Laxative Ingredients of Fresh <i>Hemerocallis citrina</i> Baroni

Hemerocallis citrina Baroni is a healthy vegetable, and consumption of fresh H. citrina can lead to defecation. However, the laxative ingredients are still not known. In the present study, the laxative effect of fresh H. citrina extracts was primarily evaluated by loperamide-induced constipated mice, and the aqueous extracts (1500 and 3000 mg/kg) showed a significant laxative effect. The aqueous extracts were divided into three parts (0%, 30%, and 50% HCW) by macroreticular resin, and all of them were further evaluated. Based on comprehensive analysis of multiple indices, the constipation-relieving effect of 30% HCW was found to be superior to that of 0% and 50% HCW. A total of 16 compounds were identified from 30% HCW by the ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) method. Three high-level ingredients including chlorogenic acid (3), 4-O-p-coumaroylquinic acid (6) and rutin (13) were selected to further evaluate their laxative effect. The experimental results demonstrate that 4-O-p-coumaroylquinic acid increases defecation frequency in constipated mice, enhances fecal moisture content, and promotes small intestinal motility in constipated mice. The high-dose 4-O-p-coumaroylquinic acid treatment group exhibited higher mean small intestinal transit rates compared to the high-dose chlorogenic acid and rutin groups. Additionally, this compound effectively alleviated loperamide-induced pathological damage, including thinning of the muscle layer and reduced goblet cell numbers, thereby enhancing small intestinal motility, increasing fecal moisture content, and facilitating defecation. This is the first study to identify 4-O-p-coumaroylquinic acid as a key laxative component in fresh H. citrina Baroni, providing novel insights into its application in functional food or pharmaceutical development.