Morphology, biological and chemical profiling of three Polyscias species, endemic to Mauritius

The aim of the study is to screen the morphological, anatomical, biological, and chemical profiles of the leave extracts of endemic Polyscias species namely P. dichroostachya (PD), P. gracilis (PG), and P. mauritiana (PM) from Mauritius. The morphology and anatomy of the leaves were studied using a microscope. Phytochemical screening of extracts using LC-MS/MS was carried out by ionization in both positive and negative modes. The leaves are pinnately compound, hypostomatic, dorsiventral, with a prominent mid vein with secretion cavities, and they can be distinguished by their midrib shape and anatomy. From the molecular mass and fragmentation data, 31 terpenoid saponins, 19 flavonoids, 17 acids, 7 terpenes, and 10 miscellaneous compounds including pyrrolidines and acetylenes in different extracts (hexane, ethanol, and aqueous) were identified. Extracts from the three species using DPPH radical scavenging activity exhibited good to moderate antioxidant activities with IC50 values in the range of 2.1-70.8 mg/ml and the ethanolic extract of PD showing the highest activity. Aqueous extracts of PG and PM potently inhibited alpha-glucosidase with IC50 values of 0.50 and 2.62 mg/ml. The different leaf extracts exhibited moderate activity against a panel of gram-positive and gram-negative bacteria. This is probably the first report on the extensive chemical profiling and morphology of these endemic Polysias spp. from Mauritius and the results indicate that these leaf extracts have beneficial health properties and are thus worth exploiting further