study showed that the topical application of aloesin following ultraviolet (UV)-irradiation (210 mJ) on the inner forearm provided pigmentation suppression in a dose-dependent manner.6 Another in vitro study showed that aloesin induced melanin aggregation in isolated tail melanophores of tadpoles, B. melanostictus, which lead to lightening of the skin.7 More recently, aloe vera was tested in a double-blinded randomized clinical trial aimed at determining the clinical efficacy of a topical liposome- encapsulated aloe vera in the treatment of melasma in pregnant women. Researchers were able to show that this drug carrier system along with aloe vera decreased the severity of melasma in pregnancy when compared to aloe vera gel extract alone, as demonstrated by a 32% improvement in MASI scores in the treatment group compared to a 10% improvement in the control group.2 When used topically, aloe vera is generally considered safe; however, some case reports of skin irritation and hypersensitivity to Aloe products have been reported.8
Bamboo
Bamboo is a type of flowering plant that belongs to the Bambusoideae subfamily and has been used as a healing treatment by Asian cultures for centuries.9 In vitro studies have shown bamboo to be an effective lightening agent. Water extract from bamboo shavings (WEBS) has demonstrated potent inhibitory effects against the activity of melanin-synthesizing enzyme, tyrosinase, in malignant melanoma B-16 cells of mice.10 In this study, the effects were dose dependent and melanin content was significantly inhibited (65.05%) at 16 mg/ml with an inhibitory concentration (IC50) of 6 mg/ml. The application of the topical formulation was shown to be non-toxic and non-irritating to the skin. Another study examined the effects of bamboo extract on UVB-induced cell damage. Human keratinocytes were exposed to UVB in the presence of bamboo extract at varying concentrations and changes in cell viability were determined.11 Bamboo extract diminished the generation of reactive oxygen species, inhibited matrix metalloproteinase 1 expression, and enhanced UVB-exposed cell survivability, as measured by apoptotic assays. These results suggest that bamboo extract may have the ability to attenuate the process of skin photoaging. Few clinical trials on human subjects have been conducted on bamboo extract. The only clinical trial to date utilized a skin cream formulated with flavonoids and extracts from bamboo leaves.12 Results showed that addition of 1.5% topical bamboo extract resulted in sun screening efficacy and protection against UVB damage as indicated by an SPF of 1.27. A UV Index reading of 0 to 2 indicates low risk of harm from unprotected sun exposure for the average person. No irritation was reported by participants with topical application to the skin.
Ginseng
Ginseng has been used for centuries in Asian traditional medicine to treat many chronic diseases.13 The popularity of the ingredient has led to its formulation in high-end Asian skin care products. In vitro studies demonstrate that P-coumaric acid extracted from the fresh leaves of Panax ginseng inhibits tyrosinase activity and melanin content in B16 melanoma cells, suggesting that this ingredient may be an effective skin lightening agent.14 Furthermore, ethanol extract from ginseng seeds reduced melanin production in melan-a-cells (melanoctyes originating from mice) by 35.1% without cytotoxicity.15 Among the active metabolites isolated, picrionoside A was shown to be effective in reducing body pigmentation in zebrafish in addition to decreasing the rate of melanin synthesis in melan-a-cells by 17.1% without cytotoxicity.16 These in vitro studies suggest that different active ingredients in ginseng may be efficacious skin lightening agents. No clinical trials have studied the effects of topical application of ginseng. However, one study evaluated the effectiveness of oral administration of ginseng on patients with melasma. A cohort of 25 female patients consumed 3 grams of Korean red ginseng powder over a 24 week period.17 Skin pigmentation was assessed using the melasma area and severity index (MASI), melasma quality of life scale (MELASQoL), and patient/investigator-rated improvement scales. After 24 weeks, the MASI score decreased from 8.8 to 5.6, and the MELASQoL showed improvement in 91% of patients (P<0.05). The mean level of pigmentation decreased from 184.3 to 159.7 and erythema levels decreased from 253.6 to 216.4 (P<0.05). The regimen showed good tolerability overall with minimal adverse events.
