Phytochemical characterization, biological screening and corrosion inhibition of mild steel from extracts of Juniperus oxycedrus L.

The aim of this research was to study the effect of solvent polarity and extraction technique of phenolic compounds from Juniperus oxycedrus L. on antioxidant and antibacterial activity. Also, this paper aims to evaluate the anti-corrosive effect of aqueous extracts. In order to evaluate the effect of solvents on the bioactive compound’s extraction efficiency, the samples were prepared with different extraction procedures. The methanolic and ethanolic extracts were prepared by using Soxhlet and maceration extraction and aqueous extracts were obtained by decoction and infusion methods. Moreover, six fractions (petroleum ether, chloroform, ethyl acetate, 1-butanol and aqueous) were prepared by partition of ethanolic extract. All the extracts were subjected to preliminary phytochemical screening; the results show the presence of flavonoids, tannins, alkaloids, triterpenes and steroids. The study of the effect of extraction methods revealed that the decoction is the most suitable for the extraction of phenolic compounds. Moreover, depending on the solvent studied, it was noted that the ethanol showed a high level of flavonoids and the high antioxidant capacity. The extracts were also tested for their antibacterial activity in vitro against two bacterial strains (Escherichia coli and Staphylococcus aureus) using the disc diffusion method. The results of antibacterial showed that the highest activity was attributed to ethanolic extract with a maximum zone of inhibition of 13 mm against Staphylococcus aureus. The corrosion inhibition effect of the aqueous extracts in mild steel in 1 M HCl solution showed that the extracts inhibit effectively corrosion of mild steel.