Phenols, antioxidant and anticancer properties of Tagetes minuta, Euphorbia granulata and Galinsoga parviflora: in vitro and in silico evaluation

Abstract

This work aimed at assessing the phenolic content, antioxidant and cytotoxicity capacities of methanol extracts obtained from Tagetes minuta, Euphorbia granulata and Galinsoga parviflora medicinal plants. Standard spectrophotometric and chromatographic methods were used for chemical analysis. Established antioxidant and cytotoxicity assays were adopted for biological activity assessment. In silico screening for the individual phenolic acids was performed using molecular docking techniques. E. granulata showed a significantly high level of polyphenols. Highest level of flavonoid and tannin contents were detected in Galinsoga parviflora. Ten phenolic acids were identified and quantified via GC–MS in all extracts, and p-Hydroxybenzoic was the most dominant acid (70 µg/g) in T. minuta while gallic was the predominant acid (73 µg/g) in E. granulata. Extracts showed higher reactive oxygen and nitrogen species scavenging activities and exhibited lower hydrogen peroxide inhibition values. The strongest cytotoxic activity was exhibited by T. minuta extract on A2780 cell line. The cytotoxic activity of G. parviflora extract was highly significant against all cancer cells. Extract of E. granulata showed best activity towards MCF7 and A2780 cell lines and was less active against HT29 cell line. In silico data revealed that caffeic acid had the lowest value of binding energy and high ligand efficiency ratios against the selected target receptors, comparable to the standards. Methanol extracts of the targeted plants showed promising antioxidant and anticancer activities which could be attributed to presence of different phenolic phytochemicals. Further work is required for determining the active compounds and their mode of action.