Item Justin Atangwho

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 β-cell regeneration.

Hypoglycemic and anti–hyperglycemic study of Gynura procumbens leaf extracts

OBJECTIVE To study the antidiabetic activity of Gynura procumbens (G. procumbens) used in the traditional management of diabetes in Southern Asia. METHODS G. procumbens leaves were extracted sequentially with graded percentage of ethanol in water (95%, 75%, 50%, 25% and 0%), and the extracts were tested for antidiabetic activity using acute (7 h), subcutaneous glucose tolerance test and sub-chronic (14 d) test in non-diabetic and streptozotocin-induced diabetic rats. The extracts were further subjected to phytochemical studies. RESULTS In acute dose (1 g/kg), the extracts significantly lowered fasting blood glucose (FBG) in streptozotocin-induced diabetic rats (P<0.05). However, the FBG-lowering effect of the 25% extract compared to the other extracts, was rapid (47% after 2 h) and the highest: 53%, 53% and 60% in the 3rd, 5th, and 7th h, respectively (P<0.05), comparable only to the effect of metformin. Furthermore, the extracts suppressed peak FBG in subcutaneous glucose tolerance test, but only the 0% and 25% extracts, and metformin sustained the decrease until the 90th min (P<0.05). Moreover, in the 14 days study, the 25% extract exerted the highest FBG-lowering effect, namely 49.38% and 65.43% on days 7 and 14, respectively (P<0.05), similar to the effect of metformin (46.26% and 65.42%). Total flavanoid and phenolic contents in the extracts were found to decrease with increase in polarity of extraction solvents. The composition of reference compounds (chlorogenic acid, rutin, astragalin and kaempferol-3-O-rutinoside) followed a similar trend. CONCLUSIONS G. procumbens contains antidiabetic principles, most extracted in 25% ethanol. Interaction among active components appears to determine the antidiabetic efficacy, achieved likely by a metformin-like mechanism.

Antioxidant versus anti-diabetic properties of leaves from Vernonia amygdalina Del. growing in Malaysia

The antioxidant and anti-diabetic properties of the sequential extracts of Vernonia amygdalina based on the chemical composition of the most effective anti-diabetic extract were studied. Using DPPH and ABTS radical scavenging as well as FRAP assays, the extracts showed a consistent dose-dependent trend of potent antioxidant activity in the following solvents: water extract>methanol extract>chloroform extract>and petroleum ether extracts. In the oral glucose tolerance test, the chloroform extract exerted the highest response (33.3%), similar to metformin (27.2%), after 2h compared to the control (50.8%, P<0.05). After a 14-day administration in diabetic rats, the chloroform extract recorded the highest blood (23.5%) and serum (21.4%) glucose-lowering effects (P<0.05). GC-MS analysis of the chloroform extract revealed high levels of linoleic acid (4.72%), α-linolenic acid (10.8%) and phytols (12.0%), as well as other compounds.

Bioassay-Guided Antidiabetic Study of Phaleria macrocarpa Fruit Extract

An earlier anti-hyperglycemic study with serial crude extracts of Phaleria macrocarpa (PM) fruit indicated methanol extract (ME) as the most effective. In the present investigation, the methanol extract was further fractionated to obtain chloroform (CF), ethyl acetate (EAF), n-butanol (NBF) and aqueous (AF) fractions, which were tested for antidiabetic activity. The NBF reduced blood glucose (p < 0.05) 15 min after administration, in an intraperitoneal glucose tolerance test (IPGTT) similar to metformin. Moreover, it lowered blood glucose in diabetic rats by 66.67% (p < 0.05), similar to metformin (51.11%), glibenclamide (66.67%) and insulin (71.43%) after a 12-day treatment, hence considered to be the most active fraction. Further fractionation of NBF yielded sub-fractions I (SFI) and II (SFII), and only SFI lowered blood glucose (p < 0.05), in IPGTT similar to glibenclamide. The ME, NBF, and SFI correspondingly lowered plasma insulin (p < 0.05) and dose-dependently inhibited glucose transport across isolated rat jejunum implying an extra-pancreatic mechanism. Phytochemical screening showed the presence of flavonoids, terpenes and tannins, in ME, NBF and SFI, and LC-MS analyses revealed 9.52%, 33.30% and 22.50% mangiferin respectively. PM fruit possesses anti-hyperglycemic effect, exerted probably through extra-pancreatic action. Magniferin, contained therein may be responsible for this reported activity.

Bioactivity-Guided Isolation of Ethyl-p-methoxycinnamate, an Anti-inflammatory Constituent, from Kaempferia galanga L. Extracts

This study evaluated the anti-inflammatory effect of Kaempferia galanga (KG) using an activity-guided approach. KG rhizomes were serially extracted with petroleum ether, chloroform, methanol and water. These extracts (2 g/kg each) were tested for their ability to inhibit carrageenan-induced rat paw edema. The chloroform extract was found to exert the highest inhibition (42.9%) compared to control (p < 0.001), hence it was further fractionated by washing serially with hexane, hexane-chloroform (1:1) and chloroform. The chloroform fraction (1 g/kg) showed the highest inhibitory effect (51.9%, p < 0.001) on carrageenan-induced edema. This chloroform fraction was further fractionated with hexane-chloroform (1:3) and chloroform, and of the two fractions, the hexane-chloroform sub-fraction was the most effective in inhibiting edema (53.7%, p < 0.001). GC-MS analysis of the active sub-fraction identified ethyl-p-methoxycinnamate (EPMC) as the major component, which was re-crystallized. EPMC dose-dependently inhibited carrageenan-induced edema with an MIC of 100 mg/kg. Moreover, in an in vitro study, EPMC non-selectively inhibited the activities of cyclooxygenases 1 and 2, with IC50 values of 1.12 µM and 0.83 µM respectively. These results validate the anti-inflammatory activity of KG which may be exerted by the inhibition of cyclooxygenases 1 and 2. EPMC isolated from this plant may be the active anti-inflammatory agent.

