Morpho-taxonomical and phytochemical analysis of Vanilla borneensis Rolfe—a rare, endemic and threatened orchid of Assam, India

摘要

© 2021, Society for Plant Research.Vanilla borneensis Rolfe, is a rare, endemic and threatened monopodial climbing orchid of Assam, India is largely unexplored. Its global distribution lies from certain parts of Malaya, Thailand and Borneo. Therefore, in this investigation, an attempt has been made to study the morpho-taxonomy, phytochemistry, liquid chromatography–high resolution mass spectrometry (LC–HRMS) analysis and the antioxidant scavenging activities of V. borneensis. The qualitative phytochemical assay of aqueous plant extract showed the presence of phytosterols, saponins, phenol, glycosides in higher amount whereas, the ethanolic plant extract showed the presence of alkaloids, tannins, diterpenoids, and flavonoids in higher amount. The antioxidant scavenging activity using 1,1-diphenyl-1-2- picryl-hydrazil (DPPH), hydrogen peroxide scavenging and reducing power assay of the methanolic leaf extract showed the activity in a dose-dependent manner. The total phenolic contents were found to be 50 µg gallic acid equivalents in 1.0 mg of methanolic leaf extract. Flavonoid content was found to be 73.87 µg quercetin equivalents in 1.0 mg of methanolic leaf extract. LC-HRMS analysis of methanolic leaf crude extract of V. borneensis showed the presence of two major compounds viz., cromolyn and quercetin-3-(6″-malonyl)-glucoside at a significant level that were not reported earlier in Vanilla spp. This report can be of valuable information for the taxonomic identification and further characterization of V. borneensis for bioprospection.