Songklanakarin Journal of Science and Technology (SJST) (Aug 2014)
Antibacterial and antioxidative compounds from Cassia alata Linn.
Abstract
Phytochemical investigation of Cassia alata Linn. led to the isolation of six known anthraquinones: aloe-emodin (1), emodin (2), ω-hydroxyemodin (3), lunatin (4), physcion (5), and ziganein (6), six flavonoids: apigenin (7), 7,4'-dihydroxy-5- methoxyflavone (8), diosmetin (9), kaempferol (10), luteolin (11), and trans-dihydrokaempferol (12) as well as one stilbene, trans-resveratrol (13). Their structures were elucidated on the basis of spectroscopic methods, including UV, IR, NMR and MS. Nine compounds (3-9 and 12-13) were reported for the first time as metabolites of C. alata. Compound 2 exhibited strong antibacterial activity against methicillin resistant S. aureus (MRSA)-SK1 and B. cereus TISTR 687 with MIC values of 4 and 8 µg/mL, respectively. Compound 10 was found to exhibit antioxidative activity with IC50 value of 9.67 µM that was three times stronger than that of ascorbic acid (IC50 25.41 µM).