HR-LCMS Profiling of Phytochemical Constituents and Evaluation of Antioxidant, Antibacterial, Anti-Cancerous and Anti-Inflammatory Potentials, Plasma Biocompatibility and Cytotoxicity of Grewia Orbiculata Rottler

Infectious diseases are one of the main reasons that are causing a greater number of deaths in the world owing to their strong resistance development and evolution. There is an immediate urgency for the discovery of drugs with a new class or new mode of action to combat these resistant bugs. In the past few decades, we have not been able to find new antibiotics, which are effective on resistant bugs. Instead of searching for synthetic molecules, if we divert our search for alternative sources that are abundant in nature, we can easily find new molecules. Plants are the best as they are known to possess complex molecules that are strong in their potency while being relatively safe for the host and tough on pathogens. With this rationale, the study was conducted to assess the phytochemical constituents of different parts of plant Grewia orbiculata Rottler using different solvents and to elucidate the biological activities. From qualitative analysis of all extracts, Methanolic Extract of Bark (MEB) and Ethyl acetate Extract of Leaf (EEL) were found to be rich in total phenolics and total flavonoids. Major phytochemicals found in MEB were Catechin, Epicatechin, and Carnitine and in EEL were Quinin acid, Gallic acid, Catechol, Isoquinoline, Coumaric acid, Kaempferol, and Quercetin of G. orbiculata. Upon testing the biopotentials of these extracts, it was found that among the different solvent extracts of leaves, twigs, buds, and bark, MEB showed the highest biological potential and therapeutic value. The antioxidant property of MEB assessed through DPPH and ABTS assays resulted in an IC50 value of 50 µg/mL and 36 µg/mL, respectively. The metal chelating property of MEB gave a FRAP value of 24 ± 0.093 mmol/g equivalent to that of Tannic acid. Further, MEB was found to possess very good antibacterial activity against human pathogens such as Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus faecalis, Enterococcus faecium, Streptococcus epidermidis, and Mycobacterium smegmatis. In addition, MEB also showed good anti-cancerous property against A549 cells, having IC50 value of 98.73 µg/mL. The anti-inflammatory assay with MEB showed protection of BSA denaturation up to a concentration of 1000 µg/mL. Finally, the biocompatibility assay with blood showed no significant agglutination of RBCs up to a concentration of 200 µg/mL and cytotoxicity of MEB resulted in less than 50% inhibition of HTE cell proliferation at the highest concentration of 320 µg/mL, proving its non-toxic nature towards normal cells. Our study is the first to report and evaluate the therapeutic value of the plant G. orbiculata. MEB was found to possess very good therapeutic potential and can be used as potent antimicrobial agent to treat deadly human infections.