Herbert Coker

Mutagenic screening of some commonly used medicinal plants in Nigeria

The uses of medicinal plants have always been part of human culture. The World Health Organization estimates that up to 80% of the worlds population relies on traditional medicinal system for some aspect of primary health care. However, there are few reports on the toxicological properties of most medicinal plants especially, their mutagenicity and carcinogenicity. Therefore, this research is to determine the mutagenic potentials of Morinda lucida [Oruwo (Root)], Azadirachta indica [Dongoyaro (Leaf)], Terapluera tetraptera [Aridan (Fruit)], Plumbago zeylanica [Inabiri (Root)], Xylopia aethiopica [Erunje (Fruit)], Newbouldia laevis [Akoko (Leaf)], Alstonia boonei [Ahun (Bark)], Enantia chlorantha [Awopa (Bark)], and Rauvolfia vomitoria [Asofeyeje (Root)] using the Allium cepa Linn. model and the modified Ames assay. Allium cepa model was used to determine the mean root length, mitotic index and chromosomal aberrations effects of these plants on onion bulbs using 0.1, 1, 5 and 10mg/ml concentration of the plant extracts. The modified Ames test which is a modification of the standard Ames test as described by Ames et al. [Ames, B.N., McCann, J., Yamasaki, E., 1975. Methods for detecting carcinogens and mutagens with the Salmonella/mammalian microsome mutagenicity test. Mutation Research 31, 347-364] was done using Escherichia coli (0157:H7) that has the phenotypic characteristics of glucose and lactose fermentation, motile, urease negative, indole positive and citrate negative. The results obtained from Allium cepa assay showed increasing root growth inhibition with increased concentration, decreasing mitotic index with increased concentration and chromosomal aberrations. The modified Ames test showed an alteration in the biochemical characteristics of Escherichia coli (0157:H7) for all plants except Rauvolfia vomitoria and Plumbago zeylanica. Three of the medicinal plants altered at least three of the normal biochemical characteristics thus demonstrating mutagenic potentials. The results of internationally accepted Allium cepa were comparable with the modified Ames test. However, a long term in vivo and dose dependent study should be carried out to validate these results and the findings should be communicated to drug and food regulatory body and also to the general public.

Modulatory activity of antioxidants against the toxicity of Rifampicin in vivo

The World Health Organization (WHO) has shown concern about the burden of tuberculosis in the developing countries. Even though rifampicin is an effective drug in the management of tuberculosis, it has been documented to have some toxic effects in humans. Therefore, this study intends to investigate the modulatory effect of vitamins C and E on the hepatotoxicity, sperm quality and brain toxicity of Rifampicin. Forty Wistar albino rats were used, 10 animals per group. Group 1 animals received 0.3 mL of distilled water, the Group 2 animals received the therapeutic dose of rifampicin, Group 3 animals received therapeutic doses of rifampicin plus vitamin E, while Group 4 received therapeutic doses of rifampicin and vitamin C. The administration was performed orally during three months; the animals were sacrificed by cervical dislocation at the end of that period. Blood samples were collected and liver function and lipid profile was analyzed using fully automated clinical chemistry device. The liver, brain and reproductive organs underwent histopathological examination. Sperm samples were collected from the epididymis to achieve count and motility and morphological analysis. Results showed rifampicin alone to raise (p < 0.05) liver function enzymes (Aspartate amino transferase [AST], Serum alanine amino transferase [ALT] and Total Bilirubin) when compared with controls. While the vitamin E treated group showed remarkable protection, the vitamin C treated group showed questionable protection against the rifampicin induced liver damage. Sperm count results showed an important (p < 0.05) increase in the sperm quality in vitamin E and C treated groups. However, the vitamin E plus Rifampicin treated group showed increased lipid peroxidation. The histopathological findings revealed structural damages by rifampicin in liver, brain and epididymis while some remarkable architectural integrity was observed in the antioxidant-treated groups. It can be concluded that vitamin E or C improved sperm quality and protected against the brain damage caused by rifampicin. Moreover, vitamin E demonstrated remarkable hepatoprotection against rifampicin induced damage while vitamin C shows a questionable hepatoprotection.

