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Flavonoids from Sophora moorcroftiana and their Synergistic Antibacterial Effects on MRSA
Author(s) -
Wang ShuangYing,
Sun ZhongLin,
Liu Tao,
Gibbons Simon,
Zhang WenJu,
Qing Mu
Publication year - 2014
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.5098
Subject(s) - norfloxacin , genistein , traditional medicine , sophora , staphylococcus aureus , ciprofloxacin , minimum inhibitory concentration , antibiotics , phytochemical , streptomycin , efflux , antibacterial activity , antibacterial agent , chemistry , microbiology and biotechnology , pharmacology , biology , medicine , biochemistry , bacteria , traditional chinese medicine , genetics , alternative medicine , pathology , endocrinology
Synergy is now a widely recognized approach that has direct applicability for new pharmaceuticals. The ethanolic extract of the aerial parts of the herb Sophora moorcroftiana showed significant antibacterial activity against drug‐resistant Staphylococcus aureus , and its minimum inhibitory concentration (MIC) was 8 µg/mL. In a phytochemical study of the extract, five flavonoids were obtained. However, the isolates exhibited antibacterial activity in the range of 32–128 µg/mL, which was weaker than the extract. In combination with antibiotics, the antibacterially inactive compound genistein (1) and diosmetin (4) showed significant synergistic activity against drug‐resistant S. aureus . In combination with norfloxacin, genistein (1) reduced the MIC to 16 µg/mL and showed synergy against strain SA1199B with a fractional inhibitory concentration index (FICI) of 0.38. With the antibiotics norfloxacin, streptomycin and ciprofloxacin, diosmetin (4) showed synergy against SA1199B, RN4220 and EMRSA‐15, with FICI values of 0.38, 0.38 and 0.09, respectively. In an efflux experiment to elucidate a plausible mechanism for the observed synergy, genistein showed marginal inhibition of the NorA efflux protein. Copyright © 2013 John Wiley & Sons, Ltd.