PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITIES OF Salvadora persica L. ROOT, LEAF AND TWIG EXTRACTS

Abstract

The Salvadora persica (Aadee in Oromo language) is well known for its ethnobotonical values among the local communities.It is distributed in low and mid-altitudinal ranges of Garamuleta district, eastern Ethiopia. An ethnobotanical information about the plant for its use as toothbrush stick, edible fruits and various ethnomedicinal aspects have been reported. The present study was undertaken to investigate qualitative phytochemical screening and antimicrobial activities of aqueous and alcoholic extracts of S. persica root, twigs and leaf extracts. The study involved S. persica root, twig and leaf sample collection from Gurawa district, East Hararghe, Ethiopia. The qualitative screening of phytochemicals was conducted using water and methanol as solvents. The antimicrobial activity was determined using the disc diffusion method for measuring the diameter of inhibition zone, and the broth dilution method was used for determination of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) as well as the Minimum Fungicidal Concentrations (MFC). The results of S. persica leaf extracts demonstrated that the majority of the tested phytochemicals in the aqueous leaf extract were found to have alkaloids, flavonoids, saponins, terpenoids, tannins and steroids while the methanolic leaf extracts contained alkaloids, flavonoids, saponins, terpenoids, and tannins. The highest inhibition zone (18.97mm) was recorded for methanolic leaf extract against S. aureus while the lowestzone of inhibition (12.83mm) was recorded for aqueous twig extract against S. aureus and leaf extract against E. coli. The highest zone of inhibition (18.03mm) was recorded for leaf methanolic extract against A. niger indicating that A. niger was more susceptible than A. versicolor. The methanolic leaf extract has demonstrated the strongest antibacterial activity with MIC (9.38mg/ml) and the corresponding MBC (12.5mg/ml) against S. aureus while the weakest antibacterial activity with MIC of 100mg/mL and a corresponding MBC of 200mg/ml which was observed for the aqueous leaf extract against E. coli, and aqueous twig extract against S. aureus showing that leaf crude extract displayed stronger antibacterial potential; and S. aureus was more susceptible to the crude extracts. The strongest antifungal activity with the MIC of 7.81mg/ml and the corresponding MFC of 12.5mg/ml was recorded for methanolic leaf extract against A. niger indicating that A. niger was more susceptible to the crude S. persica extract than A. versicolor. In general the extracts of plants have demonstrated potential antimicrobial activities against bacterial and fungal pathogens.