Search

Seven new and three known bisresorcinols, grevirobstol A (=5,5′-((6Z,9Z)-hexadeca-6,9-diene-1,16-diyl)bisresorcinol; 8), 5,5′-[(8Z)-hexadec-8-ene-1,16-diyl]bisresorcinol (9), and 2-methyl-5,5′-[8Z)-hexadec-8-ene-1,16-diyl]bisresorcinol (10) were isolated from the stems of Grevillea glauca. The new compounds were identified on the basis of spectroscopic data as (Z)-6,7-didehydroglaucone A (1), glaucones A and B (2 and 3, resp.), 2-(3-hydroxyisopentyl)bisnorstriatol (4), 2-(3-methylbut-2-en-1-yl)bisnorstriatol (5), 2′-methylgrebustol A (6), and glaucane (7).

A detailed investigation of the wood, leaf, branch and root oil of Eremophila mitchellii (Benth.) was carried out by a combination of GC-FID, GC-MS and NMR. The wood oil was composed predominantly of eremophilanes, a rare class of biologically active, bicyclic sesquiterpenoids. The root oil was also found to contain the eremophilanes together with the zizaene sesquiterpene, sesquithuriferone. 9-Hydroxy-1,7(11),9-eremophilatrien-8-one and the known 1(10),11-eremophiladien-9-one (eremophilone), 9-hydroxy-7(11),9-eremophiladien-8-one (2-hydroxyeremophilone), 8-hydroxy-11-eremophilen-9-one (santalcamphor), 8-hydroxy-10,11-eremophiladien-9-one, sesquithuriferone and 8-hydroxy-1,11-eremophiladien-9-one were purified and elucidated by NMR. Three approaches to the purification of the major eremophilanes from the wood oil are described. (+) Spathulenol, α-pinene, globulol, viridiflorene were the major constituents of the leaf oil. All of the essential oils and the eremophilanes exhibited cytotoxicity against P388D(1) mouse lymphoblast cells in-vitro.

Seven new bisresorcinol derivatives, together with four known resorcinols, have been isolated from the ethyl acetate extract of the stems of Grevillea floribunda. Five of the new compounds (floribol A–E) were characterized as bisnorstriatol derivatives substituted at C-2 of both resorcinol units with variously modified prenyl (3-methylbut-2-enyl) units. The remaining two new compounds are similarly substituted derivatived of grebustol-B.

A novel isoflavan-4-ol (pumilanol), ( re l)-3β-(2′-hydroxy-4′,5′-methylenedioxyphenyl)-6-methoxy-4α,7-dihydroxybenzo-3,4-dihydropyran ( 1 ) and two known flavonoids, tephrinone ( 2 ) and rotenone ( 3 ) together with lupeol and stigmasterol were isolated from the roots of Tephrosia pumila (Fabaceae) from a collection made in Andhra Pradesh, India. The structures of the compounds were determined by MS, 1D and 2D-NMR spectral analysis. Pumilanol ( 1 ) exhibited significant antiprotozoal activity against T. b. rhodensiense , T. cruzi and L. donovani with IC 50 of 3.7, 3.35 and 17.2 μg/mL, respectively, but displayed high toxicity towards L-6 (IC 50 of 17.12 μg/mL) rat skeletal myoblasts.

Chemical systematics sets out to interpret the phylogenetic implications of the occurrence and distribution of secondary metabolites. In this review, a number of the major contributions from the 1960's and 1970's are identified and re-assessed in the light of recent evidence gained from DNA studies. It is shown that for the most part conclusions drawn on the basis of secondary metabolite distribution have been confirmed by the new techniques and it is concluded that chemical systematics can continue to provide useful insights into plant phylogeny.

Eight phenolic compounds, including two mixtures of two compounds, were isolated from the ethyl acetate extract of leaves and stems of Homalium brachybotrys. They were identified on the basis of spectroscopic data as quercetin-3-O-beta-glucopyranoside, luteolin-7-O-beta-glucopyranoside, 5,6-dihydro-6-beta-glucopyranosyloxy-3-(hydroxyphenyl-methyl)-2(4H)-benzofuranone (cochinolide 6-O-beta-glucopyranoside) (1), 2-(6-benzoyl-beta-glucopyranosyloxy)-5-hydroxybenzyl alcohol (poliothrysoside) (2), 2-(beta-glucopyranosyloxy)-5-hydroxybenzyl alcohol (salirepin) (3), 4,5-dihydro-7a-beta-glucopyranosyloxy-3-(hydroxyphenylmethyl)-2(7aH)-benzofuranone (isocochinolide-7a-O-beta-glucopyranoside) (4), 5,6-dihydro-3-(hydroxyphenylmethyl)-2(4H)-benzofuranone (6-deoxycochinolide) (5) and 3-benzylidine-6-hydroxy-2-benzofuranone (1'deoxy-4,5,6-dehydrocochinolide) (6). Benzofuranones (4), (5) and (6) are new natural products. The compounds isolated support the argument that Homalium is best placed in the Salicaceae s.l.

