Faculty of Sciences and Philosophy, Department of Biological and Physiological Sciences, Universidad Peruana Cayetano Herediam Lima, Peru.
Int J Dermatol. 2011 Aug;50(8):928-38. doi: 10.1111/j.1365-4632.2010.04793.x.
Skin exposure to ultraviolet (UV) B radiation leads to epidermal damage and generation of reactive oxygen species. The photoprotective effect of extracts of three varieties of leaves (red, yellow, and black) from maca (Lepidium meyenii), a plant from the Peruvian highlands, was assessed in mouse skin exposed to UVB radiation.
The hydroalcoholic extracts of three varieties of maca leaves were applied topically to the dorsal skin of young-adult male mice prior to exposition to UVB radiation.
The three varieties had UVA/UVB absorptive properties and presented antioxidant activity, being highest with red maca, followed by black and yellow maca. The three varieties of maca leaves prevented the development of sunburn cells, epidermal hyperplasia, leukocytic infiltration, and other alterations produced by UVB radiation. Mice treated with black maca showed the highest superoxide dismutase levels, and mice treated with black and yellow maca showed higher catalase levels in skin, whereas red maca protected the skin and liver against significant increases in the lipid peroxidation activity observed in the unprotected animals.
The presence of significant antioxidant activity and the inhibition of lipid peroxidation suggest that the observed protection could be partly attributable to this mechanism.
皮肤暴露于紫外线 (UV) B 辐射会导致表皮损伤和活性氧的产生。本研究评估了来自秘鲁高地的植物玛卡（Lepidium meyenii）的三种叶片（红、黄、黑）提取物对暴露于 UVB 辐射的小鼠皮肤的光保护作用。
在将年轻成年雄性小鼠的背部皮肤暴露于 UVB 辐射之前，将三种玛卡叶片的水醇提取物局部应用于其皮肤。
三种玛卡叶片均具有 UVA/UVB 吸收特性，并表现出抗氧化活性，其中红玛卡最高，其次是黑玛卡和黄玛卡。三种玛卡叶片均可预防由 UVB 辐射引起的晒伤细胞、表皮增生、白细胞浸润和其他改变。用黑玛卡处理的小鼠超氧化物歧化酶水平最高，而用黑玛卡和黄玛卡处理的小鼠皮肤中的过氧化氢酶水平更高，而红玛卡可防止皮肤和肝脏中的脂质过氧化活性显著增加，这种脂质过氧化活性在未受保护的动物中观察到。
存在显著的抗氧化活性和抑制脂质过氧化作用表明，观察到的保护作用可能部分归因于这种机制。
