Activity Against <i>Pythium insidiosum</i> and Isolated Constituents of <i>Cordia insignis</i> Roots

Pythiosis, caused by the oomycete Pythium insidiosum, is a worrying disease with its challenging treatment due to the phylogeny of the pathogen. Natural products are a promising alternative in the treatment of diseases. Cordia insignis (Boraginaceae) is a poorly studied species, but Cordia species exhibit broad bioactivity. This study investigated phytochemically the roots of the species and evaluated the anti-oomycete activity of the crude extract (CE) and fractions against P. insidiosum. Seven compounds were isolated and identified, including β-sitosterol, stigmasterol, campesterol, β-sitosterol-3-O-β-d-glucopyranosyl, tridecanoic acid, scoparone, and gracicleistanthoside. The steroids, saponin and coumarin, were reported of leaves and branches of C. insignis; the fatty acid and glycoside are being first reported for the genus. The oomyceticidal assays revealed promising potential, with the hexane fraction (FH) being the most potent (minimum inhibitory concentration [MIC]/minimum oomicidal concentration [MOC] of 15.625 µg/mL). In conclusion, this study expands the chemotaxonomic knowledge of C. insignis and highlights the pharmacological potential of its roots against pythiosis.