scispace - formally typeset
Search or ask a question
Author

Nicholas Mwikwabe

Bio: Nicholas Mwikwabe is an academic researcher from Kenya Medical Research Institute. The author has contributed to research in topics: Population & Acute toxicity. The author has an hindex of 4, co-authored 7 publications receiving 62 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: The suitability of Toddalia asiatica as a good candidate for further tests to obtain a prototype for antimalarial medicine is confirmed and in vivo and safety data of the plant extracts tested for the first time are provided.

33 citations

Journal Article
TL;DR: The results of the study support the medicinal use of these plants and indicate that useful compounds from Hagenia abyssinica and Fuerstia africana can be isolated for further exploitation.
Abstract: Background: The world health organization (WHO) estimates that 80% of population in Africa relies on traditional remedies for their healthcare. However, very few studies have been carried out to establish the therapeutic effects of these remedies. Objective: Four medicinal plants were investigated for antimicrobial activity and toxicity. Materials and Methods: Plants were collected from their natural habitat, dried, and extracted with organic and aqueous solvents. Antimicrobial activity was determined by the disc diffusion assay technique. In vitro cytotoxicity studies were carried out on extracts using MTT assay on Vero cell lines while acute toxicity in Swiss mice. Results: Extracts from H. abyssinica , F. africana and A. racemosus exhibited antibacterial activity with minimum inhibitory concentration of ≤ 6.25mg/ml against S . aureus , MRSA and P. aeruginosa . However, the plants studied had weak antifungal activity. H. abyssinica and F. africana extracts were found to be cytotoxic with CC 50 of ˂ 90 µg/ml. These extracts were tested for acute toxicity and found to be safe at 5000 mg/kg body weight per day. Conclusion: The results of the study support the medicinal use of these plants and indicate that useful compounds from Hagenia abyssinica and Fuerstia africana can be isolated for further exploitation. Keywords: Medicinal plants, Antimicrobial activity, Cytotoxicity, Acute toxicity

18 citations

Journal ArticleDOI
TL;DR: Analysis of variance showed that the rate of fungal contaminants for Eldoret and Mombasa samples had significant association, and it is recommended that a policy be enacted to enable regulation of herbal products in Kenya.
Abstract: Utilization of herbal products is a major concern due to the possibility of contamination by toxigenic fungi that are mycotoxin producers such as Aspergillus species during processing and packaging. Research was carried out to determine the presence of aflatoxins and fumonisins in herbal medicinal products sold in Eldoret and Mombasa towns in Kenya. The study employed both exploratory and laboratory experimental design. The herbal products were purchased from the market and transported to Kenya Medical Research Institute for processing and analysis. Fungal contaminants were determined according to Pharmacopoeia specifications. The toxins were quantified using ELISA based technique. The genus Aspergillus was the most dominant followed by Penicillium. Fungal counts ranged between 1 CFU/g and >1000 cfu/g. Analysis of variance showed that the rate of fungal contaminants for Eldoret and Mombasa samples had significant association (). Aflatoxin levels ranged from 1 to 24 ppb, while fumonisin levels ranged from 1 to >20 ppb. Only 31% of samples met the standards for microbial limits as specified in Pharmacopoeia. There is need for product microbial quality improvement through proper harvesting, processing, storage, and marketing. It is recommended that a policy be enacted to enable regulation of herbal products in Kenya.

13 citations

Journal ArticleDOI
28 Jan 2016
TL;DR: Findings imply that conditions during harvest or postharvest processing of herbal products were unsanitary, and emphasis on improvement of plant material quality and establishing better hygienic conditions during production of herbal medicines is recommended.
Abstract: Herbal products are used worldwide for the treatment and prevention of various diseases and currently represent a substantial proportion of the global drug market. However, these products have the potential of being contaminated by different microorganisms due to poor hygienic practices during handling, processing and packaging. The main aim of this study was to evaluate microbial quality of herbal products marketed to the general population in Eldoret and Mombasa, Kenya. The study employed an exploratory as well as laboratory based experimental design. The herbal products were purchased from the markets and transported to Kenya Medical Research Institute laboratories for processing and analysis. Microbial contaminants were determined according to Pharmacopoeias and World Health Organization standards. Microbial pathogens were isolated, identified and drug susceptibility test was done as per National Laboratory Standards Institute protocol. The herbal products were in-form of powders, liquids, tablets, oils and capsules. Bacterial contamination was observed in 90% of the total samples and those with >1000×104cfu/gm or ml was 20% for Eldoret and 46% for Mombasa samples. Analysis of variance showed that the rate of microbial contaminants for Eldoret and Mombasa samples had no significant association (p = 0.084). Bacteria belonging to seven genera were isolated and antibiotic susceptibility test showed that 13.2% of the bacteria isolates were resistant. Multidrug resistance was observed with Klebsiella pneumonia, Shigella sonnei, Serratia erwinia, Serratia liquefaciens and Proteus penneri. These findings imply that conditions during harvest or postharvest processing of herbal products were unsanitary. Proper handling and storage of herbs should be observed in order to reduce the amount of microbial contaminants. Only 16% of herbal product samples evaluated met the standards for microbial limits as specified in Pharmacopoeias. Thus, emphasis on improvement of plant material quality and establishing better hygienic conditions during production of herbal medicines is recommended.

