Two new monoterpenes from the bled resin of Pistacia vera

Structure determination and synthesis of two novel bicyclic p-menthane monoterpenes isolated from Pistacia vera are reported.     

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.     

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.     

Antileishmanial activity of diterpene acids in copaiba oil

Leishmaniasis is a neglected tropical disease. According to the World Health Organization, there are approximately 1.5-two million new cases of cutaneous leishmaniasis each year worldwide. Chemotherapy against leishmaniasis is based on pentavalent antimonials, which were developed more than a century ago. The goals of this study were to investigate the antileishmanial activity of diterpene acids in copaiba oil, as well as some possible targets of their action against Leishmania amazonensis. Methyl copalate and agathic, hydroxycopalic, kaurenoic, pinifolic and polyaltic acids isolated from Copaifera officinales oleoresins were utilised. Ultrastructural changes and the specific organelle targets of diterpenes were investigated with electron microscopy and flow cytometry, respectively. All compounds had some level of activity against L. amazonensis. Hydroxycopalic acid and methyl copalate demonstrated the most activity against promastigotes and had 50% inhibitory concentration (IC₅₀) values of 2.5 and 6.0 µg/mL, respectively. However, pinifolic and kaurenoic acid demonstrated the most activity against axenic amastigote and had IC₅₀ values of 3.5 and 4.0 µg/mL, respectively. Agathic, kaurenoic and pinifolic acid caused significant increases in plasma membrane permeability and mitochondrial membrane depolarisation of the protozoan. In conclusion, copaiba oil and its diterpene acids should be explored for the development of new antileishmanial drugs.     

Fatty acids,resin acids and phenols in Pinus muricata

Acetone-soluble extractives of “blue” and “green” strain Pinus muricata D. Don were found to consist of free and “combined” fatty acids, resin acids, and phenols. The composition of the extractives from the two strains was similar though “green” strain P. muricata contained more Δ^8(9),15 isopimaric acid than “blue” strain. This difference may be used to identify these muricata strains if the age of the wood precludes a monoterpene examination.     

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.     

Tetrachyrin,a new rearranged kaurenoid lactone,and diterpene acids from Tetrachyron orizabaensis and Helianthus debilis

(?)-Kaur-16-en-19-oic acid and tetrachyrin, a new rearranged kaurenoid lactone, were isolated from Tetrachyron orizabaensis var. websteri and Helianthus debilis ssp. debilis. The latter species also afforded angeloylgrandifloric acid.     

Identity of sanadaol with β-crenulal,a diterpene from the brown alga Dictyota crenulata

β-Crenulal is a minor constituent of the marine brown alga Dictyota crenulata from Hawaii and is identical with sanadaol isolated from Pachydictyon coriaceum in Japan.     

Fatty acids of Pinus elliottii tissues

The total fatty constituents of slash pine (Pinus elliottii) tissue cultures, seeds and seedlings were examined by GLC and MS. Qualitatively, the fatty acid composition of these tissues was very similar to that reported for other pine species. The fatty acid contents of the tissue cultures resembled that of the seedling tissues. In addition to the fatty acids common to botanical materials, Δ⁵-C₁₈ and -C₂₀ nonmethy lene-interrupted polyunsaturated acids were present in low relative abundances. The branched-chain C₁₇ acid reported for several other Pinus species was confirmed as the anteiso isomer.     

Dulcosides A and B,new diterpene glycosides from Stevia rebaudiana

New diterpene glycosides, dulcosides A and B were isolated from Stevia rebaudiana Bertoni and their structures were established as 19-O-β-glu     

Sesquiterpene lactones and diterpene carboxylic acids in Helianthus niveus subspecies Canescens

Three new heliangolides (niveusin-A, -B and -C) and three known diterpene carboxylic acids were isolated and characterized from a CHCl₃, extract of Helianthus niveus. The structures of the three new lactones were deduced by ¹H and ¹³C NMR as well as extensive decoupling experiments and derivatizations.     

Sesquiterpene and diterpene lactones from melampodium longipilum

the aerial parts of Melampodium longipilum afforded two new diterpene lactones, 17-hydroxy- and 17-acetoxyacanthoaustralide, and a new sesquiterpene lactone, repandin E, besides the known melampolides enhydrin and fluctuanin.     

