Discovery of cycloheptapeptides phakefusins A-E from the marine sponge Phakellia fusca based on molecular networking.

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 β-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.

Wu Y ，Xu ZZ ，Kong C ，Zhang SS ，Lin XL ，Zhang S ，Liu LY ，Sun F ，Lin HW ，Wang SP ... -  《-》

Fuscasins A-D, Cycloheptapeptides from the Marine Sponge Phakellia fusca.

Wu Y ，Liu L ，Chen HF ，Jiao WH ，Sun F ，Liu LY ，Zhu HR ，Wang SP ，Lin HW ... -  《-》

Phakefustatins A-C: Kynurenine-Bearing Cycloheptapeptides as RXRα Modulators from the Marine Sponge Phakellia fusca.

Wu Y ，Liao H ，Liu LY ，Sun F ，Chen HF ，Jiao WH ，Zhu HR ，Yang F ，Huang G ，Zeng DQ ，Zhou M ，Wang SP ，Lin HW ... -  《-》

Phakellisins A-E, cyclopeptides from a marine sponge Phakellia sp. guided by LC-MS.

A chemical investigation of the marine sponge Phakellia sp. from the South China Sea yielded five new cyclopeptides, phakellisins A-E (1-5). Structures of these compounds were determined by comprehensive analysis of 1D/2D NMR, HRESIMS/MS spectroscopic data and the advanced Marfey's method. All compounds were evaluated for their cytotoxic activity. Compound 1 showed a strong inhibitory activity against WSU-DLCL-2 cells with an IC50 value of 5.25 ± 0.2 μM by induction of G0/G1 cell cycle arrest and apoptosis.

Kong C ，Wu Y ，Zhao HM ，Zhang SS ，Wu ZM ，Li XB ，Liu KC ，Lin HW ，Wang SP ... -  《-》

Isolation and structural elucidation of euryjanicins B-D, proline-containing cycloheptapeptides from the Caribbean marine sponge Prosuberites laughlini.

Vera B ，Vicente J ，Rodríguez AD 《-》