Assessment of polyphenols contents, antibacterial and antioxidant activities of Origanum majorana extracts

Abstract

The Algerian flora contains many species of vascular plants, including aromatic and medicinal plants, which can be very used for the treatment of diseases and health care. Origanum majorana is an Algerian medicinal plant used in the traditional pharmacopoeia. This work was conducted to evaluate the total polyphenolic content, antibacterial effect, and antioxidant capacity of O. majorana extracts. The extraction was carried out using the aerial parts of O. majorana with water and methanol to produce the aqueous extract (Aq.E) and the methanolic extract (Met.E). The total polyphenolic and flavonoids contents of the extracts were estimated using colorimetric method. The antibacterial effect was evaluated by the method of disc diffusion. ABTS, DPPH radical scavenging, and reducing power were used to determine the antioxidant capacity of the extracts. So, the results showed that the highest concentrations of polyphenolic amounts and flavonoids were recorded in the Met.E with values of 68.66 µg EAG/mg E and 11.71 µg EQ/mg E, respectively. Moreover, all extracts showed a good antibacterial effect against B. cereus with inhibition zones ranging from 9 to 13 mm, and moderate activity against S. aureus and P. aeruginosa. In addition, the Met.E showed the highest effect in case of DPPH and ABTS free radical (EC50=16.15±0.2 µg/ml and 19.66±0.56 µg/ml, respectively). This study demonstrated that the Met.E of O. majorana contains bioactive compounds that are related to potential biological activities, such as antioxidant and antibacterial effect. DOI: http://dx.doi.org/10.5281/zenodo.5608519

Keywords

• Antibacterial effect
• Antioxidant activity
• Polyphenols
• Origanum majorana