Validated RP-HPLC Method for Quantification of Phenolic Compounds in Methanol Extracts of Aerial Parts and Roots of Thymus sipyleus and Evaluation of Antioxidant Potential
Tropical Journal of Pharmaceutical Research
Purpose: To evaluate the total phenolic content and antioxidant potential of the methanol extracts of aerial parts and roots of Thymus sipyleus Boiss and also to determine some phenolic compounds using a newly developed and validated reversed phase high performance liquid chromatography (RP-HPLC) method. Methods: The total phenolic concentration of the extracts were determined using Folin Ciocalteu method. The antioxidative potential of the samples was evaluated using DPPH and ABTS assays.
... d ABTS assays. Phenolics responsible for the antioxidant activity of the plant were quantified by a newly developed and validated RP-HPLC method for the first time. Results: The total phenolic concentration of the aerial parts and roots were 215.1 ± 2.24 and 152.25 ± 2.31 mg GAE/g extracts, respectively. The extract obtained from the aerial parts reduced DPPH with a half-maximal inhibition concentration (IC50) of 0.703 ± 0.027 mg/mL, while the IC50 obtained from ABTS assay was 0.869 ± 0.066 mg/mL. IC50 values of Trolox used as standard for DPPH and ABTS radical scavenging assays were 0.0430 ± 0.0001 and 0.0420 ± 0.0001 mg/mL, respectively. The results revealed that T. sipyleus contains remarkable amounts of rosmarinic acid in the aerial parts (0.8887 ± 0.0016 g/100g dw) and in the roots (0.3454 ± 0.0006 g/100g dw) which is believed to be mostly responsible for the observed activity. Conclusion: T. sipyleus is a major potential antioxidant source for the food, pharmaceutical and cosmetic industry due to its high contents of rosmarinic acid and total phenolics.