African walnuts attenuate ectopic fat accumulation and associated peroxidation and oxidative stress in monosodium glutamate-obese Wistar rats.

AIMS: African walnuts were previously shown to modulate hepatic lipid bio-accumulation in obesity. Herein, we investigated the impact of the nuts on fat accumulation in adipose and ectopic regions, and associated oxidatiive stress status in obese rats. MATERIALS AND METHODS: Whole ethanol extract (WE) of the nuts, and its liquid-liquid fractions-ethyl acetate (ET) and residue (RES) were separately administered to obese rats for 6 weeks. The normal (NC) and obese (OC) controls received normal saline and the standard control (SC), orlistat (5.14 mg/kg b.w.), during the same period. Thereafter, the animals were euthanized and the adipose, brain, kidneys and heart tissues were studied. RESULTS: The change in body weight to naso-anal length which increased by 63.52 % in OC compared to NC (p < 0.05), decreased by 57.88, 85.80 and 70.20 % in WE, ET and RES-treated groups, respectively, relative to the OC (p < 0.05). Also, adipose tissue weights were lowered upon treatment with the extracts and fractions versus OC (p < 0.05). Total lipids, phospholipids, triacylglycerol and cholesterol concentrations in the studied tissues which were higher in OC (p < 0.05) were lowered (p < 0.05) and compared favorably with SC. Further, malondialdehyde levels in the tissues were lowered upon treatment, compared to the OC (p < 0.05). Glutathione level and activities of glutathione peroxidase, superoxide dismutase and glutathione-S-transferase which were decreased (p < 0.05) in OC, were restored upon treatment with the extracts, relative to the obese control (p < 0.05). SIGNIFICANCE: African walnuts assuaged lipogenesis, oxidative stress and peroxidation in extra-hepatic tissues of obese rats, hence, may attenuate ectopic fat accumulation and its associated pathogenesis.

Haematological changes in rats exposed to insecticidal oils from the leaves of Cassia occidentalis and Euphorbia milii.

This study analysed the effect of insecticidal oils obtained from the leaves of Cassia occidentalis and Euphorbia milii on haematological indices in rats. It also evaluated the extent ethyl ether anaesthesia affects the concentration of haematological indices in experimental rats. Oils were extracted from both plants via soxhlet and administered to Wistar rats orally once a week, for 2 weeks. Fifty-six rats were divided into two groups (28 rats each), these were further divided into seven (7) groups of four rats each. The control group (A) received feed and water only, Groups B1, B2, and B3 received 1500 mg/kg, 3000 mg/kg and 5000 mg/kg body weight of C. occidentalis oil extract, respectively, and similarly, groups C1, C2 and C3 received 1500 mg/kg, 3000 mg/kg and 5000 mg/kg body weight of E. milii oil extracts. The first set was sacrificed under mild ethyl ether anaesthesia, while the second set was sacrificed without any anaesthetic agent. Thereafter, whole blood was drawn and analysed for changes in haematological indices. Both oils caused a significant (P < 0.05) decrease in white blood cells (WBC) and platelet counts at 5000 mg/kg body weight relative to the control in both unanaesthetised and anaesthetised rats. In addition, a significant decrease in MCH, MCHC and in Red Blood Cell counts and Packed Cell Volume was also observed in unanaesthetised rats exposed to E. milii oil and C. occidentalis oil respectively at 5000 mg/kg body weight relative to the control. Since insecticides are usually applied at much lower concentrations, the plant oils may be considered safe for use as insecticidal agents.

Safety assessment of the ethanolic extract of Gongronema latifolium Benth. leaves: a 90-day oral toxicity study in Sprague Dawley rats.

BACKGROUND: The leaves of Gongronema latifolium Benth. have long been recognized traditionally as a remedy for a variety of ailments in Africa. This study was conducted to evaluate the safety profile of the ethanolic extract of G. latifolium (GLES) leaves through a repeated dose 90-day oral toxicity study in male and female of Sprague Dawley rats. METHODS: GLES was orally administered at doses of 250, 500 and 1000 mg/kg/day consecutively for 90 days. RESULTS: No behavioral or physiological changes and mortality were observed. GLES did not have a marked impact on general hematological parameters and did not precipitate nephrotoxicity. However, compared to the control, serum triglycerides, total cholesterol and low-density lipoprotein levels were lower and white adipose tissue paired retroperitoneal fat depots were depleted in male rats treated with GLES3 by the end of the experiment. The liver was significantly enlarged in GLES-treated rats of both sexes. Negative gender-specific alterations were observed with the highest dose. Adverse risk was evident in the female rats mainly due to marked body weight gain and cerebrum weight reduction. CONCLUSION: Further research is needed to reach more specific conclusions about to the safety of ingesting high doses of GLES for long periods of time.