The aerial parts of Boronia ternata var. elongata from western Australia has yielded three new 2-acyl-4(1H)-quinolinone alkaloids, characterised as 2-n-pentyl-4(1H)-quinolinone, 1-methyl-2-n-pentyl-4(1H)-quinolinone and 1-methyl-2-(1 xi-methyl)-propyl-4(1H)-quinolinone, as well as known alkaloids of this class and a furoquinoline alkaloid. Boronia alulata, from northeast Queensland, also yielded 2-n-pentyl-4(1H)-quinolinone together with the known 2-n-propyl-4(1H)-quinolinone. Both species are assigned to Boronia section Valvatae which, alone among the sections of Boronia, appears to be characterised by the presence of alkaloids.

Global change is affecting plant and animal populations and many of the changes are likely subtle and difficult to detect. Based on greenhouse experiments, changes in temperature and rainfall, along with elevated CO2, are expected to impact the nutritional quality of leaves. Here, we show a decline in the quality of tree leaves 15 and 30 years after two previous studies in an undisturbed area of tropical forest in Kibale National Park, Uganda. After 30 years in a sample of multiple individuals of ten tree species, the mature leaves of all but one species increased in fiber concentrations, with a mean increase of 10%; tagged individuals of one species increased 13% in fiber. After 15 years, in eight tree species the fiber of young leaves increased 15%, and protein decreased 6%. Like many folivores, Kibale colobus monkeys select leaves with a high protein-to-fiber ratio, so for these folivores declining leaf quality could have a major impact. Comparisons among African and Asian forests show a strong correlation between colobine biomass and the protein-to-fiber ratio of the mature leaves from common tree species. Although this model, predicts a 31% decline in monkey abundance for Kibale, we have not yet seen these declines.

The major component (35-65%) of the volatile oil obtained by steam distillation of the leaves of Melaleuca triumphalis has been identified as (rel)-1beta-pentyl-1alpha,6alpha-dihydroxy-3,3,5,5-tetramethylcyclohexa-2,4-dione (trivial name triumphalone). Relative stereochemistry was established by nuclear Overhauser experiments and X-ray studies on the 2-(3,5-dinitrobenzoic acid) derivative. The remainder of the oil was composed of mono- and sesquiterpene hydrocarbons and alcohols. On prolonged standing the presence of a rearrangement product of triumphalone was observed which was characterized as (rel)-1beta-pentyl-1alpha,3alpha-dihydroxy-4,4,6,6-tetramethylcyclohexa-2,5-dione (trivial name isotriumphalone), presumably arising from an acid catalyzed shift of the pentyl group from C-1 to C-2.

Chemical investigation of the roots of Diospyros assimilis had led to the isolation and characterization of six naphthalene derivatives, two 2-naphthaldehyes, namely 4-hydroxy-3,5-dimethoxy-2-naphthaldehyde 1, 4-hydroxy-5-methoxy-2-naphthaldehye 2, its related isomer 5-hydroxy-4-methoxy-2-naphthaldehyde 3 and three commonly occurring naphthoquinones, diospyrin 4, 8'-hydroxyisodiospyrin 5 and the simple monomer, plumbagin 6. Their chemical structures were established by detailed NMR investigations including 1H and 13C NMR, HSQC, HMBC and NOESY experiments. In addition, the naphthalene derivatives 1-5 were evaluated for their in vitro antiprotozoal activity against protozoan parasites belonging to the genera Trypanosoma, Leishmania and Plasmodium. Among the tested compounds, naphthaldehyde 1 showed moderate inhibition of the growth of the parasites, T. brucei, T. cruzi, L. donovani with IC50 values of 19.82, 12.28 and 38.78 microM and displayed cytotoxicity towards rat skeletal myoblasts (L-6 cells) with IC50 of 174.94 microM, while 2 and 3 were found to be comparatively less active to 1. The dimeric quinones 4 and 5 exhibited good activity against T. brucei and L. donovani with IC50 of 1.12 and 8.82 microM and 12.94 and 16.66 microM respectively.

Three 2-naphthaldehydes, including the novel 4-hydroxy-3,5-dimethoxy-2-naphthaldehyde, the simple naphthoquinone plumbagin and the dimeric naphthoquinones diospyrin and 8′-hydroxyisodiospyrin have been isolated from the roots of Diospyros assimilis and their structures established by spectroscopic analysis.

