Use Of Glycyrrhiza glabra L. In Improving Skin Diseases

Background:Plant extracts are being increasingly used in special skin care products with claims of effects. One of these effective plant extracts is licorice extract. Glycyrrhiza glabra L. belongs to the Papilionaceae family. The licorice root and rhizome have medicinal uses, the main ingredient being glycosides called glycyrrhizin or glycyrrhizic acid. Licorice can be used to improve symptoms including some skin diseases such as eczema, psoriasis, Striae gravidarum and cellulite, Hyperpigmentation and melasma and it is also effective in increasing hair growth, especially in women.Methods:1. The use of licorice in improving eczema:1-1. A licorice extract standardized for glycyrrhetinic acid was studied in the form of a gel with 1% and 2% extract in the therapy of atopic dermatitis in a double-blind, placebo-controlled clinical phase II study on 30 patients per group for 2 weeks.1-2. Another cream with glycyrrhetinic acid, vine leaf extract, telmesteine and allantoin was examined in a multicenter, randomized, placebo-controlled study on 281 adults with mild to moderate atopic dermatitis for 5 weeks.2. The use of licorice in the treatment of psoriasis: A total of 100 patients with psoriasis were enrolled in our study and randomized into an acitretin (Aci) group (n=50) and a compound glycyrrhizin/acitretin combined treatment (Aci+Glyc) group (n=50). Both groups were medicated with 3 × 10 mg acitretin per day for 8 weeks but the (Aci+Glyc) group received additionally 3 × 75 mg compound glycyrrhizin every day. A total of 50 healthy individuals were selected as the control group.The peripheral blood Th17 cell percentage as well as the IL-6, IL-17, IL-22 and TGF-β serum concentrations in addition to PASI scores were determined before and after medications.3. The use of licorice in improving Hyperpigmentation and melasma: The current work aimed to formulate a stable w/o cream containing Glycyrrhiza glabra L. extract and studying its effects on skin pigment melanin . Glycyrrhiza glabra L. Extract obtained by concentrating the alcoholic extract of Glycyrrhiza glabra L. roots, was entrapped in the inner aqueous phase of w/o emulsion. Base containing no active material and a formulation containing ethanolic extarct of Glycyrrhiza glabra L. (1%) were prepared. Both base and formulation were applied to the cheeks of human volunteers for 4 weeks. Different parameters of human skin like melanin, erythema were monitored every week to measure any effect produced by these creams.4. The use of licorice in improving Striae gravidarum and cellulite: The steroid saponin glycyrrhetinic acid is the main active ingredient of licorice extract. A randomized, two arm double-blind study with 18 women studied the efficacy of a cream containing 2.5% glycyrrhetinic acid on subcutaneous fat of the thigh for 4 weeks.5. The use of licorice in increasing hair growth: Female Wistar rats were used for the hair growth promotion studies. They were divided into three groups (n=6) and their dorsal skin was completely denuded to completely remove hair. Paraffin oil (control), 2% minoxidil solution (reference) or petroleum ether (60– 80 0C) root extract Glycyrrhiza glabra L. (2%), was applied to the denuded skin once daily for 30 days. During this period, they were observed visually for hair growth and thereafter skin biopsy was taken for evaluation of follicular density and cyclic phases of hair growth.Results:1. The use of licorice in improving eczema:1-1. After 2 weeks of treatment the 2% gel was superior to placebo as well as the 1% gel as erythema, edema and pruritus were significantly improved.1-2. After a treatment period of 5 weeks distinct superiority of the combination was observed as opposed to the vehicle (improvement of 10%).2. The use of licorice in the treatment of psoriasis: The Th17 cell percentages and the serum concentrations of IL-6, IL-17, IL-22 and TGF-β in the Aci and Aci+Glyc groups were significantly higher than those in the control group before treatments and were significantly declined after the treatments, but to a higher extend in the Aci+Glyc group. The clinical treatment effective rates in the Aci group and the Aci+Glyc group were 76.0% and 90.0% compared to invalid events after treatments.3. The use of licorice in improving Hyperpigmentation and melasma: Significant decrease in skin melanin was produced by formulation, where as insignificant decrease in this skin pigment was observed by base.4. The use of licorice in improving Striae gravidarum and cellulite: After 4 weeks of twice daily application a significant reduction of thigh circumference in comparison to the contralateral untreated side and to the placebo group was observed.5. The use of licorice in increasing hair growth: Animals treated with petroleum ether extract Glycyrrhiza glabra L. roots showed longer hair than those treated with either minoxidil or control. Furthermore, the time (5–13 days) for commencement of hair growth and to reach complete hair growth was least in extract-treated animals, followed by those treated with minoxidil (6-19 days). A maximum of 76% of hair follicles were in anagenic stage (active growth phase of hair) in extract-treated animals, compared to 66 and 45% in minoxidil-treated and control groups, respectively.Conclusion:According to the results of these studies, it can be concluded that due to limited side effects and high efficacy of licorice extract in improving skin diseases, it can be one of the therapeutic steps in these diseases. As a result, this plant can be considered as a suitable option for the production of herbal products to help maintain skin health.

کلیدواژه ها:

Glycyrrhiza glabra L. ، eczema ، psoriasis ، cellulite ، Hyperpigmentation.