Antibacterial Activities of Six Medicinal Plants Used Traditionally by Saudi People to Treat Common Diseases

Antibiotic resistance is increasing and dangerous problem resulting in a decrease in the used number and fully active antimicrobial agents available to treat infections with multi-drug resistant (MDR) bacteria. Herbal medicines may be an alternative treatment options. This study aimed to evaluate the antibacterial activities of some medicinal plants used traditionally in Saudi Arabia against some pathogenic and MDR bacteria. The antimicrobial activities of water and organic crude extracts were prepared. Out of the 6 plants tested, 5 showed antimicrobial activities against one or more of the tested genera using paper disc diffusion assay. The most active antimicrobial plants were the extract of Azadirachta indica (neem), Zingiber officinale (ginger) Eucalptus globules, Rosmarinus officinalis and Lawsonia inermis with minimal inhibitory concentration (MICs) values ranged from 50-150µg/ml. Lepidium sativium have very weak activity with MIC of ≥200 µg/ml. At 600µg/ml, no toxicity was recorded for all tested extracts except of A. indica extract that showed toxicity (% of mortality ≥50). No antitumor activities for the different plant extracts were recorded against Human gastric cancer SGC-7901 cells. The biological activities may be due to some photochemical compounds including Anthocyanin, Butacyanin, Phytobutanins, Flavonoides, Stetoides and/or Saponins.