Neurotoxic meroditerpenoids from the tropical marine brown alga Stypopodium flabelliforme.
Brine shrimp toxicity and TLC analysis guided the isolation of five new and biologically active meroditerpenoids [2beta,3alpha-epitaondiol (1), flabellinol (2), flabellinone (3), stypotriolaldehyde (4), and stypohydroperoxide (5)] along with five known compounds from the marine brown alga Stypopodium flabelliforme collected in Papua New Guinea. The planar structures of compounds 1-5 were determined by extensive spectroscopic analysis (1D and 2D NMR, LRMS, HRMS, IR, and UV), while relative configuration was determined by 1D and 2D NOE experiments. X-ray crystallography confirmed the relative configuration of 2beta,3alpha-epitaondiol (1), and the modified Mosher's ester method was used to establish its absolute configuration. All of the new metabolites were moderately toxic to murine neuro-2a cells (LC50 2-25 microM), and three [2beta,3alpha-epitaondiol (1), flabellinol (2), and flabellinone (3)] possessed potent sodium channel blocking activity. Stypotriolaldehyde (4) had a biphasic effect on the concentration of intracellular Ca2+ in rat cerebellar granule neurons (CGN). The previously known compound, stypoldione (6), also modulated intracellular calcium concentration and was cytotoxic in CGN. Metabolites 2beta,3alpha-epitaondiol (1), flabellinol (2), and flabellinone (3) displayed moderate cytotoxicity to the NCI-H460 human lung cancer cell line.
Sabry
Omar M M
OM
College of Pharmacy, Oregon State University, Corvallis, Oregon 97331, USA.
Andrews
Simeon
S
McPhail
Kerry L
KL
Goeger
Douglas E
DE
Yokochi
Alexandre
A
LePage
Keith T
KT
Murray
Thomas F
TF
Gerwick
William H
WH
D000818:Animals; D001156:Artemia / Q000187:drug effects; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015394:Molecular Structure; D009474:Neurons / Q000187:drug effects; D009498:Neurotoxins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010219:Papua New Guinea; D000459:Phaeophyceae / Q000737:chemistry*; D051381:Rats; D026941:Sodium Channel Blockers / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004224:Diterpenes; D009498:Neurotoxins; D026941:Sodium Channel Blockers