Green Tea
Green tea is known for its potent antioxidant and anti-inflammatory properties.18 Among the many polyphenols in green tea extract, epigallo-catechin-3-gallate (ECGC) is the primary active ingredient.19 One study using immortalized melanocytes showed that camellia sinensis water extracts containing green tea inhibited melanogenesis and tyrosinase activity in a concentration- dependent manner.20 The skin lightening effects of green tea may be due to chelating properties at the active site of tyrosinase.21 In a randomized controlled trial, 60 women with melasma were treated with a 2% analogue of green tea in a hydrophilic cream.22 Hyperpigmentation lesions were significantly reduced in 60% of the experimental group relative to the control group as measured by a reduction of mean number of hyperpigmented lesions, as determined by dermatologic and photographic evaluations. In addition to treating melasma, green tea extracts were shown to reduce skin pigmentation in healthy Asian subjects.23 The lightening effects of green tea may be due to the prevention of sun damage accumulated over time. The skin of normal volunteers was treated with green tea or one of its main ingredients.24 After thirty minutes, the treated areas were exposed to solar-simulated UV radiation and subsequent UV-induced erythema was monitored. Skin areas with green tea extract showed a dose-dependent inhibition of erythema response caused by UV radiation. Further histology showed that areas of skin treated with green tea extract had a reduced num-
Bamboo
Bamboo is a type of flowering plant that belongs to the Bambusoideae subfamily and has been used as a healing treatment by Asian cultures for centuries.9 In vitro studies have shown bamboo to be an effective lightening agent. Water extract from bamboo shavings (WEBS) has demonstrated potent inhibitory effects against the activity of melanin-synthesizing enzyme, tyrosinase, in malignant melanoma B-16 cells of mice.10 In this study, the effects were dose dependent and melanin content was significantly inhibited (65.05%) at 16 mg/ml with an inhibitory concentration (IC50) of 6 mg/ml. The application of the topical formulation was shown to be non-toxic and non-irritating to the skin. Another study examined the effects of bamboo extract on UVB-induced cell damage. Human keratinocytes were exposed to UVB in the presence of bamboo extract at varying concentrations and changes in cell viability were determined.11 Bamboo extract diminished the generation of reactive oxygen species, inhibited matrix metalloproteinase 1 expression, and enhanced UVB-exposed cell survivability, as measured by apoptotic assays. These results suggest that bamboo extract may have the ability to attenuate the process of skin photoaging. Few clinical trials on human subjects have been conducted on bamboo extract. The only clinical trial to date utilized a skin cream formulated with flavonoids and extracts from bamboo leaves.12 Results showed that addition of 1.5% topical bamboo extract resulted in sun screening efficacy and protection against UVB damage as indicated by an SPF of 1.27. A UV Index reading of 0 to 2 indicates low risk of harm from unprotected sun exposure for the average person. No irritation was reported by participants with topical application to the skin.
Ginseng
Ginseng has been used for centuries in Asian traditional medicine to treat many chronic diseases.13 The popularity of the ingredient has led to its formulation in high-end Asian skin care products. In vitro studies demonstrate that P-coumaric acid extracted from the fresh leaves of Panax ginseng inhibits tyrosinase activity and melanin content in B16 melanoma cells, suggesting that this ingredient may be an effective skin lightening agent.14 Furthermore, ethanol extract from ginseng seeds reduced melanin production in melan-a-cells (melanoctyes originating from mice) by 35.1% without cytotoxicity.15 Among the active metabolites isolated, picrionoside A was shown to be effective in reducing body pigmentation in zebrafish in addition to decreasing the rate of melanin synthesis in melan-a-cells by 17.1% without cytotoxicity.16 These in vitro studies suggest that different active ingredients in ginseng may be efficacious skin lightening agents. No clinical trials have studied the effects of topical application of ginseng. However, one study evaluated the effectiveness of oral administration of ginseng on patients with melasma. A cohort of 25 female patients consumed 3 grams of Korean red ginseng powder over a 24 week period.17 Skin pigmentation was assessed using the melasma area and severity index (MASI), melasma quality of life scale (MELASQoL), and patient/investigator-rated improvement scales. After 24 weeks, the MASI score decreased from 8.8 to 5.6, and the MELASQoL showed improvement in 91% of patients (P<0.05). The mean level of pigmentation decreased from 184.3 to 159.7 and erythema levels decreased from 253.6 to 216.4 (P<0.05). The regimen showed good tolerability overall with minimal adverse events.
Green Tea
Green tea is known for its potent antioxidant and anti-inflammatory properties.18 Among the many polyphenols in green tea extract, epigallo-catechin-3-gallate (ECGC) is the primary active ingredient.19 One study using immortalized melanocytes showed that camellia sinensis water extracts containing green tea inhibited melanogenesis and tyrosinase activity in a concentration- dependent manner.20 The skin lightening effects of green tea may be due to chelating properties at the active site of tyrosinase.21 In a randomized controlled trial, 60 women with melasma were treated with a 2% analogue of green tea in a hydrophilic cream.22 Hyperpigmentation lesions were significantly reduced in 60% of the experimental group relative to the control group as measured by a reduction of mean number of hyperpigmented lesions, as determined by dermatologic and photographic evaluations. In addition to treating melasma, green tea extracts were shown to reduce skin pigmentation in healthy Asian subjects.23 The lightening effects of green tea may be due to the prevention of sun damage accumulated over time. The skin of normal volunteers was treated with green tea or one of its main ingredients.24 After thirty minutes, the treated areas were exposed to solar-simulated UV radiation and subsequent UV-induced erythema was monitored. Skin areas with green tea extract showed a dose-dependent inhibition of erythema response caused by UV radiation. Further histology showed that areas of skin treated with green tea extract had a reduced num-
