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ARTICLE INFO Keywords: Diosmetin Diosmin Methicillin-resistant Staphylococcus aureus Pyruvate kinase Synergy Increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) worldwide with limited therapeutic options is a growing public health concern. Natural products have been shown to possess antibacterial actions against MRSA. Flavonoids from natural products have been shown to possess antibacterial actions against MRSA by antagonizing its resistance mechanisms. Diosmin and diosmetin are natural flavonoids found in a variety of citrus fruits. The aim of this study was to investigate whether diosmin and diosmetin could inhibit the growth of MRSA and the in vitro enzymatic activity of a newly discovered MRSA drug target, pyruvate kinase (PK). By using a panel of MRSA strains with known resistant mechanisms, neither diosmin nor diosmetin was shown to possess direct antibacterial activities against all tested MRSA strains. However, in checkerboard assay, we found that diosmetin together with erythromycin, could synergistically inhibit the growth of ABC-pump overexpressed MRSARN4220/pUL5054, and time kill assay also showed that the antibacterial activities of diosmetin with erythromycin were bactericidal. Diosmetin was further shown to significantly suppress the MRSA PK activities in a dose dependent manner. In conclusion, the inhibition of MRSA PK by diosmetin could lead to a deficiency of ATP and affect the bacterial efflux pump which might contribute to the antibacterial actions of diosmetin against MRSA. © 2013 Elsevier GmbH. All rights reserved., Introduction The evolution of antimicrobial resistance among nosocomial and community-acquired pathogens such as the well-known multidrug-resistant (MDR) organism Staphylococcus aureus is of great concern, and it has compromised the treatment [...]

The article discusses the modernization and evolution of the traditional Chinese medicines (TCM) in Hong Kong. Topics mention including involving diagnoses by practitioners which are trained with Chinese medicine, several modalities which encompasses TCM which include acupuncture and formulae of TCM which are composed of various raw herbal materials.

Objectives The aims of this study were to identify the active ingredients from P ortulaca oleracea L. ( PO) that could provide synergism with antibiotics against methicillin-resistant S taphylococcus aureus ( MRSA) and their possible mechanisms of resistance inhibition. Methods High-speed counter-current chromatography ( HSCCC) coupled with gas chromatography-mass spectrometry and a panel of laboratory MRSA strains were used for checkerboard and efflux inhibitory assays. Key findings Linoleic and oleic acids were identified from HSCCC fraction 18 of PO with synergistic antibacterial activity when combined with erythromycin against RN4220/ pUL5054. Ethidium bromide efflux inhibitory studies revealed that linoleic and oleic acids may interfere the activity of MsrA pump. By comparing among a panel of linoleic and oleic acids analogues, unsaturated fatty acids in salt form with cis configuration and an increase in number of double bonds were found to further increase the antibacterial activity when used alone or in combination with antibiotics. Conclusion This study reported for the first time that two active ingredients, namely linoleic and oleic acids, were identified from PO with synergistic antibacterial activity when combined with erythromycin against MRSA RN4220/ pUL5054 and possibly act by inhibiting the efflux pumps of the bacteria cells. [ABSTRACT FROM AUTHOR]

Abstract: Reduction in glucose uptake constitutes a possible means of controlling diabetic hyperglycemia. Using purified intestinal brush border membrane vesicles and everted intestinal sleeves, we have demonstrated that naringenin, a flavonoid present in citrus fruits and juices, significantly inhibited glucose uptake in the intestine. In addition, naringenin also elicited inhibitory actions towards glucose uptake in renal brush border membrane vesicles. Naringin, a glycoside of naringenin, was totally inactive in these aspects. Naringenin exhibited moderate inhibitory action on glucose uptake in rabbit intestinal brush border membrane vesicles, and showed strong inhibitory action in rat everted intestinal sleeves. The IC50 values were 205.9 and 2.4μmol/l, respectively. Lineweaver–Burk analysis demonstrated that naringenin inhibited glucose uptake in rat everted intestinal sleeves in a competitive manner with a K i value of 1.1μmol/l. Glucose uptake activities in both the intestinal and renal brush border membrane vesicles of diabetic rats were significantly higher than in normal rats. Naringenin (500μM) reduced glucose uptake by more than 60% in both the intestinal and renal brush border membrane vesicles of diabetic rats to a level similar to that of the normal rats. The IC50 values of naringenin in the renal brush border membrane vesicles of normal and diabetic rats were 323.9 and 166.1μmol/l, respectively. These results suggest that inhibition of intestinal glucose uptake and renal glucose reabsorption explains, in part at least, the in vivo antihyperglycemic action of naringenin and its derivatives. The possible application of these natural compounds in controlling hyperglycemia warrants further investigations. [Copyright &y& Elsevier]