Mini-review on the phyto-chemistry, pharmacology and toxicology of Cola nitida (Vent.) Schott & Endl. (Malvaceae): A medically interesting bio-resource of multiple purposes in Africa

The purpose of this mini-review was to summarize and update knowledge on the phytochemistry, pharmacology, and toxicity of <i>Cola nitida</i>, with the view of providing baseline data for herbal drug formulation. In January 2021, a non-exhaustive online search of relevant articles was carried out on the phytochemistry, pharmacology, and toxicology of <i>C. nitida</i> from scientifically well-established databases such as Science Direct, PubMed, Web of Science, Scopus, Google Scholar, and SciELO. The plant's scientific name as well as phytochemistry, pharmacology, pharmacognosy, bioactivity and toxicology were used as keywords. The chemical structures of the compounds isolated from this plant were drawn using ChemBioDraw Ultra 12.0 software. A literature survey has revealed that <i>C. nitida</i> is highly appreciated by African populations in various cultures, especially in West Africa. Phytochemical analyses showed that <i>C. nitida</i> contains interesting compounds like catechin, caffeine, epicatechin, polyphenols, alkaloids, tannins, saponins, bromelain, cardenolides, proanthocyanidins, triterpenes, glycosides, flavonoids, anthraquinones, steroids, anthocyanins, glycosides, alkaloids, etc. The presence of these phyto-compounds in the investigated plant species justifies its used as an antimicrobial, anti-malarial, anti-inflammatory, anti-diabetic, anti-coagulant agent. Thus, <i>C. nitida</i> could be used as a raw material for manufacturing efficient medication against various diseases, including sickle cell disease.

Kola as an Indispensable Article of Trade in West Africa

This study examines the origin of kola-nuts trade and the indispensability of kola-nut trade in West Africa. Desk research was carried out using past published literature. The study established the fact that kola nut production was indigenous to the West Africa Forest and pinpointed the actual origin of kola-nut especially Cola nitida to be along the western coast of Africa from Sierra Leone to the republic of Benin. On the other hand, the areas of Ijare and Idanre in Ondo State of Nigeria are currently believed to be the places where Cola acumunata originated. The dominant variety of kola-nut grown in Western and Eastern parts of Nigeria was cola acumunata and Cola verticillata. However, in terms of production, before the 19th century the production of cola nitida was limited to the forests west of the Volta River in Ghana. Both linguistic and ethnographic data were used to trace the origin of kola-nut and developed a chronology with regard to the origins and trade routes for kola-nuts. The research work however established the importance of kola-nut production and trade to the economies of West Africa countries where they are produced and traded. It was however recommended that considering the indispensability of kola-nut trade to West Africa particularly Nigeria, the government should take proactive steps to increase the scope of production and trade of this crop in order to improve the livelihoods of kola-nuts farmers and traders as well as increase it contributions to the national economy.

Evaluation of Antioxidant Activity of Caffeine Extracted From Kolanut (Cola Nitida)

Crude caffeine was isolated from kola nut, by treating the filtrate obtained from powdered kola nut with lead (II) acetate to precipitate acids and albumins, along with HCl to precipitate lead ions, and to make some insoluble tannins to be soluble, then Na2CO3 solution was added to neutralise the acidic HCl solution. Dichloromethane is added to the filtrate to extract the caffeine from the aqueous layer and then distilled to obtain the crude caffeine. The extracted crude caffeine is recrystallized with activated charcoal and tested for its antioxidant capacity, using the DPPH assay, which screens the antioxidant activity of plant extracts. The DPPH (2, 2-diphenyl-1-picrylhydrazyl) in methanol helps to facilitate the extraction of the antioxidant compounds from the sample. Ascorbic acid (Vitamin C) is used as the standard for this assay, due to its appreciable antioxidant activity. The IC50 value was calculated from the graph of % inhibition against concentration, and the extracted caffeine from kola nut was found out to have a high antioxidant activity comparable to that of the standard, ascorbic acid.

