Chlorophyll

Chlorophyll is a substance in plants that is created by the interaction of the plant with sunlight. This interaction results in the green coloration of plants and is part of the process by which plants convert sunlight into energy. This energy can then be used by the plants and by animals and humans who eat the plants. In the middle of the twentieth century, people became interested in the potential health benefits of consuming chlorophyll; in the twenty-first century, supplements made from chlorophyll provide an additional source of this concentrated plant energy source.

Background

The word chlorophyll is made up of two Greek words: chloros, which means "yellowish green," and phyllon, which means "leaf." While it had long been realized that plants needed sunlight to grow, the mechanism by which this happens was not discovered until near the end of the eighteenth century.

Jan Ingenhousz was a Dutch physician serving the Austrian court who conducted more than five hundred experiments with plants in 1779. Building on earlier work by English chemist Joseph Priestly, who had discovered that plants possessed the ability to restore oxygen to air, Ingenhousz experimented with the effects of light on plants. He discovered that the oxygen-restoring ability that Priestley observed was the direct result of the effect of sunlight on plants. While Priestley made similar observations, Ingenhousz took the extra step of publishing his findings; as a result, he is credited with the discovery of photosynthesis, the process by which plants convert sunlight to energy.

Other scientists built on Ingenhousz's findings. In 1817, French pharmacists Joseph Bienaimé Caventou and Pierre Joseph Pelletier used solvents to separate chlorophyll from a plant for the first time. This process paved the way for it to be used as a food additive decades later. In 1883, German botanist Julius von Sachs determined that chlorophyll is produced in the chloroplasts of virtually every plant. Chloroplasts are small subunits of the plant's cells. Over the course of eight years between 1906 and 1914, German scientist Richard Willstätter identified two different types of chlorophyll: chlorophyll a and chlorophyll b. He was awarded a Nobel Prize in Chemistry in 1915 for his work in biochemistry. In the following years, additional types of chlorophyll were identified, including a sixth type discovered by a team of Australian scientists in 2010.

Overview

Chlorophyll is the substance that makes photosynthesis possible. It acts as a photoreceptor, or light catcher, capturing the sunlight so the plant can convert it into energy. Chlorophyll is made up of a group of organic molecules arranged around a magnesium atom in a formation known as a porphyrin ring.

While additional types of chlorophyll have been identified, the two discovered by Willstätter are considered the main and most important types. Each captures light on a slightly different wavelength, mostly from the red and blue areas of the light spectrum. Plants can exist on the light from these two areas. However, plants absorb very little light from the green area, which is another large area of the spectrum. Instead of being absorbed, this light is reflected back, giving plants their green color. The green color reflected by the chlorophyll is so strong that it can overpower and block color reflected by other plant molecules. As the plant ages and its ability to produce chlorophyll fades, its capacity to reflect green light and mask the colors of the other plant molecules also fades. This is why plants change color and is the reason for the brilliant oranges, yellows, and reds displayed by fall leaves.

Chlorophyll is responsible for much more than the color of the plant, however. It also helps the plant capture and store the sun's energy. It does this by capturing carbon dioxide and water molecules as part of the photosynthesis process. Chlorophyll works in conjunction with a special protein that helps to position it so that it can best interact with these molecules. The carbon dioxide and water are then combined to create a chemical reaction that results in the production of oxygen and glucose. The oxygen is released back into the atmosphere around the plant; what is a waste product for the plant is restorative to the environment around it. The glucose can either be used immediately by the plant or converted to a starch for storage until it is needed. This stored energy makes plants nutritious for animals and humans.

After the work Caventou and Pelletier in the nineteenth century, researchers knew it was possible to extract chlorophyll from plants. In the 1940s, interest grew in using chlorophyll supplements to enhance human life and health. Wheatgrass, or young wheat shoots, attracted a great deal of attention as a chlorophyll source. Many experiments were attempted using chlorophyll to treat a variety of illnesses, from infections to skin and gum problems. While success was reported from these attempts, efforts to make a synthetic capsule form of wheatgrass chlorophyll failed.

Nevertheless, some remained interested in the potential of consuming chlorophyll in concentrated form. In the twenty-first century, chlorophyll extract is used in a number of ways. It can be taken dried via a capsule or added to a beverage, or in liquid form that is added to water. Some studies have found that ingesting chlorophyll in this way can aid weight loss, help treat cancer, assist with "detoxing" the body of heavy metals and other toxins, and deodorize bad breath and foul stools. Researchers have not found any serious side effects from consuming chlorophyll in this way beyond a potential for digestive upset and discoloration of urine and stools. However, nutritionists note it is possible to get many of the same benefits in a more natural way by consuming more fresh plant foods such as fruits, vegetables, and whole grains.

Bibliography

Bailey, Regina. "Jan Ingenhousz: Scientist Who Discovered Photosynthesis." ThoughtCo, 21 Feb. 2019, www.thoughtco.com/jan-ingenhousz-4571034. Accessed 5 Dec. 2024.

"Chlorophyll and Chlorophyllin." Oregon State University, Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/chlorophyll-chlorophyllin. Accessed 5 Dec. 2024.

Dégraff, Loraine R. The Complete Guide to Growing and Using Wheatgrass. Atlantic Publishing Company, 2011, pp. 63–65.

"Discovery of Chlorophyll." History of Science, 15 Feb. 2013, historyofsciences.blogspot.com/2013/02/discovery-of-chlorophyll.html. Accessed 5 Dec. 2024.

Lubeck, Brittany. "What Are the Benefits and Side Effects of Chlorophyll?" VeryWell Mind, 19 Spet. 2024, www.verywellhealth.com/chlorophyll-5088796. Accessed 5 Dec. 2024.

"Richard Willstätter – Biographical." The Nobel Prize, 2024, www.nobelprize.org/nobel‗prizes/chemistry/laureates/1915/willstatter-bio.html. Accessed 5 Dec. 2024.

University of Sydney. "Australian Scientists Discover First New Chlorophyll in 60 Years." Phys.org, 20 Aug. 2010, phys.org/news/2010-08-scientists-chlorophyll-years.html. Accessed 5 Dec. 2024.