Occupational Hazards and Safety Measures Amongst the Paint Factory Workers in Lagos, Nigeria

Background The manufacture of paint involves a variety of processes that present with medical hazards. Safety initiatives are hence introduced to limit hazard exposures and promote workplace safety. This aim of this study is to assess the use of available control measures/initiatives in selected paint factories in Lagos West Senatorial District, Nigeria. Methods A total of 400 randomly selected paint factory workers were involved in the study. A well-structured World Health Organization standard questionnaire was designed and distributed to the workers to elicit information on awareness to occupational hazards, use of personal protective devices, and commonly experienced adverse symptoms. Urine samples were obtained from 50 workers randomly selected from these 400 participants, and the concentrations of the heavy metals (lead, cadmium, arsenic, and chromium) were determined using atomic absorption spectroscopy. Results The results show that 72.5% of the respondents are aware of the hazards associated with their jobs; 30% have had formal training on hazards and safety measures; 40% do not use personal protective devices, and 90% of the respondents reported symptoms relating to hazard exposure. There was a statistically significant (p < 0.05) increase in the mean heavy metal concentrations in the urine samples obtained from paint factory workers as compared with nonfactory workers. Conclusion The need to develop effective frameworks that will initiate the integration and ensure implementation of safety regulations in paint factories is evident. Where these exist, there is a need to promote adherence to these practice guidelines.

Traditional medicinal plants in Nigeria--remedies or risks.

ETHNO-PHARMACOLOGICAL RELEVANCE Soil pollution due to increasing industrialization is a reality that is taking its toll on mankind today. Considering the population of people that use herbal remedies especially in developing countries and the discharge of industrial waste on surrounding herbal vegetation, it is imperative to determine the heavy metals contamination in some commonly used medicinal plants. MATERIALS AND METHODS Representative samples of five medicinal plants Ageratum conyzoides, Aspilia africana, Alchornea cordifolia, Amaranthus brasiliensis and Chromolaena odorata were collected from Ikpoba-Okha L.G.A, Edo State Nigeria, around a paint company and another set of same plants were collected from a non-polluted source. Dried leaves and roots of collected plants were digested and analyzed using Atomic Absorption Spectrophotometer (AAS) for the presence of Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni) and Zinc (Zn). Soil samples from polluted and non-polluted areas were also analyzed to ascertain the levels of these heavy metals in the environment. RESULTS Results show that the concentrations of these heavy metals in the leaves and roots of plants collected from polluted soil were significantly higher than those obtained from unpolluted soil. Correspondingly heavy metal concentrations were significantly higher in polluted than in unpolluted soil samples. CONCLUSION As part of continuing effort in the standardization of traditional remedies, environmental contamination control and abatement is evident. The source of medicinal plants/herbs should also be a cause for concern since the toxicity of medicinal plants is sometimes associated with environmental sources of the plants.

Effect of Vitamin D supplementation on glycemic control in Type 2 diabetes subjects in Lagos, Nigeria

Introduction: Improvement of glycemic control reduces the risk of diabetic complications. Reports suggest that Vitamin D supplementation improves glycemia. However, there are no data on the influence of Vitamin D on diabetes mellitus (DM) in Nigeria. Objective: To determine the effect of Vitamin D supplementation on glycemic control in Type 2 DM (T2DM) participants with Vitamin D deficiency. Design: This was a single-blind, prospective randomized placebo-controlled trial, involving T2DM participants attending the Diabetes Clinic of the Lagos University Teaching Hospital. Forty-two T2DM participants with poor glycemic control and Vitamin D deficiency were selected following a prior cross-sectional study on 114 T2DM participants for the determination of Vitamin D status and glycemia. These participants were randomized into two equal groups of treatment and placebo arms. Intervention: Three thousand IU of Vitamin D3 were given to the participants in the treatment arm. Glycemic status was determined at baseline and after 12 weeks. Statistical analysis was performed using Statistical Package for Social Sciences version 20. P < 0.05 was considered statistically significant. Results: Vitamin D3 supplementation resulted in a significant improvement in serum Vitamin D level and fasting plasma glucose in the treatment arm compared to placebo. There was a nonsignificant reduction in the mean HbA1c level in the treatment group after 12 weeks of Vitamin D3 supplementation (Z = −1.139; P = 0.127) compared to the placebo group, which had a further increase in the mean HbA1c level (Z = −1.424; P = 0.08). The proportion of participants with poor glycemic control (HbA1c > 6.5%) who converted to good control after Vitamin D supplementation was significantly higher in the treatment arm compared to placebo (P < 0.05). Conclusion: Vitamin D3 supplementation in persons with T2DM and Vitamin D deficiency results in a significant improvement in glycemic control.

