E.U. Eyong

Recent advances in caffeine and theobromine toxicities: a review

Caffeine and theobromine are purine alkaloids widely consumed as stimulants and snacks in coffee and cocoa based foods and most often as part of ingredients in drugs. Man has enjoyed a long history of consumption of caffeine and theobromine. Recent interest in these two alkoloids, however, is centered on their potential reproductive toxicities. Caffeine and theobromine are now known to cross the placental and blood brain barrier thus potentially inducing fetal malformation by affecting the expression of genes vital in development. The developing fetus may not have developed enzymes for detoxification of these methylxanthine alkaloids via demethylation. There is a need, therefore, to protect the conceptus against ‘insults’ from teratogens of this nature. Apart from its reproductive toxicity, the presence of caffeine and theobromine in cocoa could limit its potentials as a nourishing food. This is an issue that needs to be addressed by nutritionists and the food industry at large. This paper discusses the natural sources, consumption and uses, toxicity and the major advances in the reproductive toxicology of caffeine and theobromine. The biosynthesis of these compounds in plants, metabolism in mammalian systems and the involvement of cytochrome P450 are reviewed and summarized. Evidence in favor of the toxicity of these compounds in experimental animals is presented with emphasis on the implications of these findings in humans. The paper concludes with a call for caution in the use of caffeine and theobromine pending further and more elaborate investigations.

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.

Biochemical and Histological Effects of Eleophorbia drupifera Leaf Extract in Wistar Albino Rats

Water extract of Eleophorbia drupifera Leaves was administered orally in graded doses of 10, 20, 30 and 40 mg/kg body weight of experimental animals for 2 weeks. The effect of the extract on some biochemical parameters and the histology of the liver and kidney tissues were evaluated in Albino Wistar rats. Serum glucose levels were significantly (P < 0.05) elevated. The cholesterol, triacylglycerol and ALT levels of the test groups demonstrated no significant change, but AST showed a significant decrease (P < 0.05) at 20, 30 and 40 mg/kg body weight. Computed AST/ALT ratio showed a decrease but no histopathological lesions were observed in either liver or kidney tissue. The results suggest that no adverse biochemical changes are associated with the use of the extract in phytotherapy. The extract may contain some hepatoprotective agent(s) and antihistopathologic agents.

Influence of Nauclea latifolia Leaf Extracts on Some Hepatic Enzymes of Rats Fed on Coconut Oil and Non-Coconut Oil Meals

Abstract This work focuses primarily on the comparative response of rat liver enzymes to oral administration of the water-soluble fraction of 95% ethanol extract of Nauclea latifolia. Sm. (Rubiaceae) leaves with 10% coconut oil meal and normal rat chow fed for 8 weeks. Forty-eight mature male albino rats of the Wistar strain weighing between 200 and 230 g were divided into two experimental groups. In experiment 1, group 1 (n = 6) was fed normal rat chow for 8 weeks, and groups 2, 3, and 4 (n = 6) were on normal rat chow for 8 weeks before treatment with 170, 340, and 510 mg/kg body weight, respectively, of oral dose of the water-soluble fraction of the ethanol extract of N. latifolia. leaves. In experiment 2, group 1 (n = 6) was fed the 10% coconut oil meal as the experimental control, and groups 2, 3, and 4 (n = 6) were fed the 10% coconut oil meal for 8 weeks before commencing treatment for 2 weeks with the extract of N. latifolia. leaves. The effects of the N. latifolia. leaf extract on some marker enzymes were analyzed. There was a significant increase (p < 0.05) of aspartate aminotransferase (AST) activity in all the groups when compared to the control, but the increase was higher in the 10% coconut oil meal fed groups. Alanine aminotransferase (ALT) activity decreased significantly (p > 0.05) in experiment 1 animals when compared with control. Increase in ALT activity was however observed in experiment 2 (p < 0.05). Alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities did not change in both experiments. There was no significant (p > 0.05) change in γ-GT activity in experiment 1, but in experiment 2 glutamyl transferase (GGT) decreased in the water-soluble fraction of the ethanol extract. N. latifolia. leaf extract is capable of reducing the activity of γ-GT if raised by other factors. We also concluded that feeding animals with 10% coconut oil meal predisposes them to more adverse effects by the extract of N. latifolia. leaves.

Comparative Effect of Withdrawal from Exposure on Gasoline and Diesel Induced Nephrotoxicity in Male Albino Wistar Rats

