The impact of regional locality on chemical composition, anti-oxidant and biological activities of Thymelaea hirsuta L. extracts

Thymelaea hirsuta L. is a medicinal plant endemic to Tunisia, commonly used for its biological properties in traditional medicinal. This study reports, to the best of our knowledge for the first time, the effect of regional location on the chemical composition, anti-oxidant and biological activities of organics extracts obtained from aerial parts of T. hirsuta. The aerial parts collected from different locations were prepared by sequential method with solvents of increasing polarity namely hexane, ethyl acetate, ethanol and methanol. An assessment of the anti-oxidant properties of all extracts was performed using DPPH and ABTS+ assays. We also investigated the anti-cholinesterase, anti-xanthine oxidase and cytotoxic (against MCF-7 and OVCAR) activities. The study of the phytochemical composition showed that the extracts are rich in phenolics (5.38–315.65 mg GAE/g dw) and tannin (0.7–73.8 mg CE/g dw). Also, the results showed that the chemical composition as well as the biological activities varies considerably between regions. The DPPH and ABTS+ assays revealed that the highest important antioxidant activity was in the methanolic extract for all localities (IC50: 14.8–16.5 mg/l and 6.4–22.23 mg/l, respectively). However, the various extracts had moderate anti-cholinesterase activity (7.52–45.36%) at 50 mg/l. Regarding the xanthine oxidase inhibitory activity, ethyl acetate extract exhibited a moderate activity at a 50 mg/l. The highest cytotoxic activity against MCF-7 and OVCAR was recorded in the ethyl acetate extract of Fernana region (70.1% and 70.8% inhibition at 50 mg/l, respectively). The analysis of HPLC-UV indicates the presence of several phenolic compounds in different extracts of T. hirsuta, possibly accounting for its biological properties. The phenolic contents were highly correlated to anti-oxidant activity with very high correlation coefficient (R2) values. The findings show that the extracts are rich in antioxidant compounds and this plant may be used as a natural source of bioactive compounds with high anti-oxidant and potential anticancer activities. [Display omitted]