Abstract

The genus Phlogacanthus belongs to the family Acanthaceae and consists of more than 49 species, These species are widespread in tropical and subtropical zones such as Bangladesh, Bhutan, China, Indonesia, India, Myanmar and Vietnam. In Vietnam, the genus contains about 06 species. The extracts from some species in this genus have been evaluated for biological activities as analgesic, antiinflammatory, antimicrobial, antioxidant, antihyperglycemic and cytotoxic activities. In this study, the whole plant of Phlogacanthus turgidus was collected, dried, cut into small species, and extracted with ethanol to yield the ethanolic extract. Isolation of chemical constituents was performed using column chromatography on silica gel; their structures were elucidated by HRESI-MS, 1D & 2D-NMR and compared with published data. Six compounds, including two nor-isoprenoids: (+)-dehydrovomifoliol (1), (3S,5R,6R,7E,9S)-megastiman-7-ene-3,5,6,9-tetrol (2), two steroids b - sitosterol (3), daucosterol (4), one lignan (+)-syringaresinol (5), a derivative of phenylethanoid glycosides: martynoside (6) were isolated from the ethyl acetate extract of the whole plant of P. turgidus. Among them, 1, 2 were reported for the first time from the genus Phlogacanthus, while 3, 4, 5, 6, were found for the first time from this species.