# Assessment of the Diuretic Properties of Rice Bean Accessions Using a Mouse Model and Identification of Active Polyphenolic Compounds

## TL;DR

This study explores the diuretic effects of rice bean extracts in mice and identifies polyphenolic compounds that may influence urine output.

## Contribution

The study identifies specific polyphenolic compounds in rice bean seeds that correlate with diuretic effects in mice.

## Key findings

- Rice bean extracts from yellow and black seeds increased urine output and water intake in mice compared to red seeds.
- Gallic acid and genistein showed significant negative correlations with urine output, suggesting they inhibit diuresis.
- Rutin and catechin did not show clear relationships with diuretic effects despite being present in higher concentrations.

## Abstract

Rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi], an annual legume in the genus Vigna, is a promising crop suitable for cultivation in a changing climate to ensure food security. It is also a medicinal plant widely used in traditional Chinese medicine; however, little is known about the medicinal compounds in rice bean. In this study, we assessed the diuretic effect of rice bean extracts on mice as well as its relationship with the contents of eight secondary metabolites in seeds. Mice gavaged with rice bean extracts from yellow and black seeds had higher urinary output (5.44–5.47 g) and water intake (5.8–6.3 g) values than mice gavaged with rice bean extracts from red seeds. Correlation analyses revealed significant negative correlations between urine output and gallic acid (R = −0.70) and genistein (R = −0.75) concentrations, suggesting that these two polyphenols negatively regulate diuresis. There were no obvious relationships between mice diuresis-related indices (urine output, water intake, and weight loss) and rutin or catechin contents, although the concentrations of both of these polyphenols in rice bean seeds were higher than the concentrations of the other six secondary metabolites. Our study findings may be useful for future research on the diuretic effects of rice bean, but they should be confirmed on the basis of systematic medical trials.