Aminu Mohammed

Anti-trypanosomal activity of African medicinal plants: A review update

ETHNOPHARMACOLOGICAL RELEVANCE African trypanosomiasis is one of the neglected tropical diseases caused by different species of trypanosomes that affect both human and livestock with devastating consequences in the continent. Most of the affected populations commonly use traditional medicinal plants for the treatment of the disease. Consequently, this prompted ethnopharmacological research activities on the anti-trypanosomal activity of a number of these African medicinal plants in order to validate their ethnomedicinal use. Furthermore, such studies could lead to the identification of chemical leads for the development of newer anti-trypanosomal agents from those plants. This review aims to provide updated information on the ethnopharmacological evidence of African medicinal plants with anti-trypanosomal activity. METHODS Literature was collected via electronic search (PubMed, Sciencedirect, Medline and Google Scholar) from published articles that report on the in vitro or in vivo anti-trypanosomal activity of plants that were collected from different parts of Africa. RESULTS African medicinal plants investigated for in vitro and in vivo anti-trypanosomal activity from January 1993 to October 2013 are systematically compiled and all the in vivo studies are critically discussed. A total of 264 plant species belonging to 79 families were investigated for anti-trypanosomal activity. However, only 48 bioactive anti-trypanosomal compounds were successfully isolated in pure forms. Furthermore, some of the plants were investigated for possible ameliorative effects on the trypanosome-induced pathological changes out of which 18 plants were reported to be effective while a few others were not. In spite of interesting preclinical ethnopharmacological evidence for anti-trypanosomal activity, not a single African medicinal plant was investigated in a clinical study. CONCLUSION Several African medicinal plants have demonstrated promising anti-trypanosomal effects but the studies on the anti-trypanosomal potentials of these plants are not taken beyond proof of concept stage. It is hoped that the article would stimulate future clinical studies because of the paucity of knowledge in this area.

Ethnomedical Treatment of Poisonous Snakebites: Plant Extract Neutralized Naja nigricollis Venom

Abstract The neutralizing effects of methanol extracts of Indigofera pulchra. Willd (Papilionaceae), Aristolochia albida. Duch (Aristolochiaceae), Guiera senegalense. J.F.Gmel (Combretaceae), and Sterculia setigera. K. Schum (Sterculiaceae) were investigated to validate traditional claims of usefulness of the plants in management of poisonous snakebites. Extracts of Indigofera pulchra. and Aristolochia albida. gave 33.3% and 44.4% protection to mice treated with minimum lethal dose of venom; some gross pathologic symptoms of envenomation were alleviated. However, minimal activities were shown by Guiera senegalense. and Sterculia setigera.. Both Indigofera pulchra. and Aristolochia albida. were found to neutralize the anticoagulant, hemolytic, and phospholipase activity of crude venom. This study showed that Indigofera pulchra. and Aristolochia albida. are useful in some pathologic effects of Naja nigricollis. Broadley (Elapidae) venom, and this provides some scientific basis for the use of the plants in management of poisonous snakebites.

A systematic review of pentacyclic triterpenes and their derivatives as chemotherapeutic agents against tropical parasitic diseases.

Parasitic infections are among the leading global public health problems with very high economic and mortality burdens. Unfortunately, the available treatment drugs are beset with side effects and continuous parasite drug resistance is being reported. However, new findings reveal more promising compounds especially of plant origin. Among the promising leads are the pentacyclic triterpenes (PTs) made up of the oleanane, ursane, taraxastane, lupane and hopane types. This paper reviews the literature published from 1985 to date on the in vitro and in vivo anti-parasitic potency of this class of phytochemicals. Of the 191 natural and synthetic PT reported, 85 have shown high anti-parasitic activity against various species belonging to the genera of Plasmodium, Leishmania, Trypanosoma, as well as various genera of Nematoda. Moreover, structural modification especially at carbon 3 (C3) and C27 of the parent backbone of PT has led to improved anti-parasitic activity in some cases and loss of activity in others. The potential of this group of compounds as future alternatives in the treatment of parasitic diseases is discussed. It is hoped that the information presented herein will contribute to the full exploration of this promising group of compounds as possible drugs for parasitic diseases.

Inhibition of key enzymes linked to type 2 diabetes by compounds isolated from Aframomum melegueta fruit

Abstract Context: The use of Aframomum melegueta K. Schum. (Zingiberaceae) fruit for treatment of diabetes has recently been established in Nigeria. However, compounds responsible for the antidiabetic action have not been identified. Objective: The present study carried out the bioassay-guided isolation of possible bioactive compounds responsible for the antidiabetic action of A. melegueta fruit. Materials and methods: The A. melegueta fruit was sequentially extracted using ethyl acetate (EtOAc), ethanol and water, and the most active extract (EtOAc) was subjected to column chromatography on a silica gel column using solvent gradient systems of hexane (HEX):EtOAc and EtOAc:MeOH and the isolation of compounds was guided by α-glycosidase and α-amylase inhibitory activities at various concentrations (30–240 μg/mL). Results: According to the results, 3 arylalkanes, 6-paradol (1), 6-shogaol (2) and 6-gingerol (3) and a pentacyclic triterpene, oleanolic acid (4) were isolated from A. melegueta fruit. All the compounds exhibited inhibitory effects against α-amylase and α-glucosidase. 6-Gingerol (3) and oleanolic acid (4) showed higher inhibitory activity against α-amylase (IC50: 6-gingerol: 81.78 ± 7.79 μM; oleanolic acid: 91.72 ± 1.63 μM) and α-glucosidase (IC50: 6-gingerol: 21.55 ± 0.45 μM; oleanolic acid: 17.35 ± 0.88 μM) compared to the standard drug, acarbose and other isolated compounds. The kinetics of the enzyme action of the compounds showed a noncompetitive mode of inhibition. Conclusion: The data of this study suggest that the 6-gingerol (3) and oleanolic acid (4) showed higher α-amylase and α-glucosidase inhibitory action and therefore could be responsible for the antidiabetic activity of A. melegueta fruit.

