IDENTIFICATION OF ANTHRAQUINONES FROM CASSIA TORA L. SEEDS AND ANTIFUNGAL ACTIVITY

Abstract

Anthraquinones are a major group of active compounds found in Cassia plants. Cassia tora L. was a medicinal plant and its seeds and leaves have been used as laxative. C. tora seed extracts have been reported for antibacterial and antifungal activities. This study aimed to identify anthraquinones from C. tora seeds and determined antifungal activity. C. tora seeds were extracted with 80%ethanol and partial purified with column chromatography. HPLC with RP C18 column and mobile phase composition of 0.01% phosphoric acid in water and methanol were used for analysis. The antifungal activity was tested against Trichophyton mentagrophytes using broth microdilution assay. Results showed that four anthraquinone compounds were identified including aloe-emodin, emodin, chrysophanol and physcion. Total anthraquionone of crude 80% ethanolic extract was 55.60 %w/w and those of 95% ethanolic and acetone subfractions were 10.10-51.77% w/w and 54.88-70.57 %w/w, respectively. The 95%ethanolic subfraction inhibited T. mentagrophytes with a minimal concentration (MIC) of 125 and a minimal fungicidal concentration (MFC) of 1,000 μg/mL, respectively compared with ketoconazole (MIC and MFC = 20 μg/mL). Partial purified acetone fraction contained main anthraquinones including chrysophanol, physcion and emodin while 1-desmethylaurantio-obtusin and aurantio-obtusin were major compounds in ethanolic subfraction. These subfractions inhibited T. mentagrophyte about 4 to 8-folded higher than the crude extract. This extract would be useful for development of antifungal product.