In our study, the methanol leaf extract of C. alata showed a significant antibacterial activity against human pathogenic bacteria strains Staphylococcus aureus and Bacillus cereus. The organic layers such as n-hexane, ethyl acetate, and aqueous layers, were prepared by partitioning the methanol extract with n-hexane and ethyl acetate successively. We successfully isolated and identified the structures of five compounds from C. alata leaves. | Vietnam Journal of Chemistry, International Edition, 55(5): 589-594, 2017 DOI: Isolation and identification of phenolic compounds from the leaf extract of Cassia alata L. Pham Quang Duong1, Nguyen Thi Duyen2, Phung Ton Quyen3, Nguyen Quang Tung4, Vu Hong Son5, Vu Dinh Hung6, Le Dang Quang2* 1 Laboratory of Bioactive Compound Technology, Institute of Chemistry, Vietnam Academy of Science and Technology 2 R&D Center of Bioactive Compounds, Vietnam Institute of Industrial Chemistry (VIIC) 3 Phuong Dong University 4 Hanoi University of Industry 5 Hanoi University of Science and Technology 6 Foreign Language Specialized School, Vietnam National University (Hanoi) Received 5 September 2017; Accepted for publication 20 October 2017 Abstract Cassia alata is one of the most important species of the genus Cassia which is rich in anthraquinones and polyphenols. This plant is used as a medicinal material of which the leaves are known to have laxative and antibiotic properties. In our study, the methanol leaf extract of C. alata showed a significant antibacterial activity against human pathogenic bacteria strains Staphylococcus aureus and Bacillus cereus. The organic layers such as n-hexane, ethyl acetate, and aqueous layers, were prepared by partitioning the methanol extract with n-hexane and ethyl acetate successively. We successfully isolated and identified the structures of five compounds from C. alata leaves. Their structures were elucidated by MS and NMR spectroscopic methods as well as comparison with literature data. These compounds were determined to be methyl 2,4,6-trihydroxybenzoate (1), kaempferol (2), (-)epiafzelechin (3), kaempferol-3-O-glucoside (4) and kaempferol-3-O-gentiobioside (5). Keywords. Cassia alata L., epiafzelechin, kaempferol, kaempferol-3-O-glucoside, kaempferol-3-O-gentiobioside. 1. INTRODUCTION C. alata is an important medicinal plant, as well as an ornamental flowering plant in the .
