Chemical constituents and leishmanicidal activity from leaves of Kielmeyera variabilis

Many phenolic compounds such as xanthones, quinones and coumarins have been isolated from Kielmeyera species; however the presence of flavonoids have been showed in other genera in the Calophylleae tribe as Caraipa, Mesua and Calophyllum. Six known glycosidic flavonoids: quercetin 3-β-O-galactopyranoside (1), quercetin 3-β-O-glucopyranoside (2), quercetin 3-O-α-rhamnoside (3), luteolin 6-C-β-glucopyranoside (4), isovitexin (5), kaempferol 3-O-α-rhamnoside (6) and one triterpene, lupenone (7) were isolated, for the first time, from organic crude extract of Kielmeyera variabilis Mart. & Zucc., Calophyllaceae, leaves. The crude organic extract from K. variabilis leaves exhibited 95% of leishmanidal activity at 20 µg/mL on amastigote-like form of Leishmania (Leishmania) amazonensis in vitro model and only compound 3 showed 40-45% of growth inhibition at concentration ranging from 0.78 to 20 µg/mL. In addition, quercetin 3-O-α-rhamnoside (quercitrin) was found to be the major metabolite. Our results and previous reports suggest that synergistic effects of flavonoid glycosides are the cause of significant leishmanidal activity of the crude organic extract from K. variabilis leaves.