Hypoglicemic activitiy of Senecio species

Disorders of carbohydrates uptake may cause severe health problems such us diabetes and obesity (1-2). This study deals with the investigation of the a-amylase inhibitory property of extracts of S. samnitum Huet., S. ambiguus subsp ambiguus (Biv.) DC. and S. vulgaris L. aerial parts. -amylase is endoglucanases that catalyze the hydrolysis of internal alpha-1,4-glucosidic linkages in starch and other related polysaccharides (3). Dried aerial parts of S. samnitum, S. ambiguus and S. vulgaris were extracted with MeOH. The extracts was further acidified with 2.5% aq H2SO4 and then partitioned with n-hexane, CH2Cl2, EtOAc and the extracts taken to dryness under reduced pressure. The remaining solution was stirred with powdered Zn at 25°C overnight and then filtered and basified. The alkaline solution was extracted with chloroform (4). The principle of the assay is that in the presence of -amylase starch is converted into maltose. The generation of maltose can be quantified by reaction with 3,5 dinitrosalicylic acid solution in alkaline conditions. The reduction of this compound to 3-amino-5-nitrosalicylic acid by maltose corresponding to colour change from orange-yellow to red is detectable at 540 nm. The BuOH extract of S. samnitum showed at 100 g/ml a inhibition of 88.27%. Same results was obtained for BuOH extract of S. vulgaris , which gave 86.92% of inhibition at 100 μg/ml. The most active fraction of S. ambiguus was n-hexane that showed a inhibition of 84.07% at 500 g/ml.References: 1. Hengesh, E.J. in: W.O. Foye, T.L. Lemke (Eds) (1995), Principles of Medicinal Chemistry, Williams & Wilkins, Baltimore, 581-600. 2. Kordik, C.P., Reitz, A.B. (1999) J. Med Chem. 42: 181-200. 3. Davies, G.J. & Henrissat, B. (1995) Structure 3: 853-859. 4. De Vivar, A.R. et al., (1996) Biochl Syst Ecol. 24: 175-176.