Exposure to gasoline and diesel has been reported to induce nephrotoxicity in rats. This study was designed to assess the effect of withdrawal from exposure on the nephrotoxic effects associated with oral exposure to gasoline and diesel in male rats. Four groups of the experimental test rats were respectively exposed orally to diesel and gasoline solvents (4.0 mg/kg/day, 6 days/week) for 60 days, after which two respective groups were sacrificed for nephrotoxicity assay while the remaining two groups were withdrawn from exposure for the next 60 days before sacrificing them for biochemical assay. The results showed that oral exposure to diesel and gasoline induced a significant (p<0.05) increase in serum creatinine, urea, blood urea nitrogen (BUN) and kidney tissue malondialdehyde (MDA), as well as decrease in kidney tissue reduced glutathione (GSH) concentrations in rats. However, the percentage increase in serum creatinine, urea, BUN, kidney tissue MDA, and decrease in kidney tissue GSH concentrations recorded for rats exposed to diesel (300.1 ± 30.8, 130.3 ± 18.5, 125.6 ± 16.4, 141.8 ± 10.4 and 75.0 ± 8.6 percents, respectively) were significantly higher (p<0.05) compared to the percentages recorded for rats exposed to gasoline (150.0 ± 17.5, 80.3 ± 13.2, 72.1 ± 11.4, 120.9 ± 15.2 and 61.5 ± 10.1 percents, respectively). The result of this study also showed that withdrawal from exposure reverses the levels of serum creatinine, urea, BUN, and kidney tissue MDA and GSH to the levels approximately within the control range. This study confirms that oral exposure to diesel and gasoline may be a risk factor for nephrotoxicity, with diesel being more nephrotoxic than gasoline, and that withdrawal from exposure for equal duration of the exposure period is capable of reversing the induced nephrotoxicity in rats.

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.

Caffeine and theobromine levels in selected Nigerian beverages.

Caffeine and theobromine contents (mg/g) weredetermined in samples of selected Nigerian beverageproducts. The beverages were cocoa (Milo, Bournvita,Rosevita and Enervita), coffee (Nescafe, Bongo, and Maxwell House decaffeinated) and tea (Lipton). The theobromine contentsof samples of Milo, Bournvita, Rosevita, Enervita, Nescafe, Bongo, Maxwell Housedecaffeinated coffee and Lipton were 62.10 ± 5.21, 64.80 ± 6.72, 82.80 ± 4.43, 80.37 ± 6.80, 27.00 ± 4.31, 14.67 ± 2.90, 23.46 ± 3.13 and 12.60 ± 1.52 respectively. The corresponding caffeine contents of these samples were 2.78 ± 0.43 (Milo), 3.17 ± 0.36 (Bournvita), 0.92 ± 0.51 (Rosevita), 1.05 ± 0.68 (Enervita),93.66 ± 8.91 (Nescafe), 6.47 ± 2.42(Bongo), 37.22 ± 5.34 (Lipton), and 0.21 ± 0.11 (Maxwell House decaffeinatedcoffee). Semi-processed cocoa beverages (Rosevita and Enervita) had significantly (p < 0.05) higher levels oftheobromine compared with the finished cocoas (Milo and Bournvita). Similarly, Nescafe contained significantly (p < 0.05) higher levels of caffeinecompared to Maxwell House (decaffeinated coffee) and Bongo. Levels of caffeine in Lipton tea were moderate.

Serum and liver tissue hydrocarbons contents of male rats orally exposed to bonny light crude oil

