Publication Type

Journal Article

Journal Name

Heliyon

Publication Date

5-30-2024

Abstract

Globally, the demand for natural remedies such as honey to manage ailments has increased. Yet, the health benefits and chemical composition of African honeys are not well understood. Therefore, this study aimed to characterise the bio-functional properties and the phytochemical composition of 18 Apis mellifera honeys from Kenya, Uganda, and Cameroon in comparison to the popular and commercially available Manuka 5+ honey from New Zealand. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH-RSA) was used to determine the antioxidant property, whilst the agar well diffusion and broth dilution (Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) assays were used to determine antimicrobial property. Further, colorimetric methods were used for phytochemical analysis. Our results showed that honeys collected from Rift Valley region of Kenya (e.g. Poi, Salabani and Mbechot) and Western region of Cameron (e.g. Bangoulap) had the highest antioxidant (DPPH RSA of 41.52–43.81%) and antimicrobial (MIC (3.125–6.25% w/v) and MBC (6.25–12.5% w/v)) activities. Additionally, the total flavonoid (770–970 mg QE/100 g), phenol (944.79–1047.53 mg GAE/100 g), terpenoid (239.78–320.89 mg LE/100 g) and alkaloid (119.40–266.57 mg CE/100 g) contents reached the highest levels in these bioactive African honeys, which significantly and positively correlated with their bio-functional properties. The functional and phytochemical composition of these bioactive African honeys were similar to or higher than those of the Manuka 5+ honey. Furthermore, gas chromatography-mass spectrometry analysis of African honeys revealed 10 most prominent volatile organic compounds that contribute to their geographical distinction: triacontane, heptacosane, (Z)-9-tricosene, tetracosane, 6-propyl-2,3-dihydropyran-2,4-dione, octacosane, 1,2,4-trimethylcyclohexane, 1,3-bis(1,1-dimethylethyl) benzene, 2-methylheptane and phytol. Overall, our findings suggest that some of the tested African honeys are natural sources of antimicrobial and antioxidant therapies that can be exploited upon further research and commercialized as high value honey.

Keywords

African honeys, Antioxidant/antimicrobial activity, Phytochemicals, Volatile compounds

Funding Statement

Sample collection in Kenya was funded by the European Union project through Kenya Agricultural and Livestock Research Organization (KALRO), Grant/Award Number: KALRO/CS APP/LOA No. March 2019; whereas sampling in Cameroon was funded by JRS Biodiversity Foundation, Grant Number: 70054.

The authors acknowledge all beekeepers for generously providing honey samples needed for this study: KALRO-Apicultural Research Institute Baringo Kenya, KAMAKI Cooperative in Kitui, Kenya, and Coopérative avec Conseil d'administration de l'université des Montagnes (Coop-CA Udm), Bangangté, Cameroon. The authors further acknowledge the financial support for this research by the following organisations and agencies: the Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); the Australian Centre for International Agricultural Research (ACIAR); the Norwegian Agency for Development Cooperation (Norad); the German Federal Ministry for Economic Cooperation and Development (BMZ); and the Government of the Republic of Kenya. The views expressed herein do not necessarily reflect the official opinion of the donors.

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