Abstract
Food preservation has many benefits, such as increasing shelf life, retaining nutritional values and biological activities. In the current study, total phenolic content (TCP), antioxidant and anti-glucosidase activities, and kinetic of glucose inhibition of stingless bee honey, honey mixed with fruits, and extracts of Citrus japonica were evaluated by measuring color of a reaction using a spectrophotometer. The result showed that high TPC was found in ethanol extract of C. japonica leaves and fruits (26.79 ± 6.94 and 12.79 ± 0.87 mg of gallic acid per g extract), while stingless bee honey revealed the highest antioxidant activity (1/EC50 = 0.2921) and honey mixed with fruits revealed the strongest anti-glucosidase activity (1/EC50 = 1.8181), significantly (P-value <0.05). Kinetic of glucosidase inhibition of honey were found as uncompetitive and mixed competitive inhibition, while the honey mixed with fruits showed mixed competitive inhibition. The FTIR and GC-MS analysis demonstrated the presence of several bioactive compounds. Very strong positive relationship between total phenolic content with GC-MS data was found (r = 0.926, P-value < 0.05). This knowledge confirmed that stingless bee honey and honey mixed with fruits had greater anti-diabatic potential in comparison with the extracts of C. japonica leaves and fruits.