Kingkan Bunluepuech, Chatchai Wattanapiromsakul, Fameera Madaka, and Supinya Tewtrakul

pp. 659 - 664

Abstract

A stem ethanol extract of Bauhinia strychnifolia and its compounds were investigated for their anti-HIV-1 integrase
(IN) and anti-allergic activities. From bioassay-guided isolation, five compounds including quercetin (1), 3,5,7,3',5'-
pentahydroxyflavanonol-3-O-α-L-rhamnopyranoside (2), 3,5,7-trihydroxychromone-3-α-L-rhamnopyranoside (3) and a
mixture of β-sitosterol (4) and stigmasterol (5) were isolated. Of the tested samples, compound 1 (quercetin) showed the
highest activity against HIV-1 IN with an IC₅₀ value of 15.2 µM, followed by 3 (3,5,7-trihydroxychromone-3-α-Lrhamnopyranoside), 4+5 (mixture of β-sitosterol and stigmasterol) and 2 (3,5,7,3',5'-pentahydroxyflavanonol-3-O-α-Lrhamnopyranoside) with % inhibition of 28.2, 26.2 and 6.7 at 100 µM, respectively. With regard to anti-allergic activity,
quercetin (1) possessed the highest anti-allergic activity with an IC₅₀ of 8.1 µM, followed by 3 (3,5,7-trihydroxychromone-3-
α-L-rhamnopyranoside) and 4+5 (mixture of β-sitosterol and stigmasterol) with IC₅₀ values of 52.1 and 77.5 µM, respectively.
Compound 2 (3,5,7,3',5'-pentahydroxyflavanonol-3-O-α-L-rhamnopyranoside) was inactive. The present study is the first
report of chemical constituents and biological activities of Bauhinia strychnifolia.