Comparison of Antioxidant Molecules Accumulation in Euglena gracilis to Spinach, Tomato, and Other Selected Fruits and Vegetables

Abstract

Euglena gracilis (E. gracilis) is a photosynthetic green microalga that lives in freshwater. It is known that E. gracilis synthesizes antioxidants such as ascorbic acid, glutathione, carotenoid, and tocopherols to protect themselves from Reactive Oxygen Species (ROS) in order to survive in their living environment. The essentiality of these antioxidants in E. gracilis is the same as in the human body. The simultaneous production of these antioxidants in E. gracilis showed the possibility of E. gracilis as the source of new food ingredients and consideration of it as a nutritional supplement for humans. Therefore, the objective of the present experiment is to identify the eligibility of E. gracilis as a new antioxidant source ingredient. In this research, the E. gracilis cells were cultured in Cramer-Myers (CM) media, a photoautotrophic environment for a week. Meanwhile, for the samples of fruits and vegetables were tomato, spinach, yellow bell pepper, kiwi, and carrots. The antioxidants that were analyzed in this experiment are ascorbic acid, glutathione, β-carotene, and carotenoid. Tocopherols could not be analyzed due to undeveloped method and time limitation. The respective antioxidants from the samples were extracted by using solvents that are suitable with their polarity. The analysis for the ascorbic acid, glutathione, β-carotene, and carotenoid were done either by HPLC or spectrophotometry. The results showed that E. gracilis had higher content of glutathione, β-carotene, and carotenoids compared to the fruits and vegetables samples while less content of ascorbic acid. Although it is low in ascorbic acid, E. gracilis is still eligible for the future source of antioxidant as most of antioxidant content in E. gracilis are comparable towards the fruits and vegetables sample which are the main source of antioxidant in human diets.