Effects of aqueous extracts of Acacia albida stem bark on Wistar albino rats infected with Trypanosoma evansi.

The effect of aqueous extract of Acacia albida stem bark was investigated in Wistar albino rats infected with Trypanosoma evansi. The extract showed highest reduction in parasitemia at the dose of 600 mg/kg body weight (bw). A dose of 300 mg/kg bw improved packed cell volume the most by 14.35%. The group treated with 150 and 600 mg/kg bw of the extract showed significant decrease (P < 0.05) in alanine transaminase and aspartate transaminase levels which were lower than those of the group treated with diminazene aceturate. The group treated with 150 mg/kg bw of the extract showed the least urea, albumin and protein level and lowest relative organ weight. There was a significant difference (P < 0.05) in the levels of catalase and Thiobarbituric acid reactive substances in liver and kidney of the animals in the infected-untreated group and the extracts-treated groups. The results of this study show that the extracts of A. albida have antitrypanosomal activity against T. evansi infection.

Terpenoids as Emerging Therapeutic Agents: Cellular Targets and Mechanisms of Action against Protozoan Parasites

Abstract Terpenoids are the largest and structurally most diverse group of secondary metabolites derived from natural sources. Empirical evidence from several bioassays points to the therapeutic potentials of terpenoids against protozoan parasitic diseases such as malaria, trypanosomiasis, and leishmaniasis. The versatility of the parent terpenoid backbones allows for structural diversity among the group, which in turn leads to multiple cellular targets and consequently varying mechanisms of antiparasitic action. Available data implicate disruption of parasite cell membrane architecture, interference with mitochondrial respiration, interaction with various crucial proteins of the parasites among other probable mechanisms. Identification of the specific cellular targets vis-a-vis the mechanisms of action of the different terpenoids will aid the design of novel and safer antiparasitic agent(s). This chapter therefore aims to discuss parasites-related cellular targets of terpenoids and their mode of antiparasitic activity. We hope that the chapter will be a valuable source of useful information in the exploration of the full potential of terpenoids as antiparasitic agents.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Hydrogen bond interaction with trypanosomal adenosine kinase; ornithine decarboxylase and triose phosphate isomerase could not be involved in the antitrypanosomal activity of stigmasterol: An in silico study

Statement of the Problem: The exponential rise in next-generation sequencing data is presenting considerable challenges in terms of variant interpretation. Though deep sequencing is unearthing large numbers of rare single nucleotide variants (SNVs), the rarity of these variants makes it difficult to evaluate their potential deleteriousness with conventional phenotypegenotype associations. Furthermore, many disease-associated SNVs act through mechanisms that remain poorly understood. 3D protein structures may provide valuable substrates for addressing these challenges. We present two general frameworks for doing so. In our first approach, we use localized frustration, which quantifies unfavorable residue interactions, as a metric to investigate the local effects of SNVs. In contrast to this metric, previous efforts have quantified the global impacts of SNVs on protein stability, despite the fact that local effects may impact functionality without disrupting global stability (e.g. in relation to catalysis or allostery). In our second approach, we employ models of conformational change to identify key allosteric residues by predicting essential surface pockets and information-flow bottlenecks (a new software tool that enables this analysis is also described). Importantly, although these two frameworks are fundamentally structural in nature, they are computationally efficient, thereby making analyses on large datasets accessible. We detail how these database-scale analyses shed light on signatures of conservation, as well as known disease-associated variants, including those involved in cancer.

Histopathological pattern of thyroid lesions in Kano: a ten year retrospective study (2002–2011)

Objective: To describe the histopathological pattern of 522 thyroidectomy specimens received at the Pathology department of Aminu Kano Teaching Hospital, Kano, Nigeria, analyse the sex and age variations and compare with findings from previous studies done in Nigeria and elsewhere. Materials and methods: We reviewed slides from paraffin embedded blocks of all thyroidectomy specimens to confirm type of lesion and extracted data such as age and sex from the request forms. Results: The female (86.4%) to male (13.6%) ratio is 6.4:1. The ages ranged from 5 months to 86 years with a mean age of 36.3 years and the relative peak age incidence was seen in the 30–39 years age group. The most common entity was multinodular goitre (57.2%) with a mean age at presentation of 37.5 years. It was followed by thyroid adenomas (15.7%) and thyroid carcinomas (12.6%). Histologically, papillary carcinoma predominated (53%), followed by follicular carcinoma (33.3%) and medullary carcinoma (9.1%). Thyroglossal duct cysts and toxic hyperplasia accounted for 6.9% and 5.4% respectively while thyroiditis was uncommon with only 2 cases (0.4%). Conclusion: Goitre is the most common thyroid lesion in Kano while papillary carcinoma is the most common thyroid cancer, a finding at variance with most reports from Nigeria.