was a Japanese
agricultural scientist and
biochemist
Biochemists are scientists who are trained in biochemistry. They study chemical processes and chemical transformations in living organisms. Biochemists study DNA, proteins and Cell (biology), cell parts. The word "biochemist" is a portmanteau of ...
whose research focused on the components of
green tea
Green tea is a type of tea that is made from '' Camellia sinensis'' leaves and buds that have not undergone the same withering and oxidation process which is used to make oolong teas and black teas. Green tea originated in China, and since the ...
. She was the first woman in Japan to receive a
doctoral degree in
agriculture.
Early life
Tsujimura was born in 1888 in what is now Okegawa in
Saitama Prefecture
is a landlocked prefecture of Japan located in the Kantō region of Honshu. Saitama Prefecture has a population of 7,338,536 (1 January 2020) and has a geographic area of 3,797 km2 (1,466 sq mi). Saitama Prefecture borders Tochigi Prefecture ...
. She attended Tokyo Prefecture Women's Normal School, graduating in 1909, and the Division of Biochemical Science at
Tokyo Women's Higher Normal School
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and List of cities in Japan, largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, ...
. There, she was taught by the biologist
Kono Yasui, who inspired in Tsujimura an interest in scientific research. She graduated in 1913 and became a teacher at Yokohama High School for Women in
Kanagawa Prefecture. In 1917, she returned to Saitama Prefecture to teach at Saitama Women's Normal School.
Career and research
Tsujimura's research career began in 1920 when she joined
Hokkaido Imperial University
, or , is a Japanese national university in Sapporo, Hokkaido. It was the fifth Imperial University in Japan, which were established to be the nation's finest institutions of higher education or research. Hokkaido University is considered ...
as a laboratory assistant. At the time, the university did not accept female students, so Tsujimura worked in an unpaid position at the Food Nutritional Laboratory of the university's Agricultural Chemistry Department. There, she researched the nutrition of
silkworms before transferring to the Medical Chemical Laboratory at the Medical College of
Tokyo Imperial University in 1922. The laboratory was destroyed in the
1923 Great Kantō earthquake
The struck the Kantō Plain on the main Japanese island of Honshū at 11:58:44 JST (02:58:44 UTC) on Saturday, September 1, 1923. Varied accounts indicate the duration of the earthquake was between four and ten minutes. Extensive firestorms an ...
in September, so she transferred to
RIKEN as a research student in October 1923. She worked in the laboratory of
Umetaro Suzuki, a doctor of agriculture, and researched nutritional chemistry. Tsujimura and her colleague Seitaro Miura discovered
vitamin C in
green tea
Green tea is a type of tea that is made from '' Camellia sinensis'' leaves and buds that have not undergone the same withering and oxidation process which is used to make oolong teas and black teas. Green tea originated in China, and since the ...
in 1924, and published an article titled "On Vitamin C in Green Tea" in the journal ''Bioscience, Biotechnology, and Biochemistry''.
[ This finding contributed to an increase in green tea exports to North America.][
In 1929, Tsujimura isolated the ]flavonoid
Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans.
Chemically, flavonoids ...
catechin from green tea. She extracted tannin in crystal form from green tea in 1930. Her thesis on the constituents of green tea, titled "On the Chemical Components of Green Tea", earned her a doctorate in agriculture from Tokyo Imperial University in 1932, making her the first woman in Japan to receive such a degree.[ She went on to isolate gallocatechin from green tea in 1934 and registered a patent on her method of extracting vitamin C crystals from plants in 1935. She was promoted to the role of junior researcher at RIKEN in 1942 and then researcher in 1947 before becoming a professor at ]Ochanomizu University
is a women's university in the Ōtsuka neighborhood of Bunkyō-ku, Tokyo, Japan.
Ochanomizu University is one of the top national universities in Japan.
Ochanomizu is the name of a Tokyo neighborhood where the university was founded.
Hi ...
when it was established in 1949. She was a professor at Tokyo Women's Higher Normal School from 1950 and was the school's first dean of the Faculty of Home Economics.[
]
Retirement, death, and legacy
Tsujimura retired from Ochanomizu University as a professor in 1955, but continued lecturing part-time until 1961. She was a professor at Jissen Women's University in Tokyo from 1955 to 1963, when she became a professor emeritus. She was awarded the Japan Prize of Agricultural Science in 1956 for her research on green tea and was conferred the Order of the Precious Crown of the Fourth Class in 1968. She died in Toyohashi on 1 June 1969 at the age of 80.[
Tsujimura's 133rd birthday was celebrated with a Google Doodle on September 16, 2021.]
See also
* Timeline of women in science
References
{{DEFAULTSORT:Tsujimura, Michiyo
1888 births
1969 deaths
Agriculturalists
Japanese agricultural scientists
Japanese biochemists
Ochanomizu University faculty
Women biochemists
Japanese women chemists
20th-century women scientists
Riken personnel
Vitamin researchers
20th-century Japanese chemists