Flavanones with Potent Antibacterial Activity against Methicillin-resistant Staphylococcus aureus

Authors


Department of Dental Pharmacology, Asahi University School of Dentistry, 1851 Hozumi, Hozumi-cho, Motosu-gun, Gifu 501-02, Japan.

Abstract

Abstract— With the therapeutic concept of using the defensive ability of plants against microbial infections, phytoalexin, an antimicrobial phytochemical was studied for its ability to inhibit the growth of methicillin-resistant Staphylococcus aureus (MRSA). Extracts from Sophora exigua (Leguminosae) were fractionated by serial chromatography and the anti-MRSA activity of each fraction was determined by the agar-plate method. Among the active isolates, 5,7,2′,6′-tetrahydroxy-6-isoprenyl-8-lavandulyl-4′-methoxyflavanone (exiguaflavanone D) completely inhibited the growth of all the MRSA strains examined at the concentration of 1·56–6·25 μg mL−1, and 5, 2′,6′-trihydroxy-8-lavandulyl-7-methoxy-flavanone (exiguaflavanone B) inhibited at a concentration of 50 μg mL−1. This former compound is expected to be a phytotherapeutic agent for MRSA infections as an alternative to conventional antibiotics with unwanted side-effects or the appearance of antibiotic-resistant bacteria.

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