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A new analogue of gambierone, 44-methylgambierone, was isolated from the benthic dinoflagellate Gambierdiscus australes collected from Raoul Island (Rangitahua/Kermadec Islands). This molecule has been previously reported as maitotoxin-3. The structure of 44-methylgambierone was elucidated using 1D- and 2D-nuclear magnetic resonance spectroscopy and mass spectrometry techniques. The nine-ring polyether backbone (A–I) and functional groups (carbonyl, terminal diol, 1,3-diene and monosulphate) are the same for both compounds with the addition of an olefinic methyl group being the only modification in 44-methylgambierone.

Pinnatoxin H was isolated from a culture of the dinoflagellate Vulcanodinium rugosum isolated from the South China Sea. The structure of pinnatoxin H was elucidated by LC–MS/MS and NMR spectroscopy. It was found to have the same macrocyclic structure and substituents as pinnatoxins D, E and F, but the side chain on the cyclohexenyl ring was an ethenyl group, as found in pinnatoxin G and portimine. The observation that this strain of V. rugosum produced only pinnatoxin H and portimine is consistent with previous findings that the profile of pinnatoxins can vary significantly among strains. The acute toxicity of pinnatoxin H to mice was 67 μg/kg (intraperitoneal) and 163 μg/kg (gavage).

Portimine, a new polycyclic ether toxin containing a cyclic imine moiety, was isolated from the marine benthic dinoflagellate Vulcanodinium rugosum collected from Northland, New Zealand. The structure of portimine, including the relative configurations, was elucidated by spectroscopic analyses. The cyclic imine moiety consists of an unprecedented five-membered ring with a spiro-link to a cyclohexene ring. This is the only structural similarity to the pinnatoxin group of polycyclic ethers also produced by V. rugosum, which all contain a six-membered cyclic imine ring. The LD50 of portimine to mice by intraperitoneal injection was 1570 μg/kg, indicating a much lower toxicity than many other cyclic imine shellfish toxins. In contrast, portimine was highly toxic to mammalian cells in vitro with an LC50 to P388 cells of 2.7 nM, and activation of caspases indicating apoptotic activity.

Meliracemoic acid, a novel nor-sesquiterpenoid isolated from the honey of the New Zealand native tree kamahi (Weinmannia racemosa), has been shown to possess a substituted 2,5-methano-hexahydro-1,3-benzodioxolane skeleton. The structure was determined principally by ID and 2D NMR analysis of the corresponding methyl ester.

The diethyl ether extract of honey from the flowers of the New Zealand native tree Kamahi (Weinmannia racemosa) has been found to contain three diastereoisomers of an unusual degraded carotenoid with a 14 carbon skeleton. After acetylation, one of the isomers, 1b, was fully characterised by multidimensional 1H and 13C NMR spectroscopy and single crystal X-ray crystallography, showing that the parent alcohol (Kamahine C, 1a) was 4,5-dihydro-1′,5-dihydroxy-2′,4,8′,8′-tetramethylspiro[furan-2( 3 ) H,7′-[6]oxabicyclo-[3.2.1]oct[2]ene]-4′-one.

A racemic synthesis of the title compound is described starting from β-ionone. The key steps involve selective hydroboration of a triene, followed by molybdenum mediated epoxidation of the resulting homoallylic alcohol with subsequent ring opening of the epoxide to give the title compound.