**Lysophosphatidylcholines and Chlorophyll-Derived Molecules from the Diatom** *Cylindrotheca closterium* **with Anti-Inflammatory Activity**

**Chiara Lauritano 1,\*, Kirsti Helland 2, Gennaro Riccio 1, Jeanette H. Andersen 2, Adrianna Ianora <sup>1</sup> and Espen H. Hansen <sup>2</sup>**


Received: 17 January 2020; Accepted: 13 March 2020; Published: 17 March 2020

**Abstract:** Microalgae have been shown to be excellent producers of lipids, pigments, carbohydrates, and a plethora of secondary metabolites with possible applications in the pharmacological, nutraceutical, and cosmeceutical sectors. Recently, various microalgal raw extracts have been found to have anti-inflammatory properties. In this study, we performed the fractionation of raw extracts of the diatom *Cylindrotheca closterium,* previously shown to have anti-inflammatory properties, obtaining five fractions. Fractions C and D were found to significantly inhibit tumor necrosis factor alpha (TNF-α) release in LPS-stimulated human monocyte THP-1 cells. A dereplication analysis of these two fractions allowed the identification of their main components. Our data suggest that lysophosphatidylcholines and a breakdown product of chlorophyll, pheophorbide a, were probably responsible for the observed anti-inflammatory activity. Pheophorbide a is known to have anti-inflammatory properties. We tested and confirmed the anti-inflammatory activity of 1-palmitoyl-sn-glycero-3-phosphocholine, the most abundant lysophosphatidylcholine found in fraction C. This study demonstrated the importance of proper dereplication of bioactive extracts and fractions before isolation of compounds is commenced.

**Keywords:** diatoms; marine biotechnology; anti-inflammatory; drug discovery; *Cylindrotheca closterium*
