Mar. Drugs 2015, 13, 5847-5881; doi:10.3390/md13095847 OPEN ACCESS marine drugs ISSN 1660-3397 www.mdpi.com/journal/marinedrugs Review Photosynthetic Pigments in Diatoms Paulina Kuczynska 1, Malgorzata Jemiola-Rzeminska 1,2 and Kazimierz Strzalka 1,2,* 1 Faculty of Biochemistry, Biophysics and Biotechnology, Department of Plant Physiology and Biochemistry, Jagiellonian University, Gronostajowa 7, Krakow 30-387, Poland; E-Mails:
[email protected] (P.K.);
[email protected] (M.J.-R.) 2 Małopolska Centre of Biotechnology, Gronostajowa 7A, Krakow 30-387, Poland * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel.: +48-126-646-509; Fax: +48-126-646-902. Academic Editor: Véronique Martin-Jézéquel Received: 10 July 2015 / Accepted: 7 September 2015 / Published: 16 September 2015 Abstract: Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications.