Botanical ingredients in cosmeceuticals

Journal of Drugs in Dermatology, Nov, 2007 by Leslie Baumann

Abstract

During the last 10 to 15 years, complementary and alternative medicine (CAM) has become increasingly popular in the US. Within this realm of health care, oral and topical herbal supplements have become some of the most frequently used alternative therapies. Most herbal supplements are based on, or include, several botanical ingredients with long histories of traditional or folk medicine usage. Among the numerous botanical ingredients available on the market today, several are believed to confer dermatologic benefits. This article will focus on a select group of botanical compounds, many of which have long traditions in Asian medicine, with potential or exhibited dermatologic applications, including curcumin, Ginkgo biloba, ginseng, silymarin, soy, and tea tree oil. Other botanical agents, such as arnica, bromelain, chamomile, pomegranate, caffeine, green tea, licorice, and resveratrol, are also briefly considered. Some of these ingredients have been incorporated into topical formulations.

Introduction

A significant change has occurred in the US during the last 10 to 15 years as an increasing portion of the population has embraced at least some aspect of complementary and alternative medicine (CAM). Within this framework, the use of herbal therapies is the most pertinent to dermatology, particularly since herbal therapies are said to represent the most common CAM modality used by adults in the US. Botanicals with longstanding uses in traditional or folk medicine are especially popular. Several of the copious herbal ingredients under investigation for their potential medical benefits, or those established through research to exhibit such activity, are touted for imparting dermatologic benefits and various topical formulations have become available to join the more numerous array of oral botanical supplements. This article will focus on selected herbal ingredients in cosmeceutical products intended for dermatologic purposes, some of which have gained increasing attention in the West after a long history of use in Asia, including curcumin, ginkgo biloba, ginseng, silymarin, soy, and tea tree oil. Other products of botanical origin that have gained more mainstream appeal, and use within the medical establishment, such as arnica, bromelain, chamomile, pomegranate, caffeine, green tea, licorice, and resveratrol, are also briefly considered.

A thorough discussion of the very broad array of botanical products used in medicine, particularly in dermatology, or that show promise as potential components in the dermatologic armamentarium would far exceed the limitations of this article.

Curcumin/Turmeric

Turmeric (Curcuma longa, Zingiberaceae) is best known as a spice used primarily in Asian cuisine, particularly curry, and in prepared mustard. It is also used in some traditional Indian communities as a topical burn treatment. In fact, turmeric has long been used as an anti-inflammatory agent in Chinese and Ayurvedic medicine. (1) Specifically, turmeric has been used in Ayurvedic medicine to treat sprains and edema due to injury.

Curcumin (Diferuloylmethane), the key biologically active component of turmeric, has shown great potency against acute inflammation, (1) and has been shown to exhibit significant wound healing, anticarcinogenic, anti-inflammatory, and antioxidant properties. (2) Its anticarcinogenic characteristics are particularly well-documented, as are its demonstrated antioxidant and lipid peroxidation activity. (2) Antibacterial, antiparasitic, and anti-HIV activity has also reportedly been exhibited by turmeric or curcumin. In addition, curcumin reportedly has greater anti-inflammatory capacity than ibuprofen. (1)

In various animal models, topical application of curcumin has been shown to inhibit initiation and promotion of tumorigenesis. (3) In addition, very low doses of topically applied curcumin have been found to mediate TPA-induced oxidation of DNA bases in the epidermis and tumor promotion in the skin. Pretreatment with curcumin has exhibited the same inhibitory effects on TPA-mediated dermatitis. Finally, topical curcumin is considered one of the only safe therapies for radiation exposure, and it is believed to possess great potential as a therapeutic agent for wound repair, especially in reducing healing delays caused by radiation and involving combined injuries. (4) Cosmetics containing curcumin are available throughout the world, particularly in India. Several other botanical ingredients originating in Asia, and also with long histories of traditional medical use, are being used or investigated for use in dermatologic applications.

Gingko Biloba

In China and Japan, the leaves and nuts of the Ginkgo biloba (G. biloba) tree have been used for thousands of years to treat various medical conditions, including poor circulation; hypertension; poor memory, dementia, and depression, particularly among the aged; male impotence; and disorders related to an inner ear imbalance, such as deafness, tinnitus, and vertigo. In addition, G. biloba is gaining a similar reputation as a significant antioxidant and anti-inflammatory agent. The G. biloba extract EGb 761, prepared from the tree's leaves, is a natural mixture containing flavone glycosides (33%), mostly quercetin and kaempferol derivatives, and terpenes (6%), which has exhibited the capacity to reduce the number of ultraviolet B (UVB)-induced sunburn cells in mice. (5)