Update on resveratrol
• Found abundantly in nature, this polyphenolic phytoalexin is believed to exhibit a wide range of biologic activity.
• Potent antioxidant, anti-inflammatory, and antiproliferative properties.
• Highly studied polyphenolic substance also considered a chemopreventive agent against skin cancer.
• In small studies, has contributed to antiaging, antiacne, antierythema, and skin-lightening results.
Resveratrol (trans-3,5,4’-trihydroxystilbene), a polyphenolic phytoalexin synthesized in nearly 70 plant species, is found to be particularly abundant in Vitis vinifera (grape vine) and its derivatives (e.g., red wine, purple grape juice), various berries, peanuts, jackfruit, pomegranate, eucalyptus, the roots of Polygonum cuspidatum (Japanese knotweed, which is used in traditional Chinese and Japanese medicine to treat dermatitis, among other conditions)1, Scots pine, spruce, corn lily, gnetum, and butterfly orchid.2-6 Several studies have demonstrated that resveratrol possesses potent antioxidant, anticarcinogenic, anti-inflammatory, as well as antimicrobial characteristics.7-11 Specifically, in vitro and in vivo studies have shown that resveratrol exerts chemopreventive and antiproliferative activity against various cancers, including skin cancer, by suppressing cellular events associated with tumor initiation, promotion, and progression, and triggering apoptosis in such tumor cells.12-14 It also is reputed to impart antiaging benefits.15 This column will focus on recent research findings pertaining to effects on the skin as well as topical uses of this botanical agent, the main source of which, V. vinifera, has been used since antiquity.
Resveratrol was first identified from the roots of Veratrum grandiflorum (white hellebore) in 1940,16-19 but research on the compound did not take root until after a 1997 report in Science suggested chemopreventive properties. In that study, purified resveratrol was found to exhibit major inhibitory activity against cancer initiation, promotion, and progression.20 Since then, copious research on this botanical compound has yielded a reputation as a strong antioxidant, anti-inflammatory, and antiproliferative agent.7,21,22 Most importantly, resveratrol is considered to act as a chemopreventive agent against skin cancer and antiproliferative influence on oral squamous, breast, colon, and prostate cancer cells.12,14 It is also one of the most studied polyphenolic compounds.
Skin cancer and photoprotection
In 2012, Osmond et al. conducted in vitro and in vivo experiments to assess the potential of resveratrol as a chemotherapy adjunct for melanoma treatment. Resveratrol significantly reduced melanoma cell viability in both melanoma cell lines tested, and selectively spared cells in the nonmalignant fibroblast lines, compared with its cytotoxic impact on melanoma cells. Further, cytotoxicity to malignant cells was greatly enhanced by 72 hours of treatment with resveratrol and temozolomide, compared with temozolomide treatment alone. No significant differences were seen in vivo. The researchers concluded that the in vitro antitumor activity of resveratrol suggested its potential as a therapeutic agent in melanoma management.23
Resveratrol has been shown to protect against UVB-mediated cutaneous damage in SKH-1 hairless mice. Afaq et al. demonstrated that UVB-induced skin edema was significantly suppressed by the topical application of resveratrol to SKH-1 hairless mice.7
In a different study by the same team, topically applied resveratrol significantly inhibited UVB-mediated increases in bifold skin thickness and edema and greatly diminished UVB-induced lipid peroxidation, cyclo-oxygenase and ornithine decarboxylase (ODC) activities, as well as protein expression of the ODC enzyme in SKH-1 hairless mice.24 In an experiment by some of the same researchers, resveratrol was topically applied to SKH-1 hairless mice 30 minutes before exposure to UVB; 24 hours later, significant decreases were observed in bifold skin thickness, hyperplasia, and leukocyte infiltration. Critical cell cycle regulatory proteins, the target of the investigation, were substantially down-regulated because of the resveratrol. The investigators concluded that resveratrol might have the potential to play a significant role in preventing UVB-mediated photodamage and carcinogenesis.25
More recently, in 2015, Sirerol et al. found that the topical treatment with pterostilbene, a natural dimethoxy analog of resveratrol, effectively shielded SKH-1 hairless mice from UVB-induced photodamage and carcinogenesis.26
Interestingly, recent in vitro studies by Sticozzi and colleagues have shown that topical resveratrol dose-dependently protected human keratinocytes from cigarette smoke–induced reduction of scavenger receptor B1 protein expression27 and can lower cigarette smoke–induced reactive oxygen species and carbonyl formation in human keratinocytes.28
Antiaging activity
In 2010, Giardina et al. performed an in vitro study to evaluate the tonic-trophic characteristics of resveratrol alone and resveratrol plus N-acetyl-cysteine on cultured skin fibroblasts. Both formulations dose-dependently increased cell proliferation and inhibition of collagenase activity.29
In 2012, Wu et al. investigated the protective effects of resveratrate, a stable derivative of resveratrol, against damage to human skin caused by repetitive solar simulator UV radiation (ssUVR) in 15 healthy human volunteers. Six sites on nonexposed dorsal skin of each participant were assessed, with four sites exposed to ssUVR and the remaining sites serving as positive control (ssUVR only) and baseline control (no treatment or exposure). The researchers noted minimal erythema on areas treated with resveratrate and the resveratrol derivative significantly inhibited sunburn cell formation. They concluded that resveratrate protects the skin against sunburn and suntan caused by repetitive ssUVR.4
