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Your Class 11 biology book calls adrenaline an "emergency hormone". It is easy to forget that someone first had to pull this substance out of a gland and make it pure enough to study. That happened in a laboratory run by the Japanese chemist Jokichi Takamine, in 1900. This post covers who he was, how the isolation happened and who did the work, a worked example on the molecule's formula, and what students can take from the story.
Who was Jokichi Takamine?
A review in the Journal of Medical Biography by Tatsuya Yamashima (2003) describes Takamine (1854-1922) as a chemist who grew up in Kanazawa, Japan, and made his major discoveries in the United States. An obituary in Industrial and Engineering Chemistry (October 1922) marks his death that year.
Before adrenaline he worked on enzymes. The National Park Service page quoted below credits him with discovering takadiastase, and his own paper Enzymes of Aspergillus oryzae and the application of its amyloclastic enzyme to the fermentation industry (1914) shows how long he stayed with this work on starch-digesting (amyloclastic) enzymes from a mould.
Outside the lab, the US National Park Service's history of Washington's cherry trees records that in April 1909 Takamine, "the Japanese chemist who discovered adrenaline and takadiastase", offered an additional two thousand trees and asked the Mayor of Tokyo to support a gift in the city's name.
How was adrenaline isolated?
Yamashima's review states that Takamine crystallised adrenalin from the adrenal medulla in the summer of 1900, and calls it the first hormone to be isolated in the twentieth century. Takamine reported the work in 1901 in the American Journal of Pharmacy and in a shorter note in the Journal of Physiology, and the next year in JAMA as The blood-pressure raising principle of the suprarenal gland (1902). The word suprarenal simply means "above the kidney", where the adrenal glands sit.
Who actually did the purification?
A 2020 study in the Journal of Anesthesia History (Mieda and colleagues) compared four documents, including a handwritten memorandum by Takamine's assistant Keizo Uenaka titled "On Adrenaline, Memorandum, July to December, 1900", kept in a Buddhist temple in Japan. The authors found that Uenaka's notes contain precise procedures and experimental tips, and that these steps were carried into Takamine's 1901 papers. They conclude that Uenaka "was the main scientist who did the actual work of purifying adrenaline", even though his name rarely appears in textbooks.
What does adrenaline do in the body?
The NCERT Class 11 chapter Chemical Coordination and Integration states that the adrenal medulla secretes adrenaline (epinephrine) and noradrenaline (norepinephrine), together called catecholamines. They are released rapidly in stress and emergencies, which is why NCERT calls them "emergency hormones or hormones of Fight or Flight". They increase heart rate, the strength of heart contraction and the rate of breathing, and stimulate the breakdown of glycogen. For how hormone levels are kept in check, see our post on hormones and feedback loops.
Worked example: the chemistry of adrenaline
The US National Library of Medicine's PubChem record for epinephrine gives the formula C9H13NO3 and a molar mass of 183.20 g/mol. Using rounded atomic masses C = 12, H = 1, N = 14, O = 16:
Molar mass = 9 x 12 + 13 x 1 + 14 + 3 x 16 = 108 + 13 + 14 + 48 = 183 g/mol.
% C = 108 / 183 x 100 = 59.0%
% H = 13 / 183 x 100 = 7.1%
% N = 14 / 183 x 100 = 7.65%
% O = 48 / 183 x 100 = 26.2%
Now go backwards, as an early analyst would have. Take 100 g: C 59.0 / 12 = 4.92 mol, H 7.1 / 1 = 7.1 mol, N 7.65 / 14 = 0.546 mol, O 26.2 / 16 = 1.64 mol. Divide by the smallest (0.546): C 9.0, H 13.0, N 1.0, O 3.0. The empirical formula is C9H13NO3.
Common mistakes in percentage composition problems
Dividing by the wrong total. Each percentage uses the molar mass of the whole molecule (183), not the sum of the other elements.
Rounding too early. Rounding 0.546 to 0.5 before dividing turns 13 hydrogens into about 14.
Confusing empirical and molecular formulas. Here they are the same, but you need the molar mass to know that.
If empirical formula steps keep slipping, the Fermi Problem Library has a step-by-step solver that explains the reasoning, so you can see exactly where a ratio went wrong.
What can a student take from how Takamine's lab worked?
Patient routine work wins. The 2020 study notes that Uenaka "tirelessly and diligently" carried out routine experiments that some would find boring.
Write procedures down. Uenaka's memorandum is the reason we know how the crystallisation was done.
Connect chemistry to function. A pure substance made it possible to test what the gland's secretion actually does.
Practice routine: pick three hormones or drugs from NCERT, look up their formulas on PubChem, and calculate each molar mass and percentage of nitrogen by hand.
Next step: calculate the percentage composition of noradrenaline, C8H11NO3, and compare it with adrenaline's.
