Scents accompany us every day: they communicate, carry culture, spark memories, and elicit emotions. But how did people first start to extract fragrances from plants and animals? What makes the scent of whales and certain even-toed ungulates popular to this day? And what role did the “lord of the (carbon) rings,” better known as ETH Zurich Nobel laureate Leopold Ruzicka, play in this story? The Chemical and Pharmacognostic Collection of D‑CHAB provides answers.
“For years, nothing of Combray had remained alive within me until, one winter day, my mother suggested that I break my routine and drink a cup of tea (…) She ordered one of those small, plump cakes known as petites madeleines (…). I lifted a spoonful of tea, in which I had soaked a piece of the cake, to my lips. No sooner had the warm liquid with its soft crumbs touched my palate than a shiver ran through me (…) a delicious pleasure seized my senses (…) and suddenly the memory returned…”
Rarely has a text captured so precisely the powerful way in which scent and taste can trigger memories. Marcel Proust’s description became known in science as the “Madeleine effect.” Visitors to the Chemical and Pharmacognostic Collection at D-CHAB can experience this effect; the moment a well-traveled person sticks the nose into the usually-locked cabinets of the fragrance chemistry display case, he or she will be instantly transported to the sunlit flower fields of Provence—holiday feelings included.
Lavender, jasmine, and other scents travel via over 10 million olfactory cells directly to the part of the brain responsible for memory and emotion. It takes at most one second for the molecules to be consciously perceived – a record time in physiology. No other sense is as ancient or functions so directly. No wonder smells have always been so important in the socio-cultural context.
Per fumum et per vinum
Even the Egyptians and other ancient peoples appreciated the sensuality of fine fragrances and burned resins and woods so that the scents might carry their prayers ‘per fumum’ (through the smoke) to the gods. This led to the word: “perfume”.
Not until the Christian Middle Ages and the early modern period, however, did the concept of perfume as we know it today begin to take shape. Whilst any sensual or erotic effect was frowned upon, people firmly believed in the healing powers of scented waters. They were thought to prevent and dispel bad odors, which at the time were considered synonymous with disease.
In the development of these scented waters or early perfumes, new techniques such as improved hydrodistillation methods for extracting oils and producing ethanol (alcohol) from fermented wine played a key role. To this day, so‑called “essences” consist of concentrated plant extracts with alcohol serving as the carrier. The enfleurage technique was also popular: fragrance compounds were extracted from flower petals using animal fat (later replaced by modern solvent extraction) to obtain the waxy concrète and, ultimately, the liquid absolue: the pure fragrance.
Additionally, people brought out the big guns —in this case, heavy animal-based scents—to protect themselves from disease, no matter the cost. By the turn of the 20th century, these powerful notes had come to be increasingly valued as seductive base accords, the foundation of perfumes in the modern sense.
Powerful animalic scents
One example is dark, waxy ambergris —a foul‑smelling wound secretion from the digestive tract of the sperm whale, often casually referred to as “whale vomit.” Only once the lump drifts in the ocean does it transform through chemical reactions into a woody-sweet, warm-scented ambergris body. As a fragrance note, ambergris became highly prized by both perfumers and customers alike, though as costly as gold, given the rarity of finding this precious chunk.
Musk deer, in turn, fell victim to their own mating secretion. Their scent, too, was traded at a high price, as its elegant, sensually erotic scent evokes a sense of well-being and is the heart of many perfumes. The species almost died out as a result. Civet cats fared similarly; they suffered greatly—and in some cases still do—for the extraction of pricy civet. As with plant extracts, perfume makers sought cheaper, less problematic artificial alternatives.
The Lord of the (Carbon) Rings
ETH professor and Nobel laureate Leopold Ružička (1878–1976) changed the game by achieving several scientific milestones. During his time at the company Naef & Cie., he discovered that fragrance molecules can possess ring structures with up to seventeen members—including those found in muscone (from musk) and civetone (from civet). Synthesizing these molecules had previously been considered impossible. Ružička was able to reconstruct these structures, opening new pathways for the industrial, low-cost production of fragrances.
In the case of ambergris, for example, Ružička analyzed its central fragrance molecule ambrein and, together with his colleague Max Stoll, created a substitute modeled on sclareol from clary sage (Salvia sclarea): Ambrox, an extremely popular and widely used fragrance to this day.
Through his research, Ružička ushered in the era of macrocyclic fragrance compounds and forever changed the perfume industry. Today, only a few scented museum objects—such as those in the Chemical and Pharmacognostic Collection—bear witness to how things once were. Even “when from a distant past nothing remains (…) the smell and taste of things persist for a long time, like souls, ready to remind us.” (Proust)
Further Reading:
Collectif Nez & Jeanne Doré (2021): Parfum. Alles über die Welt der Düfte. Prestel Verlag: München, London, New York.
Leopold Ruzicka – Nobelpreis für Chemie 1939. Universität Zürich. URL: https://www.uzh.ch/de/researchinnovation/excellence/nobelprize/ruzicka.html
Brauckmann 2001: Der Struktur von Düften und Aromen auf der Spur. Report. ETH Research Collection. (PDF, 731 KB) doi.org/10.3929/ethz-a-004384414
Armanino et al. 2020: Heiße Luft oder cooler Duft? Die Trends der letzten 20 Jahre in der Riechstoffchemie (PDF, 27.5 MB). Angew. Chem. 2020, 132, 16450–16487. doi.org/10.1002/ange.202005719
Proust M. (1994): Auf der Suche nach der verlorenen Zeit 1. Unterwegs zu Swann. Band 1. Aufl. 1, Hrsg.: Keller L., Suhrkamp Verlag Frankfurt am Main. S. 67, S. 70