Abstract
AbstractMelosira nummuloides is a marine diatom with potential use as food, fuel, and a dietary supplement. However, the efficacy of its extraction and drying techniques have not been explored. Here, M. nummuloides powders were prepared by two drying methods—hot-air drying (HAD) and freeze-drying (FD)—and extracted with hot water, ethanol, methanol, and chloroform:methanol (CM) at a ratio of 2:1 v/v. The antioxidant and anti-inflammatory activity of each extract was investigated. The CM extract had the greatest 2,2-diphenyl-1-picrylhydrazyl and 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity among the solvent extracts, and a slight difference in antioxidant activity was observed across the various drying methods. Compared to other extracts, both the FD-CM and HAD-CM extracts showed stronger anti-inflammatory effects by inhibiting nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 cells. Furthermore, the FD-CM extract contained a wide range of lipophilic compounds. Notably, myristic acid (29.08 ± 0.45 mg/g dry weight powder extract (DW)), oleic acid (25.20 ± 0.92 mg/g DW), palmitoleic acid (10.77 ± 0.41 mg/g DW), eicosapentaenoic acid (12.53 ± 1.00 mg/g DW), neophytadiene (8.42 ± 0.51 mg/g DW), and α-linolenic acid (1.27 ± 0.005 mg/g DW) were among the prominent compounds identified. It is plausible to suggest that the abundance of these lipophilic compounds contributes to the remarkable antioxidative and anti-inflammatory potential exhibited by the FD-CM extract. Our results provide insights into the preferential drying methods and extraction solvents for producing M. nummuloides-based products with enhanced antioxidant and anti-inflammatory activity.
Funder
Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries, Korea
Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education
Publisher
Springer Science and Business Media LLC
Subject
Organic Chemistry,General Biochemistry, Genetics and Molecular Biology