Abstract

Objective: To investigate into the antimicrobial and antioxidant potential of six varieties of honey from Mauritius. Methods: Six samples [commercial (processed, syrup-flavoured and ginger) and unifloral (eucalyptus, litchi and longan)] were assessed as traditionally used. The disc diffusion method was used against five microbial strains. Antioxidant capacity was determined using eight assays: trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power, iron chelating, hydroxyl radical (OH•), 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging assay, hypochlorous acid (HOCl), nitric oxide (NO •) and 2,2’-azinobis(3-ethylbenzothiazoline-6- sulphonic acid) diammonium salt radical scavenging assay. The total phenolic (TPC) and flavonoid content (TFC) were determined to delineate any correlation with any observed bioactivity. Results: Longan honey showed the highest antimicrobial activity while processed and raw eucalyptus honeys showed moderate activity. TEAC ranged from (0.95依0.04) to (1.80依0.03) mmol trolox equivalents/100 g while ferric reducing antioxidant power varied between (160.77依1.02) to (170.50依1.84) mmol trolox equivalents/100 g. Strongest iron chelating activity was recorded for processed honey [IC50=(4.51依0.34) mg/mL] while eucalyptus and longan honeys had the highest OH• scavenging activity [IC 50=(31.24依0.75) mg/mL and (31.30依0.85) mg/mL respectively]. Ginger honey had the lowest IC50 [(2.77依0.79) mg/mL] against NO• while longan honey was most active against HOCl• [IC50=(21.67依1.09) mg/mL] and processed honey showed the lowest IC50 against 2,2’- azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical [(90.44依2.48) mg/ mL]. TPC ranged between (54.03依0.99) to (77.37依1.01) mg gallic acid equivalent/100 g and TFC between (4.55依0.06) to (11.80依0.20) μg rutin equivalent/100 g. Pearson correlation established strong correlations between antioxidant assays and TPC (TEAC: r=0.945 3; iron chelating: r=-0.696 4; OH•: r=-0.615 0; 2,2-diphenyl-1-picryl-hydrazyl-hydrate: r=-0.743 9) and TFC (HOCl•: r=-0.750 9; NO•: r=0.867 8). Conclusions: The current study has provided important baseline data on local honey which can be further exploited as a functional food.

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