Exploring Natural Dye and Bioactive Secondary Metabolites in Lonchocarpus Cyanescens Benth (Fabaceae) Plant Using Liquid Chromatography-High-Resolution Mass Spectrometry and Compound DiscovererTM Software

Lonchocarpus cyanescens Benth is a native African plant commonly known as "African Indigo" or "Indigo Vine" because locals extract dyestuff from its leaves that gives it a brilliant indigo-like hue. Several scientists have reported this plant to contain indigo dye; however, there has been no evidence to justify their claim. Therefore, the primary dye component(s) responsible for the indigo-like hue has been scientifically unexplored. In this study, we utilized UV-Vis and HPLC-DAD-ESI-HRMS (OrbitrapTM) techniques to identify the main chemical compound(s) responsible for the color of the dyestuff. To our surprise, the presence of indigo dye was not detected in the isolated dye extract; we discovered that crystal violet dye and crystal violet-like molecules are present in the extract, which can be responsible for the blue color observed. In addition to its natural dye-producing capability, this plant is used by local traditional healers to heal ailments including ulcers, arthritis, intestinal disorders, etc. Many scientists have proved that the effect of this plant extract on many of these disease states was justified; however, the molecular identities of the compounds responsible for the plant's medicinal value have been unexplored. Therefore, we also analyzed the leaf extract of L. cyanescens and identified several chemical compounds having structural similarities to active drug compounds. The details of our findings will be the focus of our research work.