Browsing by Author "Alex Muthengi"

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    A Comparative Study of Caffeine Levels in Coffee and Cocoa in Kenyan Supermarkets and Shops
    (Pan-African Journal of Health and Environmental Science, 2024-12-16) Alex Muthengi; Silas Njiru; Juster Mungiria; ; ;
    Background: Caffeine is an alkaloid belonging to the methylxanthine family. An overdose of caffeine causes the following side effects: restlessness, nervousness, excitement, insomnia, flushed face, diuresis, gastrointestinal disturbances, muscle twitching, rambling flow of thought and speech, and tachycardia or cardiac arrhythmia. This study aimed to determine the caffeine levels of various brands of coffee and cocoa and enlighten people on the safe and healthy consumption of the two products. Methods: Different brands of coffee and cocoa products were randomly sampled and purchased from supermarkets and shops in Nairobi, Kenya. Five samples of coffee and four brands of cocoa were purchased from a supermarket and taken to the laboratory for analysis. Caffeine was extracted, and quantitative analysis was done using High Performance Liquid Chromatography (HPLC). Results: The study found that coffee has a higher concentration of caffeine than cocoa. Coffee Brand A recorded the lowest level of caffeine with 30.9845 µ g/g, while Coffee Brand C recorded the highest level of caffeine with 426.9639 µ g/g. Among the Cocoa brands, Cocoa Brand B recorded the lowest level of caffeine (2.6367 µg/g), while Cocoa Brand C recorded the highest level of caffeine at 19.03 µ g/g. Conclusion: Therefore, there is a need to reduce coffee consumption per day because caffeine overdose can cause high blood pressure and other illnesses. Cocoa is recommended for consumption since it contains less caffeine per serving.
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    Phytochemical screening and repellence potencies of bioactive molecules of plant extracts derived from Ocimum suave, Ocimum americanum and Eucalyptus citriodora against Anopheles gambiae
    (Muthengi et al. Malaria Journal, 2025) Alex Muthengi; Alice Karithi and Joseph; Fidelis Ngugi; Joseph Kiambi Mworia
    Malaria poses a global threat to human health. It’s a vector-borne disease of public health concern and affects the socio-economic status of people in developing countries. Malaria management faces many challenges namely, affordability, availability, and quality of drugs. Plants are considered a very significant resource in many parts of the world due to their variety of uses in treating diseases and ailments. Conventional drugs are expensive and not readily available. Repellents have been in use for the prevention of Anopheles bites, but all these have a myriad of negative effects to the user, such as allergy and dermatitis. This study sought to develop a plant- based Anopheles gambiae repellent for control of malaria, because it is eco-friendly and non-toxic.