Experimental Study On Six Kinds Of Traditional Chinese Medicines Against Giardia

Object:The drug extracts were added to the culture medium of Giardia lamblia in logarithmic growth phase,and the drug effects of six herbal extracts,namely,Betel nut,Mume fructus,Cnidii fructus,Sophorae flavescentis radix,Omphalia and Bletillae rhizoma,on Giardia lamblia at 12 h and 24 h were observed,and the pharmacological mechanism of effective drugs against Giardia lamblia was predicted by combining with the analysis of the genome of Giardia lamblia to provide a theoretical basis for the control of Giardia lamblia.Methods:In this study,the extracts of six herbal medicines were extracted by leaching method from Omphalia,and by decoction method from Betel nut,Mume fructus,Cnidii fructus,Sophorae flavescentis radix and Bletillae rhizome.After obtaining the extracts of the six herbal medicines,they were added to the medium containing Giardia trophozoites at five concentration doses of 100.00 mg/ml,50.00 mg/ml,25.00 mg/ml,12.50 mg/ml and 6.25mg/ml,respectively.The pure medium without drug addition was set as the control group,and samples were taken at 12 h and 24 h for microscopic observation of Giardia lamblia.The survival rate of each experimental group was calculated and statistical analysis was performed.The Giardia genomic data were searched and bioinformatically analyzed to find potential target genes for effective drugs.Then,based on the efficacy analysis of the drug administration experiments,the mechanism of drug action was inferred in conjunction with the Life cycle of Giardia lamblia.Results:The 12-h IC₅₀s of the six herbal medicines were 60.21 mg/ml for the Cnidii fructus group,47.79 mg/ml for the Mume fructus group,77.78 mg/ml for the Sophorae flavescentis radix group,34.82 mg/ml for the Betel nut group,and 7.83 mg/ml for the Omphalia group.The survival rate was even higher than that of the blank control group,and the in vitro administration of the drug may have promoted the growth of the worm for the Bletillae rhizome.Combining the genome and life cycle of Giardia lamblia,it is predicted that the potential targets of each effective drug against Giardia lamblia may include protein kinases,variant-specificurface protein,（VSP）,energy metabolism genes,and DNA polymerases.The pharmacological mechanisms were hypothesized as follows: the Sophorae flavescentis radix extract inhibited the phosphorylation of protein kinase in Giardia;catechin in the Betel nut extract could disrupt the cell membrane surface proteins of Giardia;the Cnidii fructus extract could inhibit the energy metabolism of the microorganism;the Mume fructus extract could inhibit the cellular DNA synthesis;and the Omphalia extract could disrupt the cell membrane surface proteins.Conclusion:The extracts of Betel nut,Mume fructus,Cnidii fructus,Sophorae flavescentis radix,Omphalia have inactivating and inhibiting effects on Giardia lamblia,and the duration of effect and the IC50 vary depending on the target and pharmacological mechanism of different drugs.