Hyptis verticillata attenuates dyslipidaemia, oxidative stress and hepato-renal damage in streptozotocin-induced diabetic rats.

AIMS: Chronic hyperglycaemia in diabetes mellitus (DM) increases the production of free radicals which results in oxidative stress and related disorders such as cardiovascular diseases, compromised hepatic and renal functions. Hyptis verticillata reportedly demonstrated glucose lowering activity in previous studies. The present study therefore evaluated the effect of H. verticillata on hyperglycaemia-induced dyslipidaemia, hepatorenal distortions, oxidative stress, as well as calculated indices of cardiovascular function. METHODS: Wistar rats employed for this study consisted of normoglycaemic and diabetic rats in nine experimental groups. The normoglycaemic and diabetic rats were either treated with metformin (500 mg/kg b.w.), quercetin (10 mg/kg b.w.), or ethanol extract of H. verticillata leaf (250 mg/kg b.w. and 500 mg/kg b.w.) administered orally for 28 days. KEY FINDINGS: Results revealed that H. verticillata significantly lowered blood glucose level, attenuated dyslipidaemia, decreased atherogenic coefficient, atherogenic and coronary risk indices, and increased cardioprotective index in diabetic rats. Also, H. verticillata significantly decreased serum urea, creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and unconjugated bilirubin levels, relative to untreated diabetic rats. Further, H. verticillata increased serum superoxide dismutase, catalase and glutathione peroxidase activities and glutathione level, and decreased malondialdehyde level in diabetic rats in a manner similar to metformin and quercetin. Histopathological investigation of the liver and kidney revealed restored hepatocytes and amelioration of congested interstitial blood vessel of the Bowman's space of the kidneys upon intervention with H. verticillata. SIGNIFICANCE: H. verticillata in addition to its anti-hyperglycaemic activity ameliorates oxidative stress, dyslipidaemia, atherogenicity and hepatorenal lesions in DM.

Vernonia amygdalina simultaneously suppresses gluconeogenesis and potentiates glucose oxidation via the pentose phosphate pathway in streptozotocin-induced diabetic rats.

BACKGROUND: This study evaluated the impact of Vernonia amygdalina (VA) on the transcription of key enzymes involved in cellular modulation of glucose in streptozotocin-induced diabetic rats in a bid to understand the possible anti-diabetic mechanism of VA. METHODS: The chloroform fraction of VA (200 mg/kg and 400 mg/kg body weight) was administered to SDRs for 7 and 14 days. Thereafter, the expression (transcription) of key carbohydrate regulatory genes was evaluated in selected tissues - adipose, muscle and liver. Also, the body weight and blood glucose changes were monitored. RESULTS: A 14-day administration of 200 mg and 400 mg of the extract and metformin (500 mg/kg) showed a striking decrease (P <0.05) in the expression of the gluconeogenic enzymes - fructose 1,6-bisphosphatase, phosphoenol pyruvate carboxykinase and glucose 6-phosphatase in the liver and muscle compared to the diabetic control. These genes were highly expressed in tissues of untreated diabetic rats (P <0.05) indicating severe gluconeogenesis. Furthermore, the extract as well as metformin significantly increased glucose oxidation via the pentose phosphate pathway (PPP) i.e. increased expression of the glucose 6-phosphate dehydrogenase (G6PDH) gene (P <0.05) in the liver. Conversely, the expression of the G6PDH in the muscle and adipose tissues significantly decreased (P <0.05), suggesting enhanced utilization of NADPH and ribose in the clearance of reactive oxygen species and for expression of other relevant genes respectively. Also, transcription of the cell proliferation regulatory enzyme, phosphatidylinositol 3-kinase increased in the liver, but decreased in the muscle and adipose tissues (P <0.05) upon treatment with the extract or metformin, implying that the liver responded to the VA and metformin treatments more than other organs. The extract administration also caused a decrease in the expression of key enzymes of glycolysis namely hexokinase and phosphofructokinase, suggestive of a glucose sparing for ribose and NADPH production in PPP. CONCLUSION: Overall, data obtained in this study suggest that VA exerts little or no effect on glycolysis; rather, it may achieve its anti-diabetic action by a simultaneous suppression of gluconeogenesis and potentiation of glucose oxidation via PPP pathway, almost exclusively in the liver.

Multi-constituent synergism is responsible for anti-inflammatory effect of Azadirachta indica leaf extract.

