Mary T. Fletcher

Chemical studies of rectal gland secretions of some species ofBactrocera dorsalis complex of fruit flies (diptera: Tephritidae).

Male-produced rectal gland secretions of a number of species now considered to be members of theBactrocera dorsalis complex of fruit flies have been examined by combined gas chromatography-mass spectrometry. The structures of a number of previously unreported compounds have been confirmed by synthesis and Chromatographic comparisons. Compounds identified in these secretions include fatty acids, esters, amides, keto alcohols, diols and spiroacetals. These chemical findings are in agreement with taxonomic revisions based on other criteria.

Volatile compounds from the flowers of spathiphyllum Cannaefolium

Headspace analysis and solvent extraction of the pollenbearing flower spike of Spathiphyllum cannaefolium have been conducted by GC-MS, to determine the basis of the flower spike’s attractancy to certain fruit-fly species. The major components were benzyl acetate, methyleugenol, methylchavicol, p-methoxybenzyl acetate and fatty acids. Benzyl acetate is known to be attractive to D. cueurbitae, D. dorsalis and C. capitata (representing the three different ‘male-lure categories’) and methyleugenol (one of these male-lures) attracts D. cacuminatus, D. dorsalis and D. occipitalis. Thus the odoriferous flowerspike exhibits wide ranging attractancy and hence Spathiphyllum cannaefolium may have some application as a fruit-fly control measure for small orchards where ‘methyleugenol-attracted’ species (e.g. D. cacuminatus, D. dorsalis, D. occipitalis) are the dominant pests.

Pyrrolizidine Alkaloids in Crotalaria Taxa from Northern Australia: Risk to Grazing Livestock

Crotalaria species containing hepatotoxic pyrrolizidine alkaloids grow widely in pastures in northern Australia and have sporadically poisoned grazing livestock. The diverse Crotalaria taxa present in these pastures include varieties, subspecies, and chemotypes not previously chemically examined. This paper reports the pyrrolizidine alkaloid composition and content of 24 Crotalaria taxa from this region and assesses the risk of poisoning in livestock consuming them. Alkaloids present in C. goreensis , C. aridicola subsp. densifolia, and C. medicaginea var. neglecta lack the esterified 1,2-unsaturated functionality required for pyrrole adduct formation, and these taxa are not hepatotoxic. Taxa with high levels of hepatotoxic alkaloids, abundance, and biomass pose the greatest risk to livestock health, particularly C. novae-hollandiae subsp. novae-hollandiae, C. ramosissima , C. retusa var. retusa, and C. crispata . Other species containing moderate alkaloid levels, C. spectabilis and C. mitchellii , also pose significant risk when locally abundant.

Residue Potential of Norsesquiterpene Glycosides in Tissues of Cattle Fed Austral Bracken (Pteridium esculentum).

Austral bracken, Pteridium esculentum , occurs widely in Australian grazing lands and contains both the known carcinogen ptaquiloside and its hydroxy analogue, ptesculentoside, with untested carcinogenic potential. Calves were fed a diet containing 19% P. esculentum that delivered 1.8 mg of ptaquiloside and 4.0 mg of ptesculentoside per kilogram of body weight (bw) per day to explore the carcass residue potential of these compounds. Concentrations of ptaquiloside and ptesculentoside in the liver, kidney, skeletal muscle, heart, and blood of these calves were determined as their respective elimination products, pterosin B and pterosin G, by HPLC-UV analysis. Plasma concentrations of up to 0.97 μg/mL ptaquiloside and 1.30 μg/mL ptesculentoside were found, but were shown to deplete to <10% of these values within 24 h of bracken consumption. Both glycosides were also detected in all tissues assayed, with ptesculentoside appearing to be more residual than ptaquiloside. Up to 0.42 and 0.32 μg/g ptesculentoside was present in skeletal muscle and liver, respectively, 15 days after bracken consumption ended. This detection of residual glycosides in tissues of cattle feeding on Austral bracken raises health concerns for consumers and warrants further investigation.

The isomeric 1,3,3-Trimethyl-2-oxabicyclo[2.2.2]octan-6-ol (2-Hydroxy-1,8-cineoles)

The stereochemistry of the title compounds, and of the two 1,2-epoxy-p-menthan-8-ols, is discussed.

Halogenated terpenoids. XX: The seven monochlorocineoles

The seven monochlorocineoles have been synthesized, separated and characterized. Initial attempts to identify these compounds as pollutants in chlorinated water supplies from eucalypt-vegetated areas are discussed.

