Bioassay Guided Isolation of Anti-Inflammatory Compounds from Bauhinia variegata L.: A Key Ingredient in Herbo-Mineral Formulation, Gandmala Kandan Ras

Abstract

Medicinal herb Bauhinia variegata L. is the main ingredient in “Gandmala Kandan Ras” herbomineral medicine used in Ayurveda for the treatment of swelling, inflammation and tumors. This study aimed to isolate the anti-inflammatory compounds from the methanolic extract of aerial parts of Bauhinia variegata. Through bioassay-guided isolation, three known flavonoids, namely kaempferol, ombuin and quercetin were identified from methanolic extract of aerial parts of Bauhinia variega. The primary screening by protein denaturation method revealed a significant percentage of inhibition of protein denaturation of compounds kaempferol and quercetin. The anti-inflammatory assays against COX-1/2 enzymes showed significant anti-inflammatory activity of these two compounds, compared to the standard drug, indomethacin. Of which, quercetin as a potent non-selective inhibitor of COX1 and COX2 with minimal inhibitory concentration values of 172.05±4.29 and 220.62±9.13 nM, respectively; while kaempferol showed selective COX2 inhibition with the IC50 of 154.86±5.60 nM. The results provided evidence that supports the Ayurvedic usage of Gandmala Kandan Ras formulation in the treatment of inflammation, which was attributed to the natural active kaempferol and quercetin. The results indicated that plant Bauhinia variegata could be considered as an excellent natural source of remedial medicine for inflammation.