Diterpenes from Marrubium sericeum, Marrubium supinum and Marrubium alysson

From some Marrubium species endemic in the Iberian Peninsula, four new diterpenoids, 6-acetyl-marrubenol, 19-acetyl-marrubenol, premarrubenol and 6-acetyl-premarrubenol, have been isolated. The previously known diterpenes marrubiin and marrubenol have also been obtained from the same sources.     

Galeuterone and pregaleuterone,labdane diterpenoids from Galeopsis reuteri

From the aerial part of Galeopsis reuteri a furanic labdane diterpenoid, galeuterone, and its prefuranic derivative, pregaleuterone, have been isolated. The structures of these substances have been established mainly by spectroscopic means.     

Preperegrinine,a prefuranic labdane diterpene from Marrubium friwaldskyanum

From the aerial part of Marrubium friwaldskyanum the previously known diterpenoid peregrinine and its new prefuranic derivative, preperegrinine, have been isolated. The known compound 5,6-dihydroxy-7,4′-dimethoxyflavone has also been found in the same source.     

Diterpenoids from Baccharis tola

Erythroxylol-A, oleanolic acid, erythroxylol-A oxide, scopolatine, 4-hydroxy-3-methoxyacetophenone and two new diterpenes, ent-beyer-14-en-18-ol and 19-hydroxy-13-epimanoyl oxide, were isolated from B. tola.     

Rearranged labdane diterpenoids from Galeopsis angustifolia

From the aerial part of Galeopsis angustifolia collected in Spain, a labdane and three rearranged labdane diterpenoids have been isolated. The structures of these new substances have been established by chemical and spectroscopic means and by correlation with known compounds. A sample of the same species collected in Italy and other species of Galeopsis showed some remarkable chemical differences. The taxonomic significance of these results is discussed briefly.     

Teucrins H1-H4, novel clerodane-type diterpenes from Teucrium hyrcanicum

The structure and stereochemistry of teucrins H1, H2, H3 and H4, four novel diterpenes from Teucrium hyrcanicum have been established by detailed studies of the PMR and ¹³C NMR spectra, CD results and chemical transformations. Teucrin H4, a minor constituent is shown to possess a unique stereochemistry hitherto not reported for related diterpenoids.     

Diterpenoids from Teucrium scorodonia, three neo-clerodane derivatives

From the aerial parts of Teucrium scorodonia the previously known diterpenoid teupolin I and the flavone luteolin have been isolated. In addition, three new neo-clerodane derivatives have also been obtained from the same source. The structures of these new natural diterpenoids have been established by chemical and spectroscopic means and by correlation with known products.     

Diterpenoids of Halimium viscosum

From the neutral fraction of the hexane extract of Halimium viscosum the following components were isolated; 7-labdene-3β,l5-diol, 15-acetoxy-7-labden-3β-ol and a new diterpene-lactone with a rearranged ent-labdane skeleton, 13S-ent-9, 1-friedo-labd-1(10)-en-15-acetoxy-2R,18-olide. From the non-saponifiable part, beside 7-labdene-3β, 15-diol and 7, 13E-labdadiene-3β, 15-diol, the new diterpene 8(17)-labdene-3β, 7α, 15-triol was extracted. The structures were elucidated by spectroscopic methods, correlations or synthesis.     

Diterpenes from the seed of Sciadopitys verticillata

Thirteen new labdane-type diterpenes have been isolated from the seeds of Sciadopitys verticillata together with six known ones, sciadin, sciadinone, dimethyl sciadinonate, lambertianic acid and its methyl ester and trans-communic acid. Their structures have been determined by chemical and spectral methods.     

Isoeriocephalin and 20-deacetyleriocephalin,Neoclerodane Diterpenoids from Teucrium lanigerum

From the aerial part of Teucrium lanigerum two new neo-clerodane diterpenoids, 20-deacetyleriocephalin and isoeriocephalin, have been isolated, together with the previously known diterpene eriocephalin. The structures of 20-deacetyleriocephalin [19-acetoxy 4α,18:15,16-diepoxy-7α-hydroxy-6-keto-neo-cleroda-13(16),14-diene-20S,12S-hemiacetal] and isoeriocephalin [19-acetoxy-4α,18:15,16-diepoxy-6α-hydroxy-7-keto-neo-cleroda-13(16),14-diene (20-acetyl)-20S,12S-hemiacetal] were established by chemical and spectroscopic means and by correlation with known compounds.     

