Oligonol Inhibits UVB‐induced COX‐2 Expression in HR‐1 Hairless Mouse Skin—AP‐1 and C/EBP as Potential Upstream Targets^†

Abstract

Oxidative stress and inflammatory tissue damage are two major events frequently implicated in carcinogenesis. Numerous polyphenolic compounds derived from plants possess antioxidant and anti-inflammatory activities and are hence effective in preventing cancer. Oligonol is a polyphenol formulation enriched with catechin-type oligomers. As an initial approach to assess the chemopreventive potential of oligonol, we have determined its effects on inflammatory as well as oxidative damage in mouse skin irradiated with UVB. Topical application of oligonol onto the dorsal skin of male HR-1 hairless mice 30 min prior to UVB exposure diminished epidermal hyperplasia and formation of 4-hydroxynonenal, a biochemical hallmark of lipid peroxidation. Topical application of oligonol also significantly inhibited UVB-induced cyclooxygenase (COX-2) expression in mouse skin. Oligonol diminished the DNA binding of activator protein-1 (AP-1) and CCAAT/enhancer binding protein (C/EBP), and the expression of C/EBPdelta in mouse skin exposed to UVB. Our study also revealed that oligonol attenuated UVB-induced catalytic activity as well as expression of p38 mitogen-activated protein (MAP) kinase. Moreover, UVB-induced phosphorylation of another upstream kinase Akt was attenuated by oligonol. Taken together, oligonol showed antioxidative and anti-inflammatory effects in UVB-irradiated mouse skin by inhibiting COX-2 expression via blockade of the activation of AP-1 and C/EBP, and upstream kinases including p38 MAP kinase and Akt.

Amelioration of abdominal obesity by low-molecular-weight polyphenol (Oligonol) from lychee

“…It has been shown that Oligonol is readily absorbed from intestines, and has a strong antioxidative activity and ability to prevent photocarcinogenesis (Kundu et al, 2008). Regarding lipid metabolism and obesity, Oligonol promotes adiponectin production in rat visceral fat cells in conjunction with a reduction of triacylglycerol accumulation .…”

Sargassum fulvellumProtects HaCaT Cells and BALB/c Mice from UVB-Induced Proinflammatory Responses

“…Stimulation of HR-1 [14, 15, 18, 19] and SKH-1 [20] hairless mouse skin with UVB resulted in a significant increase in COX-2 expression and conversely topical application of sulforaphane [14], γ -tocotrienol [15], anthocyanins from black soybean seed coats [18], oligonol [19], and proanthocyanidins from grape [20] inhibited UVB-induced COX-2 expression.…”

Oligonol, a low-molecular-weight polyphenol derived from lychee fruit, attenuates gluco-lipotoxicity-mediated renal disorder in type 2 diabetic <i>db/db</i> mice

“…Based on recent studies, there is accumulating evidence that oligonol can induce some physiological and biochemical alterations in vitro and in vivo, such as the induction of apoptosis in cancer cells (23), antioxidant and anti-inflammatory effects in mice (24), and beneficial subjective effects on the feeling of fatigue in young athletes (67). Moreover, the oral administration of oligonol improves the regulation of genes for adipokines in white adipose tissue of mice on administering a high-fat diet (26).…”

“…This method involves binding a compound possessing a phloroglucinol ring structure (such as catechin) as a nucleophilic compound to proanthocyanidin fragmented under acidic conditions. As shown in Figure 1 (23) as well as antioxidant and anti-inflammatory effects (24), beneficial activity for nitric oxide bioavailability (25), and a regulatory effect on lipid metabolism (26,27). Indeed, dietary feeding with proanthocyanidins, which comprise oligonol, has been reported to induce a significant attenuation of tissue fat levels, without changing the total body mass of the animals compared with non-proanthocyanidin-fed animals (28).…”