Study On Antibacterial Compounds From Girardinia Suborbiculata C.J. Chen

Girardinia suborbiculata, which belongs to Urticaceae, a plant of annual herb or perennial herb or half-shrub. It is widly distributed in Shanxi, Gansu, Hunan and Sicuan. Girardinia suborbiculata is the main source of nettle in civilian. As yet, Girardinia suborbiculata has not been deeply researched in internal or overseas, the reported research mainly focused on pharmacial aspects. It is generally used for rheumatism, bleeding wound and ulcer, et al. There is no resports about antibacterial activity of Girardinia suborbiculata.This article is about research on the antibacterial compounds from Girardinia suborbiculata C.J. Chen by modern science techniques on the base of the guidance of antibacterial activity of Girardinia suborbiculata C.J. Chen, Meanwhile, the antibacterial mechanism of Girardinia suborbiculata C.J. Chen had also been researched.The results were described as follows:1 Antibacterial activity of Girardinia suborbiculata C.J. Chen(1) The agar diffusion method demonstrated that the antibacterial activity of Girardinia suborbiculata C.J. Chen on the gram-positive bacteria(Staphylococcus aureus, Sarcina lutea) had better than those on gram-negative bacteria(E.coli, Salmonella typhimurium). Among of them, Girardinia suborbiculata C.J. Chen had the highest antibacterial activity on Staphylococcus aureus. It could hardly inhibit the growth of E.coli. So Girardinia suborbiculata C.J. Chen has certain selectivity on bacterial, it has better antibacterial activity against the gram-positive bacteria, and has a lower antibacterial activity against the gram-negative bacteria.(2) MIC test showed that Girardinia suborbiculata C.J. Chen on Staphylococcus aureus has the great antibacterial activity, and the MIC concentration is 100 mg/mL. So the Staphylococcus aureus was the guidance bacterial of antibacterial activity.(3) The Girardinia suborbiculata C.J. Chen was extracted with petroleum ether, ethyl acetate and butanol. It showed that all of the extracts had some antibacterial activity. Ethyl acetate showed the highest antibacterial activity among these extracts, butanol and petroleum ether as follows, but the water layer is almost no antibacterial activity. The results showed that the main active compounds distributed in the ethyl acetate extract. 2 Separation of the antibacterial compounds from Girardinia suborbiculata C.J. ChenThe guidance of antibacterial activity of Girardinia suborbiculata C.J. Chen against Staphylococcus aureus, compounds were isolated by silica gel column chromatography, thin layer chromatography (TLC), high performance liquid chromatography (HPLC) and high speed countercurrent chromatography (HSCCC), and their structures were determined by spectral analysis and chemical evidence(1H-NMR,13C-NMR,MS). Two compounds against Staphylococcus aureus were isolated and they were identified as compoundⅠ:β-sitosterol and compoundⅡ: trans-p-hydroxycinnamic acid ethylester. The MIC of two compounds concentration were 3.4 mg/mL,2.0 mg/mL, respectively. Trans-p-hydroxycinnamic acid ethylester was isolated from Girardinia suborbiculata C.J. Chen for the first time, and its antibacterial activity against Staphylococcus aureus was first founded for the first time.3 Studies on antibacterial mechanism of ethanol extract from Girardinia suborbiculata C.J. Chen(1) Inhibition growth curves against Staphylococcus aureusIt demonstrated that the growth of Staphylococcus aureus were inhibited by the Girardinia suborbiculata C.J. Chen group, but in the control group, the Staphylococcus aureus were rapidly entered the logarithmic growth phase. The results of the growth curves revealed that the Girardinia suborbiculata C.J. Chen could inhibit cell division at logarithmic growth phase.(2) The content of cellular soluble proteinsThe result of SDS-PAGE indicated that the content of cellular soluble proteins of the Girardinia suborbiculata CJ. Chen group were obvious less than the control group.(3) The content of cellular nucleic acidIt showed that Girardinia suborbiculata C.J. Chen has the significant effects on the synthesis of cellular nucleic acid by 4'6-diamidino-2-phenylindole (DAPI) staining, inverted fluorescence microscope and fluorescence spectrophotometer observations and analysis.Therefore, the antibacterial mechanism was supposed that inhibited the growth of Staphylococcus aureus due to inhibit the synthesis of soluble proteins and nucleic acid.