Oligonol, a lychee fruit-derived low molecular weight polyphenol formulation, inhibits UVB-induced cyclooxygenase-2 expression, and induces NAD(P)H:quinone oxidoreductase-1 expression in hairless mouse skin

Plant polyphenols with antioxidant and anti-inflammatory properties are effective in chemoprotection and chemoprevention. Oligonol is a novel formulation enriched with low molecular weight catechin-type oligomeric polyphenols. Administration of oligonol-L and oligonol-G, derived, respectively, from lychee fruit and grape seeds, by gavage significantly attenuated UVB-induced expression of COX-2 in hairless mouse skin. Intragastric administration of oligonol-L attenuated UVB-induced phosphorylation of extracellular signal-regulated protein kinase-1/2 and p38 mitogen-activated protein kinase in UVB-irradiated mouse skin. UVB irradiation induced phosphorylation of mitogen- and stress-activated kinase-1 (Msk1), Janus-activated kinase-2 (JAK2) and signal transducer and activator of transcription-3 (STAT3) in mouse skin. Pretreatment with oligonol-L diminished UVB-induced phosphorylation of Msk1, JAK2 and STAT3 in UVB-irradiated mouse skin. Furthermore, oligonol-L significantly induced the expression of NAD(P)H:quinone oxidoreductase-1 (NQO-1) in mouse skin. In summary, oligonol-L inhibited UVB-induced expression of COX-2 and various upstream kinases, and induced the expression of NQO-1, which may account for its protective effects against photoinjury, including photoageing and photocarcinogenesis.