Herbert A B Coker

University of Lagos | Unilag · Department of Pharmaceutical Chemistry

Background and objectives Psydrax is a genus of flowering plants in the family Rubiaceae with over 80 accepted plant species. Psydrax subcordata is a small tree or shrub that grows in Central and Western Africa countries where its roots, leaves and stem are used locally by traditional healers for medicinal purposes. These local uses include the tre...

Fruits are important worldwide due to their nutritional, commercial, and nutraceutical values. Doubtless, the increased demand for fruits is instrumental in the use of various artificial ripening methods in their production. The most frequently applied chemical for this purpose is calcium carbide (CaC2). However, due to its toxicity, the use of cal...

Oxidative stress has been implicated in thepathogenesis of many diseases, while multiple drug resistance constitutes a major problem in management of infectious diseases. These stressrequires continuous investigations for development of novel antioxidant and antimicrobial agents. Here, phytochemical constituents, antioxidant, and antimicrobialactiv...

Background: Malaria remains a devastating disease, particularly in the tropics, where it is the highest killer of pregnant women and children under the age of 5 years. Significant efforts and resources have been vested in malaria control and eradication programmes, but the unavailability of malaria vaccine and the emergence of resistance of malaria...

Propolis is an attractive natural ingredient to design health products due to its pharmacological effects. Our chemical investigation of a polar extract of Nigerian propolis (NP) led the isolation and identification of five isoflavonoids (1-4, 6), one diarylpropane (5) and one prenylated flavanone (7) by the combination of chromatographic and spect...

Molecular interaction between ciprofloxacin (CPX), a poorly soluble second generation fluoroquinolone antibiotic and a bacteriostatic polymer, chitosan (CT) has been amplified to enhance saturated solubility of CPX, enabling its penetration into the bacterial cell at higher concentrations to produce extended synergistic antimicrobial potency. This...

Purpose: The purpose of this study is to enhance the oral solubility and potency of the free base ciprofloxacin (CPX) using a single step CPX-chitosan (CT) self-assembly to form nanoplexes with organic counterions. It was envisioned that this would allow the delivery of larger amounts of active drug into the microorganisms. Ciprofloxacin free base...

Phytochemical investigation of the leaves and bark of Psydrax subcordata has led to the isolation of six new iridoids, subcordatanols I-V (1-4 and 6) and 1-O-methylcrescentin I (5), along with two known analogues (7 and 8). Among them, subcordatanol I (1) is the first example of a 3,8-monoepoxy-iridoid featuring a caged 2-oxa-bicyclo[3.2.1]octane c...

Ethnopharmacological relevance: Coccinia barteri (Hook. F.) is traditional used in Southeast of Nigeria in management of fever. This study aimed to evaluate the antimalarial activities of hydro-methanol crude extract and solvent fractions of Coccinia barteri leaf. Materials and methods: Two animal models employed for the study were, 4-day suppre...

The search for novel, safe and effective anticancer agents has been a continuous and recurring objective in cancer research. Olax subscorpioidea is a medicinal plant used for ethnomedicinal treatment of cancer in Nigeria. In this study, we investigated the cytotoxic, anti-mitotic and cytogenetic effects of methanol extracts of the leaves and stems...

Herbs constitute a common medicinal alternative for disease treatment in many cultures around the world. In Nigeria, these medicinal herbs are widely used in the treatment and prevention of various ailments including malaria, a global disease endemic to the tropics. In spite of their cultural trust and claimed medicinal properties, lack of standard...

The discovery and development of the statins provides an insight into the many facets of the drug discovery process and also shows the time and resources that must be devoted to developing a clinically useful drug from an initial concept. It began from the conceptual search for metabolites that could inhibit an important enzyme in cholesterol biosy...

Background: Malaria is a leading cause of death in Nigeria. Aim: Antimalarial activity of Stemonocoleus micranthus stem bark was evaluated in mice with an objective to finding scientific evidence for its use as antimalarial remedy in South-east Nigeria. Methods: Antiplasmodial activities of hydro-methanolic extract and solvent fractions (hexan...

Methanolic extracts from 4 medicinal plants representing 4 families, used traditionally for malaria treatment in South east Nigeria were screened for their in vivo antimalarial activity in mice against a chloroquine (CQ)-sensitive Plasmodium berghei NK65, alone and in combination as polyherbal remedy. The methanolic extracts of individual plants in...

The plant,Hydrolea glabra, is used in neurodegenerative disorders associated with dementia, where personality changes present as symptoms such as anxiety, depression and sleep changes. This notwithstanding, no pharmacological studies have been carried out on the anxiolytic and sedative properties of the plant. This research evaluated the anxiolytic...

Received: 19 th December 2017 Pharmaceuticals are medicinal products used in the prevention, treatment, and diagnosis of diseases. As such, the presence of microorganisms' especially fungal toxins can reduce or eliminate the product's therapeutic activity and constitute a potential danger to patient health. This study attempts to determine the fung...

Phytochemical constituents of plants extracts have been well investigated as leads for drug discovery and development. However, aside their immense medicinal properties, their safety is also of paramount importance, therefore evaluating the toxicity of plants extracts and their phytochemicals is an important aspect of quality measures to meet the r...