CONTEXT: Azadirachta indica A. Juss. (Meliaceaes) leaves have been used traditionally to treat swelling and rheumatism in Indian cultures. OBJECTIVE: To fractionate A. indica leaf extracts using bioactivity guided manner for identification of the active anti-inflammatory principles. MATERIALS AND METHODS: Polarity-gradient sequential extracts (petroleum ether, chloroform, methanol, and water) of A. indica leaves were screened for their anti-inflammatory potential using the carrageenan-induced rat paw edema model (1 g/kg). The chloroform extract was sequentially fractionated to obtain n-hexane (F-1), n-hexane-chloroform (F-2), and chloroform (F-3) fractions and their inhibitory effect on rat paw edema was evaluated (500 mg/kg). Inhibitory effect of F-2 on granuloma formation, plasma interleukin (IL-1), and tumor necrosis factor (TNF-α) was assessed at the doses of 100, 200, and 400 mg/kg using the cotton pellet assay in rats. Three sub-fractions (SF-1, SF-2, and SF-3) were obtained upon chromatography of F-2, and their inhibitory effect on cyclooxygenase was assessed at 200 µg/mL concentration. The sub-fractions were subjected to gas chromatography-mass spectrometry (GC-MS). RESULTS: All the extracts showed significant anti-inflammatory effect; however, chloroform extract was the most effective against paw edema (53.25% inhibition). The three fractions of chloroform extract showed significant effect, while F-2 being the most potent (51.02%). F-2 demonstrated dose-dependent inhibition of granuloma and cytokines. Interestingly, all the sub-fractions of F-2 inhibited COX-1 and COX-2 with almost equal potential. GC-MS revealed that chemically the sub-fractions were totally different from each other. DISCUSSION AND CONCLUSION: Anti-inflammatory effect of A. indica is a result of cumulative and synergistic effects of diversified constituents with varying polarities that collectively exert the effect via suppression of cyclo-oxygenases and cytokines (IL-1 and TNF-α).

Synergistic antidiabetic activity of Vernonia amygdalina and Azadirachta indica: biochemical effects and possible mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: A decoction from a combination of herbs is commonly used in Traditional African Medicine for the management of chronic ailments. In Nigeria, the leaves of Vernonia amygdalina Del. (VA) and Azadirachta indica A. Juss (AI) are used traditionally as a remedy against diabetes mellitus for which empirical evidence attests to its efficacy. AIM OF THE STUDY: To evaluate the synergistic antidiabetic action of VA and AI, the biochemical effects and possible mechanism in streptozotocin-induced diabetic rat (SDR) models. MATERIALS AND METHODS: Ethanolic extracts of VA and AI were co-administered (200 mg/kg, 50:50) to non-diabetic rats (NDRs) and SDRs for 28 days. Blood glucose and body weight were monitored during this period, and at end of treatment, serum glucose, insulin, triiodothyronine (T3), tetraiodothyronine (T4) and α-amylase activity were studied. Glucose and activities of antioxidant enzymes, e.g., catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD), were estimated in hepatocytes, along with the impact on the histology of the liver and pancreas. Medium acting insulin, HU (5 IU/kg, s.c.) was used as a positive control. RESULTS: The study reveals that compared with single extracts, the combined extract (VA/AI) promptly lowered blood glucose and maintained a relatively steady level over the study period, in tandem with HU. During this period, body weight gain successively increased. In SDRs, fasting blood glucose at days 0 and 28 was raised by 4.33 and 3.16 fold, respectively, and the serum glucose was raised by 7.70 fold vs. normal control (P<0.05). The discrepancies in the individual effects of VA and AI on hepatic glucose and α-amylase activity were also restored. In NDRs, VA/AI lowered blood and serum glucose (1.14 and 1.94 fold, respectively), although to a lesser extent when compared with HU. Furthermore, VA/AI was found to lower serum insulin, T3 and T4 by 1.66, 1.57 and 2.16 fold, respectively, in SDR (P<0.05). This was similar to HU, which demonstrated 1.79 and 1.68 fold reduction of insulin and T3, respectively (P<0.05), but had no effect on T4. Conversely, in NDRs, VA/AI caused 1.32, 4.93 and 1.04 fold increase in insulin, T3 and T4, respectively, reciprocal to its effect on blood and serum glucose. Oxidative stress in SDR, characterised by decreased GPx and CAT activities, was ameliorated, as the activities of the enzymes and SOD increased following a 28-day treatment with VA/AI (P<0.05). The features of diabetic pathology, indicated in the histology of the liver and pancreas, were reversed. However, the extent of recovery was partial with VA, better with AI, and distinct and total with VA/AI, compared with a null effect by HU. CONCLUSION: Taken together, our results contribute towards validation of enhanced antidiabetic efficacy of VA and AI when combined. This synergy may be exerted by oxidative stress attenuation, insulin mimetic action and ß-cell regeneration.