Assay of total flavonoids in dried extract of Aleurites moluccana

Abstract

The flavonoid 2''-O-rhamnosylswertisin in Aleurites moluccana is related to the therapeutic effect of the plant, making it an adequate marker. In this work a method of total flavonoid assay was developed and validated, expressed in its marker. A double reflux of dried extract obtained from A. moluccana leaves (0.4 g) with 50 % (v/v) ethanol was carried out. After filtration, the solution was complexed with 2 % AlCl₃ in 50 % (v/v) ethanol, and the absorbance read at 397 nm after 90 min. The number of refluxes (1-2), volume of complexing agent (0.5-3 mL), stability of complexing agent and complexation time (15-120 min) were evaluated. The specific absorption coefficient (E^1%_1cm) of the marker compound was 77.18. The method showed linearity (r² > 0.99) at the tested range, good precision (RSD % ≈ 5 %, intra-day and inter-days) and accuracy of 99.3 %. The dried extract of leaves of A. moluccana showed 0.15 % total flavonoids, expressed in 2''-O-rhamnosylswertisin.