MD Ranzu Ahmed, Tania Sultana, Rayesha Routary, MD Shahinul Haque Khan, Khozirah Shaari, M Abu Sayeed, M Mosihuzzaman and Begum Rokeya
The present study was carried out to evaluate the chemical constituents and antidiabetic activity of flower extracts of Phlogacanthus thyrsiflorus Nees in streptozotocin induced diabetic Long-Evans rats by feeding for 28 days. The ethanolic extract (1.25 mg/kg bw) exhibited significant reduction of fasting serum glucose level in diabetic rats. The ethanolic extract also showed improvement in parameters of lipid profile. Five compounds namely, β- sitosterol (1), stigmasterol (2), 8(17),13-labdadien-15,16-olide-19-oic acid (3), 19-hydroxy-8(17),13- labdadien-15,16-olide (4) were isolated from the dichloromethane extract and 2-(3,4-dihydroxyphenyl)-5,7- dihydroxy-4-chromenone (Luteolin) (5) were isolated from the 1-butanol part of methanol extract of flowers. The structures of these compounds were elucidated by extensive spectroscopic studies. This is the first report of isolation of compounds (1-5) from flowers of this plant. The activities of the flower extract may be due to the presence of some of these compounds which demands further studies.