Occurrence of a potent piscicidal diterpenedial in the liverwort Riccardia lobata var. Yakushimensis

Sacculatal and isosacculatal, two diterpene dialdehydes, have been isolated from the liverwort Riccardia lobata var. yakushimensis as the major components. Orizia latipes ( killie fish) is killed within 2 hr by a 0.4 ppm solution of sacculatal. It is suggested that R. lobata var. yakushimensis and Pellia endiviifolia might have originated from a common ancestor since the latter produces the same sacculatals as the former species.     

New diterpenes from Porella perrottetiana

Perrottetianal A and perrottetianal B, two new diterpene dialdehydes and a new ent-labdane-type diterpene diol have been isolated from the liverwort Porella perrottetiana and their structures have been elucidated by the chemical and spectral evidence.     

Two guaiane-type sesquiterpene lactones and their related sesquiterpene lactones from Porella japonica

Two new guaiane-type sesquiterpene dilactones, porelladiolide and 3α,4α-epoxyporelladiolide and a new germacranolide, 3β-hydroxycostunolide, together with the previously known germacranolides, guaianolides, pinguisane-type sesquiterpenes, and a sacculatane-type diterpene dialdehyde have been isolated from the liverwort, Porella japonica and their structures have been established by the spectral evidence and some chemical transformations. Porelladiolide, 3α,4α-epoxyporelladiolide and the sesquiterpene with α-methylene γ-lactone group showed inhibitory activity toward the germination and growth of roots of rice in the husk.     

Le diterpenoid du gout piquant de Pellia endiviaefolia

A unique pungent component of the new buds of Pellia endiviaefolia is due to a diterpene dialdehyde 2, which was recently isolated from another liverwort, Trichocoleopsis sacculata.     

Sesquiterpene lactones from a texas population of Helianthus maximiliani

A population of Helianthus maximiliani from south-central Texas was shown to have a sesquiterpene lactone chemistry which was completely different from that reported for collections of this species from Kansas and north-central Texas. A series of five new guaianolides, two germacrolides (trans, trans-1(10),4(5)-germacradienolides), one of which is new, and a known labdane diterpene acid were isolated from a chloroform extract. Structures were determined by spectral and chemical methods. The structure of one guaianolide had been previously determined by X-ray crystallography.     

Germacranolides from Helianthus californicus

Five germacranolide sesquiterpene lactones and a trachylobane diterpene were isolated from the hexaploid species Helianthus californicus. Four of the sesquiterpene lactones are new, including a 1-oxo-3,10-diol without any carbon-carbon double bonds in the main ring whose structure was confirmed by X-ray crystallography. These results require revision of the structures of several previously published compounds. Two of the germacranolides have alkyl ether functions at a position β to a ketone and are believed to be artifacts of the isolation process. Based on terpenoid chemistry, there are no obvious progenitors of H. californicus among the diploid species of Helianthus examined to date.     

Diterpenoids from Viguiera insignis

The isolation of several known diterpenoids and one new diterpene diol from aerial parts of Viguiera insignis is reported.     

A diterpene acid from baccharis tucumanensis

The new clerodane diterpene 1 was isolated from the aerial parts of Baccharis tucumanensis (Compositae). Its structure has been determined from spectral data combined with chemical transformations.     

Sesquiterpene lactone and diterpene constituents of helianthus annuus

One new furanoheliangolide derivative, 4,5-dihydroniveusin A, as well as the known compounds niveusin B and argophyllin A and B, were isolated from a Texas population of Helianthus annuus. Three previously characterized diterpene acids, grandifloric acid, ciliaric acid and 17-hydroxy-ent-isokaur-15(16)-en-19-oic acid were the principal constituents of this population.     