Propolis has been used as medicinal agent for centuries. Among the many compounds identified in propolis, flavonoids are considered to be responsible for its main biological activities. Therefore, determination of flavonoids in propolis is a key parameter for evaluation of propolis quality. To continue our research on chemical composition of propol...

Background: Gastric ulcer haemorrhage and implication of Helicobacter pylori to stomach and gastric cancer are major health concern in the 21st Century. Objectives: The aim of this study was is to investigate the cyto-protective, healing and anti H. pylori activities of extract and fractions of Nauclea latifolia. Methods: Hydromethanolic stem-bark...

Introduction: Borreria ocymoides (Burm F) DC is a weak, erect and decumbent herb that has several folkloric, ethno medicinal uses and is included in antimalarial preparations by some traditional healers. It is also used in treatment of ring worm, eczema and microbial infections. Objectives: To evaluate antimalarial activity of extract and fractions...

Malaria is one of the leading causes of morbidity and mortality in Southeast part of Nigeria. One approach towards control and eradication of this disease is acquiring and conservation of medicinal plant knowledge that helped the past generations survive before emergency of orthodox medicine. To identify and document medicinal plants used as single...

Purpose: To investigate and compare the physicochemical properties and lubricant potentials of Blighia sapida seed oil (BSSO) with those of magnesium stearate, a commercial lubricant. Methods: The dried seeds of Blighia sapida (BS) powder were macerated with n-hexane for five days to separate the oil. The physicochemical properties; solubility prof...

The root of Hippocratea africana (Celastraceae) is used in ethnomedicine in South-Western Nigeria to treat infectious and parasitic diseases. This study aimed at identifying the compound(s) that are responsible for the antimicrobial activities of the roots and also to contribute to the chemistry of the plant species. Investigation of the phytochemi...

Background: Studies have reported a relationship between Vitamin D deficiency and type 2 diabetes mellitus (T2DM). There is no information on the Vitamin D status or relationship between Vitamin D and glycaemia in Nigerian patients with T2DM. The objective of this study was to determine the relationship between serum Vitamin D levels and glycaemic...

Background: Type 2 DM is a disease caused by both insulin resistance and an insulin secretory defect. Reports suggest that vitamin D supplementation improves insulin resistance and pancreatic beta-cell function, however, there is paucity of data on vitamin D and glycaemia among type 2 diabetes mellitus in Nigeria. Objective: To determine the effect...

Background: Petersianthus macrocarpus (Lecythidaceae) is widely used in the folk medicine in Nigeria to relieve pain and fever associated with malaria. This study evaluated the analgesic and antioxidant activities of the methanol extract and fractions of the stem bark of the plant. Materials and Methods: The analgesic activity was determined in mic...

Medicinal plants are well-known natural sources of remedies used in the treatment of innumerable diseases since antiquity. The search for newer synthetic drugs is of immense importance due to the increasing development of resistance. Antioxidant assay is a very useful technique in identifying plants which contain antioxidants which are substances t...

Plants in their natural habitats have been of tremendous value containing innumerable phytocompounds with immense chemical compositions and medicinal importance. The words “wild edible plants” represent those plants; fruits, seeds, leaves, roots in their natural habitats that grow without being cultivated and are fit for consumption. They have been...

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...

Four new prenylated anthranols, harunganols C-F (1-4), along with kenganthranol A (5), harunganin (6), and ferruginin A (7), were identified from the leaves of Harungana madagascariensis. The structures of compounds 2, 5, and 7 were confirmed by single-crystal X-ray diffraction analysis. Compound 1 is a unique symmetrical anthranol dimer connected...

Four new prenylated anthranols (1 – 4), along with two known structures kenganthranol (5) and harunganin (6), were identified from the leaves of the African medicinal plant Harungana magdagascariensis. All anthranols were evaluated for cytotoxic activity against MDA-MB-435, MDA-MB-231, and OVCAR3 cell lines. 6 showed activities with IC50 values of...

Callichilia stenopetala is a medicinal plant and its root is used as chewing stick in the treatment of toothache and fever in south-east of Nigeria. The methanolic extract of its root bark and fractions obtained after successive liquid-liquid partitioning (hexane, chloroform, ethyl acetate and methanol fractions) of the crude extract were investiga...

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, Ni...

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 m...

Diabetes mellitus is caused by the abnormality of carbohydrates metabolism which is linked to low blood insulin level or insensitivity of target organ to insulin. The digestion of starch by α-glucosidases contributes to sharp increase in blood glucose resulting in postprandial hyperglycemia which has been implicated in the development of type 2 dia...

Erratum for Planta Medica 10/2013: The name of the second author of the congress-abstract “Anti-Helicobacter Pylori Activities of Nigerian Propolis (Bee Product)” (Planta Medica 2013; 79 (10):809–896) was changed to L. Rastrelli.

Adverse effects attributed to exposure to paints are currently a concern because of the continued widespread use of paint containing trace elements. Thus, occupational survey amongst painters in Lagos and determination of trace elements and oxidative stress parameters were carried out. Descriptive cross-sectional survey was done using a standardize...

