The Anti-rotavirus Effect Of The Saponin And Volatile Oil From Psidium Guajava Leaves In Vitro

BACKGROUNDRotavirus infection remains the most common cause of severe, dehydrating gastroenteritis among children worldwide. Almost every child in the world, in both developed and developing countries, will be infected with rotavirus in the first 5 years of life. Globally, approximately 600,000 children die every year from rotavirus gastroenteritis, with the vast majority of these deaths occurring in the poorest countries. In developed nations, rotavirus infection rarely results in death but remains the most common cause of hospitalizations for acute gastroenteritis in children and leads to major medical and societal costs. In the United States ,the costs on therapy of rotavirus diarrhea up to 454 million US dollars. Researches from china also show that more than 40 percent of diarrhea in hospitalized children, is caused by rotavirus. China's estimated annual rotavirus deaths of at least 40,000 people and become the main burden of public health resources. At present, there are no specific anti-rotavirus drugs, and TCM has unique advantages.In our long-term clinical practice, we found that using guava leaf as the main drug, supplemented with other medicine, has the exact effect on rotavirus diarrhea, can significantly improve symptoms such as diarrhea. In our previous studies ,we found that guava leaf can enhance the tolerance of MA-104 cells on the rotavirus, reduce the virus' toxicity, and damage rotavirus particle shell and core. We also found that different ingredients from the guava leaf can treat the rotavirus diarrhea by different mechanisms. Such as volatile oil has analgesic, anti-inflammatory properties; Quercetin can inhibit intestinal contraction, ease intestinal cramps, reduce intestinal secretion of water and electrolytes. In the experiments, we extracted essential oil and saponins from the guava leaf, and studied their anti-rotavirus effect in vitro.OBJECTIVETo evaluate the anti-rotavirus effect of the saponin and volatile oil from Psidium guajava leaves using MTT assay, to conform their roles on prevention and therapy of rotavirus infection.METHODSExtract volatile oil and saponins from Guava leaf.1,Using different concentrations of saponin interfered the MA-104 cells, we get the median cytotoxic concentration(TC50) by MTT assay, Then added the components of saponin of different concentrations which are below the median toxic concen - tration(TC50) to interfere the rotavirus in infecting the MA104 cells. and using the MTT assay to evaluate this components' effect on the MA104 cell viability before and after its infected by rotavirus ,and determine their anti-rotavirus effects in vitro.2,Using different concentrations of volatile oil interfered the MA-104 cells, we get the median cytotoxic concentration(TC50) by MTT assay, Then added the components of volatile oil of different concentrations which are below the median toxic concentration(TC50) to interfere the rotavirus in infecting the MA104 cells. and using the MTT assay to evaluate this components' effect on the MA104 cell viability before and after its infected by rotavirus ,and determine their anti-rotavirus effects in vitro. RESULT1,By Probit regression analysis we find the TC50 of saponin on MA-104 cells is112.24ug/ml.then we added saponin of different concentrations which are below the median toxic concentration to interfere the rotavirus in infecting the MA104 cells. 48 hours latter, we found the cytopathic effect in groups of 100μg/ml and 75μg/ml are slighter than other groups either used for prevention or therapy;Through MTT assay analysis, we found the maximum inhibit ratio are 62.12% and 77.98%, the median inhibition contraction are 63.83μg/ml and 33.19μg/ml, and the therapeutic index (TI) are 1.76 and 3.38,when the saponin used for prevention and therapy respectively. Also, The inhibit ratio of rotavirus increase with the raise of concentration of the components, no matter we add it before or after the virus infected the cells.2,Through Probit regression analysis we find the TC50 of volatile oil on MA-104 cells is 4.09μl/ml in this experiment . In our experiment we found the cytopathic effect in group of 4μl/ml is slighter than other groups either used for prevention or therapy ;Through MTT assay analysis, we found the maximum inhibit ratio are 60.04 % and 86.55 %, the median inhibition contraction are 2.72μl/ml and 1.14μl/ml, and the therapeutic index are 1.50 and 3.59, when the volatile oil used for prevention and therapy respectively. Also, The inhibit ratio of rotavirus increase with the raise of concentration of the components, no matter we add it before or after the virus infected the cells.CONCLUSIONThe saponin and volatile oil from Psidium guajava leaves have nice and exact anti-rotavirus effect in vitro.