Evaluation of radical scavenging activity and colour intensity of nine Malaysian honeys of different origin
Md. Ibrahim Khalil, Mohamed Mahaneem, Syed Mohsin Sahil Jamalullail, Nadia Alam and Siti Amrah Sulaiman
It is important to know the antioxidant properties of Malaysian honey of different sources to ensure their quality. In this study, we analysed nine common Malaysian honeys and one manuka honey to determine the total phenolics, flavonoids, antioxidant capacity and colour intensity. The Folin-Ciocalteu test was used to determine the total polyphenols content, ferric reducing antioxidant power (FRAP) assay for reducing capacity and 1,1-diphenyl-2-picryl-hydrazyl (DPPH·) assays for radical scavenging capacity. The colour intensity measure, ABS450, was used to approximate the contribution of coloured phytochemicals (carotenoids, flavonoids) to the overall antioxidant capacity of honey. The results showed that all the honey samples showed high content of phenolic compounds (876.58-166.97 mg GAE/kg) and high colour intensity (169.89-740.59 mAU) but that the results differ widely among the honey types. Out of nine honey samples, tualang honey 1 and 2 had the highest content of polyphenols and showed the highest colour intensity at ABS450. All of the honey samples tested have high antioxidant properties as analysed by FRAP and DPPH· assay. Correlations between the parameters analysed were found to be statistically significant (p < 0.01). On the basis of employed analytical methods, the tested honey samples may be considered easily accessible natural sources of antioxidants and valuable additions to everyday diet. The results have shown that tualang honey 1 and 2 were characterized by the highest total polyphenols content (876.58 mg GAE/kg and 652 mg GAE/kg), the highest reducing capacity (755.33 mM Fe(II) and 794.67 mM Fe(II)) and the best radical scavenging properties with respect to DPPH· (81.64% and 77.25%) of the analysed Malaysian honey samples. Radical scavenging activity and antioxidant properties of the honey samples showed good correlation with polyphenols content and colour intensity.