Phytochemical screening and in vitro evaluation of antioxidant and antibacterial activities of Teucrium trifidum crude extracts

The objective of the investigation was to identify biologically active polyphenols and to determine the antioxidant and antimicrobial capacity of Teucrium trifidum extracted with different organic solvents (acetone, ethanol and methanol) and distilled water. The results of the study revealed varying levels of polyphenols in the different solvent extracts. Condensed tannin, flavonoid and total phenolic content ranged from (77.339 ± 1.068) to (99.395 ± 1.490) mg CE/g; (3.398 ± 0.2410) to (53.253 ± 0.638) mg QE/g; (14.1087 ± 0.0915) to (21.7977 ± 0.0279) mg GAE/g, respectively. The extracts demonstrated high antioxidant activity in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and total antioxidant capacity (TAC) assays which were comparable to rutin and butylated hydroxytoluene (BHT) and increased with increasing concentrations of polyphenols extract (P < 0.05). The agar dilution assay of acetone, ethanol and methanol extracts revealed an appreciable broad-spectrum activity against tested pathogenic bacteria. The findings of this study provide evidence that T. trifidum can be used as a natural source of antioxidant and antimicrobial components.

Keywords: Antimicrobial activity; Antioxidant activity; Food safety; Food science; Food technology; Medicinal plants; Nutrition; Polyphenolic contents; Preservatives; Radical scavenging activity.