BASF Beauty Care Solutions France SAS, 32 rue Saint-Jean-de-Dieu, Lyon, France.
Int J Cosmet Sci. 2011 Feb;33(1):44-52. doi: 10.1111/j.1468-2494.2010.00581.x. Epub 2010 Aug 30.
Overproduction of sebum is very common and results in an undesirable oily, shiny complexion with enlarged pores. Sebum secretion is basically under the control of 5-α reductase, and more particularly under that of type 1 isozyme. But it is also highly sensitive to environmental factors such as temperature, humidity and food. Moreover, in Asia, the edicts of a flawless facial skin turn oily skin into a major concern for Asian women. We identified Orthosiphon stamineus leaf extract as an interesting ingredient for reducing the oily appearance of skin thanks to its ability to reduce 5-α reductase type 1 expression in normal human epidermal keratinocytes in vitro. This was confirmed ex vivo, where Orthosiphon stamineus leaf extract was shown to reduce 5-α reductase activity as well as the production of squalene, one of the main components of sebum that was used as a tracer of sebum. To evaluate the efficacy of Orthosiphon stamineus leaf extract at reducing sebum-related skin imperfections in vivo, we performed two different clinical studies, one in France on a panel of Caucasian volunteers and the other one in Thailand on a panel of Asian volunteers. Using instrumental techniques as well as clinical evaluation and self-evaluation, we could highlight that an O/W cosmetic formula containing 2% of Orthosiphon stamineus leaf extract could visibly reduce the oily appearance of skin as well as the size of pores, thus leading to a significant improvement of complexion evenness and radiance. Overall, the results obtained were better than those observed with the same formula containing 1% of zinc gluconate, an ingredient frequently used in oily skin care products.
皮脂过度分泌非常常见，会导致皮肤出现不理想的油腻、发亮外观，并伴有毛孔粗大。皮脂分泌基本上受 5-α 还原酶控制，尤其是 1 型同工酶。但它也对环境因素如温度、湿度和食物高度敏感。此外，在亚洲，完美无瑕的面部皮肤的要求使油性皮肤成为亚洲女性的主要关注点。我们发现，由于其能够在体外减少正常人类表皮角质形成细胞中 1 型 5-α 还原酶的表达，因此，越南参叶提取物是一种很有前途的减少皮肤油腻外观的成分。这在离体实验中得到了证实，其中越南参叶提取物被证明可以减少 5-α 还原酶的活性以及角鲨烯的产生，角鲨烯是皮脂的主要成分之一，被用作皮脂的示踪剂。为了评估越南参叶提取物在减少体内皮脂相关皮肤瑕疵方面的功效，我们进行了两项不同的临床研究，一项在法国对一组白种人志愿者进行，另一项在泰国对一组亚洲志愿者进行。使用仪器技术以及临床评估和自我评估，我们可以强调，含有 2%越南参叶提取物的 O/W 化妆品配方可以明显减少皮肤的油腻外观和毛孔大小，从而显著改善肤色均匀度和光泽度。总的来说，与含有 1%葡萄糖酸锌的相同配方相比，所得结果更好，葡萄糖酸锌是常用于油性皮肤护理产品的成分。
