Chemical Composition and Biological Activities of Marrubium vulgare L

The present study was conducted to evaluate the antioxidant and antibacterial activity of the extract of leaves and flowering of Marrubium vulgare L. The quantification of total phenols was determined using the Folin-Ciocalteu reagent, it is 2.23 mg EAG/g DM. The identification of flavonoids by the Alcl3 method, revealed the presence of anthocyanins, C-glycosides and aglycones, whose contents are 1.266mg/g, 0.385mg/g and 0.0331 mg/g, respectively. The antioxidant activity of the compounds in the methanolic extract was evaluated in vitro through two tests. In the case of DPPH test, the IC50 are 0.55, 0.97, and 1.2, 0.033 mg/ml for anthocyanins, c-glycosides, polyphenols and aglycones respectively. For FRAP assay, at a concentration of 1 mg/ml, the reducing power of iron manifested ODs of 1.389 nm; 0.752 nm, 0.496 and 0.114 nm for anthocyanins, C-glycosides, total polyphenols and aglycones respectively. The results show an excellent correlation between the two tests used, and the contents of anthocyanins and c-glycosides. The antimicrobial activity was evaluated by the agar diffusion method against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922). The antibiogram shows that anthocyanins have a very important antibacterial activity on S. aureus with an inhibition zone of 16.5 mm and a diameter of 13.5 for Escherichia coli. Anthocyanins show the lowest MIC values against the two strains Staphylococcus aureus and Escherichia coli (MIC=1/16 and 1/8 respectively). C-glycosides also have an inhibitory effect on the growth of Escherichia coli and particularly on Staphylococcus aureus (MIC= 1/32 and 1/8 respectively) which is a sensitive bacterium (gram+). Anthocyanins have marked a strong sensitivity towards the two strains. In conclusion, this work presents the compounds of Marrubium vulgare L as novel antimicrobial agents and as a potential source for combating bacteria, which are increasingly resistant to antibiotics.