Assessment of the PAHs contamination threat on groundwater: a case study of the Niger Delta region of Nigeria

Contamination of the environment by polynuclear aromatic hydrocarbon (PAHs) is becoming a rising environmental concern. The interest this subject attracts has continually increased by the day because of the threat these compounds pose to human health. Water samples from several hand-dug wells in the Niger Delta region of Nigeria where extensive crude oil production activities take place were analysed for the presence of 16 US EPA priority PAHs and their consequent health implication on the population extrapolated. The analyses were done using a gas chromatograph coupled to an ion trap mass spectrometer. Individual PAHs were identified through both retention time match with authentic standards and simultaneous maximisation of several ions from GC/MS data. The quantitation was done by means of internal standardisation using four isotopically labelled internal standards namely acenaphthene-d10, chrysene-d12, phenanthrene-d10 and perylene-d12. The sums of the 16 PAHs in the samples vary depending on the proximity of the sample source to crude oil production facility. The concentrations ranged from 1.92 μg/L to 40.47 μg/L. High molecular mass PAHs such as benzo(ghi)perylene, dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene were mostly absent confirming low water solubility of these compounds. These concentrations were above the WHO recommended maximum for safe drinking water.

The anticoagulant activity of some selected warfarin analogues

The anticoagulant activities of 6‐, 7‐, 8‐, 4′‐hydroxy, 6‐chloro‐ and 6‐bromowarfarin were determined in rabbits after intraperitoneal administration of 16.2 μmol kg−1 over 96 h. Substitution on the 4‐hydroxycoumarin moiety resulted in reduction of the anticoagulant activity. 6‐Chlorowarfarin was more potent than 6‐bromowarfarin suggesting that the molecular size of 4‐hydroxycoumarin moiety may be crucial for biological activity.

Evaluation of Antioxidant Potential of Melanthera scandens

A methanol extract of dried leaves of Melanthera scandens was examined for antioxidant activities using a variety of assays, including 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power, ferrous chelating, and ferric thiocyanate methods with ascorbic acid and EDTA as positive controls. The extract showed noticeable activities in most of these in vitro tests. The amount of phenolic compounds in the extract expressed in gallic acid equivalent was found to be 52.8 mg/g. The extract demonstrated inhibition of linoleic acid lipid peroxidation, active reducing power, and DPPH radical scavenging activities which were less than that of the positive controls. The extract also showed weaker iron chelating effect when compared with the EDTA positive control. The present results showed that M. scandens leaf extract possessed antioxidant properties and this plant is a potential useful source of natural antioxidants.

Antinociceptive and Antioxidant Activities of Methanol Extract and Fractions of the Root Bark of Callichilia stenopetala Stapf. (Family Apocynaceae) In Mice

Plants are important part of the culture of any group of people. Natural medicinal products have been sourced from these plants over centuries to combat health challenges because of their effectiveness. Today, these plants have greater value globally as they play important role at various level of healthcare system because of their therapeutic properties. High percentage (25 %) of conventional drugs on the shelves in the pharmacies have their origin from medicinal plant. The current reinsurgence of interest in ethnomedicinal use of medicinal plants particularly the ones locally available and with long history in the management of diverse ailments has been argued to be as result of treatment failures associated with some orthodox drugs. 5 Some of the wide range of ideal properties promoted for medicinal plant products include high target effectiveness, low cellular toxicity, low cost, easy biodegradability, abundant growth in endemic areas. 7 Pain is a major clinical symptom that serves as warning signal to patients of abnormality in the body system. It serve as unpleasant body response to tissue injury that could affect both the physical and emotional wellbeing. 10 The mechanism of pain initiation involves activating sensorial neurons that transmit nociceptive stimulus at spinal and supra-spinal levels.

Metabolic N-oxidation of metronidazole

Metronidazole when treated at the N‐3 nitrogen with a mixture of hydrogen peroxide and acetic acid, or liver homogenate preparations, yields the N‐3 oxide as identified by thin‐layer chromatographic analysis on silica gel G, RF 0ṁ62 in ethanol‐chloroform‐ammonia (50:49:1), by chemical reduction with sulphur dioxide, and by ultra‐violet spectrophotometry and nuclear magnetic resonance spectroscopy. Incubation of metronidazole at 37°C with rat liver 10 000g supernatant fortified with cofactors gave a product with identical chromatographic and UV spectral data suggesting that metronidazole like other tertiary amine drugs undergoes microsomal N‐oxidation.