Michio Tsujimura (辻村みちよ, 1888–1969) was a Japanese biochemist whose research at Tokyo Imperial University transformed the scientific understanding of green tea — discovering the presence of vitamin C (1924) and later isolating catechins (1929), the polyphenol family now recognized as central to green tea’s antioxidant activity and health effects — and who simultaneously broke new ground as the first woman to earn a doctoral degree in agriculture in Japan.
In-Depth Explanation
Tsujimura was born in 1888 in Yamanashi Prefecture and showed exceptional academic ability from a young age. In an era when women in Japan faced enormous institutional barriers to higher education and research careers, she persistently pursued scientific work.
Academic career: She worked at Riken (the Institute of Physical and Chemical Research), Japan’s foremost scientific research institution, under biochemist Umetaro Suzuki. Her work focused on the chemical composition of green tea — a subject of both scientific and economic importance to Japan.
Vitamin C discovery (1924): Working with green tea extracts, Tsujimura demonstrated the presence of ascorbic acid (vitamin C) in green tea — at a time when the vitamin had only recently been characterized and its presence in a traditional drink was significant. This finding provided a scientific explanation for some of the health benefits associated with green tea consumption.
Catechin research (1929): Her more structurally significant achievement was the isolation and characterization of catechins from green tea. Catechins are a family of flavonoid polyphenols now known to be the primary antioxidant compounds in green tea, and the subject of enormous ongoing health research (EGCG — epigallocatechin gallate — is the most studied). Tsujimura’s isolation work laid the foundation for all subsequent research.
Doctor of Agriculture (1932): In 1932, Tsujimura received her Doctor of Agriculture degree from Tokyo Imperial University — the first woman in Japan to receive this degree. This milestone in Japanese academic history is recognized alongside her scientific contributions.
Later career: She went on to teach at Ochanomizu University in Tokyo, contributing to women’s higher education in postwar Japan. She received Japan’s Order of the Rising Sun in 1968 for her scientific contributions.
Related Terms
See Also
- Catechin Types — the compounds Tsujimura first isolated and identified in green tea
- Tea and Heart — health research area grounded in Tsujimura’s catechin discoveries
- Sakubo – Study Japanese
Research
- Watanabe, M. (2005). Women and the history of science in Japan, in Osiris Vol. 20. Covers Tsujimura’s place in the history of Japanese science.
- Cabrera, C., et al. (2006). Beneficial effects of green tea — a review. Journal of the American College of Nutrition, 25(2). Modern overview of catechin research grounded in Tsujimura’s foundational work.