Not every ingredient in the Botanical Library began in a garden.
Vitamin E entered our understanding not through an ancient herbal, a monastery physic garden or a perfumer’s still, but through an experiment in a Californian laboratory little more than a century ago. Its story belongs to an entirely different period of botanical history, when scientists were beginning to discover that food contained substances needed in quantities too small to be explained by the conventional language of proteins, fats and carbohydrates.
In 1922, Herbert McLean Evans and Katharine Scott Bishop at the University of California, Berkeley, were studying reproduction in laboratory rats. The animals appeared to receive an adequate purified diet, including the vitamins then known, and grew normally. Yet reproduction failed. When certain natural foods were returned to the diet, normal reproductive function could be restored, suggesting that something essential was missing from the supposedly complete laboratory food. Their findings were published in Science that December under the wonderfully understated title, On the Existence of a Hitherto Unrecognized Dietary Factor Essential for Reproduction.
At the time, the science of vitamins was itself remarkably young. The word vitamine had been proposed only a decade earlier, and researchers were still discovering that tiny quantities of particular dietary compounds could determine whether an animal grew normally, reproduced successfully or developed deficiency disease. Vitamins A, B, C and D had begun to emerge from this new nutritional science; the unknown reproductive factor would eventually acquire the next available letter. It became vitamin E.
The first experiments did not reveal what vitamin E was chemically. They revealed where scientists might begin looking for it. Lettuce could restore reproductive function in the experimental animals, and Evans and Bishop subsequently identified wheat germ as an especially rich source. Wheat-germ oil consequently became one of the principal materials through which researchers attempted to concentrate and understand the elusive substance.
What followed was more than a decade of painstaking chemical work. The difficulty is easy to underestimate from the perspective of modern analytical chemistry. Today, a laboratory can separate and identify extraordinarily small quantities of molecules using chromatographic and spectrometric techniques that the researchers of the 1920s could scarcely have imagined. Early vitamin researchers instead had to work through oils and biological extracts, repeatedly concentrating fractions and then testing whether those fractions retained the biological activity they were searching for.
By the mid-1930s, the mystery had begun to yield. In 1936, Evans, Oliver Emerson and Gladys Emerson reported the isolation from wheat-germ oil of an alcohol possessing vitamin E activity. They called it alpha-tocopherol. Their original paper described a substance capable of restoring reproductive success in vitamin-E-deficient experimental animals and proposed the molecular formula C29H50O2.
The name they chose preserved the circumstances of the vitamin’s discovery. Tocopherol was constructed from Greek roots associated with childbirth and bearing, together with the chemical suffix denoting an alcohol. George Miller Calhoun, a professor of Greek at Berkeley, is credited with helping devise the term. It is an unusual example of a chemical name carrying within it a fragment of the experiment through which the substance first became known.
Vitamin E did not remain one molecule for long. Other tocopherols were identified, including beta- and gamma-tocopherol, while delta-tocopherol was subsequently isolated from soybean oil. The family would eventually expand further to encompass the tocotrienols, leaving the apparently simple expression vitamin E as an umbrella for a group of chemically related compounds rather than a single substance.
Then, in 1938, another important threshold was crossed. The structure of alpha-tocopherol was established and Paul Karrer and colleagues achieved its chemical synthesis. In just sixteen years, vitamin E had travelled from an unexplained biological observation to an isolated, structurally understood and synthesised molecule. Yet solving its structure did not solve the larger question of what vitamin E actually does. That question would occupy researchers for the remainder of the century and, in important respects, remains open today.
One of the most influential developments was the recognition of vitamin E’s relationship with oxidation. Work on fats and biological systems gradually helped establish tocopherols as lipid-soluble antioxidants, capable of interrupting the chain reactions through which lipid oxidation propagates. This transformed vitamin E from the rather narrowly conceived reproductive factor of its early history into a molecule of much wider biochemical interest. Modern research has subsequently explored roles extending beyond straightforward antioxidant chemistry, including effects involving signalling, gene expression, membrane biology and metabolism. A major review marking almost a century of research concluded that our understanding of vitamin E’s mechanisms remains incomplete despite the enormous literature accumulated around it.
That uncertainty is an important part of the story. Scientific history is often retold as though discovery proceeds through a neat sequence: something is observed, a molecule is identified, its function is established and the problem is solved. Vitamin E offers a more realistic picture. Evans and Bishop discovered a nutritional phenomenon in 1922; chemists subsequently isolated and synthesised the responsible compounds; antioxidant chemistry provided an increasingly persuasive explanation for some of their biological behaviour; and yet, more than a century after the original experiment, researchers continue to investigate precisely how different forms of vitamin E function within living systems.
Meanwhile, vitamin E escaped the laboratory. Its association with wheat-germ oil helped carry it into the expanding nutritional and health-product markets of the twentieth century. Wheat-germ concentrates had already been used extensively during the scientific effort to isolate vitamin E, and the material became an early commercial source of the vitamin during the 1930s. As extraction and manufacturing developed, vitamin E became increasingly available not merely as a subject of biochemical investigation but as an ingredient. That transition eventually brought it into cosmetics.
