Isolation, Structure Determination, and Biological Activity of Lyngbyabellin A from the Marine Cyanobacterium Lyngbya majuscula

Abstract

Lyngbyabellin A (1), a significantly cytotoxic compound with unusual structural features, was isolated from a Guamanian strain of the marine cyanobacterium Lyngbya majuscula. This novel peptolide is structurally related to dolabellin (2) in that both depsipeptides bear a dichlorinated beta-hydroxy acid and two functionalized thiazole carboxylic acid units. Its gross structure has been elucidated by spectral analysis, including 2D NMR techniques. The absolute stereochemistry of 1 was determined by chiral HPLC analysis of hydrolysis products and by characterization of the degradation products methyl 7,7-dichloro-3-hydroxy-2,2-dimethyloctanoate (3) and the corresponding acid 4. The total structure was further supported by molecular modeling studies. The isolation of 1 from L. majuscula once more supports the proposal that many compounds originally isolated from the sea hare Dolabella auricularia are of cyanobacterial origin. Lyngbyabellin A (1) was shown to be a potent disrupter of the cellular microfilament network.

Continuing Studies on the Cyanobacterium Lyngbya sp.: Isolation and Structure Determination of 15-Norlyngbyapeptin A and Lyngbyabellin D

“…A solution of 100 /ug of 3 was ozonized and saponified as previously described. 10 The resulting mixture was analyzed by chiral HPLC [column CHIRALPAK MA(+), (4.6 x 50 mm), 0.8 mL/min, detection at 254 nm]. The retention times (min) with 5% CH3CN/2 mM CuS0 4 of the a^-dihydroxy-yS-methylpentanoic acid standards prepared by the diastereoselective route were (2fl,3i?…”

SyrB2 in syringomycin E biosynthesis is a nonheme Fe II α-ketoglutarate- and O 2 -dependent halogenase

“…There are also aliphatic carbons bearing one, two, or three chlorine atoms in natural products, such as the 4-Cl-L-Thr at residue nine of the peptide scaffold of the phytotoxic syringomycin E from Pseudomonas syringae pv. syringae B301D (6), the dichlorinated ␤-hydroxy acid of lyngbyabellin A (7), and the trichloroleucine-derived moiety in barbamide (8) (Fig. 1B).…”

Macrolactamas bioativas e síntese de macrociclos por reação de carbociclização radicalar mediada por hidreto de tri-n-butilestanho

“…Outros depsipeptídeos cíclicos, isolados de cianobactéria marinha (Lyngbya majuscula) e denominados lingbiabelinas A e B (Esquema 1), apresentam atividade contra células tumorais. 9,10 A indolactama-V e benzolactama-V8 (Esquema 2), de 9 e 8 membros respectivamente, ligam-se à proteína quinase C ativando-a para a promoção de tumores. Esta atividade parece estar diretamente…”