Chemical profile and in vitro antischistosomal activity of Crotalaria madurensis different extracts

Chromatographic isolation of Crotalaria madurensis Wight & Arn leaves aqueous methanol extract availed a new potassium sulfonate acylated flavonol glycosides named quercetin 8-potassium sulfonate 3-O-[2-O-sulfonyl]-β-D-⁴C₁-glucopyranosyl-(1''''→3''')-4-O-[E- caffeoyl]-β-D-⁴C₁-glucopyranosyl-(1'''→2'')-3-O-[E-caffeoyl]-β-D-⁴C₁-glucopyranoside (Crotalamadoside A) (1), along with three known flavonoids identified as quercetin 7-O-neohispredoside (2), 3',4'-dimethoxy quercetin 3-O-neohispredoside (3) and isoquercetin (6) besides two triterpene saponin compounds named as hedragenin 3-O-β-D-⁴C₁-glucopyranoside (4) and hedragenin 3-O-α-L-¹C_4-rhamnopyranoside (5). This was in addition, to two cinnamic acid derivatives named as E-caffeic acid 4-O-β-D-⁴C_1-glucopranoside (7) and E-caffeic acid (8). Identification of the isolated compounds relied on their chromatographic properties and spectral data (UV, ESI-MS, ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HSQC, and HMBC). The antischistosomal activity of the C. madurensis different extracts were assessed in vitro using schistosome worm killing, findings revealed that the aqueous methanol extract was the most effective extract, chromatographic fractionation of this extract revealed significant antischistosomal activity for fractions number V and VI rich in flavonoids and triterpene saponins, respectively.