Acidic Hydrolysis And Allelopathic Effect Of Glycoalkaloid Tomatine From Lycopersicum Esculentum Mill

Glycoalkaloids are important secondary metabolites produced by Solanaceae. Plants produce them in order to protect themselves against stress coming from outside envirment. For this point, glycoalkaloids have strong toxicity to animal. Glycoalkalo- ids are pharmaceutically active components of the plants used as herb against some diseases, and have potent anticancer activity, anti-pathogenic microorganism activity and anti-malaria activity. Tomatine, a glycoside in which four carbohydrate residues are attached to the 3-OH group of the aglycon tomatidine, occurs naturally in tomatoes (Lycopersiconesculentum). In this paper the effect of different extraction ways and solvents on extraction radio of tomatine were carried out. The product was purified by silica gel column chromatography and characterized by TLC, HPLC and 13C NMR spectra. Selectively acidic hydrolysis and acetolysis of tomatine and the relationship of the structure and activity of tomatine have also been studied.Firstly, tomatine was isolated from tomatoes , the best method is use 5% sulphu- ric acid as solvent.this way is simple on manipulation and save in cost and has the highest extraction ration.Secondly,selectively acidic hydrolysis and kinetics of acid-catalyzed hydrolysis of carboh-ydrate groups of tomato glycoalkaloid were reported. TLC showed that partial acidic hydrolysis of tomatine can produce three products: the disaccharideγ-tomatine, the monosaccharideδ-tomatine and the aglycon tomatidine. and the yield was 21.0%, 6.05%, 16.6%, respectively. Our efforts to isolateβ1-tomatine,β2-tomatine were unsuccessful. In addition, the yield ofδ-tomatine is quite low, compared toγ-tomatine, this could be caused by direct cleavage ofγ-tomatine. Acetolysis of tomatine catalyzed by Lewis acids ZnCL2 was first carried out. Tomatine was acetylated and then treated with a 100:100:1 mixture of CH3COOH–Ac2O–concentrated H2SO4.Foll- owed by deprotection, gave the acetolysis product tomatidine. then detected and cha- racterized by TLC and HPLC.Thirdly, the inhibition effect on cucumbe radicle growth of tomatine and its hydrolysis products in different pH value was compared, The results showed that tomatine had no obvious difference in inhibiting cucumber radicle growth in pH 4.0, 5.0 and 5.8. Tomatine and the hydrolysis products of tomatine inhibited the radicle growth of cucumber in a PH value was also evaluated. The results showed that tomatine,γ-tomatine and tomatidine could inhibit the growth of cucumber radicle, and the inhibition effect was concentration-dependent in the range of 0.025 mM~1mM. It was more obvious that the radicle growth inhibition effect of tomatine was larger than its hydrolysis products, The inhibitory rate of tomatine,δ-tomatine and the aglycon tomatidine were79.0%,25.2%,21.9%, respectively. the results indicated that the monosaccharide types, numbers, and the conjunction forms of the glycoalkaloid carbohydrate side chain part had significant influence on the activities of tomatine.