A Simple Method for Isolating Fucoxanthin, Which Shows a Wide Range of Physiological Effects, from Microalga, Chaetoceros calcitrans

Fucoxanthin is a carotenoid belonging to the xanthophyll family and has been shown to exhibit various physiological activities. While brown algae have traditionally been used as a source of fucoxanthin, microalgae have been attracting attention as an alternative source to brown algae in recent years. Although various methods have been devised to isolate fucoxanthin from microalgae, these methods have drawbacks such as requiring special equipment or being unsuitable for large-scale production. Therefore, we tried to develop a simple method that anyone can easily try and that allows for mass production. First, the extraction yields using various solvents were compared. Acetone showed the most efficient extraction yield for short extraction times, but as the extraction time increased, there was almost no difference in the extraction yields among methanol, ethanol, and acetone. Compared to ethanol, methanol had an extraction efficiency of approximately 98%, while acetone had an extraction efficiency of 90%. Then, our efforts have resulted in the development of a method that can isolate fucoxanthin with a purity of over 90% with just a single run of a silica gel column chromatography. Furthermore, the fucoxanthin with this method retained a wide range of physiological activities, including antioxidant, anti-cancer, and anti-inflammatory effects. Our findings might broaden the scope of fucoxanthin research and contribute to process development of fucoxanthin.