GC-MS ANALYSIS AND ANTICANCER ACTIVITY OF METHANOL EXTRACT OF LEAVES OF HYPERICUM HOOKERIANUM WIGHT & ARN
Objective: The present investigation was an attempt to study the anticancer activity of the methanol extract of the leaves of H. hookerianum. GC-MS analysis revealed that the methanol extract of leaves contained important secondary metabolites viz. oxygenated hydrocarbons and phenolic hydrocarbons. These phytochemicals w e r e p r e s u m e d responsible for various pharmacological actions like antioxidant, and anticancer activities. Cytotoxic changes observed in MCF 7 cell line by the treatment of methanol extract included cell aggregation, cell rounding and cell death. The overall result indicates that the methanol extract of leaves of H. hookerianum showed promising baseline information for its potential use as an anti cancer agent.
Free radical scavenging activity and lipid peroxidation inhibition of Hypericum helianthemoides (spach) Boiss
Antioxidants are compounds that obstruct the oxidation of macromolecules in the body. In general, there are two categories of antioxidants, natural and synthetic. Recently, interest has been increased considerably for obtaining new natural antioxidants. In this study, the scavenging of free radicals such as DPPH, NO and OH by Hypericum helianthemoides extract was evaluated. Also, the antioxidant properties of this extract were evaluated by FRAP, FTC methods and determination phenolic compounds. The plant was collected from north of Fars Province and plant extraction was obtained using ethanol. In DPPH radical scavenging, different concentrations of the Hypericum extract were added to DPPH radical. In hydroxyl radical scavenging, Fenton reaction mixture, TCA and TBA were mixed with Hypericum extract. In nitric radical scavenging, nitropruside was mixed with Hypericum extract and then sulphanilic acid, naphthylene diamine were added. In determination of phenolic compounds, Folin-ciocalteu and sodium carbonate were added to Hypericum extract. In DPPH radical scavenging, the IC50 of Hypericum extract (309.35±6.5µg/ml) was higher than the antioxidant standards, BHT (IC50=81.9±2.6 µg/ml) and quercetin (IC50=60.04±6.48 µg/ml). The highest scavenging of hydroxyl radicals was observed in Hypericum extract (70.3±0.8%, 125 µg/ml). In gallic acid it was (73.8±3.3%). In 200 µg/ml of Hypericum extract scavenged NO radical (85.2±2.7%). In FRAP method, the IC50 of this extract was 109.7±10.5 µg/ml. In FTC method, the inhibition of lipid peroxidation by Hypericum extract, BHT and ascorbic acid were 59.2±2.2, 66.9±0.15, 64.06±0.02 respectively. Total phenol of the plant extract was 3±0.4 mg/g.//
Modelling of Mooney viscosity relaxation in natural rubber
Abstract Better assessment of natural rubber (NR) quality and processability, through the identification of new attributes, is still a major challenge. With this scope, 12 model samples of natural polyisoprene and two of synthetic polyisoprene were characterized in terms of Mooney torque relaxation, using the standardized ISO289 method (ML(1+4)100, explained later in the Section 1 ). The main purpose of this study was to identify a model that gave a better fit for the experimental decay of Mooney torque over time (ML(t)=f(t)) than the usual power law model used before (Y=at−b, [G.M. Bristow, A.G. Sears, The use of novel parameters in the assessment of natural rubber processability, NR Technol. 18 (1987); H.G. Burhin, W. Spreutels, J.M. Campbell, MV2000 Mooney viscometer: Mooney relaxation measurements on raw polymers and compounded rubber stocks, Kautsch. Gummi Kunstst. 43 (1990) 431]). The results showed that a generalized Maxwell model, and the Wu–Abbott empirical model ( Y = 1 − a Ln ( t ) − ( b t / ( c + t ) ) ) [T. Wu, J.A. Abbott, Firmness and force relaxation characteristics of tomatoes stored intact or as slices, Postharvest Biol. Technol. 24 (2002) 59–68], recently used for describing stress relaxation of tomato flesh, allowed a better description of the relaxation curve for the samples studied than the power law or stretched exponential traditionally used. Moreover, the total relaxation time (τm) given by the generalized Maxwell model showed good correlation with the total gel content of the samples studied.