<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Antiproteolytic and leishmanicidal activity of <i style="mso-bidi-font-style: normal">Coccinia grandis </i>(L.) Voigt<i style="mso-bidi-font-style:normal"> </i>leaf extract against <i style="mso-bidi-font-style:normal">Leishmania donovani</i> promastigotes</span>

Abstract

In visceral leishmaniasis (VL), development of alternative safe therapeutic strategy is gaining paramount wherein natural components of plant origin have prominence. We explored <i style="mso-bidi-font-style: normal">Coccinia grandis </i>(L.) Voigt, a medicinal plant known in traditional folk medicine, for its antileishmanial efficacy. SDS-PAGE analysis of the <i style="mso-bidi-font-style:normal">C. grandis</i> leaf extract (Cg-Ex) showed few protein bands about 14-66 kDa among which three (64.8, 55.8 and 15.3 kDa) were identified as serine protease inhibitors by reverse zymography. Since the virulence of <i style="mso-bidi-font-style:normal">Leishmania</i> is also attributed by serine proteases, objective of the present study was to evaluate <i style="mso-bidi-font-style:normal">in vitro</i> antileishmanial activity of Cg-Ex, targeting <i style="mso-bidi-font-style:normal">Leishmania donovani</i> serine protease(s). Inhibition study of Cg-Ex in gelatin-zymogram and spectrophotometric assay revealed its strong inhibitory activity against bovine trypsin rather than chymotrypsin, and also showed significant inhibition of <i style="mso-bidi-font-style:normal">L</i>.<i style="mso-bidi-font-style:normal"> donovani</i> serine protease(s). Further, studies with Cg-Ex were extended to estimate its antileishmanial efficacy with half maximal inhibitory concentration (IC₅₀) at 308.0 ± 2.42 µg/ml along with significant morphological alterations. The results have demonstrated the potential of the serine protease inhibitor rich fraction of the <i style="mso-bidi-font-style: normal">C. grandis</i> leaf extract against visceral leishmaniasis.