Absolute configuration of sordidin and 7-episordidin emitted by the banana weevil, Cosmopolites sordidus

Abstract Male-specific volatile components released by the banana weevil, Cosmopolites sordidus Germar, from Australia have been identified as (1 S ,3 R ,5 R ,7 S )-1-ethyl-3,5,7-trimethyl-2,8-dioxabicyclo[3.2.1]octane and the 7 R -epimer (as a minor component) by synthesis and enantioselective gas chromatography.

Norsesquiterpene glycosides in bracken ferns (Pteridium esculentum and Pteridium aquilinum subsp. wightianum) from eastern Australia: reassessed poisoning risk to animals

Austral bracken Pteridium esculentum contains three unstable norsesquiterpene glycosides: ptaquiloside, ptesculentoside, and caudatoside, in variable proportions. The concentration of each of the glycosides was determined in this study as their respective degradation products, pterosin B, pterosin G and pterosin A, by HPLC-UV analysis. Samples of P. esculentum collected from six sites in eastern Australia contained up to 17 mg of total glycoside/g DW, with both ptaquiloside and ptesculentoside present as major components accompanied by smaller amounts of caudatoside. Ratios of ptaquiloside to ptesculentoside varied from 1:3 to 4:3, but in all Australian samples ptesculentoside was a significant component. This profile differed substantially from that of P. esculentum from New Zealand, which contained only small amounts of both ptesculentoside and caudatoside, with ptaquiloside as the dominant component. A similar profile with ptaquiloside as the dominant glycoside was obtained for Pteridium aquilinum subsp. wightianum (previously P. revolutum ) from northern Queensland and also P. aquilinum from European sources. Ptesculentoside has chemical reactivity similar to that of ptaquiloside and presumably biological activity similar to that of this potent carcinogen. The presence of this additional reactive glycoside in Australian P. esculentum implies greater toxicity for consuming animals than previously estimated from ptaquiloside content alone.

Chemistry of fruit flies: Nature of glandular secretion and volatile emission ofBactrocera (bactrocera) cacuminatus (Héring)

The major component of the rectal glandular extract and volatile emission of maleBactrocera cacuminatus is racemic 1,7-dioxaspiro[5.5]undecane. l-Hydroxy-5-nonanone as its open chain form, together with 6-n-butyl-3,4-dihydro-2H-pyran are minor components. 1,7-Dioxaspiro[5.5]undecan-4-ol is present at a low level and is shown to be exclusively the diastereomer with an equatorial hydroxy group by comparison with synthesized samples of both epimers. Examination of the trifiuoroacetate by chiral gas chromatography has established the (4S,6S) stereochemistry (ca. 80% ee). The presence of 1,7-dioxaspiro[5.5]undecan-3-ol, or its isomerization product, 1,6-dioxaspiro[4.5]decan-2-ylmethanol, could not be confirmed. Trapping of the volatiles released by sexually mature male flies at dusk revealed that a number of the glandular components described above are released at mating time. Reexamination of the glandular secretion of sexually mature female olive flies (B. oleae) has failed to confirm the presence of any 1,7-dioxaspiro[5.5]undecanols, with the only volatile component (other than fatty acids) being 1,7-dioxaspiro[5.5]undecane.

Isoquinoline alkaloids and keto-fatty acids of Argemone ochroleuca and A. mexicana (mexican poppy) seed. I. An assay method and factors affecting their concentration

An assay for the isoquinoline alkaloids of Argemone ochroleuca and A. mexicana seeds is described. The method consists of extraction into weakly acidified methanol and ion-pair high performance liquid chromatography with sodium lauryl sulfate and tartaric acid in acetonitri1e:water as eluent. Analysis of A. ochroleuca seed showed it to contain dihydrosanguinarine and dihydrochelerythrine (c. 3 : 2) as major alkaloid components with minor amounts of protopine, sanguinarine, berberine and chelerythrine. A single sample of authenticated A. mexicana seed contained dihydrosanguinarine as the major alkaloid with minor amounts of sanguinarine and berberine, in agreement with earlier studies. Dihydrosanguinarine and dihydrochelerythrine were measured as their oxidized products, sanguinarine and chelerythrine, after U.V. irradiation. A crystalline solid which separates from A. ochroleuca seed oil was shown to contain 11-oxo-octacosanoic acid and 11-oxo-triacontanoic acid, which are also the major components of a similar solid from A. mexicana seed oil. Mexican poppy seed (probably A. ochroleuca) collected from various regions of Queensland during 1987-89 showed that place of origin and length of storage of intact seed had little effect on alkaloid levels. Exposure of crushed seed to light, however, caused a rapid decrease in the concentration of dihydro-alkaloids. Total alkaloid content correlated with seed maturity, with immature seed containing much less than mature seed.