PROBLEM TO BE SOLVED: To provide a new and useful kinesin inhibitor and to provide a composition which is useful for easing, preventing or improving various pigmentation symptoms such as a skin blemish and a freckle.SOLUTION: A kinesin inhibitor containing a specific plant extract (a geranium extract, a Zanthoxylum piperitum extract, a Paeonia lactiflora extract, a mugwort extract, a lemon balm extract, and a rose hip extract) as an active ingredient, a pigmentation inhibitor based on kinesin inhibition action, and various compositions (pharmaceutical compositions, food compositions and cosmetic compositions) containing the kinesin inhibitor are provided.COPYRIGHT: (C)2013,JPO&INPIT【課題】新規で有用なキネシン抑制剤及び、シミやソバカスをはじめとする様々な色素沈着症状の緩和、予防・改善に有用な組成物を提供する。【解決手段】特定の植物抽出物(ゲンノショウコ抽出物、サンショウ抽出物、シャクヤク抽出物、ヨモギ抽出物、レモンバーム抽出物、ローズヒップ抽出物)を有効成分とするキネシン抑制剤、及びキネシン抑制作用に基づく色素沈着抑制剤。更に、キネシン抑制剤を含有する各種組成物(医薬組成物、食品組成物、化粧料組成物)。【選択図】なし