Many commonly consumed plants are used as folk medicines, often with unclear molecular mechanisms. Recent studies uncovered the ubiquitous and influential KCNQ family of voltage-gated potassium (Kv) channels as a therapeutic target for several medicinal plant compounds. Capers - immature flower buds of Capparis spinosa - have been consumed for food and medicinal purposes for millennia. Here, we show that caper extract hyperpolarizes cells expressing KCNQ1 or KCNQ2/3 Kv channels. Capers are the richest known natural source of quercetin, the most consumed dietary flavonoid. Quercetin potentiated KCNQ1/KCNE1, KCNQ2/3 and KCNQ4 currents but, unusually, not KCNQ5. Strikingly, quercetin augmented both activation and inactivation of KCNQ1, via a unique KCNQ activation mechanism involving sites atop the voltage sensor and in the pore. The findings uncover a novel potential molecular basis for therapeutic effects of quercetin-rich foods and a new chemical space for atypical modes of KCNQ channel modulation.

许多常用的植物被用作民间药物，通常具有不清楚的分子机制。最近的研究发现电压门控钾（Kv）通道普遍存在且具有影响力的KCNQ家族可作为几种药用植物化合物的治疗靶标。刺山柑-Capparis spinosa的未成熟花蕾-几千年以来一直被用作食品和药物。在这里，我们显示雀跃提取物使表达KCNQ1或KCNQ2 / 3 Kv通道的细胞超极化。刺山柑是槲皮素的最丰富的天然来源，槲皮素是最消耗的饮食类黄酮。槲皮素增强了KCNQ1 / KCNE1，KCNQ2 / 3和KCNQ4的电流，但不常见的不是KCNQ5。令人惊讶的是，槲皮素通过独特的KCNQ激活机制（包括电压传感器顶部和孔中的位点）增强了KCNQ1的激活和失活。这些发现揭示了富含槲皮素的食品具有治疗作用的新的潜在分子基础，以及非典型模式的KCNQ通道调节的新化学空间。