Featured Plant Resources
Research Advances in Whitening Ingredients
The shade of skin color is mainly related to melanin in the epidermis, which is synthesized in melanocytes, then transferred to basal cells through melanocytes, and distributed in various epidermal cell layers with the migration of keratinocytes, and finally detached from the skin surface with the exfoliation of keratinocytes. The melanocytes in the underlying skin layer are the key factor affecting the melanin content in the skin. During the skin renewal process, tyrosine in melanocytes is gradually transformed into true melanin or brown melanin through a series of oxidation reactions. Therefore, the main pathways to solve skin whitening problems include: (i) reducing oxidative free radical damage brought about by UV rays through protective measures; (ii) inhibiting signaling receptors related to melanin signaling pathway; (iii) inhibiting melanin synthesis; (iv) inhibiting melanin transport; and (v) accelerating melanin peeling metabolism in the skin surface.
The mechanism by which many characteristic plant whitening ingredients function is also based on the above pathways. Through modern scientific research, the common characteristic plant resources used for whitening effects are as follows.
1. Resveratrol and its derivatives
Resveratrol, which is mainly produced in plants and can be extracted and isolated from a variety of plants such as grapes, can reduce melanin synthesis in melanocytes by inhibiting the function of melanocytes and the activity of tyrosinase. Resveratrol is also associated with TPR and MITF, proteins involved in melanogenesis, and is also able to inhibit mRNA and protein expression of transcription factors. Some studies have shown that topical resveratrol can have an effect on skin color and can have a whitening effect with no adverse effects and a high safety profile. However, resveratrol is unstable and poorly bioavailable during its use. Currently, its derivatives such as pentaalkyl ether derivatives and tetraester derivatives can effectively inhibit the synthesis of melanin and are more bioavailable. Therefore, resveratrol and its derivatives are more widely used as skin whitening ingredients.
2. Sambucus extract
Sambucus is a plant of the genus Sambucus in the family Sambucus, which is mainly distributed in Henan, Hebei and the Yangtze River basin in China. Some studies have shown that Sambucus extract can inhibit the proliferation of B16 melanoma cells and the activity of tyrosinase in them, reducing the amount of melanin. It has also been shown that skin care creams containing Sambucus extract are less irritating to the skin and have a higher stability of the product, with a significantly higher whitening effect than the control group. As a whitening efficacy ingredient of plant origin, Sambucus extract is expected to have a promising use in the cosmetic field.
3. Camellia sinensis extract
The flower bud extract of Camellia sinensis has the effect of inhibiting melanin production. Some studies have shown that the effect of Camellia sinensis branch extract on cell proliferation and inhibition of tyrosinase activity is better than that of arbutin, while the safety test results show that its safety is better than that of arbutin, and it can be used as an efficacious ingredient for whitening in cosmetics.
4. Licorice Extract
The active ingredients of licorice extract are mainly flavonoids. Among them, glycyrrhizin can lighten melanin aggregation; the main role of licorice flavonoids is to achieve whitening effect by inhibiting the activity of various enzymes in melanin formation, such as inhibition of tyrosinase and dopa pigment interchangease. Some studies have found that skin care products containing licorice extracts help in the treatment of melasma and post-inflammatory hyperpigmentation, and have fewer adverse effects and higher safety, usually added at 10% or more in whitening products. However, the flavonoids in licorice are more expensive to use due to the high requirements of the separation and purification process.
5. Rhodiola Rosea Extract
Rhodiola rosea extract mainly contains rhodiola glycosides and flavonoids. It has been shown that rhodiola glycosides can reduce cell membrane damage caused by UV light. The extract can inhibit the synthesis of melanin and reduce the activity of tyrosinase, making it an effective ingredient for skin whitening. Studies on the safety of Rhodiola rosea extract have shown that at low concentrations (under 5%) Rhodiola rosea extract is not irritating to humans and can be safely used in cosmetics.
6. Tea extract
Tea is a famous trading raw material in our history, which contains a variety of recognized whitening active ingredients, such as theaflavin and catechic acid (EGCG). Theaflavin and EGCG have various physiological effects, including inhibiting the transfer of melanin vesicles and inhibiting the activity of tyrosinase, thus exerting a whitening effect. In addition, they can prevent UV damage to skin cells and have a good antioxidant effect, thus enhancing the whitening effect.
Some researchers have studied the ethanolic extracts of more than 100 herbal medicines, and the results showed that the ingredients such as Glycyrrhiza glabra and Schisandra chinensis have an inhibitory effect on the abnormal increase of pigment components in the skin. Some studies found that plants such as Rhodiola rosea extract, licorice extract, ginkgo extract and antiphlogistic extract have strong inhibition of tyrosinase activity and can be developed and used as whitening efficacy ingredients in whitening cosmetics. It can be seen that plant resources will gradually become the chasing object of whitening efficacy ingredients in cosmetics, and the characteristic plant resources whitening ingredients will surely become a hot spot for whitening cosmetics.
