Antibacterial, Antioxidant, and Angiotensin-I Converting Enzyme Inhibition Effects of Margotia gummifera Extracts Rich in Phenolic Compounds

Background: Aromatic and medicinal plants have been used to substitute synthetic drugs with natural bioactive products. Objective: The current investigation was conducted to evaluate phenol and flavonoid contents, antibacterial, antioxidant, and anti-hypertensive potentials of three extracts of Margotia gummifera aerial parts. Methods: The antibacterial effect was assessed using the wells agar diffusion method against 11 strains. The antioxidant effect was evaluated using different methods, 2, 2-diphenyl-1-picrylhydrazyl, total antioxidant capacity, ferric reducing ability power, cupric reducing antioxidant capacity, and β-carotene/linoleic acid bleaching assay. The anti-hypertensive activity was performed using hippuryl-histidyl-leucine substrates. Results: The highest yield, i.e., 19.801%, was obtained by the hydro-methanolic extract. However, ethyl acetate extract seemed to be rich in phenolic and flavonoid compounds compared to other extracts, i.e., 822.14±69.10 mg GAE g^-1 ext. and 117.28±1.80 mg RE g^-1 ext., respectively. The high free radical scavenging activity was mentioned in ethyl acetate extract with IC50 of 48.820±1.25 μg/ml. The same extract showed better antioxidant activity in all tested procedures. In antibacterial activity, the hydro-methanolic extract exhibited moderate effect against all tested bacteria except Salmonella enterica and Enterococcus faecalis which gave 18±2.0 and 16±1.0 mm of inhibition, whereas it seemed to be inactive towards two Gram-negative bacteria. Concerning anti-hypertensive activity, all extracts can inhibit the Angiotensin-I Converting Enzyme, but the potential effect was given by hydro-methanolic and aqueous extracts, 97.75% and 96.65%, respectively. Conclusion: It can be stated that the bioactive compounds of Margotia gummifera extracts had different biological activities, which confirm their therapeutic uses in traditional medicine.