arbutin and Dermatitis--Contact

Hydroquinone (HQ) has been used as a skin-lightening cosmetic ingredient, while it has been known that HQ shows sensitizing potential and cross-reactivity toward a strong sensitizer, p-phenylenediamine (PPD). alpha-Arbutin, a glycoside of HQ (4-hydroxyphenyl alpha-D-glucopyranoside), is used worldwide as a skin-lightening agent. The aim of this study was to evaluate the cross-reactivity of alpha-arbutin toward PPD and HQ. All tests were performed using the guinea pig maximization test. In experiments on the cross-reactivity of alpha-arbutin or HQ to PPD, six animals in each group were induced with PPD at 0.1% by i.d. injection and at 1.0% by topical application. The animals were challenged with alpha-arbutin, HQ or PPD (as a positive control) at concentrations of 0.01%, 0.05% and 0.1%. In experiments on the cross-reactivity of alpha-arbutin to HQ, four animals in each group were induced with HQ at 2% by i.d. injection and at 1% by topical application. The animals were challenged with alpha-arbutin or HQ (as a positive control) at concentrations of 0.2%, 2% and 20%. The cross-reactivity toward PPD was observed with HQ (4/6) only at 0.1% challenge. However, alpha-arbutin showed no apparent cross-reactivity to either PPD or HQ even at their highest challenge concentrations. Potent sensitization was observed with PPD (6/6) even at 0.01% challenge and with HQ (3/4) at 0.2%. In conclusion, glycosylation of HQ remarkably reduced the sensitization potency of HQ and the cross-reactivity of HQ to PPD.

Topics: Animals; Arbutin; Cross Reactions; Dermatitis, Contact; Dose-Response Relationship, Drug; Female; Guinea Pigs; Hydroquinones; Phenylenediamines; Reference Standards; Skin Pigmentation

The effect of 50% methanolic extract (U-ext) from Bearberry leaf on immuno-inflammation was studied by contact dermatitis caused by picryl chloride (PC-CD) in mice. The combined effect of U-ext and prednisolone was also investigated by using similar experimental model. When given orally twice immediately before and 16 h after the application of PC-CD, U-ext did not show an inhibitory effect on the swelling induced by PC-CD while it exhibited a significant therapeutic effect at a dose of 100 mg/kg or more once 24 h after the application. When U-ext (p.o.) and prednisolone (s.c.) in a given portion were simultaneously administered, the inhibitory effect was more potent than that of prednisolone alone in both administration immediately before and 16 h after or once 24 h after the application. Arbutin isolated from U-ext also increased the inhibitory effect of prednisolone similarly to that of U-ext. These results suggest that Bearberry leaf possesses a therapeutic effect against immuno-inflammation induced by PC-CD and also increases the inhibitory effect of prednisolone, and its active principle may be arbutin.

Topics: Animals; Arbutin; Arthritis, Experimental; Capillary Permeability; Dermatitis, Contact; Drug Therapy, Combination; Edema; Glycosides; Histamine Release; Mice; Picryl Chloride; Prednisolone; Rats

A study was carried out to examine the combined effect of arbutin isolated from the leaves of Arctostaphylos uva-ursi (L.) Spreng. (Bearberry leaf) and prednisolone or dexamethazone on Type IV allergic reaction-induced immuno-inflammation. Contact dermatitis caused by picryl chloride (PC-CD) and sheep red cell delayed type hypersensitivity (SRBC-DTH) in mice was not inhibited by the oral application of arbutin at 2 divided doses immediately before and 16 h after the application, but arbutin at doses of 10, 50 mg/kg 24 h after the application speedily decreased the swelling of PC-CD and SRBC-DTH. Arbutin plus prednisolone or dexamethazone showed the inhibitory effect on the swelling of PC-CD and SRBC-DTH stronger than that of prednisolone or dexamethazone alone. Prednisolone and dexamethazone decreased the weight of thymus and spleen in intact, PC-CD and SRBC-DTH mice, but arbutin did not show these effects. These results suggest that arbutin may increase the inhibitory action of prednisolone and dexamethazone on PC-CD and SRBC-DTH, but further investigations are required to understand the mechanism involved.

Topics: Animals; Arbutin; Dermatitis, Contact; Dexamethasone; Drug Therapy, Combination; Female; Glycosides; Hypersensitivity, Delayed; Male; Mice; Picryl Chloride; Prednisolone