Preparation Of Three Kinds Of Bee Pollen Polyphenols In Yunnan And Its Biological Activity In Inhibiting Melanoma B16 Cells

To study the antioxidant and biological activities of phenolic extract from rape, maize and rose bee pollen, the free and bound phenolic composition and contents were analyzed. The antioxidant property was evaluated by Ferric Reducing Ability of Plasma (FRAP),2,2’-DiphenyI-1-picrylhydrazyl (DPPH) and 2,2-Azino-bis-3-ethylbenzothiazoline-6-sulfonic Acid (ABTS) radical scavenging capacity assay, and the mushroom tyrosinase activity inhibition was also determined. Furthermore, the cell viability, melanin contents, tyrosinase activity and antioxidant level in B16 cells were studied. Finally the mRNA level of related factor of melanin biosynthesis were analyzed to conduct a preliminary study of molecular mechanism.The results showed that the total phenolic contents of free and bound phenolic extract of three kinds of pollen were 11.37～23.36 mg GAE/g DW and 0.69-1.47 mg GAE/g DW, respectively. And the total flavonoid contents were 17.25-19.24 mg RE/g DW and 2.42-3.65 mg RE/g DW. The phenolic compounds existed mainly in the free extract of pollen, rutin exsited in all free phenolic extract of three kinds of pollen and all the bound phenolic extracts have higher content of ellagic acid. Certain antioxidant properties of the free and bound phenolic extracts of three kinds of pollen were exhibited, and the free phenolic extract of rape pollen showed the best antioxidant property. The mushroom tyrosinase inhibitory activities of three kinds of pollen were better than Vc, and the bound extract of maize pollen and free phenolic extract of rape pollen showed the better mushroom tyrosinase inhibitory activities than other extracts. The phenolic extracts also had an effect on the cell proliferation and morphology to some extent. Not only the melanin contents but also the tyrosinase activities in B16 cells treated by the phenolic extracts of three kinds of pollen were significantly declined. And the free phenolic extract from rape pollen had the better biological activity than other extracts. According to the analysis of GSH/GSSG, the antioxidant levels in B16 cells were increased by treating with the phnolic extracts of these three kinds of pollen. The mRNA level of Tyrosinase, TRP-1, TRP-2, MITF and MC1R were analyzed to conduct a preliminary study of molecular mechanism about melanin biosynthesis. The results showed that the free phenolic extract of rape pollen had an effect on the melanin biosynthesis by down regulating the mRNA level of Tyrosinase and TRP-1. And the level of MITF and MCIR also had an effect on the melanin biosynthesis. But futher studies are needed for the specific pathway of melanin biosynthesis affected by the free phenolic extract of rape pollen.