Major resin acids of Pinus nigra needles

Labdane diterpene acids were found to be the major resin acid components in Pinus nigra needles of various seed sources. The major constituents have been identified as 4-epiimbricataloic acid, manoyl oxide 19-oic acid, 4-epicommunic acid, and 15-monomethyl pinifolate. A GC method was developed to analytically differentiate pinifolic acid from its monomethyl ester in an admixture of both compounds. A minor resin acid was identified as 18-acetoxy-8(17)-labden-15-oic acid. 10-Nonacosanol and isoabienol were identified as major constituents of the needle and cortex extractives, respectively.     

Distribution of alkaloids in Anthocercis littorea and A. viscosa

The distribution of tropane alkaloids in organs of Anthocercis littorea and A. viscosa is reported. The following alkaloids have been isolated: atropine (hyoscyamine), apoatropine, noratropine (norhyoscyamine), littorine, hyoscine, norhyoscine, meteloidine, 3α, 6β-ditigloyloxytropan-7β-ol, 6β-tigloyloxytropan-3α-ol, 3α-tigloyloxytropane, tigloidine, tropine, ψ-tropine, (?)-tropan-3α-6β-diol, cuscohygrine and unknown bases.     

Hydroxylated glutamic acids in Phlox,lepidium and Rheum species

The two diastereoisomers, (2S,4R)-4-hydroxyglutamic acid and (2S,4S)-4-hydroxyglutamic acid, occur in characteristic concentration ratios in Phlox species. The second of these compounds is the principal free amino acid in the green parts of the plants. The presence of (2S,4R)-4-hydroxyglutamic acid in plants is reported for the first tiine. No other 4-substituted acidic amino acids were detected in the Phlox species analysed, although special attention was paid to the possible presence of 4-hydroxy-4-methylglutamic acids which have previously been reported in plants. It was found, however, that both diastereoisomers of (2S)-4-hydroxy-4-methylglutamic acid co-exist in Ledenbergia roseoaenea and also in Pandanus veitchii. Although the presence of 3,4-dihydroxyglutamic acids in green parts of Lepidium sativum and Rheum rhaponticum has been previously reported, we were not able to detect or isolate any of the possible diastereoisomers from the green parts or seeds of these plants. We did isolate glutathione which was found to have some properties in common with those reported for the dihydroxy compounds.     

Diterpene acids from Helianthus species and their microbiological conversion by Gibberella fujikuroi, mutant B1-41a

The diterpene acid content in 10 species of Helianthus has been investigated. Ent-12,16-cyclokauranoic acid, isolated from H. annuus, is converted into a series of 12,16-cyclogibberellins by cultures of Gibberella fujikuroi, mutant B1-41a, and 12,16-cyclogibberellins A₉, and A₁₂ have been isolated. Ent-12β-acetoxykaurenoic acid and ent-13(S)-angeloxyatisenoic acid have been isolated from H. decapetalus; the metabolism of ent-13(S)-hydroxyatisenoic acid and atisenoic acid by B1-41a is also described.     

Amino acids in Hordeum distichon and Panicum miliaceum grown in sand culture

In comparison with barley, Proso millet was characterized by high levels of alanine and glutamic acid in the leaf free amino acid fraction. In both species, analyses of root amino acids and xylem exudates suggest the existence of specific mechanisms for the transfer of certain amino acids into the xylem vessels.     

Three new cardenolides from the milkweeds Asclepias eriocarpa and A. Labriformis

Asclepias eriocarpa and A. labriformis contain three new cardenolides, the structures of which have been partially assigned by their spectral properties and comparison with the known cardenolides of A. curassavica. They include labriformin (C₃₁H₃₉O₁₀NS), labriformidin (C₂₉H₃₁O₁₁) and eriocarpin.     

Stereochemistry of 2-aminopimelic acid and related amino acids in three species of asplenium

We previously reported two free D-amino acids, D-2-aminopimelic acid (D-APA) and trans-3,4-dehydro-D-2-aminopimelic acid (D-Δ-APA), from Asplenium unilaterale. In the present work we isolated 4-hydroxy-2-aminopimelic acid (OH-APA) from the same plant and determined it to be the α-L-form. We also investigated the configurations of these amino acids isolated from A. prolongatum and A. wilfordii which are morphologically distinct from A. unilaterale. In A. prolongatum, APA was the D- and OH-APA was the L-isomer. In contrast, APA from A. wilfordii was partially racemized and the degree of racemization was significantly different in plant material collected in July and November, L:D = 3:2 and 3:7, respectively. In A. wilfordii OH-APA was almost pure L- and Δ-APA was mostly the D-isomer.     

Halogenated acetic and acrylic acids from the red alga Asparagopsis taxiformis

Nine halogenated acetic acids and nine halogenated acrylic acids have been identified in the aqueous extract of Hawaiian Asparagopsis taxiformis.