| Chloranthus japonicus Sieb. and Chloranthus multistachys Pei belongs to the genus Chloranthuus in the family of Chloranthaceae. As folklore medicines of China, the whole plants, their rhizomes and their roots have been traditionally used in the treatment of bruises, rheumatic pains, snake bites and other symptoms. In recent years, the studies on their chemical constituents increased gradually. Current researches showed that they had antimicrobial activities, antitumor, anti-inflammatory. However, the active constituens and the mechanism of their antimicrobial function still remain unclear. Therefore, this paper aimed to discuss their antimicrobial activities, confirm the active parts and preliminarily explored antimicrobial mechanism. The main results were as follows:1. Antimicrobial activities of the extracts of C. japonicus Sieb. and C. multistachys Pei.C. japonicus Sieb. and C. multistachys Pei were extracted with the different polarity solvents (methanol, ethyl acetate, n-butyl alcohol and water). Antimicrobial properties of the different extracts obtained were evaluated in vitro via oxford-cup test and microbroth dilution assays. Activities were strong against 13 tested microorganisms (8 gram-positive bacteria,2 gram-negative bacteria,3 yeasts). The gram-positive bacteria and gram-negative bacteria showed more sensitive effects than yeast. Their ethyl acetate extracts had more distinctly antibacterial activities. The ethyl acetate extracts of C. japonicus Sieb. showed the strongest antibacterial and bactericidal activity against Sarcina luteu, as evidenced by the lowest values for MIC (0.98 mg/mL) and MBC (6.25 mg/mL). In contrast, the ethyl acetate extracts from C. multistachys Pei. exerted the strongest bactericidal activity against Sarcina luteu, with the lowest MIC (1.56 mg/mL) and MBC (6.25 mg/mL), respectively.2. Antimicrobial mechanism of the active site of C. japonicus Sieb. and C. multistachys Pei (Y1 and D1) were discussed by taking standard Escherichia coli as instruction bacteria.(1) The influence of Y1 and D1 on E. coli showed that they significantly inhibited the growth and reproduction of E. coli. Compared with the control group, Y1 and D1 reduced growth speed of E. coli. and the xperiment group didn't enter the logarithmic growth phase, but early got into the aging and atrophy. Y1 and D1 were likely influence the logarithmic growth phase.(2) Compared with the control group, Y1 and D1 destroyed the cell wall of E. coli and the AKPase were leaked. It leaded to increase cell permeability.(3) Y1 and D1 reduced the SDHase activities, and Y1 was more efficient for reducing activities. It explained that Y1 and D1 interfere with the tricarboxylic acid cycle and respiratory chain of E. coli cell.(4) The result of SDS-PAGE indicated that Y1 and D1 completely destroyed or inhibited small moleculars proteins of E. coli while large moleculars proteins were also affect to some extent.(5) Environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM) were both performed on E. coli treated by Y1 and D1. Compared with the control group, photograph of E. coli treated by Y1 and D1 displayed that the cells became shriveled, illegibility and adhesive to each other. The cell wall was invariably broken, and intracellular structure got disorder, even disappeared. Therefore, the results suggested that Y1 and D1 could destroy and disrupt the cell.This paper indicated that the extracts of C. japonicus Sieb. and C. multistachys Pei were found to inhibit the growth of tested bacteria. Furthermore, they could inhibit the cell permeability, respiratory metabolism and protein expression. These researches will provide some guidance for the application of controlling bacteria. |
PDF Full Text Request