Ashleigh Hampton, MSc
Scientific and Regulatory Affairs Associate, Dicentra

There have been some challenges faced while assessing the therapeutic effects of resveratrol in humans. Phase 1 clinical trials have reported that resveratrol is readily absorbed, but undergoes extensive metabolism in the liver and intestine resulting in a very low oral bioavailability of the parent compound. Furthermore, in vitro evaluations have suggested that resveratrol metabolites are themselves inactive, but may undergo beta-glucuronidase activation to become efficacious at target tissues (As reviewed by Walle, 2011).

Irrespective of the fact that in vitro evidence suggests that inactive resveratrol metabolites may become activated at target sites, the available human clinical literature has not been sufficient to support health claims for orally administered resveratrol. Alternatively, a recently published clinical trial has demonstrated the effective use of topical trans-resveratrol as a treatment for acne vulgaris.

Acne vulgaris is characterized by hyperkeratinisation resulting in obstruction of the sebaceous follicles, androgenic stimulation of the sebaceous glands and the colonization of Propionibactereum acne. It has been suggested that the associated clinical symptoms are the result of negative feedback regulation or overstimulation of the inflammatory process resulting in increased function of the sebaceous gland. The recently published study by Fabbrocini et al. (2011) aimed to assess the effects of a topical trans-resveratrol preparation in patients with inflammatory acne vulgaris.

Twenty individuals with facial acne vulgaris were recruited for a single-blind, vehicle-controlled study. Baseline severity of the acne was evaluated using 2 different assessments: 1) the Global Acne Grading System (GAGS) and 2) a skin surface biopsy to identify the average area occupied by microcomedones, lesions which are characterized by the accumulation of abnormally desquamated corneocytes and excess oil. Following baseline analysis, a 0.001% trans-resveratrol-containing hydrogel and a chemically identical placebo control were provided to the study participants. The participants were instructed to apply the resveratrol-containing gel (labelled R) to the right side of their faces and the placebo gel (labelled C) to the left side of their faces nightly for 60 days.

After 60 consecutive days of treatment, application of trans-resveratrol resulted in a 53.75% reduction from baseline GAGS score, whereas the placebo controlled group experienced a 6.1% reduction from baseline, on average. Furthermore, when compared to baseline, the average area of microcomedones was reduced 66.7% and 9.7% following treatment with resveratrol and placebo, respectively.

In summary, the results of the study suggest that a topical preparation containing 0.001% trans-resveratrol was effective in reducing the severity of acne vulgaris.

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References:

Fabbrocini G, Staibano S, De Rosa G, Battimiello V, Fardella N, Ilardi G, La Rotonda MI, Longobardi A, Mazzella M, Siano M, Pastore F, De Vita V, Vecchione ML, Ayala F. Resveratrol-containing gel for the treatment of acne vulgaris: a single-blind, vehicle-controlled, pilot study. Am J Clin Dermatol. 2011 Apr 1;12(2):133-41. doi: 10.2165/11530630-000000000-00000.

Walle T. Bioavailability of resveratrol. Ann N Y Acad Sci. 2011 Jan;1215:9-15.

doi: 10.1111/j.1749-6632.2010.05842.x. Review.