Protective effects of daily topical cocoa extract to the expression of 8-ohdg and pcna on uvb-exposed albino mice

Authors:A Adriani, SA Armin, MN Massi, K Djawad
Int J Biol Med Res. 2014; 5(4): 4607-4611  |  PDF File

Abstract

Background. Chronic impact caused by repeated exposure to low energy levels of ultraviolet B (UVB), in the form of precancerous, skin cancer and premature aging. 8-hydroxy-2-deoxyguanosine (8-OHdG) and proliferating cell nuclear antigen (PCNA) known as biomarker for UVB-induced DNA damage. Antioxidant are used to protect the skin from UVB-induced DNA damage, and cocoa is one of them due to their polyphenol content. Aims. Examine the protective effects of daily topical cocoa on UVB-exposed albino mice by measuring the expression of 8-OHdG (photoproduct) and PCNA. Method. 25 mice were randomly divided into 2 groups: group A and group B. Group A was a control group consisting of 5 negative controls mice (without cocoa extract and without exposure to UVB), and 5 control mice (without cocoa extract but exposed to UVB). Group B consisted of 3 groups, which were given daily topical cocoa extract in various concentrations then exposed to UVB 450 mJ /cm2 (3 times a week) for 12 weeks. All the animal were sacrificed 24 h after last exposure and samples were taken and proccess for 8-OHdG and PCNA expressions. Result. For 8-OHdG expression, cocoa extract 100 ppm had shown protective effects which improving along with increasing dose of cocoa extract, but at 400 ppm protective effect has declined. It has been shown that cocoa extract 200 ppm gave the best protection against UVB exposure. For PCNA expression, extracts of 100 ppm and 200 ppm showed significant protective effect against UVB, but at 400 ppm the effect has declined. Similar to 8-OHdG expression, cocoa extract 200 ppm gave the best protective effect against UVB. Conclusion. The best concentration of cocoa extract to exhibit protective effect against UVB is 200 ppm.