15-lipoxygenase and serine protease inhibitory activities of Heritiera fomes (buch. -ham), a mangrove plant of the Sundarbans

Abstract

15-Lipoxygenase (15-Lox) oxidizes fatty acid, thereby producing inflammatory mediators which cause diverse inflammatory diseases such as atherosclerosis, asthma, cancer etc. Serine proteases are enzymes that activate tissue factor VII by proteolytic cleavage, eventually activating blood coagulation pathway. Antioxidants play role in 15-Lox and serine protease inhibition to dampen elevation of cytokine levels, thereby function as anti-inflammation and anticoagulation agent. In this study, we examined 15-Lox and serine protease inhibitory activities of the ethanolic bark and leaf crude extract of Heritiera fomes. The crude bark extract (HFB) exhibited 15-Lox and serine protease inhibition with IC50 117.14 and 409.61 μg/ml, respectively. Chromatographically separated active fraction HFBPF1 demonstrated highest 15-Lox and serine protease inhibitory activity with IC50 62.68 and 72.62 μg/ml, respectively. The antioxidant activity and total flavonoid content were substantially increased in the chromatographic fractions compared to the crude extracts. The LC-MS/MS analysis of bark and leaf active fractions revealed the presence of 2,4,6-octatrienal, apigenin 7 (4˝-Z-p-coumerylglucoside), brosimacutin B, gambrin B2, kandelin A1 and tetraneurin A which we report for the first time in H. fomes. Therefore, we conclude the significant augmentation in the 15-Lox and serine protease inhibition activity of the fractions which could be exerted by the enriched flavonoid content.