There was a certain chemical logic to the move. Skin contains lipids vulnerable to oxidation, while alpha-tocopherol itself forms part of the antioxidant environment of human skin. Tocopherols can also help protect oxidation-sensitive oils within formulations, making vitamin E interesting both as a biologically relevant compound and as a practical cosmetic ingredient. But commercial familiarity gradually created a problem of its own. The words vitamin E began to imply much more than the evidence necessarily supported. Antioxidant chemistry expanded into claims about anti-ageing, skin repair and scar reduction, while the reassuring familiarity of the word vitamin made the ingredient seem almost universally beneficial.
The history of the molecule makes those claims particularly interesting because it demonstrates how easily scientific ideas can acquire additional meanings as they move from laboratory to marketplace. Vitamin E really is an antioxidant. It really is biologically important. It really is present within human skin. None of those facts automatically proves that every cream containing Tocopherol or Tocopheryl Acetate will remove scars, reverse ageing or protect the skin from sunlight.
The ingredient itself also became more complicated as cosmetic chemistry developed. Tocopherol and Tocopheryl Acetate, two names now commonly encountered on ingredient lists, are not simply interchangeable spellings for the same material. Free tocopherol possesses direct antioxidant activity but is itself susceptible to oxidation, while esterification produces tocopheryl acetate, a more stable derivative widely used in cosmetics. The formulation scientist therefore encounters vitamin E not as the mysterious reproductive factor of 1922 but as a family of ingredients whose selection depends upon stability, chemistry and intended purpose.
There is something rather satisfying about that journey. The first researchers were trying to understand why an apparently complete diet was incomplete. A century later, a cosmetic chemist may add tocopherol to a plant-oil formulation partly to slow the oxidation of the oils themselves. Between those two moments lies an extraordinary period of nutritional science, organic chemistry, biochemistry, dermatology and cosmetic formulation.
And plants remain present throughout the story. Vitamin E may not be a botanical in the same sense as lavender or rose, but plants manufacture tocopherols and tocotrienols, and vegetable oils, nuts and seeds remain important natural sources. Wheat germ led the early researchers towards the molecule; cottonseed and soybean oils contributed to the identification of additional tocopherols; and modern commercial tocopherols can still originate within the much larger world of plant-oil processing.
This makes vitamin E an important addition to the Botanical Archives because it broadens what we mean by botanical history. Not every ingredient reaches us through folklore or traditional herbal medicine. Some arrive through chromatography, molecular structures and controlled experiments. Some have histories measured in decades rather than millennia. And sometimes our understanding of a plant-derived material owes less to the gardener or herbalist than to the scientist trying to explain an unexpected result.
Today, Tocopherol or Tocopheryl Acetate can sit quietly halfway down the ingredient list of an ordinary moisturiser, scarcely noticed among emulsifiers, oils and humectants. There is nothing about those names to suggest the rats that unexpectedly failed to reproduce in Berkeley, the wheat-germ oil through which researchers pursued the missing nutrient, or the chemists who eventually isolated and synthesised the molecule. Yet all of that history is there.
Lavender carries the history of gardens, domestic life and herbal tradition. Rose carries the history of fragrance, distillation and trade. Vitamin E carries the history of discovery. And perhaps that is its most interesting contribution to the Botanical Archives: a reminder that our relationship with natural ingredients is still being written, and that sometimes a substance can have existed within plants for millions of years before a curious experiment finally teaches us to notice it.
References and further reading
- Evans, H. M. & Bishop, K. S. (1922). On the existence of a hitherto unrecognized dietary factor essential for reproduction. Science, 56(1458), 650-651. doi:10.1126/science.56.1458.650
- Evans, H. M., Emerson, O. H. & Emerson, G. A. (1936). The isolation from wheat germ oil of an alcohol, alpha-tocopherol, having the properties of vitamin E. Journal of Biological Chemistry, 113(1), 319-332. doi:10.1016/S0021-9258(18)74918-1
- Carpenter, K. J. (2003). A short history of nutritional science: part 3 (1912-1944). The Journal of Nutrition, 133(10), 3023-3032. doi:10.1093/jn/133.10.3023
- Brigelius-Flohé, R. (2021). Vitamin E research: past, now and future. Free Radical Biology and Medicine, 177, 381-390. doi:10.1016/j.freeradbiomed.2021.10.029
- Brigelius-Flohé, R. & Traber, M. G. (1999). Vitamin E: function and metabolism. FASEB Journal, 13(10), 1145-1155. doi:10.1096/fasebj.13.10.1145
- Shastak, Y., Obermueller-Jevic, U. & Pelletier, W. (2023). A century of vitamin E: early milestones and future directions in animal nutrition. Agriculture, 13(8), 1526. doi:10.3390/agriculture13081526