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

Area of Science:

• Food Science
• Molecular Biology
• Biochemistry

Background:

• Matcha, a traditional Japanese green tea, is recognized for health benefits.
• Bioactive components like polyphenols, caffeine, and amino acids are known.
• The presence and role of other functional RNAs, such as microRNAs (miRNAs), in Matcha remain largely unexplored.

Purpose of the Study:

• To identify and quantify diverse microRNAs (miRNAs) as novel bioactive components in Matcha.
• To investigate factors influencing miRNA extraction and yield from Matcha.
• To explore the correlation between miRNA content and other major Matcha components.

Main Methods:

• Next-generation sequencing was employed to discover miRNAs in Matcha.
• Quantitative reverse-transcription PCR was used to analyze miRNA levels in 10 different Matcha samples.
• RNA extraction efficiency was assessed using various methods, including soaking at 95°C.
• Correlation analysis was performed between total RNA, miRNA yields, and major Matcha components.

Main Results:

• Diverse miRNAs were identified as new components of Matcha.
• miRNA levels varied significantly based on Matcha cultivar and harvest season.
• Soaking at 95°C optimized total RNA and miRNA extraction yields.
• Matcha demonstrated particularly high levels of four specific miRNAs (lja-miR166-3p, csn-miR396d-5p, gma-miR396e, csn-miRn409).
• A positive correlation was found between miRNA yields and major Matcha components.

Conclusions:

• Matcha is a significant source of microRNAs (miRNAs), expanding its profile as a bioactive food.
• Extraction conditions and plant characteristics critically affect miRNA recovery.
• These findings offer new perspectives on Matcha's health-promoting properties and the functional roles of miRNAs in tea.