A neo-clerodane glucoside and neo-clerodane diterpenoids from Teucrium flavum subsp. Glaucum

From the aerial part of Teucrium flavum subsp. glaucum a new neo-clerodane diterpenoid, teuflavin, and a new 19-nor-neo-clerodane glucoside, teuflavoside, have been isolated, besides the previously known diterpene teuflin. The structures of teuflavin (19-acetoxy-4α,18:15,16-diepoxy-6β-hydroxy-3-keto-neo-cleroda-13(16),14-diene-20,ξ,12S-hemiacetal) and teuflavoside (18-acetoxy-15,16-epoxy-19-nor-neo-cleroda-4,13(16),14-trien-20,12S-olid-6β-yl-2′-O-acetyl-β-d-glucopyranoside) were established by chemical and spectroscopic means and by correlation with known compounds. In addition, the previously known flavone salvigenin has also been obtained from the same source.     

Grindelane diterpenoid acids from Grindelia humilis: Feeding deterrency of diterpene acids towards aphids

Two new labdane diterpene acids have been isolated from Grindelia humilis. The spectroscopic properties of the acids and their derivatives, as well as conversion to methyl 6-oxogrindelate, showed that they were the epimeric pair 6α-hydroxy- and 6β- hydroxygrindelic acid. A series of 11 diterpene acids were surveyed for their feeding deterrency towards the aphid Schizaphis graminum. The substances tested showed a wide range of activity.     

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.     

An abietane diterpene from the labiate Coleus barbatus

20-Deoxocarnosol, isolated from the stems of Coleus barbatus, was shown by chemical and spectral methods to be a new phenolic diterpene with an abietane skeleton.     

Gymnospermin: A new labdan triol from Gymnosperma glutinosa

The structure of gymnospermin (1), a new diterpene triol isolated from a collection of Gymnosperma glutinosa (Compositae) from Mexico, has been determined to be (?)-7β,8α,15-trihydroxy-labdan.     

Terpenoids of Rhododendron japonicum

From Rhododendron japonicum were isolated two diterpene glucosides, pieroside B and grayanoside B, and two new triterpenes, 2α,3α,24-trihydroxy     

A diterpene from Euphorbia maddeni

From the anticancer-active CHCl₃, extract of the plant Euphorbia maddeni, a polyacylated diterpene of jatrophone type, euphornin, has been isolated and its structure elucidated by physico-chemical methods.     

The structure and stereochemistry of phlogantholide-A,a diterpene from Phlogacanthus thyrsiflorus

The structure and stereochemistry of phlogantholide-A, a new diterpene lactone isolated from the leaves of Phlogacanthus thyrsiflorus has been determined as 2β,15,18-trihydroxy-ent-labd-8(17),13-dien-16-oic lactone by chemical and spectroscopic means.     

Pinguisanin,pinguisanolide and β-pinguisenediol,three new pinguisane-type sesquiterpenes from Porella platyphylla

Three new pinguisane-type sesquiterpenes, pinguisanin, pinguisanolide and β-pinguisenediol, together with the previously known deoxopinguisone, have been isolated from a European liverwort, Porella platyphylla, and their structures have been established by the spectral evidence and some chemical transformations.     

Dehydropinguisanin,dehydropinguisenol and pinguisenal,three pinguisane-type sesquiterpenes from Trocholejeunea sandvicensis

Three new pinguisane-type sesquiterpenes, dehydropinguisanin, dehydropinguisenol and pinguisenal together with the previously known deoxopinguisone, pinguisanin, pinguisanolide and (—)-bicyclogermacrene, have been isolated from the liverwort, Trocholejeunea sandvicensis, and their structures have been established from spectral evidence.     

Dolabellane-type diterpene alkaloids from Nigella glandulifera

A new dolabellane-type diterpene alkaloid, deoxynigellamine, together with three known dolabellane-type diterpene alkaloids, were isolated from the seeds of Nigella glandulifera. Their structures were identified as nigellamine A₁ (1), nigellamine A₂ (2), nigellamine B₁ (3) and nigeglamine (4), respectively, based on spectroscopic analysis and by comparison of their spectral data with those reported previously in the literature.