Study on Cell Cycle of Candida Albicans and Affected by Antifungal Monomes from Chinese Herbs

Abstract: High morbidity of deep fungal infections, lack of antifungal drugs, and large of drug-resistant isolates are puzzling our clinical works in now days. Developing high-effective and low-adverse antifungal agents and founding reproducible drug susceptibility testing methods are getting more attentions. It requires considerable time and high expense to get a new antifungal agents by chemosynthesis. It has been occupying very long in time that fungal infections treated by Traditional Chinese Medicine, and plenty of experiences have been accumulated. It may be a good approach to developing new agents by separating effective components from Chinese herbs using modern techniques. Flow cytometry (FCM) which colligated a few of modern techniques is widely used in biology, basic medicine and clinical medicine. In this study, we were through detecting cell cycle by FCM to investigate the inhibition of four Chinese herb monomes, i.e. berberine, baicalin, eugenol and curcumin, to proliferation of Candida albicans. We hoped to find effective antifungal agents from Chinese herbs and found drug susceptibility testing method by FCM.We at first investigated the cell cycle of Candida albicans which was incubated in natural condition. The majority of logarithm-growth-phase Candida albicans which was incubated at early 28 hours was in S-phase, G2/M-phase or S-G2/M-phase of cell cycle, and then the majority of stationary-growth-phase Candida albicans after incubated 28 hours was in G1-phase. It was first discovered that like other eukaryon cells Candida albicans also had apoptosis phenomenon. The apoptosis rate did not changed accompanying with incubating time or growth rate but kept in a comparative stable value. This indicated that apoptosis of Candida albicans also controlled by genes, and affected little by environment agents.We investigated the cell cycle of Candida albicans affected by berberine,baicalin, eugenol and curcumin, respectively. Histograms of FCM indicated the fluorescence intensity of cellular DNA. The smaller of peak value, the lower of fluorescence intensity was. Compared with control group, the fluorescence intensity of Candida albicans which treated with antifunal agents changed. The peak value shifted to left. The high concentration of antifungal agents, the more the peak value shifted to left, which meant the severer damage of nucleus. On scatter diagram, the ordinate, i.e. FS (Forward angle light scatter) indicated the volum of cell. The lower of FS, the smaller of cell was. While the abscissa (SS) indicated the refraction and granule attribute of cell. The smaller of SS, the severer damage of cell was. Among the FCM histograms of Candida albicans treated with antifungal agents, there is a sub-G1 peak (apoptosis peak) in front of G1 peak. The value of apoptosis peak did not changed accompanying with the concentration of agents, which indicated that the four antifungal agents could not induce the cellular apoptosis but may act on the cellular ultrastructure directly to inhibit the growth of Candida albicans.There are plenty of treasure in traditional Chinese medicine mine. High-effective and low-adverse antigungal drugs can be separated from traditional Chinese medicine through unceasing research. FCM detects the cell cycle of fungi which indicates fungi was inhibited by agent in single cell level. This reflects the innate character of antifungal agents. FCM combining laser, computer and other techniques has the superiority of high-automatization, impersonality outcome and convenience operation, which may become a standard method of drug susceptibility testing. Of course, there are many things to be done before FCM is used in clinical laboratory for drug susceptibility testing…
Key words: Candida albicans; cell cycle; Chinese herb; antifungal; flow cytometry

This entry was posted in Doctoral Dissertation. Bookmark the permalink.