Antioxidant and Antimicrobial Activities of Melissa officinalis L. (Lemon Balm) Extracts

Family lamiaceae is an important plant family, its includes 236 genera and 250 spicies in which Melissa officinalis  (M. officinalis) is the most common one Plants of this genus contain many chemical compounds like essential oils, terepenes, flavonoids, glucasinolates, anthocyanins and alkaloids. Also it exhibited different biological activities as antioxidant and antibacterial.  Methanolic extract of plant  was prepared where total phenolic content (TPC) and total flavonoid content (TFC) were estimated by colorimetrically. Antioxidant activity was estimated by DPPH radical scavenging activity. Also, six microbial species were used to estimate the antimicrobial activity of M. officinalis  .Total phenolic and flavonoids of M. officinalis  ethyl acetate  extract  are 143.50  mg GAE/g (dw) and 124.96 mg QE/g dw, respectively. These results confirm the antioxidant effect of the plant sample under study.The effect of M. officinalis  methanolic extract on Staphylococcus aureus ranged between 9.0 and 14 mm with concentration varied between 30 and 100 μl, respectively, while, E. Coli inhibition zone was fluctuated between 10.0 and 11.0 mm for the same concentration. This plant extract was considered sensitive agent against Staphylococcus aureus and E. Coli . Moreover, the stronger effect of M. officinalis  extracts was detected on Saccharomyces cerevisiae with a diameter of 16.0 mm when a concentration of 100 μl was used