Natural Products Chemistry: The Joy of Discovering and Cultivating Treasures from the Natural World

Kiyotake Suenaga (Associate Professor, Department of Chemistry)

Many of the medicines in use today are substances found in nature or are inspired by them. Even with today's advanced science, it remains extremely difficult to design entirely new drugs from scratch. Nature creates amazing substances that are beyond human ingenuity. Natural products chemistry is the academic field dedicated to discovering these substances and studying them chemically.

While there are many potential sources in the natural world to search for substances, we focus on marine organisms. Because marine life inhabits environments that are unusual and different from those of terrestrial organisms—in terms of temperature, light, water pressure, and salinity—we expect to find unique substances. "Unique substances" refers to those with complex and rare chemical structures or potent biological activities, such as anticancer, antibacterial, or toxic properties.

Our research process begins with collecting organisms from coastlines and other locations across the country (see photo). Next, we perform an extraction using organic solvents and then separate the components using techniques such as chromatography. Often, the target substance is obtained in only minuscule amounts, making the experiments a daunting task. However, by using biological activity as an indicator, we can successfully isolate the target substance. (To give an analogy, it is like finding a few grams of sugar mixed in a drum full of soil—you can find the sugar by following its sweetness.) We then use various methods to determine the chemical structure of the discovered substance. Once the structure is known, we proceed with research to synthesize it artificially (chemically). We also investigate how the discovered substance functions to produce its biological activity.

As we advance this research, we prioritize our academic curiosity—whether or not we find it interesting. We believe, however, that truly interesting substances will always prove to be useful. We aim to discover and cultivate these fascinating substances (= treasures) that lie hidden in the natural world.

A scene from our collection work. It looks like fun, but this is also part of our research. (Note: Suenaga is not in the photo as he was the one taking it.)