Identification And Mechanistic Study On Anti-staphylococcus Aureus Natural Small Molecules From Corylus Heterophylla Flowers

Corylus heterophylla Flowers are the staminate flowers of filbert. It has been well defined that Corylus heterophylla Flowers have many biological activities including hemostatic, antiphlogistic, hypoglycemic as well as antioxidant effect. Though molecular pharmalogical mechanism of these effects have not been fully cleared, Corylus heterophylla Flowers are widely used in clinical medicine. Aim of this study is to identify and isolate anti-staphylococcus aureus (SA) natural compounds from Crylus heterophylla Fowers and investigate the mechanism involved. Our study may provide molecular pharmacological basis for the clinical use of Corylus heterophylla Flowers.Heat reflux by organic solvents was used in extraction of Crylus heterophylla Fowers; the extract was separated by using liquid-liquid extraction. The ethyl acetate phase showed significant anti-SA activities. The ethyl acetate phase was fractionated by silica gel column chromatography and 109 components (ZF1-ZF109) were collected. Three out of the 109 fractioned components (ZF15, ZF34 and ZF75) showed marked anti-SA activities. Three activity compounds (hirsutanone, hirsutanonol,KCR), as revealed by Mass spectrometry (MS), 1H-nuclear magnetic resonance (NMR) and 13C NMR, were obtained from ZF15, ZF34 and ZF75 respectively by using high performance liquid chromatography (HPLC) technique.Activity analysis showed that hirsutanone, hirsutanonol, KCR manifested significant anti-SA activities with minimum inhibitory concentration (MIC) as 0.008mg/ml, 0.008mg/ml and 0.02mg/ml, respectively. Primary mechanism studies were performed by using membrane integrity analysis and SDS-PAGE method. It showed that all the active compounds could destroy membrane integrity of SA. Hirsutanone and hirsutanonol decreased total soluble protein of SA to 10.5% and 6.43%, respectively. In KCR treated group, total soluble protein of SA was also decreased except that a 25kD protein was increased to 47.6%.All the above mentioned compounds showed broad spectrum antibiotic activities. Hirsutanone and hirsutanonol significantly inhibited the growth of Staphylococcus aureus, Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Listeria monocytogens, Candida albicans, Escherichia coli, Bacillus proteus and Micrococcus luteus. KCR significantly inhibited the growth of Staphylococcus aureus, Bacillus cereus, Bacillus pumilus, Escherichia coli and Listeria monocytogens, but it didn't inhibit the growth of Bacillus subtilis, Candida albicans, Bacillus proteus and Micrococcus luteus. The multidrug resistance bacterium SA (MRSA) is one of the most common pathogens creates intrahospital infection. Notably, all three compounds showed anti MRSA activities.