Deterrent activity of sesquiterpene lactones from the umbelliferae against storage pests

The deterrent activity of eight native sesquiterpene lactones isolated from the species Laserpitium siler L., L. archangelica Wulf. and Laser trilobum (L.) Borkh. and one synthetically prepared lactone have been tested against selected storage pest insects. All nine lactones under investigation showed deterrent activity differing according to their structure.     

Structure-antimicrobial activity relationships among the sesquiterpene lactones and related compounds

Thirty-six sesquiterpene lactones and related compounds were evaluated for antimicrobial activity against six strains of bacteria. The results obtained show that the beta unsubstituted cyclopentenone ring moiety contributes to moderate antimicrobial activity against Gram positive bacteria. The corresponding saturated compounds gave a more than ten-fold decrease in activity. The significant antimicrobial activity appears to be independent of the presence or absence of an α-methylene-γ-lactone moiety. A more than ten-fold diminution in antimicrobial activity was also observed when the beta position of the cyclopentenone ring was substituted. A similar result was found when the beta unsubstituted enone system was present in a six-membered ring. Enhanced activity was obtained by esterification of the hydroxyl group of helenalin as well as epoxidation of mexicanin-A.     

Anticancer sesquiterpene lactones of Michelia compressa (magnoliaceae)

Investigation of the cytotoxic active components of Michelia compressa afforded two new cytotoxic sesquiterpene lactones, michelenolide and micheliolide. Parthenolide, costunolide, santamarine, reynosin and liriodenine were also isolated and exhibited cytotoxic activity. The known sesquiterpene lactones, lanuginolide and dihydroparthenolide, were isolated but were not active. Two other new inactive sesquiterpene lactones, compressanolide and dihydroreynosin, were also obtained. The structures of michelenolide and micheliolide were confirmed by partial synthesis from parthenolide and the structure of compressanolide by partial synthesis from dihydroparthenolide.     

Ineupatorolide-like sesquiterpene lactones from Dittrichia viscosa

Dittrichia viscosa afforded, in addition to known compounds, minute amounts of nine sesquiterpene lactones, all closely related to ineupatorolide B     

Hirsutinolides and other sesquiterpene lactones from Vernonia species

The investigation of Vernonia compactiflora afforded in addition to known compounds a hirsutinolide and a glaucolide; the latter is most probably the direct precursor of the former. The aerial parts of V. monocephala contain the same hirsutinolide as well as the corresponding acetate, while those of V. chalybaea afforded glaucolide B. A reinvestigation of the aerial parts of V. cotoneaster gave in addition to the allenic lactone isolated before two further known ones as well as a new glaucolide. The structures of the lactones were elucidated by spectroscopic methods and some chemical transformations. The erroneously assigned stereochemistry at C-10 in the hirsutinolides has been revised. The biogenetic relationship of the Vernonia lactones is discussed briefly.     

Minor sesquiterpene lactones of Helianthus pumilus

The isolation of four known and two new germacradienolides and one known heliangolide from Helianthus pumilus, in addition to the previously report     

Further sesquiterpene lactones from Helianthus maximiliani

By using HPLC, a new melampolide, a known heliangolide and three known germacrolides were isolated as minor constituents from a north central Texas population of Helianthus maximiliani. In an earlier report, we identified the germacrolide desacetyleupaserrin as the principal sesquiterpene lactone from this population.     

Biological activities of sesquiterpene lactones

Sesquiterpene lactones are characteristic constituents of the Compositae but also occur sporadically in other angiosperm families and even in some liverworts. These bitter substances often contain as a major structural feature an α,β-unsaturated-γ-lactone, which in recent studies has been shown to be associated with anti-tumor, cytotoxic, anti-microbial and phytotoxic activity. They are known to poison livestock, to act as insect feeding deterrents and to cause allergic contact dermatitis in humans. This review highlights the present state of knowledge on the biological activities and mechanism of action of some sesquiterpene lactones.     

The first sesquiterpene lactones esterified with a sesquiterpenic acid

From Hypochoeris glabra two guaianolides esterified with an unusual sesquiterpenic acid were isolated. Proton-catalysed rearrangement of the cyclopropane derivative led to a phenolic acid. The structures were elucidated by high-field ¹H NMR spectroscopy. Further guaianolides were isolated from H. uniflora and Lactuca floridana. These structures were elucidated by spectroscopic methods. The chemotaxonomic situation in the tribe is discussed briefly.     

