海洋細菌由来希少カロテノイドが抗酸化作用や抗炎症効果を示すことを発見～C30カロテノイドの機能性食品素材などの応用に向けた研究進展に期待～

2025-07-23 北海道大学

本研究で単離したoki7株が産生するC₃₀カロテノイドの分子構造

<関連情報>

• https://www.hokudai.ac.jp/news/2025/07/c30.html
• https://www.hokudai.ac.jp/news/pdf/250723_pr2.pdf
• https://link.springer.com/article/10.1007/s12562-025-01897-z

海洋細菌Exiguobacterium sp. oki7株が産生するカロテノイド配糖体エステルの構造決定とその抗酸化作用及び抗炎症作用 Structural determination of the carotenoid glycoside ester produced by the marine bacterium Exiguobacterium sp. strain oki7 and its antioxidant and anti-inflammatory effects

Naoki Takatani,Takashi Maoka,Misaki Aoike,Munekimi Nanao,Tomoo Sawabe,Fumiaki Beppu & Masashi Hosokawa
Fisheries Science  Published:01 July 2025
DOI:https://doi.org/10.1007/s12562-025-01897-z

Abstract

Exiguobacterium bacteria produce yellowish‒orange pigments, but their detailed characteristics have not been fully elucidated. Here, we report that the newly isolated Exiguobacterium strain oki7 from the surface of seaweed collected from Senaga-Jima Island, Okinawa, Japan, produces a rare C₃₀ carotenoid. The major orange carotenoid was purified from oki7 using thin-layer chromatography and high-performance liquid chromatography. Structural analysis using nuclear magnetic resonance and high-resolution mass spectrometry revealed that the major carotenoid produced by oki7 was methyl 5′-(6-iso-C_13:0)-glucosyl-5′,6′-dihydro-4,4′-diapolycopenoate (methyl 5′-[6-O-(11-methyldodecanoyl)-β-D-glucopyranosyl]-5′,6′-dihydro-4,4′-diapo-ψ,ψ-caroten-4-oate), the first carotenoid to be identified from the genus Exiguobacterium. Furthermore, several derivatives with different fatty acids bound to this C₃₀ carotenoid glycoside backbone were also predicted by mass spectrometry/mass spectrometry analysis. Compared with naturally abundant β-carotene and zeaxanthin, methyl 5′-(6-iso-C_13:0)-glucosyl-5′,6′-dihydro-4,4′-diapolycopenoate showed stronger singlet oxygen-quenching activity. Furthermore, methyl 5′-(6-iso-C_13:0)-glucosyl-5′,6′-dihydro-4,4′-diapolycopenoate inhibited the overproduction of the inflammatory cytokine interleukin-6 and the inflammatory mediator nitric oxide in lipopolysaccharide-stimulated RAW264.7 macrophages through the downregulation of their gene expression. This study provides fundamental insights into the potential of Exiguobacterium bacteria as a source of health-beneficial carotenoids and the application of C₃₀ carotenoids as nutraceuticals and pharmaceuticals.