Ken-Ichi Onodera | PubMed Health

PubMed2006

Camellianoside, a novel antioxidant glycoside from the leaves of Camellia japonica.

A novel flavonol glycoside named camellianoside and three known flavonol glycosides were isolated from the leaves of Camellia japonica. The structure of camellianoside was established as quercetin-3-O-beta-D-xylopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->6)-O-beta-D-glucopyranoside by spectroscopic and chemical methods. The antioxidant activities of these glycosides evaluated by the diphenylpicrylhydrazyl (DPPH) radical scavenging reaction was higher than those of L-cysteine and L-ascorbic acid used as the reference antioxidants.

Antioxidants↗

PubMed2005

Zooxanthellamide Cs: vasoconstrictive polyhydroxylated macrolides with the largest lactone ring size from a marine dinoflagellate of Symbiodinium sp.

Zooxanthellamide Cs (ZAD-Cs), C(128)H(220)N(2)O(53)S(2) (ca. 2.7 kDa), was obtained from a cultured marine dinoflagellate of the genus Symbiodinium as an inseparable isomeric mixture of polyhydroxylated 61- to 66-membered macrolides. The chemical structures of the components were clarified by detailed 2D NMR analysis to be the macrolactonized analogues of zooxanthellamide A (ZAD-A), which had been previously isolated from the same microalgae. Chemical lability of ZAD-Cs suggests that ZAD-A is an artifact derived from ZAD-Cs during the isolation steps. Three of the components possess the largest (63-, 64-, and 66-membered) ring sizes found to date among the natural macrolides. ZAD-Cs exhibited higher vasoconstrictive activity than that of the zooxanthellatoxins, the first vasoconstrictive macrolides from Symbiodinium sp. The structure-activity relationship suggests that the huge macrolactone structure is important for biological activity. The relationship between the structures of the polyol metabolites and the phylogenetic systematics of Symbiodinium sp. is also discussed.

Animals↗