AQ‐induced oxidative stress leads to increased atresia which in turn leads to reduced follicle numbers, and reduced oocyte numbers at ovulation. This research study the effect of the co‐administration of amodiaquine hydrochloride (AQ.HCl) with Vitamin C on oestrous cycle, ovulation, oxidative stress markers and the histomorphology of the ovary of m...

It has been shown that heavy metals toxicity to humans is as a result of long term or high level exposure to pollutants common in the environment including the air, water, food and numerous consumer products such as the cosmetics and toiletries. In this study, we assessed the levels of toxic metals in different cosmetic products sold at local shops...

Use of pesticides in agriculture to protect crops against destructive pests often leads to residues of these chemicals in foods. The levels of pesticide residues in food are often determined as a means of assessing appropriate use as well as the potential for human exposure to these chemicals and hence their potential damage to human health. The ai...

Anthocleista vogelii Planch (Loganiaceae) is a medicinal plant used widely in Nigeria for management of malaria and other ailments. The aim of this present study was to investigate the anti-plasmodial activities of the leaf extract against residual infection in chloroquine sensitive Plasmodium berghei infected mice. Phytochemical analysis and oral...

This study determined whether exogenous supplementation with Vitamin E could confer ameliorative effect against the deleterious effect of AQ.HCl on ovarian function of matured S-D rats. Thirty S-D rats divided into two groups were used in this study: Group A – determined the effect of AQ.HCl 1 Vitamin E administered for 28 days on the oestrous cycl...

The use of herbal remedies in Nigeria is as old as the existence of Nigerians. The approval of these herbal remedies by regulatory bodies has further encouraged the use of herbal remedies. The safety of these herbal remedies is however poorly understood. In this research we determined the concentration of arsenic, cadmium, lead and mercury in twent...

Ficus congensis (Moraceae) is used traditionally in the treatment of various diseases including infectious diseases, infertility, and gastrointestinal disorders. Investigation of hexane extract of the stem bark using chromatographic techniques led to isolation of a xanthone, 1-hydroxy-3,7,8-trimethoxyxanthone (Decussatin). The compound was elucidat...

Chemical investigations into samples of Hunteria umbellata (K. Schum) collected in Osun State, Nigeria, led to the discovery of a new indole alkaloid, ikirydinium A, featuring an unprecedented 3-alkylpyridinium-indole-2-carboxylate scaffold. Ikirydinium A was found to exhibit antimicrobial activity (IC500.6μM) against Bacillus subtilis ATCC 6051. T...

Pesticides are used widely in agriculture to control destructive pests and hence increase food supply. Their use inadvertently leads to residues in food crops and the environment. Pesticides, by nature are poisonous and exposure of humans to their residues may cause health hazards which include neurotoxicity and carcinogenicity among others. Evalua...

Chemical fingerprinting is an aspect of environmental forensic investigation which involves chemical analysis of contaminants and associated chemicals to provide source specific information. Polynuclear Aromatic Hydrocarbons (PAHs) in the environment have 3 categories of sources namely petrogenic, pyrogenic and biogenic sources. Petrogenic PAHs are...

The concentrations of some heavy metals in the effluents of nine pharmaceutical companies operating in Lagos, Nigeria were determined using atomic absorption spectrophotometer. The heavy metals analyzed in this study included Cadmium, Chromium, Lead, Nickel, Zinc and Copper. Most of the samples were found to contain the metals in varying concentrat...

This study was aimed at evaluating the claimed anti-diabetic property of the aqueous extract of Graptophyllum pictum leaf and to establish an effective dose for the extract. It also attempted to unravel if the extract could be acutely toxic to mice. The anti-diabetic study was carried out on alloxan-induced diabetic Wistar rats. After diabetic indu...

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays....

Quinolones have a broad spectrum of activity against bacteria and are a class of synthetic antimicrobial modeled after nalidixic acid. To determine the dissolution efficiencies of ciprofloxacin and sparfloxacin in 0.1NHCL, deionized water, 0.1 M acetic acid and pH 7.4 phosphate buffer. The in-vitro dissolution profiles of ciprofloxacin (250 mg and...

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...

The stem bark extract of S. ellipticum (Hochst) Pax was investigated for its antioxidant properties in this study. The extract was evaluated for antioxidant activity in vitro in terms of its ability to inhibit lipid peroxidation and its free radical scavenging reducing, metal chelation powers [1,2,3]. The total amount phenolic compounds in the extr...

In various studies globally, the prevalence of anemia in persons with HIV infection range from 10 to 20% at initial presentation, and anemia is diagnosed in 70 to 80% of these patients over the course of HIV disease. The etiology of anemia in this group of patients has not been fully established, thus a need to evaluate the role of plasma folate as...

Isolation of the bioactive phytoconstituents of the leaves of Persea americana (Lauraceae), yielded, isorhamnetin (1), luteolin (2), rutin (3), quercetin (4) and apigenin (5). Compound 1 has been fully characterized. Compounds were evaluated for their ability to scavenge free radical using DPPH  and H 2 O 2 systems. The IC 50 (mg/ml) of quercetin...