Cytotoxic, in vitro Enzyme Inhibitory Potential and Phytochemical Profiling of Odontonema strictum

Abstract

Background Odontonema strictum is an herbaceous plant, indigenous to Central America and Central Africa, and has been used traditionally by the local community against various ailments. The current piece of work was carried out to evaluate the cytotoxic potential of O. strictum by using brine shrimp lethality and the in vitro cytotoxicity/viability assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide [MTT]), as well as the in vitro enzyme inhibitory potential by using alpha-amylase, protein kinase enzymes and phytochemical analysis of the different extracts of aerial parts of O. strictum. Materials and Methods Extracts of aerial parts of O. strictum were prepared through the successive extraction method using solvents with the order of polarity as n-hexane, dichloromethane, ethyl acetate, methanol and water. Cytotoxicity was assessed through brine shrimp lethality assay and in vitro cell viability assay (MTT), whereas enzyme inhibition potential was evaluated through Alpha-amylase and protein kinase assay. Phytochemical analysis was done by assessing the total phenolic and total flavonoid contents of both leaves and flowers. Results All the extracts exhibited various phytochemical and biological activities. Remarkable toxicity profiles against the brine shrimp lethality assay (LD50:11.5 µg/mL) were shown by the leaf extracts, whereas both leaves and flowers exhibited promising anti-proliferative activity, assessed by the MTT assay. Significant alpha-amylase and protein kinase inhibition potential were manifested by leave extracts with IC50:195.6 µg/mL and minimum inhibitory concentration (MIC): 16.3 µg/mL respectively. The phytochemical analysis of the plant showed that it was sufficiently rich in phenolic compounds with a total phenolic content and total flavonoid content (96.8 µg GAE/mg and 65.1 µg QE/mg, respectively). Conclusion It is plausible to believe that the cytotoxic and enzymatic activity of the aerial parts of O. strictum aerial parts might be, at least partly, to the presence of phenolic chemicals and could be a possible source of cytotoxic agent and an enzyme inhibitor.