Assessment of phytochemical, functional molecule from Rheum emodi Wall. Ex Meissn. rhizome and its antibacterial activity against ESKAPE pathogens

Abstract

R. emodi is the most valuable medicinal plant in folk medicine with a wide range of pharmacological properties. The present research aimed to investigate the phytochemical constituents and isolation of antibacterial compounds from R. emodi. The extract showed the presence of phenolic compounds, flavonoids, saponins, and anthraquinones. The extract is rich in phenols (99.45 mg GAE/g) and flavonoids (61.25 mg QE/g). R. emodi is capable of scavenging 80% of DPPH activity at 100 mg/ml and indicated moderate to high antioxidant activity. The antibacterial activity revealed that ethyl acetate extract at 60 mg/ml was effective against S. aureus, A. baumannii, and E. cloacae. Active fraction with Rf value 0.77 showed an inhibitory zone using TLC-bioautography. The structural identification of the antibacterial compound was performed by LC-MS and 1H-NMR, and the compound was identified as emodin. In conclusion, the analysed compound revealed R. emodi can be a source of lead compounds for the development of alternative natural drugs to control multi-drug resistance.