Investigation On Antioxidant Activites Of Chinese Honeys

Honey is the nature sweet substance produced by honey bees from nectar of blossoms or from secretions of living parts of plants or secretions of plant sucking insects on the living parts of plants, which honey bees collect, transform and combine with specific substances of their own, store and leave in the honey comb to ripen and mature. Antioxidant activities of Chinese honeys were determined by several in vitro systems. This thesis consisted of six chapters, and the author's contributions are in the following four aspects:1. The radical scavenging abilities and total phenolic contents of 14 different types of Chinese honeys were evaluated. The results showed the total phenolic contents of honeys varied greatly according to their floral types and all of honeys had evident scavenging effects on DPPH radical, hydroxyl radical, superoxide anion radical and inhibition effects on lipid peroxidation. The radical scavenging abilities of Loquot honey, Chinese date honey, Astragalus menbranacers honey, Tang shen honey and Chinese wolfberry honey increased with increasing in honey concentration. A positive correlation was observed between the total phenolic contents and the reducing power assay(R=0.94), DPPH radical assay(R=0.92), superoxide anion radical assay(R=0.95), hydroxyl radical assay(R=0.87) and lipid peroxidation assay (R=0.64), which indicated that the phenolic compounds might contributed significia-ntly to the antioxidant properties of Chinese honeys.2. The Chinese honeys' ablity of conterracting the damaging effects of oxidation in rat tissues were evaluated by the hemolysis of red blood cells assay, the lipoprotein oxidation of liver homogenate assay and the swelling of mitochondria assay. The results showed Loquat honey and Vitex honey could inhibit the lipo protein oxidation of liver homogenate induced by Fe²⁺ and H₂O₂, the hemolysis of red blood cells induced by H₂O₂ and the swelling of mitochondria induced by Fe²⁺ and VC.3. The inhibition effects of five Chinese honeys on lipoprotein oxidation in human serum exposed to Cu2+ were assessed. The results showed all of five Chinese honeys exhibited inhibition effects on human serum lipoprotein oxidation in a dose-dependent manner.4. The change in antioxidant activity of buckwheat honey heated at different temperatures (40°C,60°C,80°C) was assessed by DPPH radical. The results showed antioxidant activity and brown pigment formation increased with treatment temperature and time. The positive relationship between the antioxidant activity and browning of the buckwheat honey was observed.