Formulation and In Vitro Evaluation of Oral Capsules and Suspension from the Ethanolic Extract of Cola nitida Seeds for the Treatment of Diarrhea

Management of diarrhea has evolved over the years from relatively inadequate interventions in the early years to more successful physiological approaches. The use of herbal medicinal products and supplements has grown significantly over the past three decades, with more than half of the global population depending on it for some aspect of their primary health care needs. This study is aimed at formulating solid and liquid oral dosage forms of the ethanolic extract of Cola nitida seeds for the treatment of diarrhea. The flow property of the dried ethanolic extract was determined and subsequently formulated into granules for encapsulation. The ethanolic extract was also used in formulating an oral suspension. Pharmacopeia tests such as uniformity of weight, disintegration, drug content, and dissolution were carried out on the formulated capsules. The formulated suspension was also assessed using the following parameters; viscosity, flow rate, drug content, dissolution, sedimentation rate, and sedimentation volume. The dried ethanolic extract and formulated granules exhibited good flow properties. The formulated capsules exhibited optimal in vitro release of extract (>90% after 45 minutes) and passed the uniformity of weight, disintegration, and drug content tests. The formulated suspension also passed the drug content test and had a good sedimentation rate, sedimentation volume, and flow rate. The formulated suspension also exhibited pseudoplastic flow, optimal viscosity, and a good in vitro release profile (>90% after 45 minutes). Capsules and suspension of the ethanolic extract of Cola nitida seeds have been successfully formulated and can be used as standard dosage forms for the management of diarrhea.

Phytochemical screening and antibacterial activity of Cola nitida seed on selected bacterial isolates

Kola nut (Cola nitida) is chewed in many West African cultures and it is used ceremonially, industrially, medicinally and economically. The aim of this study was to assess the phytochemical properties and antibacterial activity of Cola nitida seeds. The seeds were purchased, dried and then powdered for phytochemical screening and extraction. Ethanol and aqueous (hot water) extracts were used for this study. The antibacterial activity of each extract at 30 mg/ml and 60 mg/ml was tested on four bacterial isolates; Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli using the disc diffusion method on Mueller Hinton agar. The results revealed the presence of various potent phytochemicals such as alkaloids, polyphenols, tannins, flavonoids and glycosides. The zones of inhibition ranged from 0.0 mm to 28.0 mm for both concentrations of the ethanol extract and from 0.0 mm to 31.0 mm for both concentrations of the aqueous extract. The Minimum Inhibitory Concentration (MIC) ranged from 7.5 mg/ml to 30.0 mg/ml for the ethanol extract and 3.75 mg/ml to 30.0 mg/ml for the aqueous extract. No minimum bactericidal concentration was recorded. Analysis of variance (ANOVA) performed on the data showed that there were significant differences in the zones of inhibition for each concentration of the extracts (P<0.05). The purified extract of Cola nitida seeds can be used to treat infections caused by these selected bacterial species.

Aqueous extract of Cola nitida and Garcinia kola synergistically enhances hippocampal-hypothalamic glutamate and Na+/K+-ATPase activity in male Wistar rats

Background: The incidence of cognitive decline has been proposed to rise exponentially in coming years. Therapies targeting molecular pathways involved in enhancement of memory and energy regulation could be a major breakthrough in prevention or management of dementia in susceptible populations. Objectives: This study investigated the effects of aqueous extracts of Cola nitida (AECONS) and Garcinia kola (AEGAK) on glutamate level and Na+/K+-ATPase activity in the hippocampus and hypothalamus of male Wistar rats. Methods: Adult male Wistar rats (170-200) were randomly allotted into groups (n=5/group); control (distilled water p.o.), AECONS1 (200 mg/kg), AECONS2 (400 mg/kg), AEGAK1 (200 mg/kg), AEGAK2 (400 mg/kg), AECONS1+AEGAK1 and AECONS2+AEGAK2. The extract was prepared and the administration was done daily for 6 weeks. Results and Discussion: Administration of AECONS or AEGAK increased plasma, hippocampal and hypothalamic glutamate, Na+/K+-ATPase activity, NO, SOD except hippocampal glutamate in AECONS1/AEGAK1, Na+/K+-ATPase activity and SOD in AEGAK1, hypothalamic glutamate and SOD in AECONS1 when compared with control. Besides, MDA level decreased in AEGAK2 and hippocampal but not hypothalamic MDA decreased in AEGAK1 compared with control. However, concomitant administration of AECONS and AEGAK enhanced plasma, hippocampal and hypothalamic biomarkers except hypothalamic MDA level. The present study demonstrates that AECONS and AEGAK synergistically enhances hippocampal and hypothalamic glutamate and Na+/K+-ATPase activity, which are accompanied by NO and SOD-dependent antioxidant enrichment. Conclusion: These findings therefore suggest that AECONS+AEGAK could be a better therapeutic candidate in hippocampal-hypothalamic-related neurodegenerative diseases.