Quantitative HPLC determination and extraction of anthraquinones in Senna alata leaves.
A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of four anthraquinones: rhein, aloe-emodin, emodin, and chrysophanol in Senna alata leaves. The method involves the use of a TSK-gel ODS-80Tm column (5 microm, 4.6 x 150 mm) at 25 degrees C with the mixture of methanol and 2% aqueous acetic acid (70:30, v/v) as the mobile phase and detection at 254 nm. The parameters of linearity, precision, accuracy, and specificity of the method were evaluated. The recovery of the method is 100.3-100.5%, and linearity (r(2) > 0.9998) was obtained for all anthraquinones. A high degree of specificity as well as repeatability and reproducibility (relative standard deviation values less than 5%) were also achieved. The solvent for extraction of anthraquinones from S. alata leaves was examined in order to increase the anthraquinone content of the leaf extract. It was found that a solution of 5% hydrochloric acid (v/v), 5% ferric chloride (w/v), and 15% water in methanol (v/v) was capable of increasing the anthraquinone content in the leaf extract up to 1.67% (w/w).
Anthraquinone Production in Senna alata. Root Cultures
Abstract Root cultures of Senna alata. (L.) Roxb. were established in liquid B5 medium, supplemented with 0.5 mg l−1 α.-naphthalene acetic acid (NAA) and 1.0 mg l−1 kinetin. The root cultures, which were established from the high-anthraquinone-producing plants, accumulated higher amounts of emodin and chrysophanol than those established from the low-anthraquinone-producing plants and leaves and roots of the intact plants.
Isolation and inhibitory activity against ERK phosphorylation of hydroxyanthraquinones from rhubarb.
Five hydroxyanthraquinone compounds were purified from Chinese medicinal herb rhubarb by microwave-assisted extraction and silica gel column isolation. Their structures were identified by spectroscopic analysis. One of them, emodin, was found to block the ERK phosphorylation of PC3 cells at 20 microM. And two other compounds had potent proliferation inhibitory activity on A431 and PC3 cells at 20 microM. Furthermore, crude extracts revealed an antifungal activity stronger than that of purified compounds against several plant pathogens tested. Together, our study suggests that these compounds are biologically active and may lead to development of anticancer medicine.