# Comprehensive microRNA analysis toward exploring a new functional component in Matcha green tea

## TL;DR

This study identifies microRNAs (miRNAs) as new bioactive components in Matcha green tea, showing they vary by cultivar and harvest season and can be efficiently extracted with hot water.

## Contribution

The discovery of diverse miRNAs in Matcha and their correlation with major components provides a new functional perspective on this traditional tea.

## Key findings

- Matcha contains diverse miRNAs, revealed through next-generation sequencing.
- Soaking Matcha in 95°C water significantly increases RNA and miRNA yields.
- Matcha has the highest levels of four representative miRNAs among plant-based powders.

## Abstract

Matcha, a traditional Japanese green tea, has health-promoting effects. However, little is known about its bioactive components, except for polyphenols, caffeine, and amino acids. Here, we revealed the presence of diverse miRNAs, a type of functional RNAs, as new components of Matcha, using next-generation sequencing. Quantitative reverse-transcription PCR analysis of 10 different Matcha showed that miRNA levels varied depending on the cultivar and harvest season. As extraction methods of miRNAs, we found that soaking at 95 °C significantly enhanced total RNA and miRNA yields. Furthermore, a positive correlation was observed between total RNA and miRNA yields extracted from 27 plant-based dried powders. Notably, Matcha exhibited the highest levels of four representative miRNAs: lja-miR166-3p, csn-miR396d-5p, gma-miR396e, and csn-miRn409. The miRNA yields in Matcha were correlated with the major Matcha components. These results highlight Matcha as a source of miRNAs and candidate bioactive components. These findings provide new insights into the functionality of Matcha.

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•Next-generation sequencing revealed the presence of diverse miRNAs in matcha.•MiRNA levels in matcha differed depending on cultivars and harvesting seasons.•Soaking matcha powders in 95 °C hot water enhanced RNA and miRNA yields.•Matcha showed the highest levels of representative miRNA among plant-based powders.•MiRNA yields in matcha were correlated with the major three matcha components.

Next-generation sequencing revealed the presence of diverse miRNAs in matcha.

MiRNA levels in matcha differed depending on cultivars and harvesting seasons.

Soaking matcha powders in 95 °C hot water enhanced RNA and miRNA yields.

Matcha showed the highest levels of representative miRNA among plant-based powders.

MiRNA yields in matcha were correlated with the major three matcha components.