Antimicrobial properties of 3 medicinal plants from Saudi Arabia against some clinical isolates of bacteria.

OBJECTIVES: To examine the in vitro antibacterial activity of the ethanol extract of fresh fruits of Solanum incanum L., fresh leaves of Ricinus communis L. and Allium ampeloprasum var. porrum L., and to determine and quantify the phenol compounds of the investigated plant parts.

METHODS: This study was carried out at the Faculty of Science, King Khalid University, Abha, Kingdom of Saudi Arabia from July 2011 to September 2011. Nine clinical strains of bacteria and 3 ethanol extracts of 3 plant species were used for the antimicrobial study. Thirty grams of each sample was ground, filtrated, and each filtrate mixed with 100 ml ethanol and placed in a shaker for 48 hours. The ethanol was evaporated from the sample, weighed, and subjected to an antibacterial activity test using the agar diffusion method. The high-performance liquid chromatography was used to identify and quantify the phenols extracts of investigated samples.

RESULTS: Ethanol extract of the investigated plant parts showed antibacterial activities against different pathogenic bacteria. Leaf extracts of Ricinus communis showed the highest antibacterial activity, followed by the leaves of Allium ampeloprasum var. porrum, while the fruits of Solanum incanum showed the least activity. The amounts of main phenols detected in Ricinus communis leaves were higher than those of Solanum incanum fruits and Allium ampeloprasum var. porrum leaves.

CONCLUSIONS: The ethanol extract of the tested plants could be considered as an alternative source of new antibacterial drugs.