Phytochemical and pharmacological studies of Crotalaria madurensis leaves

From the leaves of Crotalaria madurensis Wight&Arn (Fabaceae) two triterpenoidal saponins have been identified as 16-β-hydroxy-β-amyrin 3-O-β-glucopyranosyl-(1→6)-O-β-glucopyranosyl-(1→4)-O-β-glucuronopyranoside (1) and 16-β-hydroxy-β-amyrin 6^'-O-β-glucopyranosyl-[(2^'-β-glucopyranosyl) glucuronopyranoside] (2), together with three flavonoid glycosides, i.e. isorhamnetin 3-O-β-D-galactopyranoside (3), kaempferol 3-O-β-D-galactopyranoside (4) and quercetin 3-O-β-D-galactopyranoside (hyperin, 5). Their structures were established on the basis of chromatographic properties and spectroscopic analysis (UV, ¹H and ¹³C NMR). Two sets of experiments were carried out, the first experiment indicated that LD₅₀ for aqueous methanol (AME) and chloroform extracts (CE) were non toxic up to 5g/kg b.wt. The second experiment revealed that the two extracts exhibited significant anti-inflammatory, analgesic, antioxidant activites and gastric protective properties. The effect of administration of AME & CE extracts at two dose levels (25 & 50mg/100g b.wt) orally, 30min prior to carrageenan significantly inhibited the rat paw oedema response. In acute pain models, namely, the acetic acid-induced writhing and hot-plate assay, the two extracts exhibited marked analgesic properties. In addition, the two extracts administered at time of indomethacin injection inhibited the development of gastric lesion in rats. Also, the individual treatment with each extract of C. madurensis at the above doses resulted significant decrease in plasma alkaline phosphatase and lipid peroxide, while glutathione caused a significant increase, in a dose dependent manner, in CCl₄-intoxicated rats.