Antimicrobial Activity an Physicochemical Characterization of Extracts and Fractions of Rosmarinus officinalis and Origanum vulgare

Abstract

Rosmarinus officinalis L. (Lamiaceae) is a shrubby woody with a bittersweet taste, used in chips, broths, desserts, cookies, jams, fruit salads, and marmalades. Origanum vulgare L. (Lamiaceae) is a small plant used in meats, salads, soups, rice, potatoes, and boiled eggs, as well as perfumery and flavoring oils. Both have medicinal and aromatic properties. The aims of this study were: perform the phytochemical screening of the powder leaves and the physicochemical characterization of the crude ethanol extracts of R. officinalis and O. vulgare; determine the content of polyphenols, tannins, flavonoids; quantify rosmarinic acid; evaluate the antimicrobial activity of rosmarinic acid, extracts, fractions of R. officinalis and O. vulgare against clinical and foodborne strains. The antimicrobial activity was evaluated by the microdilution broth method. The hexane and dichloromethane fractions of R. officinalis and O. vulgare and rosmarinic acid exhibited good inhibitory activity (MIC < 100 μg/mL) against some Gram-positive bacteria and food isolates. Ethyl acetate fraction of R. officinalis (MIC = 62.5 μg/mL), ethanol extract (MIC = 15.6 μg/mL), hexane fraction (MIC = 62.5 μg/mL), dichloromethane fraction (MIC = 31.2 μg/mL) and aqueous fraction (MIC = 62.5 μg/mL) of O. vulgare and rosmarinic acid (MIC = 31.2 μg/mL) presented good inhibitory activity against Cryptococcus. These fractions have promising potential in the control of food pathogens and they can be used in the future as an alternative natural preservative in the industry.