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Background & Aims: Yacon ( Smallanthus sonchifolius, Asteraceae) is a native Andean plant, cultivated for its tubers throughout South America. The leaves are used in folk medicine as a medicinal tea for hypoglycemia. This paper describes the antioxidant activity of various extracts from S. sonchifolius leaves for their content of phenolic components., Methods: The dried leaves were extracted in several ways. Two fractions were selected for their high content of phenolic compounds and analyzed by RP-HPLC. The antioxidant activity of these fractions was tested in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine/XOD superoxide radical scavenging assays, as inhibition of lipoperoxidation of subcellular membranes and as protective activity against oxidative injury of rat hepatocytes in primary cultures., Results and Conclusions: The presence of protocatechuic (2.5 and 0.12 mg/g), chlorogenic (9.9 and 1.7 mg/g), caffeic (14.7 and 0.09 mg/g) and ferulic (traces) acids were determined in the two fractions. Both fractions showed potent antioxidant activity in DPPH (IC(50) = 16.1 +/- 3.4 and 24.3 +/- 2.7 mg/ml) and xanthine/XOD superoxide radical scavenging (42.0 +/- 20.3 and 34.3 +/- 11.4 SOD equivalents (U/mg)) tests, they inhibited the lipoperoxidation of rat liver subcellular membranes and they protected rat hepatocytes against oxidative injury. Our results may predetermine the use of S. sonchifolius leaves in human diet as a potential remedy in the prevention of chronic diseases caused by radicals, e. g., arteriosclerosis.

To study the influence of polymerised polyphenolics (PP), a fraction of silymarin (SM), on lipids and oxidant status, rats were fed high-cholesterol (1%), high-fat (10%) diets containing either lard fat (LFD) rich in saturated/monounsaturated fatty acids, or currant oil (COD) rich in polyunsaturated fatty acids. PP and SM were administered as dietary supplements (0.1-0.5-1.0%) for 3 weeks. PP (1%) decreased cholesterol (C) in VLDL (from 0.72+/-0.08 mmol l(-1) in LFD control to 0.35+/-0.07 mmol l(-1), P<0.01, and from 0.33+/-0.05 mmol l(-1) in COD control to 0.09+/-0.02 mmol l(-1), P<0.001), and increased HDL-C/VLDL-C ratio, however, without effect on the total plasma C and LDL-C. Liver C content (LFD 19.32+/-1.50 micromol g(-1), COD 18.64+/-2.13 micromol g(-1), N.S.) decreased after PP (1%) to 12.24+/-0.76 micromol g(-1), P<0.01, and 8.78+/-0.95 micromol g(-1), P<0.001, respectively. Triacylglycerols (TAG) in plasma and VLDL decreased after PP in the LFD group only, which displayed higher TAG levels than the COD group. Likewise, LFD caused a higher liver TAG content than did COD (31.16+/-3.00 micromol g(-1) versus 17.31+/-1.48 micromol g(-1), P<0.01), and PP (1%) decreased liver TAG only in rats fed LFD (19.55+/-2.43 micromol g(-1), P<0.02). Blood glutathione (GSH) increased after PP (1%) in the LFD group from 0.97+/-0.11 to 1.54+/-0.19 mmol l(-1) (P<0.05) and in the COD group from 0.58+/-0.15 to 1.23+/-0.10 mmol l(-1) (P<0.01), while liver GSH and plasma TBARS did not change. On principle, effects of PP were dose-dependent and parallel to SM. These results suggest that the polyphenolic fraction of SM positively modifies lipoprotein profile, counteracts the development of fatty liver and ameliorates an antioxidant status in circulation.

From a mixture of lysergamide and its epimer isolysergamide, Rhodococcus equi A4 containing amidase preferentially hydrolyzed lysergamide into lysergic acid.

Glucose tolerance, total plasma cholesterol and plasma triglycerides were studied in the genetically hypertensive obese Koletsky rats (SHR/N-cp) and in their lean siblings. The initial part of the glucose tolerance curve was substantially elevated in both obese and lean Koletsky animals compared to normotensive Wistar rats. The abnormal glucose tolerance in hypertensive rats was accompanied by increased total plasma cholesterol and plasma triglycerides. Long-term treatment with dopaminergic agonists terguride or bromocriptine (0.2 and 2.0 mg/kg/day, respectively) exerted similar effects on lipid metabolism but both drugs differed in their influence on glucose tolerance. Terguride lowered plasma lipids and normalized glucose tolerance in both obese and lean Koletsky rats. Bromocriptine reduced hyperlipidaemia but did not attenuate the abnormalities of glucose tolerance in either lean or obese Koletsky animals.