James N. Roitman

A pear-derived kairomone with pheromonal potency that attracts male and female codling moth, Cydia pomonella (L.)

Abstract. Ethyl (2E, 4Z)-2,4-decadienoate, a pear-derived volatile, is a species-specific, durable, and highly potent attractant to the codling moth (CM), Cydia pomonella (L.), a serious pest of walnuts, apples, and pears worldwide. This kairomone attracts both CM males and virgin and mated females. It is highly attractive to CM in both walnut and apple orchard contexts, but has shown limited effectiveness in a pear orchard context. Rubber septa lures loaded with ethyl (2E, 4Z)-2,4-decadienoate remained attractive for several months under field conditions. At the same low microgram load rates on septa, the combined gender capture of CM in kairomone-baited traps was similar to the capture rate of males in traps baited with codlemone, the major sex pheromone component. The particular attribute of attracting CM females renders this kairomone a novel tool for monitoring population flight and mating–ovipositional status, and potentially a major new weapon for directly controlling CM populations.

6-Epicastanospermine, a novel indolizidine alkaloid that inhibits α-glucosidase

Abstract A second indolizidine alkaloid, epimeric with castanospermine, has been isolated from seeds of the Australian tree Castanospermum australe . The structure was established as 6-epicastanospermine by proton and carbon-13 nuclear magnetic resonance spectroscopy and mass spectrometry. 6-Epicastanospermine was found to be a potent inhibitor of amyloglucosidase, (an exo-1,4,-α-glucosidase), a weak inhibitor of β-galactosidase, and not to inhibit β-glucosidase and α-mannosidase. These results indicate that glycosidase inhibitory activity cannot be predicted by comparison of the structure and stereochemistry with the appropriate sugars, since 6-epicastanospermine is an analog of mannose and not of glucose. The inhibition of amyloglucosidase was found to be competitive and to be more effective at higher pH values. Castanospermine and 6-epicastanospermine differed in their effect upon the mung bean processing enzymes, glucosidase I and II, in that the former is a potent inhibitor whereas the latter is a very poor inhibitor. Subtle alterations in stereochemistry of these alkaloids can therefore produce significant changes in their biological activity.

Exudate flavonoids of Inula viscosa

Abstract Aerial parts of Inula viscose exhibit a resinous exudate of terpenoid nature, containing flavonoid aglycones. Nine flavonoids are reported in addition to 13 previously known components. The.study of samples collected in France, Spain and Turkey indicates the existence of a qualitatively constant exudate flavonoid profile in this species.

Chemodiversity of exudate flavonoids in some members of the Lamiaceae

Several newly studied species and further accessions of the Lamiaceae have been analyzed for their exudate flavonoid profiles. The principal compounds accumulated were flavones and their 6-methoxy derivatives, whereas flavonols were rarely encountered. The chemodiversity observed was relatively low, with only some 15 derivatives being found. The new data are discussed in relation to published data, and chemosystematic aspects are briefly addressed. Of the studied species, Salvia arizonica yielded only a rare diterpene quinone, demethylfruticulin A. Glandular hair diversification and different qualities of their secretions are briefly discussed.

External leaf flavonoids of Polanisia trachysperma

Abstract Polanisia trachysperma , a sticky annual weed, produces a terpenoid leaf resin. This exudate is shown to contain more than a dozen methylated flavonoid aglycones, some of which are rare natural products. Compounds with 6,8-dimethoxy substitution are predominant. Polanysia trachysperma is the first Capparaceae species found to accumulate external flavonoids.

Exudate flavonoids from two australian asteraceae, Bracteantha viscosa and cassinia quinquefaria

Abstract Nineteen flavonoids were identified in the leaf and stem exudates of Bracteantha viscosa : 12 flavones and seven flavanones. Two flavones and four flavanones are rare 6-methoxyflavonoids. The resinous exudate accumulating on aerial parts of Cassinia quinquefaria contains six flavonoid aglycones. One of them is a novel natural flavonol: 6-hydroxygalangin.

Flavonoid aglycones excreted by three Calceolaria species

Abstract The lipophilic exudate produced by Calceolaria irazuensis leaf glands was shown to contain small amounts of three rare 8-methoxy flavonoids and one new one: gossypetin 7,8,3′-trimethyl ether. The leaf exudates of C. chelidonioides and C. scabiosifolia also contain trace amounts of flavonoid aglycones.

A geranyl α-pyrone from the leaf resin of Diplacus aurantiacus

Abstract A novel prenylated α-pyrone has been isolated from the leaf resin of Diplacus aurantiacus. From its 1 H and 13 C NMR spectra, it is shown to be 3-(2-hydroxypropyl)-4-hydroxy-6-geranyl-2-pyrone. A geranylflavanone isolated from the same material is identified as 3′-methyl-6-geranyltaxifolin. The earlier tentative structure of 4′-methyldiplacol thus needs to be revised.

Xanthones and Triterpene Acids as Leaf Exudate Constituents in Orphium frutescens

Summary The exudate produced by glandular trichomes on leaves and stems of Orphium frutescens (Gesneriaceae) has been analyzed. Oleanolic acid and 2α-hydroxy oleanolic acid account for the major portion of this material. At least five xanthones are also present, three of which were identified as the known tetrasubstituted compounds decussatin, swertianin, and nor-swertianin.

β,β-Dimethacrylophenones and a chromanone from Nama hispidum and N. Johnstonii

Abstract A β,β-dimethacrylophenone and the corresponding chromanone were isolated from the leaf resin of Nama hispidum. The leaf exudate of N. johnstonii contains another β,β-dimethacrylophenone as colouring matter.