Interactions Between The Solanaceae Glycoalkaloids Chaconine, Solanine And Tomatine In Relation To Inhibition Of Fungul Growth And Ecological Effects Of Glycoalkaloids

Glycoalkaloids are secondary metabolism of plants and distributed mainly in Solanaceae and Liliaceae. These molecules have an oligosaccharide chain attached at the C3 position of the nitrogenous steroidal alkaloid backbone.the sugar chain are uaually trisaccharide or tetrasaccharide. Some investigation have indicated that glycoalkaloids must have been evolved in nature to protect plants against bacteria, fungi, insects, and animals. They are toxic to a wide range of organisms and are generally considered to be defensive allelochmicals.The biological activity of glycoalkaloids is largely due to their membrane-disruptive effects.They complex with sterols in membranes, ultimately to form aggregates and cause loss of membrane integrity.The study about the untifungal activity of glycoalkaloids is an important moiety in the ecology and exploitation of plant resources.But much less information is available on these compounds in china,so it is valuable for us to understand and study the biological activity of glycoalkaloids to pathogenic fungi in china and their mechanism. In this paper the effect of different extraction ways and solvents on extraction radio ofα-chaconine,α-solanine andα-tomatine were reviewed. with two phytopathogenic fungi Cercosporella brassicae Hoehnel and Alternaria porri Cif as texted strain,the characteristics of antifungal activity ofα-chaconine,α-solanine andα-tomatine and their mixtrue were examined by means of inhibition of mycelial growth. In order to study the relationship between the structures and the antifungal activities of carbohydrate chains, the selective sulfation to the 6-hydroxy groups of chaconine and solanine was carried out in a strategy by the use of protective groups.The main results obtained from this work are as follows:1. extraction methods have significant effect on extraction ration of glycoalkaloids.The methanol method has the highest extraction ration,But this way is complicated and is adapted to use in laboratory the second higher method is use 5% sulphuric acid as solvent.this way is simple on manipulation and save in cost and is adapted to use in industry.2. purified glycoalkaloids were obtained through repetitive column chromatography on silica gel and crystallization.3. The glycoalkaloids show a pronounced concentration dependency in their inhibition of pathgenic fungal growth.In all cases,tomatine has the highest antifungal activity, chaconine has less activity,and solanine is the least so.