The salted radish takuan-zuke shows antihypertension effects in spontaneously hypertensive rats

Abstract

Recently, we reported that the antihypertensive compound, γ-aminobutyrate (GABA), increases over time during the dehydration of salted radish, known as takuan-zuke, a popular pickle in Japan. The objective of this study was to clarify the antihypertensive effects of takuan-zuke. We prepared two types of takuan-zuke by sun-drying (hoshi takuan-zuke) and salt-pressing (shio-oshi takuan-zuke) using dehydration processes. The oral administration of takuan-zuke lowered systolic blood pressure in spontaneously hypertensive rats (SHRs). Shio-oshi takuan-zuke (SR) demonstrated a clear antihypertension effect compared with hoshi takuan-zuke (DR), despite equal GABA concentrations in the feed. Furthermore, takuan-zuke demonstrated angiotensin converting enzyme (ACE) inhibition in vitro. These findings indicated that takuan-zuke contains unknown substances that have hypotensive actions independent of GABA. Further evaluation revealed that takuan-zuke contains polyphenols, arginine, and α-linolenic acid as possible antihypertensive factors. Collectively, our results suggest that the salty Japanese food takuan-zuke has antihypertensive effects in vivo, likely involving complex mechanisms.

Salted and Unsalted Zhàcài (Brassica juncea var. tumida) Alleviated High‐Fat Diet‐Induced Dyslipidemia by Regulating Gut Microbiota: A Multiomics Study

“…[22] Interestingly, salted radish also possesses antihypertension and antioxidant effects like fresh radish because it still contains dietary fibers, polyphenols, and -linolenic acid. [10,11,23] We found that salted ZC had a higher total content of dietary fiber, a primary constituent in ZC, than unsalted ZC. Dietary fiber is typically divided into two categories, namely soluble (e.g., pectin) and insoluble (e.g., cellulose).…”

“…Long-term salting fermentation not only endows vegetables with a new flavor but also changes the nutritional contents, including sugars, fatty acids, and glucoraphanin, which might imply changes in the health benefits. [10][11][12] Generally, salted vegetables are considered detrimental to cardiovascular health because an excessive intake of salt can cause health problems, including hypertension, cardiovascular disease, and others. [13] However, the salted radish also presents a health effect in reducing the blood pressure of rats, which might be because it still contains polyphenols, arginine, -linolenic acid, and other unknown antihypertension substances.…”

Salted Radish Root Biology during Food Processing

“…It has also been shown that GABA has an enhancement effect on salty taste [37,38]. We reported that the intake of takuan-zuke, containing GABA antihypertensive factor, improves renal function and suppresses blood pressure elevation in hypertension model rats [39]. The report also revealed that antihypertensive effects are high in salt-pressed takuan-zuke, which has low GABA content.…”

Nutritional Content Dynamics and Correlation of Bacterial Communities and Metabolites in Fermented Pickled Radishes Supplemented With Wheat Bran

“…GABA is a non-protein amino acid that is widely found in microorganisms, animals, various vegetables, fruits, and fermented foods, and is produced via the enzymatic decarboxylation of L-glutamate. The physiological functions of GABA as a neurotransmitter on human health include alleviating hypertension, neurological, and sleep disorders, as well as diuretic effects ( 38 , 39 ). The dehydration process for takuan-zuke has been shown to increase the concentration of GABA ( 40 ), which was consistent with our findings.…”