Diterpenes from sideritis dendrochahorra and s. cystosiphon

A new diterpene, sidendrodiol (ent-16β,18-dihydroxykaur-11-ene), has been isolated from Sideritis dendrochahorra. From S. cystosiphon two new diterpenic esters, the 18-palmitate of epicandicandiol and the diacetate of epicandicandiol have been identified. The ¹³CNMR spectra of ent-16β-hydroxykaur-11-ene and ent-16β-hydroxykaurane derivatives have been assigned.     

Ceriopsins F and G,diterpenoids from Ceriops decandra

Chemical examination of the ethyl acetate solubles of the CH(3)OH:CH(2)Cl(2) (1:1) extract of the roots of Ceriops decandra collected from Kauvery estuary resulted in the isolation of two more diterpenoids, ceriopsins F and G (1-2) and five known compounds, ent-13-hydroxy-16-kauren-19-oic acid (steviol, 3), methyl ent-16beta,17-dihydroxy-9(11)-kauren-19-oate (4), ent-16beta,17-dihydroxy-9(11)-kauren-19-oic acid (5), ent-16-oxobeyeran-19-oic acid (isosteviol, 6), 8,15R-epoxypimaran-16-ol (7). The structures of the new diterpenoids were elucidated by a study of their physical and spectral data as methyl ent-13,17-epoxy-16-hydroxykauran-19-oate (1) and ent-16-oxobeyeran-19-al (2).     

Ent-kaurane derivatives from the root cortex of yacon and other three Smallanthus species (Heliantheae,Asteraceae)

The metabolites produced by the secretory canals of the root cortex from four Smallanthus species belonging to the yacon group were identified as ent-kaurane-type diterpenes. The dichloromethane root cortex extracts of the four species were treated with diazomethane and analyzed comparatively by GC–MS using a simple and rapid procedure which is very sensitive and reproducible permitting detection of minor components. In all cases, ent-16-kauren-19-oic acid (kaurenoic acid) methyl ester was the main component, differences being observed only in the minor components. The minor components identified were grandiflorenic acid methyl ester, ent-16-kauren-19-al, 16α,17-epoxy-15α-angeloyloxy-kauran-19-oic acid methyl ester and several O-acyl derivatives at C-15 or C-18 of kaurenoic acid. One of the minor components, 18-isobutyroyloxy-ent-kaur-16-en-19-oic acid is a new kaurenoic acid derivative. Grandiflorenic acid and 15-α-angeloyloxy-16,17-α-epoxy-ent-16-kauren-19-oic acid were present only in Smallanthus sonchifolius and Smallanthus siegesbeckius which showed very similar GC traces. The different GC profile of RC diterpenes from Smallanthus connatus and Smallanthus macroscyphus supports the view that they are different taxa. Some chemotaxonomic aspects of the genus Smallanthus and the subtribe Milleriinae are briefly discussed.     

中国紫堇属曲花堇组的研究

曲花紫堇组(Sect．Rapiferae)是1936年由Fedde建立的,当时大约有20种。我们在做中国植物志的过程中,对大量标本进行了分析研究后,本组已是包括有41种的大组。模式种:曲花紫Corydalis curviflora Maxim．     

STRUCTURE OF RABDOFORRESTIN A

A new ent-kaurene diterpene, rabdoforrestin A (1 ) , mp 204- 206°C, [α]22/D -83°(c=0.96,CHCL3)was isolated from the leaves of Rabdosia forrestii (Diels) Hara (Labiatae) collected Lijiang, Yunnan. Its structure has been shown to be ent-11β-hydroxy-2α, 3α,6β, 7α-tetraacetoxy-16-kauren-15-one (1 ) on the basis of spwctroscopic and chemical evidence and compared with known compound lushanrubescensin B .     

Two new ent-kaurene diterpene glucosides from the roots of Mikania micrantha

Two new ent-kaurene diterpene glucosides, β-d-glucopyranosyl-15α-(3-hydroxyl-3-methylbutanoyloxy)-ent-16-kauren-19-oate (1) and β-d-glucopyranosyl-15α-hydroxy-ent-16-kauren-19-oate (2), were isolated from the roots of Mikania micrantha. Their structures were elucidated on the basis of spectroscopic evidence. Both compounds were evaluated for allelopathic effects on the seed germination and seedling growth of Arabidopsis thaliana. Compound 1 inhibited the seedling growth by 68.3% at the concentration of 0.5 mM.     

