The Topical Skin Application of Purple Corn Extract (Zea mays) Inhibited the Increase in MMP-1 Levels and Decreased Collagen in Wistar rats (Rattus norvegicus) Exposed to UV-B Rays

Formation of free radicals is an important mechanism causing skin aging. Free radicals are highly reactive molecules with unpaired electrons which can directly disrupt various structures of cell membrane, lipids, proteins, and DNA. Antioxidant is a substance which can give protection from endogenous and exogenous oxidative pressure caused by free radicals. Purple corn contains phenolic acid, vitamin C, and anthocyanin. Anthocyanin is the main contained substance in purple corn and acts as antioxidant and able to inhibit aging process on skin surface of mice exposed with UV-B ray. This research aims to prove the effectivity of administration of purple corn extract cream on inhibiting the elevation of MMP-1 level and the decrease of collagen amount on Wistar mice (Rattus norvegicus) exposed with UV-B. This research is animal experiment with post test only control group design. As many as 36 mice were divided into 2 groups containing 18 mice each, control group with appliance of placebo cream and intervention group applied with 50% purple corn extract cream. All groups were exposed with UV-B with dose of 840 mJ/cm² for 4 weeks, and biopsy was taken to examine the level of MMP-1 and collagen amount on dermis. The results of Shapiro-Wilk and Levene’s test showed that the data distribution between the two groups was normally distributed with homogenous variance and p e” 0.05. Comparative analysis with t-independent test showed that there is a significant difference between both groups, either on the mean level of MMP-1 or the collagen amount on both groups with p < 0.05. The mean collagen amount and mean MMP-1 level of intervention 2 are 71.7% and 1.9 mg/ml, respectively. Intervention-1 group shows the mean amount of collagen and MMP-1 level are 65.54 % and 3.22 mg/ml, respectively. The conclusion of this research is the administration of 50% purple corn extract cream inhibits the increase of MMP-1 level and the decrease of the amount of dermal collagen on mice’s skin exposed with UV-B.