Zygophyllum album (L.) البوقريبة نبات و Thymelaea hirsuta (L تاثير مدة النقع و نوع المذيب على المحتوى الفينولي و الفلافونويدي لمستخلصات نبات المثنان

Abstract

This study aimed to conduct a comparative evaluation of the effects of maceration time, solvent type, and solvent renewal (with or without replacement) on the phenolic and flavonoid contents of two medicinal plants growing in the Oued Souf region of Algeria. Different maceration periods (6, 24, 48, and 72 h) were investigated using various extraction solvents, namely distilled water, 70% ethanol, and 80% ethanol, either with or without solvent replacement during the process. The resulting extracts of Thymelaea hirsuta (L.) and Zygophyllum album (L.) were evaluated for total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. Preliminary phytochemical screening revealed the presence of several secondary metabolites in both species, including flavonoids, tannins, saponins, alkaloids, terpenoids, and reducing sugars. Extraction yield was significantly influenced by both solvent type and maceration duration. The highest yield (30.1%) was obtained from Z. album extracted with 80% ethanol for 72 h under solvent replacement conditions. Regarding TPC, the highest value for T. hirsuta (157.340 ± 4.690 µg GAE/mg extract) was recorded in the 70% ethanolic extract obtained after 72 h of maceration without solvent replacement. Similarly, Z. album showed a comparably high phenolic content (156.90 ± 0.34 µg GAE/mg extract) in the 80% ethanolic extract prepared after 48 h of maceration without solvent replacement. For TFC, the aqueous extract of Z. album obtained after 6 h of maceration showed the highest concentration (179.800 ± 0.917 µg QE/mg extract), suggesting that under these conditions, water was more efficient than ethanolic solvents in extracting flavonoid compounds from this species. The antioxidant activity assay revealed marked differences among the extracts. The strongest activity was observed for the 70% and 80% ethanolic extracts obtained after 6 h of maceration, with IC₅₀ values of 45.84 ± 0.084 and 44.37 ± 0.218 µg/mL, respectively. This enhanced activity was positively associated with higher phenolic and flavonoid contents, highlighting the crucial role of these phytochemicals in free radical scavenging and oxidative stress inhibition. Overall, Thymelaea hirsuta and Zygophyllum album represent promising natural sources of bioactive compounds with potential applications in pharmaceutical and cosmetic industries.