Evolution of sesquiterpene lactones in asteraceae

The two basic micromolecular phenomena which accompany the introduction of a novel lineage in angiosperms, vigorous increase in oxidation state of allelochemics and reduction of the number of major biosynthetic routes, are shown to characterize the evolutionary development of sesquiterpene lactones in tribes of Asteraceae.     

Seven sesquiterpene lactones from Ferreyanthus species

The investigation of two Ferreyanthus species afforded seven germacranolides which have not been isolated previously. Two derivatives of linalol were also present. The structures were elucidated by spectroscopic methods. Chemotaxonomic relationships are briefly discussed.     

Two sesquiterpene lactones from artemisia species

Two new sesquiterpene lactones, himeyoshin and montanone, were isolated from Artemisia feddei and A. montana, respectively and identified by chemical and spectral data as1α,2α-epoxy-3-oxo-5,6-dihydroalantolactone and 1,10-dihydro-11,13-dehydromatricarin.     

Ant-repellent sesquiterpene lactones from Eupatorium quadrangularae

The chloroform extract from the leaves of Eupatorium quadrangularae has been systematically fractionated by following biological activity in a bioassay which measures repellency to the leafcutter ant Atta cephalotes (Formicidae, Attini). Several sesquiterpene lactones were isolated, two of which showed significant ant-repellency.     

Two sesquiterpene and three diterpene lactones from Acanthospermum australe

The aerial parts of Acanthospermum australe afforded two new sesquiterpene lactones, an acid and a cis,cis-germacranolide, as well as three diterpene lactones of a new type, most probably formed by intermolecular nucleophilic attack of the carboxyl group of an acid epoxide derived from geranylgeraniol. The structures were proposed on the basis of spectroscopic studies.     

New types of sesquiterpene lactones and other constituents from Trichogonia species

The investigation of five Trichogonia species afforded seven new furanoheliangolides, three dilactones of a new type, four pairs of epimeric rearra     

Two sesquiterpene lactones from Trichogonia gardneri

The structures and stereochemistries of two sesquiterpene lactones from Trichogonia gardneri were established as (6R,7S,8S,9S,IOR)-4E-9,10-dihydroxy-8-tigloxygermacr-4-en-6,12-olide) and (5R*,6R*,7S*,8S*,9R*)-14-acetoxy-3-chloro-9-hydroxy-2-oxo-8-tigloxyguia-1(10),3-dien-6,12-of olide by a combination of NMR spectrometry and X-ray diffraction. The results show that the structures of several sesquiterpene lactones which were isolated previously from related species require revision.     

New germacrolide- and heliangolide-type sesquiterpene lactones from Melampodium linearilobum

Chemical analysis of Melampodium linearilobum yielded, besides coumarin, seven germacrolide-type sesquiterpene lactones, linearilobin A to G and two heliangolides, linearilobin H and I. All new sesquiterpene lactones are oxygenated at C-14 and C-15 and differ by the number and types of ester moieties at C-8, C-14 and C-15. M. linearilobum represents the first species within the genus known to produce germacrolides and heliangolides instead of the more common melampolides.     

Glaucolide-like sesquiterpene lactones from Cotula cinerea

The aerial parts of Cotula cinerea gave, in addition to widespread compounds, a characteristic diacetylenic spiroketal enolether and several sesquiterpene lactones, three of them being glaucolide-like lactones. The structures were elucidated by highfield ¹H NMR spectroscopy.     

Pungent sesquiterpene lactones of the european liverworts Chiloscyphus polyanthus and Diplophyllum albicans

The characteristic pungency of the European liverwort, Chiloscyphus polyanthus, is due to a mixture of four sesquiterpene lactones, two new structures ent-5β-hydroxydiplophyllin and ent-3-oxodiplophyllin, and the previously known diplophyllin and diplophyllolide. A new dihydrodiplophyllin, together with the pungent diplophyllolide and diplophyllin, has been isolated from Diplophyllum albicans. Ent-dihydrodiplophyllolides derived from the above pungent diplophyllolides produce intense numbness of the tongue. All pungent sesquiterpene lactones showed inhibitory activity towards the germination and root elongation of rice husks.