nagaraja HS. Protective antioxidant effect of Centella asiatica bioflavonoids on lead acetate induced neurotoxicity. Med J Malaysia . 2008;(63 suppl A):102.
96. Flora SJ, Gupta R. Beneficial effects of Centella asiatica aqueous extract against arsenic-induced oxidative stress and essential metal status in rats. Phytother Res . 2007;21(10):980-988.
97. Siddique YH, Ara G, Beg T, Faisal M, Ahmad M, Afzal M. Antigenotoxic role of Centella asiatica L. extract against cyproterone acetate induced genotoxic damage in cultured human lymphocytes. Toxicol In Vitro . 2008;22(1):10-17.
98. Shinomol GK, Muralidhara. Prophylactic neuroprotective property of Centella asiatica against 3-nitropropionic acid induced oxidative stress and mitochondrial dysfunctions in brain regions of prepubertal mice. Neurotoxicology . 2008;29(6):948-957.
99. Shinomol GK, Muralidhara. Effect of Centella asiatica leaf powder on oxidative markers in brain regions of prepubertal mice in vivo and its in vitro efficacy to ameliorate 3-NPA-induced oxidative stress in mitochondria. Phytomedicine . 2008;15:971-984.
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