11 citations

Journal Article
TL;DR: The herbal formulations demonstrated significant antitussive activity in sulphur dioxide induced cough model in rats, and exhibited cough inhibitions of between 15 and 27%, and 14 and 38%, with respect to the control group, 30 and 60 minutes after sample administration respectively.
Abstract: Background: Cough is an important defensive pulmonary reflex that removes irritants, fluids or foreign materials from the airways. Frequently, cough is non-productive and requires suppression and opioid receptor agonists such as codeine are commonly used as antitussive agents. However, opioids produce side effects that include sedation, addiction potential and constipation. Novel cough suppressant therapies should maintain or improve upon the antitussive efficacy profile of opioids but with minimum or no side effects. Objective: To evaluate antitussive activity of combination of herbal medicines as formulations in sulphur dioxide - induced cough model in rats. Methodology: Wister rats of either sex, weighing 150 - 200 g, were divided into 7 groups (n = 6). Group 1 served as a control and received normal saline, groups 2 received codeine phosphate, group 3 and 4 received the coded market samples and groups 5, 6 and 7 received the test samples, respectively. Thirty or sixty minutes following administration, the rats were exposed to sulphur dioxide gas for 1 minute and then placed in an open chamber for counting of cough bouts. Results: The formulations exhibited cough inhibitions of between 15 and 27%, and 14 and 38%, with respect to the control group, 30 and 60 minutes after sample administration respectively. Conclusion: The herbal formulations demonstrated significant (p < 0.05) antitussive activity in sulphur dioxide induced cough model. Key words: Antitussive activity; herbal formulations; sulphur dioxide; cough

3 citations


Cited by
More filters
Journal ArticleDOI
02 Feb 2018-Toxins
TL;DR: This review focuses on analytical techniques including sampling, extraction, cleanup, and detection for mycotoxin determination in herbal medicines established within the past ten years and provides a good insight regarding the advanced research that has been done and closes with an indication of future demand for the emerging technologies.
Abstract: The presence of mycotoxins in herbal medicines is an established problem throughout the entire world. The sensitive and accurate analysis of mycotoxin in complicated matrices (e.g., herbs) typically involves challenging sample pretreatment procedures and an efficient detection instrument. However, although numerous reviews have been published regarding the occurrence of mycotoxins in herbal medicines, few of them provided a detailed summary of related analytical methods for mycotoxin determination. This review focuses on analytical techniques including sampling, extraction, cleanup, and detection for mycotoxin determination in herbal medicines established within the past ten years. Dedicated sections of this article address the significant developments in sample preparation, and highlight the importance of this procedure in the analytical technology. This review also summarizes conventional chromatographic techniques for mycotoxin qualification or quantitation, as well as recent studies regarding the development and application of screening assays such as enzyme-linked immunosorbent assays, lateral flow immunoassays, aptamer-based lateral flow assays, and cytometric bead arrays. The present work provides a good insight regarding the advanced research that has been done and closes with an indication of future demand for the emerging technologies.

151 citations

Journal ArticleDOI
TL;DR: Local knowledge of medicinal plants in the treatment of malaria still exists in all four villages surveyed and traditional healers appear to play an important role in primary health care services in this remote rural area in Zimbabwe.

128 citations

Journal ArticleDOI
TL;DR: The aim of this work is to review the current status of mycotoxins contamination in Africa, and recommend the possible control strategies, and mainly focuses on aflatoxins, fumonisins, ochratoxins and deoxynivalenol which frequently occurred in Africa in currently published research.

75 citations

Book ChapterDOI
01 Jan 2014
TL;DR: The selectivity index is an important measure to identify substances with promising biological activity and negligible cytotoxicity, and extracting solvents ranging in polarity have been used to extract different plant parts, contributing to the wide variety of cytot toxicity results of African plants.
Abstract: Cytotoxicity studies are a useful initial step in determining the potential toxicity of a test substance, including plant extracts or biologically active compounds isolated from plants. Minimal to no toxicity is essential for the successful development of a pharmaceutical or cosmetic preparation and in this regard, cellular toxicity studies play a crucial role. The concept of basal cytotoxicity, where deleterious effects are noted on structures and functions common to all human cells, is relevant when considering the relationship between acute toxicity and cytotoxicity. The selectivity index is an important measure to identify substances with promising biological activity and negligible cytotoxicity. Various bioassays and a number of different cell lines have been used to assess cytotoxicity of African medicinal plants. Additionally, extracting solvents ranging in polarity have been used to extract different plant parts, contributing to the wide variety of cytotoxicity results of African plants.

56 citations

Journal ArticleDOI
TL;DR: The review proposes improved linkages between agriculture, nutrition and health sectors to address aflatoxins contamination better and highlights knowledge gaps that can direct future management efforts.
Abstract: Aflatoxins are highly toxic metabolites of several Aspergillus species widely distributed throughout the environment These toxins have adverse effects on humans and livestock at a few micrograms p

45 citations