Extraction, Purification And Antibacterial Activity Of Total Saponins From Leaves Of Torubam

Solanum torvum Swartz is a Solanaceae Solanum suffruticosa plant with a wide range of biological activities and functions.Solanum torvum Swartz is rich in saponins and has anti-fungal,antioxidant and antiviral effects,and an excellent disease-resistant rootstock in agricultural production.However,there is no in-depth research on agriculture.In this paper,the leaves of Solanum torvum Swartz were used as research materials to extract and purify total saponins,and the anti-fungal activities of Solanum torvum Swartz saponins were studied,which provided theoretical basis for the development of Solanum torvum Swartz saponins active substances.The results are as follows:1.Among the four different solvents extracted from Solanum torvum Swartz leaves,n-butanol extract had the best fungicidal effect,10 mg/m L n-butanol extract showed strong inhibitory effect on Fusarium moniliforme,Fusarium oxysporum f.sp.cucumebrium and Pyricularia oryzae tested.Qualitative detection showed that the n-butanol extract of Solanum torvum Swartz leaves contained saponins.2.Using single factor test and response surface methodology,the optimum technological conditions of ultrasonic assisted extraction of total saponins from Solanum torvum Swartz leaves were studied: ethanol concentration 80.30%,solid-liquid ratio 1:15.06（g/m L）,extraction time 95.56 min and extraction temperature 62.29℃.Under these conditions,the theoretical extraction rate of total saponins in Solanum torvum Swartz leaves was 38.82%.3.The purification process conditions of total saponins from Solanum torvum Swartz leaves were studied by macroporous resin adsorption method: the loading concentration was 1 mg/m L,the loading flow rate was 1 m L/min,the amount of ethanol elution was 5 BV,the concentration was 90%,and the elution rate was 1 m L/min.Under this process,the purity of saponins was 44.18%.4.The growth rate method were used to study the inhibitory activity of total saponins from leaves of Solanum torvum Swartz against plant pathogenic fungi.Scanning electron microscope was used to observe the influence of the mycelium morphology.The anti-fungal mechanism of total saponins in leaves of Solanum torvum Swartz was studied by measuring mycelium content and enzyme activity.The total saponins in leaves of Solanum torvum Swartz showed inhibitory effects on the mycelial growth of 14 plant pathogenic fungi.The inhibition rate on mycelial growth of 9 plant pathogenic fungi was more than 60%.The inhibition effect on Pestalotiopsis trachicarpicola was the strongest,reaching 97.47%.The inhibition rates of Fusarium vasinfectum were 78.99%.Total saponins caused abnormal hyphae of Fusarium vasinfectum and Pestalotiopsis trachicarpicola;Destroy the integrity of the mycelial membrane system of Fusarium vasinfectum;Inhibit the synthesis of pyruvate,soluble protein and soluble sugar,so as to affect the metabolic cycle and osmotic regulation function of mycelium;Make the production and accumulation of superoxide dismutase in mycelium,increase the activity of polyphenol oxidase,and affect the defense system of mycelium.