Piceatannol: The other potent antioxidant in grapes and wine

Present in grape skins, passion fruit, and wine among several other plants and their derivatives, piceatannol is a natural stilbene, as well as an analogue of the much-studied antioxidant resveratrol. Similarly, piceatannol is thought to provide robust antioxidant and other salutary benefits.^1,2

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Two decades ago, the hydroxystilbenes piceatannol and transresveratrol were found, in a study of the antioxidant potential of natural products, to hinder carcinogen-induced preneoplastic lesion development in a murine mammary gland organ culture model.³ Piceatannol is naturally present in various plants and is a primary active ingredient in several. It is known to exhibit a wide range of biologic activities, including antioxidant, antibacterial, anti-inflammatory, and anticancer functions. Native to southern and southeastern Asia, Rhodomyrtus tomentosa (rose myrtle, which is a member of the Myrtaceae family), which has been utilized in traditional medicine in China, Malaysia, and Vietnam for myriad indications including wound healing, contains piceatannol as an active ingredient.⁴

The reported cutaneous benefits of piceatannol include promotion of collagen synthesis, suppression of melanin production, induction of the antioxidant glutathione, and the destruction of reactive oxygen species.⁵This column focuses on the potential or realized biologic activities of piceatannol that can or do affect skin health.

Antimelanogenic activity

In 2007, Yokozawa and Kim looked into the capacity of piceatannol, given its antioxidant activities, to suppress melanogenesis. This ability was tested using the B16F10 melanoma culture system, and piceatannol was found to have a potent antityrosinase activity – stronger than kojic acid and resveratrol. Melanin content was also down-regulated by piceatannol. In addition, the researchers determined that piceatannol inhibited reactive oxygen species production, which improved the ratio of glutathione to oxidized glutathione. They concluded that the observed antimelanogenic activities of piceatannol could be attributed to its dynamic antioxidant qualities.⁶

Four years later, Matsui et al. ascertained that piceatannol (3,4,3’,5’-tetrahydroxy-trans-stilbene) is present in copious supply in the seeds of Passiflora edulis (passion fruit) and that this constituent of the fruit largely accounts for its antimelanogenic activities, as well as its promotion of collagen production.⁷

Anti-inflammatory activity

In 2014, Liu et al. used female HR-1 hairless mice in a study to shed light on the molecular mechanisms of the anti-inflammatory activity of topically applied piceatannol in vivo. Mice, either pretreated with piceatannol or not, were topically treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), and pretreatment was found to yield diminished TPA-induced cyclooxygenase-2 (COX-2) expression and inducible nitric oxide synthase (iNOS). This occurred through the suppression of NF-kappa-B and AP-1 activation as a result of hindering IKK-beta activity and phosphorylation of mitogen-activated protein kinases.⁸

Photoprotection

Maruki-Uchida et al. studied the effects of the antioxidants piceatannol and its dimer scirpusin B, which is found in passion fruit, on human keratinocytes. In this 2013 study, they found that piceatannol dose-dependently up-regulated glutathione levels. In addition, piceatannol pretreatment blocked UVB-induced reactive oxygen species development. Pretreatment with piceatannol also reduced matrix metalloproteinase-1 activity in a nonirradiated medium of fibroblasts. The investigators concluded that piceatannol and piceatannol-rich passion fruit seed extract warrant attention as possible antiphotoaging cosmetic agents.⁹