Discovery of cycloheptapeptides phakefusins A-E from the marine sponge Phakellia fusca based on molecular networking.
Phytochemistry
; 229: 114248, 2024 Aug 26.
Article
in En
| MEDLINE
| ID: mdl-39197714
ABSTRACT
Guided by a probe-based molecular networking strategy, five undescribed cycloheptapeptides, phakefusins A-E (1-5), were isolated from the marine sponge Phakellia fusca. Compounds 1 and 2 contain the nonproteinogenic amino acid residues of dioxindolyalanine (Dioia) and ß-3-oxindolylalanine (Oia), respectively. Compound 3 possesses a unique methionine sulfoxide, whereas compound 5 includes a glutamic acid ethyl ester unit. Their structures were elucidated through NMR spectroscopy, HR-MS/MS analysis, and the advanced Marfey's method. By synthesizing the (S, S/R)-Oia standard through tryptophan oxidation, we determined the configuration of this amino acid in compound 2 using the advanced Marfey's method. These cycloheptapeptides were evaluated for their antitumor, antibacterial, and antioxidant activities. Compound 1 showed moderate cytotoxicity against MCF-7 and PC9 cells, with IC50 values of 6.8 and 9.6 µM, respectively, while compounds 2-5 demonstrated potential antioxidant effects by upregulating HO-1, NQO1, and SOD2 levels, as well as inducing Nrf2 activation.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Phytochemistry
Year:
2024
Document type:
Article
Affiliation country:
China
Country of publication:
Reino Unido