The Diuretic Effects of Coconut Water by Suppressing Aquaporin and Renin-Angiotensin-Aldosterone System in Saline-Loaded Rats

Jing Wei; Mantong Zhao; Keke Meng; Guanghua Xia; Yonggui Pan; Congfa Li; Weimin Zhang

doi:10.3389/fnut.2022.930506

The Diuretic Effects of Coconut Water by Suppressing Aquaporin and Renin-Angiotensin-Aldosterone System in Saline-Loaded Rats

Front Nutr. 2022 Jun 23:9:930506. doi: 10.3389/fnut.2022.930506. eCollection 2022.

Authors

Jing Wei^{1

2}, Mantong Zhao¹, Keke Meng¹, Guanghua Xia^{1

2}, Yonggui Pan¹, Congfa Li¹, Weimin Zhang^{1

2}

Affiliations

¹ Hainan Engineering Research Center of Aquatic Resources Efficient Utilization in South China Sea, Key Laboratory of Food Nutrition and Functional Food of Hainan Province, Key Laboratory of Seafood Processing of Haikou, College of Food Science and Engineering, Hainan University, Haikou, China.
² Key Laboratory of Tropical Fruits and Vegetables Quality and Safety for State Market Regulation, Hainan Institute for Food Control, Haikou, China.

Abstract

The acute and prolonged diuretic effects of coconut water (CW) and the underlying mechanism were investigated with a saline-loaded rat model. In an acute diuretic experiment, CW could significantly increase urine excretion. In addition, the treatment of CW significantly increased urinary sodium and chloride ions, thereby considerably increasing the excretion of NaCl. However, the calcium concentration and pH value were not affected. In the prolonged diuretic experiment, CW dramatically increased the urine output and urine electrolyte concentrations (Na⁺, K⁺, and Cl^-). Furthermore, CW could suppress the activation of renin-angiotensin-aldosterone system by decreasing serum antidiuretic hormone, angiotensin II, and aldosterone levels, and significantly increasing the serum atriopeptin level. CW treatment significantly reduced the mRNA expressions and protein levels of aquaporin 1 (AQP1), AQP2, and AQP 3. This report provided basic data for explaining the natural tropical beverage of CW as an alternative diuretic agent.

Keywords: AQP; coconut (Cocos nucifera L.); coconut water; polyphenols; water-electrolyte metabolism.