Cytotoxic metabolites from Botryotinia fuckeliana A-S-3: An endophytic fungus from Ajuga decumbens

Available online from an cytotoxic endophytic fungus Botryotinia fuckeliana A-S-3, three cytochalasans phenochalasin B (4), [12]-cytochalasin (5) and one [1,3] dioxacyclotridecino (6), along with two new ent-eudesmane sesquiterpenes, 1-keto-4α,15-epoxyeudesm-11-ol (1), and ent-4(15)-eudesmen-5,6-ol-1-one (2), and one known ent-eudesmane sesquiterpene ent-4(15)-eudesmen-11-ol-1-one (3) were isolated. The structures of these compounds were elucidated by interpretation of spectroscopic data. Among these compounds, two cytotoxic constituents were identified.     

Diterpenoids from Sideritis varoi subspecies cuatrecasasii: 13C NMR of ent-13-epi-manoyl oxides functionalized at C-12

Several ent-13-epi-manoyl oxides and a new natural product, ent-8α-hydroxylabda-13(16),14-dien-19-oic acid, have been isolated from Sideritis varoi subsp. cuatrecasasii. In addition, a study has been made of some natural and semisynthetic ent-13-epi-manoyl oxides functionalized at C-12.     

The fatty acid and sterol composition of two marine dinoflagellates

The fatty acid, sterol and chlorophyll pigment compositions of the marine dinoflagellates Gymnodinium wilczeki and Prorocentrum cordatum are reported. The fatty acids of both algae show a typical dinoflagellate distribution pattern with a predominance of C₁₈, C₂₀ and C₂₂ unsaturated components. The acid 18:5ω3 is present at high concentration in these two dinoflagellates. G. wilczeki contains a high proportion (93.4%) of 4-methyl-5α-stanols including 4,23,24-trimethyl-5α-cholest-22E-en-3β-ol (dinosterol), dinostanol and 4,23,24-trimethyl-5α-cholest-7-en-3β-ol reported for the first time in dinoflagellates. The role of this sterol in the biosynthesis of 5α-stanols in dinoflagellates is discussed. P. cordatum contains high concentrations of a number of δ ²⁴⁽²⁸⁾-sterols with dinosterol, 24-methylcholesta-5,24(28)-dien-3β-ol, 23,24-dimethylcholesta-5,22E-dien-3β-ol, 4,24-dimethyl-5α-cholest-24(28)-en-3β-ol and a sterol identified as either 4,23,24-trimethyl- or 4-methyl-24-ethyl-5α-cholest-24(28)-en-3β-ol present as the five major components. The role of marine dinoflagellates in the input of both 4-methyl- and 4-desmethyl-5α-stanols to marine sediments is discussed.     

Ent-kauren-19-oic acid derivatives from the stem bark of Croton pseudopulchellus Pax

Two new ent-kauren-19-oic acid derivatives, ent-14S*-hydroxykaur-16-en-19-oic acid and ent-14S*,17-dihydroxykaur-15-en-19-oic acid together with eleven known compounds ent-kaur-16-en-19-oic acid, ent-kaur-16-en-19-al, ent-12β-hydroxykaur-16-en-19-oic acid, ent-12β-acetoxykaur-16-en-19-oic acid, 8R,13R-epoxylabd-14-ene, eudesm-4(15)-ene-1β,6α-diol, (?)-7-epivaleran-4-one, germacra-4(15), 5E,10(14)-trien-9β-ol, acetyl aleuritolic acid, β-amyrin, and stigmasterol were isolated from the stem bark of Croton pseudopulchellus (Euphorbiaceae). Structures were determined using spectroscopic techniques. Ent-14S*-hydroxykaur-16-en-19-oic acid, ent-kaur-16-en-19-oic acid, ent-12β-hydroxykaur-16-en-19-oic acid, ent-12β-acetoxykaur-16-en-19-oic acid and 8R,13R-epoxylabd-14-ene were tested for their effects on Semliki Forest virus replication and for cytotoxicity against human liver tumour cells (Huh-7 strain) but were found to be inactive. Ent-kaur-16-en-19-oic acid, the major constituent, showed weak activity against the Plasmodium falciparum (CQS) D10 strain.     

