Anti-inflammatory activity of a new triterpenoidal saponin from Bauhinia variegata Linn. (Fabaceae)

Many Bauhinia species are used extensively for traditional medicinal uses especially as anti-inflammatory agents [1,2,3]. The present study aimed to the identification of triterpenoidal saponins and polyphenols from the leaves of B. variegata. The n-butanol and ethyl acetate extracts of B. variegata leaves were separately fractionated on silica gel columns, followed by successive chromatography on cellulose and sephadex LH-20 for final purification of the new 23-hydroxy-3α-[(O-α-L-¹C₄-rhamnopyranosyl-(1“→4')-O-α-L-⁴C₁-arabinopyranosyl-oxy]olean12-en-28-oic acid O-α-L-¹C₄-rhamnopyranosyl-(1'''''→4'''')-O-β-D-⁴C₁-glucopyranosyl-(1''''→6''')-O-β-D-⁴C₁-glucopyranosyl ester (1) and eight known compounds, i.e. quercetin, 3,3'-dimethoxy-quercetin, 3,3',6-trimethoxy-quercetin, isoquercitrin, quercetin 3-O-β-D-galacturonopyranoside, quercetin 3-O-β-D-neohespridoside [4], caffeic acid and ferulic acid, based on UV, HRESI-MS, 1D and 2D NMR. Moreover, as a conclusion for the biological study on male Swiss Albino mice (18–20g), it was found that the new saponin (1) is non-toxic (LD₅₀ 1000mg/kg b. wt.) and has a significant anti-inflammatory activity in comparison with indomethacine. A significant anti-inflammatory effect was concluded from the reduction recorded in granuloma diameter on treatment with 1 (19.2% and 20.9%) in comparison with indomethacin (32.1 and 35.5%) at 32 and 48 days after ova injection, respectively, relative to control group. PGE2 level in granuloma was also reduced after treatment with 1 (36.1 and 22.1%) with respect to that of indomethacine (44.4 and 32.4%) at 32 and 48 days after ova injection, respectively.

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