John A. Findlay

Metabolites toxic to spruce budworm from balsam fir needle endophytes

The bioactive constituents of extracts of three strains of balsam fir endophytic fungi, reported to cause reduced growth rate and mortality of spruce budworm larvae, have been isolated and characterized. Bioassay-directed fractionation has resulted in the identification of heptelidic acid, 1,5a,6,7,8,9a-hexahydro-6-(1-methylethyl)-1-oxo-spiro[2-benzoxepin-9(3H),2′oxirane]-4-carboxylic acid ( 1 ), and two new analogues, heptelidic acid chlorohydrin ( 2 ), and hydroheptelidic acid ( 3 ), as the biologically active components of ? Phyllosticta sp. strain 76. The active component of Hormonema dematioides strains 53 and 143 was identified as (+)rugulosin ( 4 ), an anthraquinone previously reported to exhibit a wide spectrum of biological activity. This is the first report of the identification of toxins from fungal endophytes of woody plants.

Needles of white spruce inoculated with rugulosin-producing endophytes contain rugulosin reducing spruce budworm growth rate

Conifer needles, like many grasses, are infected by systemic fungal endophytes. Following suggestions made in the early 1980s that (1) conifer needle endophytes may produce anti-insectan compounds, and (2) population dynamics of the eastern spruce budworm in New Brunswick could not be completely explained based on existing knowledge, we discovered that a low percentage of needle endophytes made a range of known and new metabolites toxic to this insect. Here, we report that wound inoculations of toxigenic endophytes of seedlings from a breeding population of white spruce were successful across a range of genotypes. The needles colonized by a rugulosin-producing endophyte were found to contain rugulosin in concentrations that are effective in vitro at retarding the growth of spruce budworm larvae. Larvae presented with endophyte infected needles containing rugulosin do not gain as much weight as those eating uncolonized needles. This represents the first positive evidence that the kind of mutualism between toxigenic endophytes and grasses affecting insect herbivory also may occur in white spruce.

A novel sterol peroxide from the sea anenome Metridium senile

Nine 5 alpha, 8 alpha-epidioxy delta 6 and delta 6,9(11) sterols were identified including the hitherto unknown (22E)-5,8-epidioxy-5 alpha, 8 alpha-stigmasta-6,9(11),22-trien-3 beta-ol 9 from the sea anenome Metridium senile based on 200 MHz 1Hnmr and mass spectral data.

A triterpenoid saponin from Cucumaria frondosa

The structure of a new triterpenoid saponin, frondoside D, isolated from Cucumaria frondosa has been determined principally by high field 1D and 2D NMR and FAB-MS spectrometry. Frondoside D was shown to be 3 beta-[3-O-methyl-O-beta-D-glucopyranosyl-(1-3)-O-beta-D- xylopyranosyl-(1-4)-[O-beta-D-xylopyranosyl-(1-2)]-O-beta-D- quinovopyranosyl-(1-2)-O-beta-D-4-sulfonatoxylo-pyranosyl]-1 6 beta-acetoxy-23S-hydroxy-holost-7-ene, sodium salt.

Antibacterial constituents of the red alga cystoclonium purpureum

Abstract The red alga Cystoclonium purpreum was found to contain α-carotene, plastoquinone-9, trans -phytol, ubiquinol-9, lutein and fucoxanthin. The composition of the antibacterial fatty acid fraction was determined by GC/MS.

Chapter 3 Pyridine and Piperidine Alkaloids

Publisher Summary The designation of pyridine and piperidine alkaloids as a group introduces a level of arbitrariness. These compounds do not stem from a common biosynthetic precursor, they are not unique to a single taxonomic family, and even the structural characteristics that might seem to define the group are open to interpretation. However, the historical recognition of these alkaloids as a class, and the practice of reviewing them as such are sufficient reasons to continue these traditions. This chapter represents a survey of the relevant literature on pyridine and piperidine alkaloids. It includes alkaloids containing a piperidine-type nitrogen heterocycle (at any oxidation level) that is not fused to a carbocyclic system. Alkaloids in which the nitrogen-containing ring is fused to a second heterocycle, such as gentianine have in some cases been included, except where such fusion generates another readily identifiable heterocyclic moiety, such as the quinolizidine system. The alkaloids are grouped in sections, largely on the basis of their structural characteristics, although biogenetic or taxonomic considerations have also been taken into account in some instances.

The chemistry of some 6-methyl-4-hydroxy-2-pyridones

Some oxidations and reductions of 4-hydroxy-6-methyl-2-pyridones are discussed. A remarkable reduction–cyclization of 4-hydroxy-3-(1′-hydroxy-2′-oxopropyl-)-6-methyl-2-pyridone (2b) produces the novel system 10a.

Reactions of 4-Hydroxy-6-Methyl-2-Pyridone with aldehydes And Glyoxals

Abstract Recently we reported the structure 1 for flavipucine, an antibiotic factor isolated from culture filtrates of Aspergillus flavipes.1 In considering synthetic approaches to this novel highly functionalized system we regarded compounds 2a and 2b to be potentially useful intermediates. This prompted us to study the reactions of 4-hydroxy-6-methyl-2-pyridone2 with some aldehydes and glyoxals.

Some constituents of the sea cucumber Cucumaria frondosa

Abstract Solvent extraction of Cucumaria frondosa , collected in Passamaquoddy Bay, has afforded a variety of natural products. Silica gel chromatography of the chloroform extract has provided an abundance of sterol glycosides, sterol sulfates and free sterols which have been examined by gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance spectroscopy ( 1 H nmr). It appears that the free sterol and the sterol glycoside mixtures are composed mainly of Δ 7 -sterols, whereas the sterol sulfate mixture is composed predominantly of cholesterol and cholestanol. By methanol extraction, a mixture of triterpenoid saponins has been obtained. Partial hydrolysis of this material has yielded several monosaccharides, aglycones and one aglycone with a xylose unit attached. A new triterpenoid lactone has been isolated and its structure is proposed on the basis of 1 H nmr, infrared (IR), and MS data. From the light petroleum ether extract, a number of compounds have been obtained, including the known carotenoid canthaxanthin and a plastochromanol never previously reported from marine sources. Alkaline hydrolysis of the lipid fraction provided a mixture of sterols and the known compound batyl alcohol.

Total Synthesis of (±) Flavipucine

Abstract In 1972 we proposed1 structure 3 for flavipucine, an antibiotic from an Aspergillus flavipes strain. Later we reported2 a novel reaction of 6-methyl-4-hydroxy-2-pyridone with α keto aldehydes which provided 1a from isobutylglyoxal and it was stated that we believed 1a would serve as a key intermediate in the total synthesis of flavipucine 3.