Ent-Kaurene Diterpenoids from Rabdosia eriocalyx

Two new named maoecrystal F(1) and G(2) and seven known ent-kaurene diterpenoids were isolated from the leaves of Rabdosia eriocalyx (Dunn) Hara collected at Xundian County, Yunnan Province, and their structures were determined by spectroscopic analysis. Maoecrystal F and G are elucidated as ent-7α, 15α-dihydrooxyl- lβ,6α-diacetoxyl-7β, 20-epoxy-16-kaurene (1) and ent-7α,15α-dihydroxyl-6α-ace-toxyl-7β, 20-epoxy-16-kaurene(2), respectively.     

Diterpenoids from Nepeta tuberosa subsp. reticulata

Three new diterpene compounds have been isolated from Nepeta tuberosa subsp. reticulata and their structures elucidated by spectroscopic methods. They were identified as diisopimaryl malonate isopimarylmalonic acid and 7-oxo-isopimara-8,15-dien-18-ol. We have also isolated 4aα,7α,7aβ-nepetalactone, 4aα,7α,7aα-nepetalactone, 3α-hydroxy-4α,4aα,7α 4α,4aα,7α,7aα-dihydronepetalactone, isopimaryl acetate, isopimarol, isopimaric acid, 8(14),15-isopimaradien-7α,18-diol, myrceocomunic acid and α-tocopheryl quinone.     

ent-Kauranoid derivatives from Sideritis moorei

Seven new ent-kauranoid derivatives ent-7alpha,18-dihydroxykaur-16-en-3-one, ent-18-acetoxy-3beta,7alpha-dihydroxykaur-15-en-17-al, ent-3beta-acetoxy-7alpha,18-dihydroxykaur-15-en-17-al, ent-18-acetoxy-3beta,7alpha,17-trihydroxykaur-15-ene, ent-3beta-acetoxy-7alpha,17,18-trihydroxykaur-15-ene, ent-18-acetoxy-3beta,7alpha,17-trihydroxy-15beta,16beta-epoxykaurane and ent-3beta-acetoxy-7alpha,17,18-trihydroxy-15beta,16beta-epoxykaurane have been isolated from Sideritis moorei. The structures of these compounds have been established by spectroscopic means and chemical correlations.     

Kaurene derivatives from Alepidea amatynsia

Alepidea amatynsia afforded several known diterpenes, ent-16-kauren-19-oic acid, its 9(11)-dehydro derivative, ent-16-kauren-12-on-19-oic acid, wedelia seco-kaurenolide and a further seco-diterpene. The structure of the latter was established by ¹H NMR spectroscopy.     

The microbiological transformation of some ent-beyerene diterpenoids by Gibberella fujikuroi to beyergibberellins and beyerenolides

The microbiological transformation by Gibberelia fujikuroi of ent-beyer-15-ene into the beyergibberellins A₉ and A₁₃, 7β-hydroxy- and 7β,18-dihydroxybeyerenolides, and of ent-beyer-15-en-19-ol into beyergibberellins A₄, A₇, A₉, A₁₃ and A₂₅,and 7β-hydroxy-and 7β,18-dihydroxybeyerenolides is described. In contrast, ent-beyer-15-en-18-ol gave _ent-7α, 18,19-trihydroxybeyer-15-ene, 7β,18-dihydroxybeyerenolide and _ent-7α,18-dihydroxybeyer-15-en-19-oic acid again revealing the inhibitory effect of an 18-hydroxyl group on oxidative transformations at C-6β by Gibberella fujikuroi.     

Epimerisation of 3β-ol to 3α-ol steroid alkaloids by Nocardia restrictus

(22S,25S)-5α-tomatanin-3β-ol, N-acetyl-(22S,25S)-5α-tomatanin-3β-ol, (22R,25R)-5α-tomatanin-3β-ol and (22R,25S)-22,26-epimino-5α-cholestane-3β,16β-diol are transformed by Nocardia restrictus into corresponding 3α-ol compounds with yields from 70 to 5%.     

