Squalene isolated from marine macroalgae Caulerpa racemosa and its potent antioxidant and anti-inflammatory activities

Abstract

Evaluating biofunctional properties of marine natural products receives increased attention in recent research. Current study explores the biofunctional properties of Caulerpa racemosa 70% ethanol extract (CRE) to identify bioactive principals. Ethyl acetate (CREE) and hexane (CREH) fractions of CRE indicated potent antioxidant and anti-inflammatory activity. Bioassay-guided purification of CREH led to the isolation of squalene, which indicated prominent antioxidant and anti-inflammatory activity. Squalene reduced alkyl and hydroxyl radical scavenging and 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH) and H2O2-induced intracellular reactive oxygen species (ROS) levels. Squalene increased protective effects in HaCaT keratinocytes against UV-induced cell damage by reducing ROS levels. Furthermore, squalene could reduce nitric oxide (NO), inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), cyclooxygenase (COX-2) levels, and some key pro-inflammatory cytokines in lipopolysaccharide-induced RAW macrophages. Structure of squalene was confirmed by NMR and GC-MS/MS analysis. This is the first study to report the isolation of squalene from the macroalgae C. racemosa. Practical applications Caulerpa racemosa is an edible green alga popularly consumed as a salad in South East Asia. The current study highlights the antioxidant and the broad range of anti-inflammatory functionality of its 70% ethanol extract and solvent fractions. The studies led to the isolation of squalene which also indicated prominent antioxidant and anti-inflammatory activity. Hence C. racemosa possesses nutraceutical and bioactive properties which enable it to be used as a functional food ingredient or in manufacturing cosmeceuticals.