ANTIOXIDATIVE PROPERTIES AND ANTIMICROBIAL ACTIVITY OF DIFFERENT AROMATIC EXTRACTS OF MELISSA officinalis L

The present study was carried out to maintain aromatic extracts of Melissa using different techniques (water distillation, steam distillation and extraction with acetone). The volatile components of these extracts were identified. Likewise, the antioxidative properties and antimicrobial activity of these extracts were determined.  Data confirmed that the yield percent of acetone oleoresin extract was higher than both of water distillation and steam distillation extracts. Moreover, fractionation of volatile components using GC/MS technique showed the ability of acetone to extract more components than that of other techniques. In addition to being more effective in extracting higher amounts of sesquiterpene and phenols fractions.  Odor threshold level confirmed that the concentration up to 1000 ppm from either water distillation or steam distillation extracts could be mixed with sunflower oil without affecting its odor, while acetone oleoresin extract could be used at concentration up to 800 ppm. Likewise, the different aromatic extracts of melissa exhibited antioxidative properties on sunflower oil. However, acetone oleoresin was markedly superior to that of water distillation as well as steam distillation extracts as antioxidant agents. This could probably attributable to the high content of some active components such as phenolic compounds in the acetone oleoresin extract. Also, antioxidant synergistic effect was observed for a mixture of 200 ppm tested extracts and BHT at 100 ppm. However, a mixture includes acetone oleoresin extract was the most effective as an antioxidant on sunflower oil. In conformity with antimicrobial activity, all tested extracts exhibited antimicrobial activities, however acetone oleoresin extract appeared the most potential antimicrobial spectra.