Alkaloids of Datura suaveolens

The alkaloid mixture of Datura suaveolens shows distinct differences compared with that of other tree daturas. Aerial parts contain in addition to hyoscine, apohyoscine, norhyoscine, atropine and noratropine, a relatively high proportion of tigloyl esters—3α,6β-ditigloyloxytropan-7β-ol, 6β-tigloyloxytropan-3α,7β-diol,3α-tigloyloxytropan-6β,7β-diol (meteloidine) and (—)- and (±)-3α-tigloyloxytropan-6β-ol. The roots contain hyoscine, meteloidine, atropine, littorine, 3α-acetoxytropane, 6β-(α-methylbutyryloxy)-3α-tigloyloxytropane, 3α,6β-ditigloyloxytropan-7β-ol, 3α-tigloyloxytropan-6β-ol, tropine and cuscohygrine. Other, as yet uncharacterized, bases are present in the plant. Norhyoscine is a principal alkaloid of the corollas.     

Biotransformation of ent-kaur-16-ene and ent-trachylobane 7β-acetoxy derivatives by the fungus Gibberella fujikuroi (Fusarium fujikuroi)

Candol A (7β-hydroxy-ent-kaur-16-ene) (6) is efficiently transformed by Gibberella fujikuroi into the gibberellin plant hormones. In this work, the biotransformation of its acetate by this fungus has led to the formation of 7β-acetoxy-ent-kaur-16-en-19-oic acid (3), whose corresponding alcohol is a short-lived intermediate in the biosynthesis of gibberellins and seco-ring ent-kaurenoids in this fungus. Further biotransformation of this compound led to the hydroxylation of the 3β-positions to give 7β-acetoxy-3β-hydroxy-ent-kaur-16-en-19-oic acid (14), followed by a 2β- or 18-hydroxylation of this metabolite. The incubation of epicandicandiol 7β-monoacetate (7β-acetoxy-18-hydroxy-ent-kaur-16-ene) (10) produces also the 19-hydroxylation to form the 18,19 diol (20), which is oxidized to give the corresponding C-18 or C-19 acids. These results indicated that the presence of a 7β-acetoxy group does not inhibit the fungal oxidation of C-19 in 7β-acetoxy-ent-kaur-16-ene, but avoids the ring B contraction that leads to the gibberellins and the 6β-hydroxylation necessary for the formation of seco-ring B ent-kaurenoids. The biotransformation of 7β-acetoxy-ent-trachylobane (trachinol acetate) (27) only led to the formation of 7β-acetoxy-18-hydroxy-ent-trachylobane (33).     

The sterols of Argania spinosa seed oil

The sterol fraction of Argan seed oil (Argania spinosa) contains two main compounds, 5α-stigmast-7-en-3β-ol (schottenol) and 5α-stigmast-7,22(E)-dien-3β-ol (spinasterol).     

Novel dinoflagellate 4α-methylated sterols from four caribbean gorgonians

Fourteen 4α-methyl sterols have been isolated from the gorgonians Briareum asbestinum, Gorgonia mariae, Muriceopsis flavida and Pseudoplexaura wagenaari, including the following five new sterols: 4α-methyl-24-methylene-5α-cholestan-3β-ol, (24R)-4α, 24-dimethyl-5α-cholesta-7,22-dien-3,β-ol, 4α,24S(or 23ξ)-dimethyl-5α-cholest-7-en-3β-ol, (22E, 24R)-4α,23,24-trimethyl-5α-cholesta-7,22-dien-3β-ol and (24R)-4α,24-dimethyl-5α-cholesta-8(14),22-dien-3β-ol. There is strong evidence that these 4α-methyl sterols are synthesized by the algal (dinoflagellate) symbionts (zooxanthellae) of the gorgonians. It is suggested that analysis of 4Δ-methyl sterol mixtures isolated from a zooxanthellae-bearing invertebrate, collected in several different geographic locations, might give information on the specificity of the symbiotic association between a given animal species and a particular strain of zooxanthellae.