Hepatotoxicity following separate administration of two phosphodiesterase-5 inhibitors (sildenafil & tadalafil) and opioid (tramadol); evaluation of possible reversal following their withdrawal -

The use of phosphodiesterase-5 inhibitors (PDE5i) and tramadol in the absence of erectile and ejaculatory dysfunctions in Nigeria has become a norm. In this study, we comparatively assess the effects of chronic use of these drugs on hepatotoxicity. Fifty male albino wistar rats weighing 180–200g were randomly assigned into 5 groups (n=10) as follows; control, sildenafil (1mg/100g b.w), tadalafil (1mg/100g b.w), tramadol (2mg/100g b.w) and sildenafil+tramadol treated group (1mg/100g and 2mg/100g b.w, respectively). Drugs were orally administered, once, every two days for 8weeks, at the end of which five animals were sacrificed per group (batch 1), while the remaining five animals per group were allowed for another 8weeks without drug administration (batch 2). Serum concentration of liver enzymes (AST, ALT and ALP) and bilirubin were assessed in both batches. Serum concentrations of AST, ALT, ALP, total bilirubin and unconjugated bilirubin were significantly (p

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

Abstract 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).

Biochemical Effects of Some Traditional Nigerian Diets in Experimental Diabetic Rat Models

Diet, besides its simplicity and affordability, has been clinically recommended as the first line of intervention in type 2 diabetes. However, compliance with the so-called diabetic diet has been notoriously poor, mostly because the social and cultural aspects of eating as well as the degree of difficulty involved in entrenching permanent changes in diet have greatly been underestimated. The present study therefore evaluated the suitability of some traditional Nigerian diets namely Garri with afang soup (GAS), pounded yam with edikang ikong soup (PYES) and ekpang nkukwo (EN) in alloxan diabetic rats. 15-day feeding with GAS and PYES respectively reduced (P<0.05) fasting blood glucose by 25.61% and 25.19%, compared to the reference diet, plantain with beans (37.22%). The glucose lowering effect of EN was however, not significant. Except GAS, the effect of the test diets on serum lipid profile was similar and comparable to the reference diet. Further, the impact on serum biochemical indices - β-carotene, total protein, albumin, urea and creatinine, though not dramatic, was not different from the reference diet, except serum β-carotene that was higher in the reference diet-fed animals than others (P<0.05). Taken together, these results suggest that the studied diets, can potentially offer the patients the needed dietary diversification in diabetes management.

Haematological and immunological effect of co- administration of extracts of Vernonia amygdalina and Azadirachta indica on normal and diabetic rats

This study evaluated the effect of co-administration of extracts of Vernonia amygdalina Del. (VA) and Azadirachta indica Linn.(AI) on haemapoietic and immunological indices of normal and diabetic rats. White blood cells which were non-significantly decreased (p>0.05) in diabetic control rats relative to the normal control, respectively increased and decreased non-significantly (p>0.05) upon administration of the combined extracts of VA and AI to diabetic and non-diabetic test rats. Packed cell volume, haemoglobin content and red cell count as well as its derived factors (mean cell volume, mean cell haemoglobin and mean cell haemoglobin concentration) of both diabetic and non-diabetic rats were not affected by the treatment, relative to their respective controls. As compared to insulin treatment, the combined extracts significantly increased (p 0.05) in diabetic control rats as compared to non-diabetic control was further decreased non-significantly (p>0.05) upon administration of the combined extracts and insulin. Diabetes induction significantly increased CD 4 + count (p<0.05) as compared to the normal control. This was however decreased significantly (p<0.05) upon treatment with the combined extracts and insulin. The combined extract similarly decreased CD 4 + counts in normal test rats as compared to the normal control. Combined extracts of VA and AI is non-haematotoxic and may possess some anti-inflammatory properties when used as a management against diabetes mellitus. Key words: Diabetes, haematological and immunological indices, Vernonia amygdalina, Azadirachta indica.

Effects of Calliandra Portoricensis Extracts on the Haematological Indices of Wistar Rats Challenged With Venom of Echis Ocellatus

Effect of whole ethanolic and selective solvent extracts of C. portoricensis plant was carried out in wistar rats to ascertain their efficacy in ameliorating or attenuating the haemotoxicity of venom of carpet viper. A total of 30 wistar rats were used, divided into 6 rats per group of control, venom, venom/flavonoid-rich, venom/polyphenol-rich and venom/whole ethanolic extracts. The control was given nothing while the other groups were given 200μg venom/rat and 0.5 ml 100mg/100g body weight (b.w.) of rat as “anti-dote” concentration. This “antidote” was given intramuscularly 4-6 hours after the administration of the venom. The result obtained showed significant increase (P<0.05) in the haemoglobin concentration, red blood cell count, mean corpuscular volume, white blood cell count especially in neutrophils and marked decrease (P<0.05) in platelet parameters. These findings suggest that whole ethanolic and selective solvent extract of C. portoricensis may be effective in ameliorating and indeed reversing the haemotoxicity occasioned by carpet viper haemotoxin in wistar rats.