Lin Yin-Shiou, Lu Yeh-Lin, Wang Guei-Jane, Liang Hong-Jen, Hou Wen-Chi
Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan.
School of Pharmacy, Taipei Medical University, Taipei, Taiwan.
Bot Stud. 2014 Dec;55(1):49. doi: 10.1186/s40529-014-0049-3. Epub 2014 Jun 7.
We reported that yam dioscorin and its peptic hydrolysates exhibited ACE inhibition and antihypertensive effects on SHRs, however, the active peptides are not really isolated until now. Using ACE inhibitory screenings, two penta-peptides, KTCGY and KRIHF, were selected for ex vivo and in vivo experiments.
KTCGY, KRIHF, and captopril were shown to have similar vasodilating effects against phenylephrine (PE)-induced tensions in rat endothelium-dependent thoracic aortic rings, however, KTCGYKTCGY (two-repeated KTCGY) and TCGYTCGY (two-repeated TCGY) were showed endothelium-independent vasodilating effects against PE-induced tensions. KTCGY, KRIHF (10 or 20 mg/kg), and captopril (10 mg/kg) were used to evaluate antihypertensive activity during 24-h after a single oral administration to spontaneously hypertensive rats (SHRs). The KTCGY and KRIHF showed significantly different and reduced the systolic blood pressure of SHRs compared to the blank.
These results suggest that KTCGY and KRIHF may contribute important roles in yam dioscorin for regulating blood pressure in vivo.
我们曾报道山药薯蓣皂素及其胃蛋白酶水解产物对自发性高血压大鼠（SHRs）具有血管紧张素转换酶（ACE）抑制作用和降压效果，然而，活性肽至今尚未真正分离出来。通过ACE抑制筛选，选择了两种五肽KTCGY和KRIHF进行体外和体内实验。
KTCGY、KRIHF和卡托普利对苯肾上腺素（PE）诱导的大鼠内皮依赖性胸主动脉环张力具有相似的舒张血管作用，然而，KTCGYKTCGY（两个重复的KTCGY）和TCGYTCGY（两个重复的TCGY）对PE诱导的张力表现出非内皮依赖性舒张血管作用。将KTCGY、KRIHF（10或20mg/kg）和卡托普利（10mg/kg）用于评估单次口服给药后24小时内对自发性高血压大鼠（SHRs）的降压活性。与空白组相比，KTCGY和KRIHF显著降低了SHRs的收缩压。
这些结果表明，KTCGY和KRIHF可能在山药薯蓣皂素体内调节血压中发挥重要作用。
