PROBLEM TO BE SOLVED: To provide novel skin quality improving agents.SOLUTION: Provided is a filaggrin gene expression promoting agent, an involucrin gene expression promoting agent, a PPARα gene expression promoting agent, a PPARγ gene expression promoting agent, an endothelin gene silencing agent, or a cornified envelope maturation agent which contains Passiflora-caerulea (except a seed and a fruit) extract as an active ingredient. A skin pigmentation inhibitor comprising the endothelin gene silencing agent is also provided. A skin quality improving agent containing either of the agents is also provided. A method for using the skin quality improving agent as a material of various food and drinks, pharmaceuticals, or cosmetics is also provided.SELECTED DRAWING: None【課題】新規な肌質改善剤の提供。【解決手段】トケイソウ（種子及び果実を除く）抽出物を有効成分とする、フィラグリン遺伝子発現促進剤、インボルクリン遺伝子発現促進剤、ＰＰＡＲα遺伝子発現促進剤、ＰＰＡＲγ遺伝子発現促進剤、エンドセリン遺伝子発現抑制剤又はコーニファイドエンベロープ成熟化剤。前記エンドセリン遺伝子発現抑制剤を含む皮膚色素沈着抑制剤。前記いずれかの剤を含有する肌質改善剤。前記肌質改善剤は各種飲食品、医薬品又は化粧品の素材として使用する方法。【選択図】なし
