An article published in Targets and Therapy discussed that treating hyperpigmentation can be challenging and a wide array of agents may be required to improve outcomes of topical therapy. The authors stated that the current gold standard treatment is hydroquinone. However, it has been associated with a number of adverse effects, including skin irritation, contact dermatitis and exogenous ochronosis in individuals with darker complexion.

Cosmeceuticals are topical cosmetic-pharmaceutical hybrids containing biologically active ingredients that may improve the appearance of skin and are increasingly popular alternatives to standard agents. Among these, plant derived compounds known as phytochemicals, have been shown to have a multitude of cellular actions for various dermatological diseases.

Some examples are:

• Aleosin – obtained from the Aloe vera plant, is found to inhibit hyperpigmentation after UV radiation in a dose-dependent manner. While cotreatment with aleosin and arbutin demonstrates an additive effect.
• Arbutin – obtained from the leaves of the bearberry plant—Aesculus californica (Spach) Nutt and in lesser quantities from cranberry and blueberry leaves, is structurally related to hydroquinone. It is a naturally occurring glucopyranoside that acts to inhibit melanosomal tyrosinase and 5,6-dihydroxyindole-2-carboxylic acid polymerase activities at noncytotoxic concentrations.
• Alpha-bisabolol – the primary constituent of the Matricaria chamomilla plant, inhibits alpha-melanocyte-stimulating hormone-induced melanogenesis by suppressing intracellular cyclic adenosine monophosphate levels.
• Ellagic acid – a polyphenol phytochemical that can be found in certain plants and in some nutrients like green tea, strawberry, geranium, grapes, cherries and walnuts, inhibits skin pigmentation resulting from UV irradiation.
• Glabridin – an active ingredient in licorice extract derived from Glycyrrhiza glabra, inhibits tyrosinase activity but has no effect on DNA synthesis. Further experimentation is needed to explore the lightening effects of glabridin on the human skin.
• Liquiritin – an active compound of licorice; clinical studies on Asian patients with melasma have shown that 4% liquiritin renders significantly better results than 4% hydroquinone.
• Procyanidin – the main active component of Pinus pinaster bark extract, confers significant improvement in the degree of lightening of melasma. In addition, oral intake of procyanidin with vitamins A, C, and E has been found to be safe and well tolerated and can aid in reducing the degree of pigmentation.
• Silymarin – a natural polyphenolic flavonoid derived from the milk thistle plant Silybum marianum, can reduce and suppress harmful effects of solar UV radiation, such as UV-induced oxidative stress, inflammation, immune responses and DNA damage, as well as the induction of apoptosis.

Although plant extracts are not free of side effects, clinical trials testing the safety and efficacy of multiple botanicals revealed that patients had fewer adverse effects in comparison to gold standard therapies.

Source: Targets and Therapy. 2016 Sept 16. 2016:6 (89-96). Doi: 10.2147/BTAT.S69113