Effect of organic agriculture on phytochemical content and antioxidant activity of Thymus syriacus

Thymus syriacus is widely distributed in Syria and is known for its rich essential oil (EO) content, which exhibits strong antioxidant and antimicrobial properties. Organic farming restricts the use of synthetic pesticides and chemical fertilizers, reducing environmental pollution and enhancing crop quality for human consumption. This study aimed to evaluate the effects of organic agriculture compared to conventional agriculture on the phytochemical content and free radical scavenging activity of T. syriacus. EOs from plant samples of both production systems were obtained by hydrodistillation and then analyzed using Gas Chromatograph-Mass Spectrometer (GC-MS). The total phenolic content (TPC) and the total flavonoid content (TFC) were determined in ethanolic and aqueous extracts of both samples. The antioxidant activity of all extracts and EOs was assessed through 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH•) free radical scavenging using micro-methods. The results showed no significant difference in TFC between the two sample types in ethanolic extracts (n = 3, p > .05). However, conventional aqueous extracts exhibited significantly higher TPC and TFC than organic extracts (n = 3, p < .05). GC-MS analysis revealed that carvacrol was the major component in the EOs of both samples, while thymol was detected exclusively in the organic sample. The EOs from organically grown plants exhibited stronger antioxidant activity against DPPH• radicals. In contrast, the aqueous extracts from conventionally grown samples showed higher antioxidant activity than those from organic farming, whereas the ethanolic extracts showed no significant difference between the two systems. Overall, the advantages of organic agriculture were primarily reflected in the antioxidant potential of the EOs.