Isolation and characterization of phytochemicals from leaf extract of Memecylon lushingtonii Gamble and their evaluation for biological properties

Abstract

Memecylon lushingtonii Gamble (MLG) belongs to the Melastomataceae family and is used in Ayurvedic and Siddha medicine. Several Memecylon species have been recorded to be utilized by tribal in the treatment of various maladies. This plant is not explored scientifically except for the preliminary phytochemicals, antioxidant, and antimicrobial activities in the methanol leaves extract (Sivu et al., 2013). Discovery of new phytochemicals may help in drug discovery. The present study was an attempt to determine the phytochemical constituents in MLG leaves ethyl acetate (EtOAc) extract and to isolate bioactive compounds and evaluate their potential therapeutic applications. Ethyl acetate extract was evaluated for total phenolics and flavonoids; phytochemical constituents, antibacterial and antioxidant activities. Further, bioactive compound from 4th fraction of column chromatography was isolated and characterized by HPLC,LC-MS and H1NMR. The results indicated 37.5 µg/mL of phenolics, 60 µg/mL of flavanoids and twenty-one bioactive compounds by GCMS– analysis. The extract demonstrated considerable antibacterial activity with different concentrations like 50, 100 and 150 µg against Staphylococcus aureus, Bacillus licheniformis, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae. Highest antibacterial activity was found against K.pneumoniae (Zone of inhibition was 11 mm) at 150 µg .In addition, the EtOAc extract displayed free radical scavenging activity (IC50= 39.83 µg/ml). The isolated compound from 4th fraction of column chromatography was characterized as a triterpenoid, ursolic acid. In conclusion, our findings show that M. lushingtonii Gamble leaf EtOAc extract contains triterpenoid, ursolic acid, and also, many types of active compounds with therapeutic activities, particularly antibacterial and free radical scavenging activity.