School of Food Science and Engineering, South China University of Technology, Guangzhou, 510641, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, 510641, China.
School of Food Science and Engineering, South China University of Technology, Guangzhou, 510641, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, 510641, China.
J Ethnopharmacol. 2021 Apr 24;270:113808. doi: 10.1016/j.jep.2021.113808. Epub 2021 Jan 12.
Moringa oleifera Lam. leaf (MOL), a rich source of protein and phenolics, was traditionally used to treat various diseases including headaches, fevers, sore throat and dyslipidemia. Recently, MOL was reported to possess antioxidant, anti-dyslipidemia and hepato-renal protective activities, indicating that MOL could become a potential agent to improve metabolic disorders associated with hyperuricemia. The antihyperuricemic effect of MOL hydrolysate (MOLH) with high contents of phenolics and peptides remains unknown.
The aim of this study is to investigate xanthine oxidase (XO) inhibitory activity of MOLH, to clarify phenolic and peptide profiles of MOLH, and to evaluate possible mechanism underlying the antihyperuricemic effect of MOLH.
MOLH was prepared by enzymatic hydrolysis using commercial trypsin. XO inhibitory activity was determined by XO reaction-UPLC-MS coupling method. The chemical profiles of the phenolic and peptide fractions of MOLH were determined by UPLC-QTOF-MS/MS. The antihyperuricemic effect of MOLH was evaluated in a potassium oxonate-induced hyperuricemic rat model at doses of 200 and 500 mg/kg. Serum uric acid (UA), urea nitrogen, creatinine (CRE), triglyceride (TG), total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol levels, serum XO activity, liver malondialdehyde (MDA) equivalent level, renal tumor necrosis factor-α and interleukin-1β levels, and protein expression of renal urate-anion transporter 1, glucose transporter 9 and ATP-binding cassette transporter G2 were determined.
The phenolic and peptide fractions played key roles in inhibiting XO activity and blocking uric acid production. Five flavonoids and sixteen polypeptides were identified in the phenolic and peptide fractions of MOLH, respectively. MOLH (200 and 500 mg/kg) could effectively reduce the serum UA level of hyperuricemic rats (p < 0.001) by regulation of serum XO activity (p < 0.05 at 200 mg/kg, p < 0.01 at 500 mg/kg) and renal urate transporters. Besides, MOLH could improve metabolic disorders associated with hyperuricemia by its multiple actions on liver MDA (p < 0.001), serum CRE (p < 0.05 at 500 mg/kg) and serum TG (p < 0.001).
The results provided scientific evidence that MOLH rich in phenolics and peptides ameliorated hyperuricemia and metabolic disorders. This study validated the potential use of MOLH for regulation of hyperuricemia.
辣木（Moringa oleifera Lam.）叶是一种富含蛋白质和酚类化合物的丰富来源，传统上用于治疗各种疾病，包括头痛、发热、喉咙痛和血脂异常。最近，辣木叶被报道具有抗氧化、抗血脂异常和肝肾功能保护作用，这表明辣木叶可能成为改善与高尿酸血症相关的代谢紊乱的潜在药物。具有高含量酚类和肽类的辣木叶水解物（MOLH）的降尿酸作用尚不清楚。
本研究旨在研究 MOLH 的黄嘌呤氧化酶（XO）抑制活性，阐明 MOLH 的酚类和肽类特征，并评估 MOLH 降尿酸作用的可能机制。
采用商业胰蛋白酶酶解制备 MOLH。通过 XO 反应-UPLC-MS 偶联法测定 XO 抑制活性。采用 UPLC-QTOF-MS/MS 测定 MOLH 中酚类和肽类的化学特征。在 200 和 500mg/kg 剂量下，在氧嗪酸钾诱导的高尿酸血症大鼠模型中评价 MOLH 的降尿酸作用。测定血清尿酸（UA）、尿素氮、肌酐（CRE）、甘油三酯（TG）、总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇水平、血清 XO 活性、肝丙二醛（MDA）当量水平、肾肿瘤坏死因子-α和白细胞介素-1β水平以及肾尿酸阴离子转运蛋白 1、葡萄糖转运蛋白 9 和 ATP 结合盒转运蛋白 G2 的蛋白表达。
酚类和肽类成分在抑制 XO 活性和阻断尿酸生成方面发挥了关键作用。在 MOLH 的酚类和肽类成分中分别鉴定出 5 种黄酮类化合物和 16 种多肽。MOLH（200 和 500mg/kg）可通过调节血清 XO 活性（200mg/kg 时 p<0.05，500mg/kg 时 p<0.01）和肾脏尿酸转运体，有效降低高尿酸血症大鼠的血清 UA 水平（p<0.001）。此外，MOLH 通过对肝 MDA（p<0.001）、血清 CRE（500mg/kg 时 p<0.05）和血清 TG（p<0.001）的多种作用，改善了与高尿酸血症相关的代谢紊乱。
这些结果为 MOLH 富含酚类和肽类化合物改善高尿酸血症和代谢紊乱提供了科学依据。本研究验证了 MOLH 用于调节高尿酸血症的潜在用途。
