In vitro biological activities and phenolic compounds analysis by RP-HPLC-PDA of Thymus ciliatus (Desf.) Benth. ssp. coloratus extracts from Western Algeria

The aim of the present study was to investigate phenolic content, antioxidant and antibacterial activities of Thymus ciliatus aerial part crude extracts, harvested from Western Algeria. The macerated water–ethanol extract was the most concentrated in total phenolic (126.60 ± 0.99 mg GAE/g) and flavonoids (112.20 ± 0.19 CE/g). The RP-HPLC-PDA spectroscopy revealed the presence of one flavonoid (rutin) and five phenolic acids (sinapic, syringic, p-coumaric, chlorogenic and gallic acids). The water ethanol extract has the highest activity with 2,2-diphenyl-1-picryl-hydrazyl-hydrate (IC₅₀ = 0.28 ± 0.009 mg/mL), reducing power (EC₅₀ = 0.21 ± 0.004 mg/mL) and, thiobarbituric acid reactive substances (IC₅₀ = 2.14 ± 0.10 mg/mL) assays. It was found that the macerated ethanol extract exhibited appreciable antibacterial activity against Staphylococcus aureus with minimal inhibitory concentration of 620 µg/mL. Our results suggest that T. ciliatus aerial part may serve as a potential source of natural antibacterial and antioxidant compounds.