Abstract:We investigated the lipid-lowering effects of methanolic extract of Vernonia amygdalina (VA) leaves in rats fed an high cholesterol diet, and compared with a standard hypolipidemic drug, Questran (Qu). The effects of VA on the lipid profi le were assessed by measuring the levels of total cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, lipid peroxidation (LPO), phospholipid, and glutathione (GSH) in the plasma and liver of the rats. Administration of cholesterol at a dose of 30 mg/0.3 ml, fi ve times in a week for nine consecutive weeks resulted in a signifi cant increase (p Ͻ 0.05) in plasma and post mitochondrial fraction (PMF) cholesterol levels by 33% and 55%, respectively. However, treatment with extract of VA at doses of 100 and 200 mg/kg caused a dose dependent reduction in the plasma and PMF cholesterol by 20%, 23% and 23%, 29%, respectively. Similar reduction in cholesterol levels was obtained in Qu-treated rats. Furthermore, VA at 200 mg/kg decreased the plasma and PMF LDL-cholesterol levels by 23% and 49%, and also decreased plasma and PMF triglyceride levels by 29% and 28%, respectively. Also, VA at 100 and 200 mg/kg caused a dosedependent increase in plasma HDL-cholesterol levels by 41% and 59%, respectively. However, there were no signifi cant differences (p Ͼ 0.05) in the PMF HDL-cholesterol and phospholipid levels of the treated rats when compared to hypercholesterolemic rats. There were signifi cant decreases (p Ͻ 0.05) in the LPO levels of extract-treated rats. Precisely, VA at 100 and 200 mg/kg decreased the levels of plasma and PMF LPO by 38%, 42% and 35%, 45%, respectively. In addition, VA augmented the cholesterol-induced decrease in PMF glutathione levels of the rats. Taken together, these results suggest the lipid-lowering effects of VA and, probably serve as a new potential natural product for the treatment of hyperlipidemia.

1. The hypolipidaemic effect of kolaviron, a mixture of Garcinia biflavonoid 1 (GB1), Garcinia biflavonoid 2 (GB2) and kolaflavanone, used in the treatment of various ailments in southern Nigeria, was investigated in rats. The ability of Questran (Bristol-Myers Squibb, Hounslow, UK), a hypolipidaemic therapeutic drug, to attenuate hypercholesterolaemia in rats was also examined. 2. In order to assess the hypolipidaemic effect of this extract in experimental animals, thiobarbituric acid-reactive substances (TBARS), cholesterol, phospholipid, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol and triglyceride levels were determined in the plasma and liver. 3. Cholesterol administered orally to rats at a dose of 30 mg/0.3 mL five times a week for 8 consecutive weeks resulted in a significant increase (P<0.001) in the relative weight of the heart of hypercholesterolaemic animals compared with control. However, cotreatment with kolaviron and Questran ameliorated the cholesterol-induced enlargement of the heart. Kolaviron (100 and 200 mg/kg) elicited 88.5 and 87.4% reductions, respectively, in plasma cholesterol levels of pretreated animals compared with the cholesterol-fed group. In addition, kolaviron produced a significant decrease (P<0.05) in post-mitochondrial fraction (PMF) cholesterol levels in treated animals compared with untreated hypercholesterolaemic animals. Similarly, Questran significantly decreased (P<0.05) the cholesterol-induced increase in plasma cholesterol levels compared with untreated hypercholesterolaemic animals. In addition, (100 and 200 mg/kg) significantly (P<0.05) decreased plasma LDL-C levels by over 70% in treated animals compared with untreated hypercholesterolaemic animals. Similarly, kolaviron significantly decreased (P<0.05) PMF LDL-C levels by over 60% in treated animals compared with untreated hypercholesterolaemic animals. 4. The significantly (P<0.05) higher values of plasma and PMF triglycerides obtained in cholesterol-fed animals compared with control animals were unaltered following cotreatment with kolaviron and Questran. In the present study, there was a significant decrease (P<0.05) in plasma formation of malondialdehyde in kolaviron- and Questran-treated animals compared with untreated hypercholesterolaemic animals. 5. The results of the present study demonstrate that kolaviron exerts a hypocholesterolaemic effect and reduces the relative weight of the heart in cholesterol-fed animals. This reduction and the favourable lipid profile indicate a possible anti-atherogenic property of the extract.