T study aimed to investigate the potential role of Rosmarinic acid (RA) in the management of diabetes. RA is an ester of caffeic acid found in various plants which have reflected beneficial effects on different disorders. In our study design, the normal rats were treated with different doses of RA to evaluate acute toxicity. Further on the basis of acute toxicity results, two doses of RA were selected for antidiabetic study on STZ-nicotinamide induced diabetic rats. Diabetic rats were fed 50 and 100 mg/kg body weight of RA daily for 90 days and weekly measured with certain biochemical parameters, blood glucose, insulin, C-peptide, lipid profiles and body weight. At the end of the study period, all the group animals were sacrificed and the blood glucose, insulin, C-peptide, and HbA1c levels were determined in the serum of rats. In addition, histology of pancreas and the expression of glucose transporters (GLUT 1, 2 and 4) proteins were assessed in skeletal muscles and pancreatic tissues. The overall study result demonstrated that RA has potentially normalized the elevated blood glucose levels and significantly improved serum insulin, C-peptide and HbA1c levels thereby reducing cholesterol and bad lipids. Furthermore, the histology result reported recovery in the structural degeneration in the pancreatic tissues, and the western blot analysis showed the significant increase in the GLUT-2 and GLUT-4 protein expression in the skeletal and pancreatic tissues. Altogether, we may postulate that the translocation of glucose transporter proteins (GLUT-4) accelerates the insulin-mediated glucose uptake in muscle and adipose tissue. Thus, we may conclude that RA could be the potential targets for the management of diabetic complications and needs further in depth mechanistic studies at molecular level.L toxicity has been proved to be related with inducing oxidative stress of organisms, and causing inactivation of antioxidant enzymes, the mechanism of which remains unknown. This study investigated and compared superoxide dismutase (Cu/Zn SOD) activity inhibited in lead-treated zebrafish livers and explored the mechanism of SOD inactivation by lead at the molecular level using multiple spectroscopic techniques, isothermal titration calorimetric (ITC) measurement, molecular docking study and ICP-AES detection. Results showed lead exposure decreased SOD activities in zebrafish livers due to direct interactions between lead and SOD, resulting in conformational and functional changes of the enzyme. To be specific, studies at the molecular level indicated that lead bound into the active site channel of SOD, hindered the path of the catalytic substrate (O2-·), damaged its skeleton conformation and secondary structure, and interacted with the enzymatically related residue (Arg 141) through electrostatic forces (ΔH 0), and caused the release of Cu2+ and Zn2+ from the catalytic pocket of SOD. This work shows a correlation between results on organismal and molecular levels, and obtains a possible model hypothesizing mechanisms of lead toxicity using in vitro experiments instead of in vivo ones.N have received enormous attention for their potential applications in biology and medicine. A key issue in evaluating the utility of these materials is the assessment of their potential toxicity−either due to their inherent chemical composition or as a consequence of their nanoscale properties. Quantum dots are an example of a nanomaterial that has been shown to be useful as an alternative to fluorescent dyes for use in biological imaging, due to their bright fluorescence, narrow emission, broad UV excitation, and high photo stability. In addition to labeling of cellular structures in vitro, several groups have demonstrated the use of quantum dots (QDs) for fluorescence imaging in vivo. Several in vitro and in vivo studies have been cited in the literature as demonstrating the lack of evidence for QD-induced cytotoxicity. The sensitivity of the cytotoxicity assay used differs depending on the different mechanisms, which lead to cell death. The MTT assay is simple and rapid to use, which determines, the metabolic activity of the mitochondria can be determined. We aimed to evaluate the cytotoxic effects of silver sulfide quantum dots coated with 2-Mercaptopropionic acid (2MPA) and Meso-2, 3-dimercapto succinic acid (DMSA) because of the lack of studies in this area. Cytotoxicity was evaluated by the MTT assay in HeLa cells. Our results showed that Ag2S QDs were not cytotoxic effects after 24 h exposure.I has become increasingly obvious that both environmental and genetic factors may influence the development of many diseases. Genes coding for enzymes that are involved in the metabolism of foreign chemical substances have mostly been primary candidates for gene-environment interactions studies. This study investigated the influence of gene-gene and gene-environment interactions on the risk of developing asbestosis. The study comprised 262 cases with asbestosis and 265 controls with no asbestos-related disease previously studied for MnSOD, ECSOD, CAT, GSTT1, GSTM1, GSTP1, and iNOS polymorphisms. Data on cumulative asbestos exposure and smoking were available for all subjects. PCR-based methods were used to genotype MnSOD Ala –9Val, ECSOD Arg213Gly, CAT –262C>T, iNOS (CCTTT)n, GSTM1-null, GSTT1-null, GSTP1 Ile105Val and Ala114Val polymorphisms. To assess gene-gene and gene-environmental interactions, logistic regression was used. The analysis showed that the associations between MnSOD Ala–9Val polymorphism and the risk of asbestosis as well as between iNOS genotypes and asbestosis were modified by CAT –262 C>T polymorphism (p=0.038; p=0.031). A strong interaction was found between GSTM1-null polymorphism and smoking (p=0.007), iNOS (CCTTT)n polymorphism and smoking (p=0.054) as well as between iNOS (CCTTT)n polymorphism and cumulative asbestos exposure (p=0.037). The findings of this study suggest that the interactions between different genotypes, genotypes and smoking, as well as between genotypes and asbestos exposure have an important influence on the development of asbestosis and should be considered seriously in future research on occupational/ environmental asbestos-related diseases.T standard methods and guidelines prescribed by EPA for TLC and GLC procedures, the tissues of fish and frog viz. Gill, Muscle, Liver kidney, Brain and Tests (Frog only) were extracted, cleaned up and concentrated to less than one ml and are qualified and quantified. The qualified residues by their standard ‘Rf values’ and are repository at nano level. The residues are varied in different tissues of fish and also in different fish as well as in frog due to lipophillic nature. The latent residues are known to bio-accumulate via the food chain and reach human beings and the risk to the health of the people may be cautioned. The bio-concentrations will show an impact on reproductive impairment of the commercially important fishes and to higher carnivores especially to birds. The need to protect the fast declining population like frogs which are natural pest controllers from under exposure to insecticides cannot be ignored too a part from consumption of fish and frog. In disease management of aqua farming, the chemical treatment is contemplated and use of organophosphates like chloropyriphos result to reach a level either acute or chronic and the fish are subjected to more stress, avoid feeding which is detrimental for their growth. An attempt has been made to study the effect of three mixed pesiticides in ratios as 1:1:1 (Organochlorine-Endosulphate, Organophosphate-Dimetheote and a Synthetic pyrathrod cypermethrin. The results of the study revealed that prolonged exposure to sub-lethal concentration of mixture of pesticides ratios in the fish Labeo rohita leads to increased accumulation. The study also revealed that at sub-lethal concentrations of pesticide mixture lead to high residue concentrations. The uptake and persistence of endosulphan, dimetheote and cypermethrin varies according to the residues which is a prerequisite to observe any biochemical or histopathological change which are really the indices of toxicity. It is also confirmed that many of the bio chemical changes in the tissues resulting to do away from their normal functions and triggers of a cascade mechanism that reverberate.