Pharmacological activities of Thymelaea hirsuta L. extracts

Abstract

Thymelaea hirsuta (L). Endl (T. hirsuta) belongs to Thymeleaceae family. It is an evergreen perennial flowering shrub. An ethnobotanical study was conducted to investigate the traditional uses of T. hirsuta, followed by an in vitro assessment of the antioxidant and the anti-enzymatic activities. Additionally, an In vivo investigation explored its effects on gastric emptying, intestinal transit, and gastric protection. T. hirsuta emerged as a common employed remedy, for dermatological, respiratory and digestive tract disorders, particularly in the treatment of gastric ulcers. In a comparative study of DE(DE), hydromethanol extract (HME) and methanol extract (ME), the results showed a respective increase in total phenolic, flavonoids and tannins contents. The chemical profile of the chosen extracts (DE and HME) revealed by HPLC-DAD analysis showed the abondance of trans-cinnamic acid, vanillin and chlorogenic acid. In series of In vitro experiments, both extracts exhibited respectively a high antioxidant activity through DPPH, phenanthroline, ferrous ion chelating, and β-carotene bleaching assays. The plant extracts inhibited moderately AChE and BChE. Additionnaly, DE and HME showed a significant inhibitory effect on α-amylase with an IC50 values of 52.80 ± 0.77 and 43.71 ± 0.95 at 100 µg/mL, respectively, and α-glucosidase with IC50 values of 69.72 ± 0.95 and 53.36 ± 0.85 μg/mL, respectively. Both extracts demonstrated a weak tyrosinase inhibition. In terms of In vivo study, the plant extracts demonstrated a favorable safety profile at the tested doses. Notably, both DE and HME induced a significant delay in gastric emptying in mice involving prostaglandin pathway, while accelerating intestinal transit and involving both prostaglandin and Nitric oxide (NO) pathways. In the other hand, the treatment of rats with increasing doses of DE or HME resulted in a high level of protection against ethanol-induced ulcer in the stomach, particularly in the case of HME surpassing the protective effect of ranitidine as a refference drug. The extracts had a divergent mechanism of action while sharing the NO pathway. Furthermore, they enhanced glutathione (GSH) and protein levels, catalase activity and/or inhibited lipid peroxidation.