Phenolics profiling and biological activities of different solvent extracts from aerial parts of wild thyme (Thymus vulgaris L.)

The current research work appraises the variation in antioxidant, antibacterial and cytotoxic potential of thyme extracts in relation to different extraction solvents along with phenolics profiling using Reversed-phase HPLC (RP-HPLC). Maximum extract yield (21.60%) was obtained with 80% ethanol, while minimum (15.42%) for 100% ethanol. Maximum total phenolic content (TPC), total flavonoid content (TFC), reducing power, and DPPH radical scavenging activities were exhibited by 80% methanolic extract with contribution 123.60 +/- 1.51 mg/100 g, 38.11 +/- 0.11 mg/100 g, 0.69 +/- 0.36, and 72.35 +/- 0.14%, respectively. The tested thyme extracts exhibited considerable antibacterial activities as well. Maximum zone of growth inhibition was observed against Escherichia coli (22.51 +/- 1.33 mm) by 100% ethanolic extract. Minimum hemolytic activity (4.59 +/- 0.02) was observed in 80% ethanolic extract; whereas blood clot lysis (thrombolytic activity) was offered by 100% methanolic extract (15.42 +/- 0.1%). Individual phenolic and flavonoid contents were analyzed by using RP-HPLC which showed that thyme extracts mainly contained benzoic acid (12.91-12.92 mu g/g) whereas gallic acid was present in least amount (6.98-7.09 mu g/g). The major flavonoid component was myricetin (35.33-181.26 mu g/g) followed by kaempferol (9.14-15.20 mu g/g). Overall, a considerable variation in the biological activities and phenolics composition of aerial parts of wild thyme were noted as a function of extraction solvents. Based on the properties evaluated in this work, the tested thyme plants may be used as an ingredient in nutra-pharmaceutical products.