Effects of rambutan (Nephelium lappaceum) peel phenolics and Leu-Ser-Gly-Tyr-Gly-Pro on hairless mice skin photoaging induced by ultraviolet irradiation.

Rambutan peel phenolics (RPP) have high antioxidant and anti-inflammatory activities. Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) possesses good radical scavenging activity and matrix metalloproteinase (MMPs) inhibitory ability. These underlying mechanisms indicated that RPP and LSGYGP may be used for antiphotoaging. Few data on the effects of RPP and LSGYGP on in vivo photoaging are available. We evaluated the effects of RPP and/or LSGYGP on ultraviolet (UV)-induced hairless mice skin photoaging. In particular, we analyzed the additive effect of RPP and LSGYGP. The biochemical indices of mice skin, including composition (collagen and hyaluronic acid [HA] contents), oxidant stress (antioxidant enzyme activities and glutathione and malondialdehyde contents), MMPs (MMP-1, MMP-3, and MMP-9 levels), inflammatory cytokines (interleukin (IL)-1α, tumor nuclear factor-α, and IL-6 levels) and the phosphorylation of the mitogen-activated protein kinase pathway, were determined. Results showed a protective effect of RPP and/or LSGYGP on photoaging skin. LSGYGP showed considerable effects on skin collagen and HA contents. RPP showed improved effects on the regulation of the oxidant stress and inflammatory cytokine levels. RPP and LSGYGP exerted an additive effect on the amelioration of the biochemical indices of UV-induced photoaging skin. The histological changes showed that RPP and LSGYGP recovered the changes in skin tissue and endogenous collagen.