Artemether, artemether-lumefantrine, or coartem and halofantrine are alternative antimalarial drugs to chloroquine. Their efficacy and potential to delay drug resistance in falciparum malaria had led to their increased use. Although these drugs have proven to be well tolerated, there are adverse effects associated with them. This study was designed to examine the toxic potential of acute administration of these drugs in rats. Twenty-four rats were divided into four groups: group I (control) received distilled water; group II received artemether for 5 days with an initial dose of 3.2 g/kg body weight on day 1 and 1.6 mg/kg body weight on days 2-5; group III received coartem (27 mg/kg body weight/day) for 3 days, which was divided into two equal portions per day; and group IV received halofantrine (24 mg/kg body weight/day) in three equal portions. Administration of artemether, coartem and halofantrine caused significant decrease (P < 0.05) in reduced glutathione levels in the liver by 29%, 21% and 26%, respectively. In contrast, there were no significant differences (P > 0.05) in the kidney glutathione levels. Furthermore, artemether, coartem and halofantrine decreased the liver-and kidney-enzymatic antioxidant status of the animals. Precisely, artemether, coartem and halofantrine decreased liver superoxide dismutase and catalase activities by 45%, 50% and 57%; and 20%, 29% and 23%, respectively. While the kidney catalase activities were decreased by 41%, 28% and 30%, respectively, the drugs however did not produce significant effect (P > 0.05) on the kidney superoxide dismutase activities. In addition, artemether, coartem and halofantrine decreased the hepatic levels of glutathione S-transferase by 64%, 51% and 53%, respectively. Administration of artemether, coartem and halofantrine significantly increased (P < 0.05) liver and kidney lipid peroxidation levels by 67%, 50% and 81%; and 58%, 43% and 31%, respectively. This indicates that the liver is considerably more affected than the kidneys. Similarly, halofantrine treatment caused significant elevation (P < 0.05) in the levels of serum creatinine, aspartate and alanine aminotransferases and blood urea nitrogen by 73%, 66%, 61% and 63%, respectively. These data indicate that oral administration of artemether, coartem and halofantrine has adverse effects on both enzymic and non-enzymatic antioxidant status of the animals.

No abstract

In the search for natural hypoglycaemic agents as alternatives to synthetic ones that are expensive and not easily accessible, and to justify the use of Garcinia kola seeds in traditional African medicine to treat diabetes, the hypoglycaemic and hypolipidaemic effects of fractions from kolaviron (KV) (a Garcinia kola seed extract) were investigated in normal and streptozotocin (STZ)-diabetic rats. KV, a biflavonoid complex from Garcinia kola seed, was separated by thin-layer chromatography into three fractions; Fraction I (FI), Fraction II (FII) and Fraction III (FIII) with RF values of 0.48, 0.71 and 0.76, respectively. In normoglycaemic rats, KV, FI and FII administered at a dose of 100 mg kg(-1) body weight elicited significant (P < 0.05) hypoglycaemic activity within 4 h of oral administration. Precisely, KV, FI and FII decreased blood glucose levels of normoglycaemic rats by 66%, 50% and 61%, respectively, when compared with controls 30 min after oral administration of the extracts. In hyperglycaemic rats, KV, FI and FII significantly (P < 0.05) reduced blood sugar levels in STZ-diabetic rats within 4 h of oral administration. Furthermore, KV alone produced a significant (P < 0.05) anti-diabetic effect from day 3 to day 7 of oral intubation of STZ-diabetic rats. In addition, the extracts showed favourable effect on the plasma lipid profile of STZ-diabetic rats, and also decreased significantly (P < 0.05) the STZ-induced increase in the activity of microsomal glucose-6-phosphatase and lipid peroxidation (LPO) products. This study confirms the anti-diabetic and hypolipidaemic effects of KV in STZ-diabetic rats. These observed effects of KV are attributed to two of its fractions, FI and FII, with RF values of 0.48 and 0.71, respectively.