Applied Biological Chemistry (Sep 2023)

Effects of the drying method and extraction solvent on antioxidant and anti-inflammatory activity of Melosira nummuloides bioproducts

  • Do Manh Cuong,
  • Dae Kyeong Kim,
  • Meran Keshawa Ediriweera,
  • Jong-Eun Park,
  • Jeong Yong Moon,
  • Somi Kim Cho

DOI
https://doi.org/10.1186/s13765-023-00817-y
Journal volume & issue
Vol. 66, no. 1
pp. 1 – 10

Abstract

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Abstract Melosira 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.

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