Phenolic Content Analysis of Two Species Belonging to the Lamiaceae Family: Antioxidant, Anticholinergic, and Antibacterial Activities.

Abstract

The Lamiaceae family are utilized as ornamental, medicinal, and food supplements throughout the world. The current study focuses on a comparative analysis of the phenolic compositions and bioactivities (including antioxidant, anticholinergic, and antibacterial activities) of ethanolic extracts derived from the aerial parts of the two species (Lavandula stoechas L. and Thymus sipyleus Boiss). The presence of phenolic compounds and phytochemicals in the plant extracts was identified using the LC-MS/MS technique. The LC-MS/MS analysis revealed that vanillic acid (125,596.66 µg/L) was the most abundant phytochemical in L. stoechas. Kaempferol (8550.52 µg/L) was the most abundant substance in Thymus sipyleus. The assessment of the antioxidant efficacy of the species extracts was conducted using the DPPH (2.2-diphenyl-1-picryl-hydrazyl-hydrate), ABTS (2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), Fe3+-Fe2+ reducing, and CUPRAC (Cu2+-Cu+ reducing) assays. The anticholinergic activity of the samples was determined using the acetylcholinesterase (AChE) inhibition assay. The results of antioxidant activity were higher in the T. sipyleus than in the L. stoechas ethanol extracts. The extracts of L. stoechas exhibited radical scavenging activity ranging from 15 to 18%, while T. sipyleus had activity effects ranging from 34% to 38%. The AChE inhibition potential for L. stoechas and T. sipyleus extracts as IC50 values were 0.221 ± 0.01 mg/mL and 0.067 ± 0.02 mg/mL, respectively. The antibacterial effects of the ethanolic extracts of these species against pathogenic bacteria isolates were determined using the MIC (minimal inhibitory concentration) method. These findings indicated that the extracts from L. stoechas and T. sipyleus possess the potential to be natural antioxidants in the realm of food preservation. Additionally, their antioxidant, anticholinergic, and antimicrobial properties suggest potential therapeutic utility in the management of certain diseases.