Diterpenoids from Salvia oxyodon and Salvia lavandulifolia

Three new diterpenoids have been detected in Salvia oxyodon and identified as 3β-hydroxy-dehydroabietic acid, 3β-acetoxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide and 3β-hydroxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide. Salvia lavandulifolia yielded two known compounds ursolic acid and galdosol.     

New labdane diterpenoids from Sideritis chamaedryfolia

From the aerial parts of Sideritis chamaedryfolia six previously known ent-kaurene diterpenoids have been isolated. In addition, seven new labdane derivatives have also been obtained from the same source. The structures of these new natural diterpenoids have been established by chemical spectroscopic means and by correlation with known products.     

The structure of leocardin,two epimers of a diterpenoid from Leonurus cardiaca

From the aerial part of Leonurus cardiaca a new labdane diterpenoid, leocardin, has been isolated and its structure was established by spectroscopic and chemical means. It has been shown to be 8β-acetoxy-9α,13α,15,16-bisepoxy-15-hydroxy-7-oxo-labdan-6β,19-olide present as a C-15 epimeric mixture.     

Resin acids of Pinus resinosa needles

The principal resin acids in the needles of Pinus resinosa are the labdane diterpenes, the new 8,13-epoxy-14-labden-19-oic acid (epimanoyl oxide acid), 8,13β-epoxy-14-labden-19-oic acid (manoyl oxide acid), 8(17),E-12,14-labdatrien-19-oic acid (communic acid) and 15-oxo-8(17)-labden-19-oic acid (imbricataloic acid). A survey of needles from representative populations of P. resinosa showed a limited variability in resin acid composition consistent with the uniformity of other traits. The composition of needle resin acids for putative P. nigra x resinosa hybrids strongly suggests the improbability of P. resinosa as the pollen parent.     

Diterpenoids from Ajuga chamaepitys: Two neo-clerodane derivatives

From the whole plant of Ajuga chamaepitys two new neo-clerodane diterpenoids, ajugapitin and its dihydro derivative, have been isolated. Their     

Pigment formation by callus of Lavandula angustifolia

Callus cultures of Lavandula angustifolia accumulated and secreted the (Z,E)-2-(3,4-dihydroxyphenyl)ethenyl ester of 3-(3,4-dihydroxyphenyl)-2-propenoic acid and its (E,E)-isomer under a wide range of culture conditions. The secreted compounds formed intensely blue pigments by chelation with Fe(su2+)in the media. These unusual enol esters could not be detected in the parent plant but the (Z,E)-isomer occurred in shoots and foliage of Plectranthus caninus.     

Diterpenes from the roots of Salvia canariensis

The new diterpenes, deoxocarnosol 12-methyl ether, salvicanol and 6α-hydroxydemethylcryptojaponol, and the known ones, sugiol and demethylcryptojaponol, have been isolated from the bark of the roots of Salvia canariensis.     

Gutierrezial and further diterpenes from Gutierrezia sarothrae

The aerial parts of Gutierrezia sarothrae afforded in addition to polyalthic acid, daniellic acid and nivenolide, 14 new diterpenes, most of them closely related to polyalthic acid. One of these compounds has a new carbon skeleton. The structures were elucidated by spectroscopic methods and by some chemical transformations.     

Diterpenes from Salvia mellifera

Two new aromatic diterpenes have been obtained from the aerial part of Salvia mellifera and their structures identified, on the basis of spectral data and chemical correlations, as 11,12,20-trihydroxy-abieta-8,11,13-triene and 11,12,16-trihydroxy- abieta-8,11,13-trien-20-al. The known diterpenes, carnosic acid, carnosol, rosmanol, isorosmanol, galdosol, rosmadial, 9 (10 → 20)-abeo-abieta-8,11,13-triene-10β,11,12-triol (demethylsalvicanol)and salvicanol were also isolated from the same source. The absolute configuration of salvicanol was established by X-ray diffraction analysis of its 11-p-bromobenzoate derivative.