Abstract

The skin consists of collagen fibers, which play a role in maintaining the stability of the skin and regeneration of damaged cells. Several studies have shown that exposure to UVB typically causes a decrease in the production of collagen fibers. Noni (Morinda citrifolia) has been reported to be an effective medicinal plant with strong antioxidant activity. Therefore, this study aimed to determine the effect of noni gel on collagen density and p53 protein expression in rats exposed to UVB. Twenty-Five male Wistar rats were divided into five groups of five rats each, and treated as follows; Group I consisted of healthy rats not exposed to UVB, Group II consisted of rats exposed to UVB, while Groups III, IV, and V were consisted of rats exposed to UVB and treated with gel base, noni extract gel (10%), and tretinoin (vitacid 0.025%) gel, respectively. UVB exposure was carried out for 5 days/week over a period of 14 days. On the 14th day, skin tissues were collected and assessed for collagen using Masson's Trichrome staining, and p53 expression was assayed by polymerase chain reaction (PCR) technique. The results showed that noni extract gel significantly increased collagen density, and significantly decreased p53 gene expression in the skin of UVB-exposed rats. The effects were comparable to that of the positive control (tretinoin). These observations suggest that noni extract could be a natural source of compound(s) with potential anti-aging properties that could be used in the prevention and treatment of photo-induced aging.