The species of Clematis (Ranunculaceae) have been traditionally used for inflammatory conditions by indigenous Australians. We have previously reported that the ethanol extract of Clematis pickeringii inhibited COX-1. In this study, we examined the ethanol extracts and fractions of three Clematis species, Clematis pickeringii, Clematis glycinoides and Clematis microphylla, on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). We further examined the activating effects on the protein expression of peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (PPARgamma) in HepG2 cells. The ethanol extracts of three Clematis species inhibited the activities of COX-1, COX-2 and 5-LOX in the different extents. The stem extract of Clematis pickeringii showed the highest inhibitory activities among the three species on COX-1, COX-2 and 5-LOX with the IC(50) values of 73.5, 101.2 and 29.3 microg/mL. One of its fractions also significantly elevated PPARalpha expression by 173, 280 and 435% and PPARgamma expression by 140, 228 and 296% at 4, 8 and 16 microg/mL, respectively.

From the leaves of Zizyphus glabrata, a new dammarane-type triterpene, pseudojujubogenin -3-O- β -D-glucopyranoside, along with the known ceanothane triterpenes, granulosic acid, ceanothic acid and daucosterol were isolated. The structures of the compounds were fully characterized by detailed NMR investigations including 1H and 13C NMR, HSQC, COSY, HMBC and NOESY experiments. In addition, the dammarane glycoside was tested for its potential to inhibit various bacteria and was found to possess significant bactericidal activity. The 1H, 13C and full 2D-NMR data on granulosic acid has also been presented. This is the first report on the chemical constituents of the leaves of Z. glabrata.

Three novel polyketide metabolites were isolated from laboratory-scale fermentation of the Streptomyces rimosus mutant strain R1059. Structural elucidation of the compounds was based on NMR experiments. The compounds were characterized as naphthalene derivatives: (rel)-4beta,8-dihydroxy-3alpha-hydroxymethyl-4alpha-methyl-1,2,3,4-tetrahydronaphthalene1-one (1), 4xi8-dihydroxy-3-hydroxymethyl-4xi-methyl-1,4-dihydronaphthalene-1-one (2) and (rel)-4beta,8-dihydroxy-3alpha-O-[alpha-glucopyranosyl]hydroxymethyl-4alpha-methyl-1,2,3,4-tetrahydronaphthalene-1-one (3). The compounds isolated appear to be derived via a shorter polyketide backbone than oxytetracycline (4), the normal end-product made by the parent of this strain. Compound 3 was the glucoside of 1 and must be formed as a post-PKS reaction by the activation of a glycosyl transferase, which has not been reported in this species before.

International audience

From the above ground parts of Leionema ellipticum (Rutaceae), the new flavonoid 3,4′,5-trimethoxyflavone-7- O -α-rhamnoside, the 8-prenylated coumarin osthol, and the cinnamyl alcohol derivative boropinol-B were isolated and identified. Osthol is of systematic significance as coumarins with this substitution pattern have proved to be very common in species now assigned to Leionema . The presence of osthol in L. ellipticum is, therefore, supportive of a close relationship with other species of Leionema , despite the presence of a number of anomalous morphological features in the flowers.

The twigs of Rhadinothamnus rudis ssp. amblycarpus (Phebalium rude ssp. amblycarpum) yielded three new 3-substituted coumarins: rudicoumarin A-C (1- 3). Their structures were established on the basis of their NMR and mass spectral data. In addition, ten other known compounds were also isolated, including phebaclavin I, schinicoumarin, seselin, and seven linear furocoumarins.

A total of 27 methanol extracts obtained from different plant parts of 10 species of rain forest trees belonging to four genera of the Flacourtiaceae and originating from Australia were investigated. In vitro cytotoxicity was measured by an ATP Lite-M assay method against the mouse P388 lymphocytic leukemia cell line. The total antioxidant activity has been assessed based on scavenging activity of stable ABTS free radicals. The minimum inhibition concentration (MIC) was determined by the dilution method performed in 96 well plates against four different microbes. The leaf extract of Casearia sp. (RB 3051), mature stem extract of Casearia grayi and stem extract of Scolopia braunii were found to have most antioxidant activity (IC50 = 2.9 microg/ml), cytotoxic activity (LC50 = 0.89 microg/ml) and antimicrobial activity against all four different microbes, respectively. The results obtained suggested that among the four genera studied Casearia is the most promising in respect of finding significant antioxidant, cytotoxic and also antimicrobial activity.

Tinospora smilacina Benth. has been used in Australian indigenous medicine for the treatment of headache, rheumatoid arthritis and other inflammatory disorders. As part of an investigation into the anti-inflammatory potential of plants using an ethnopharmacological approach, the present study sought to evaluate the efficacy and safety of Tinospora smilacina. An ethanol extract of this plant was evaluated in vitro for anti-inflammatory activities on cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LO) and phospholipase A(2) (PA(2)). The ethanol extract of Tinospora smilacina showed inhibitory activities on COX-1, COX-2, 5-LO and PA(2) with the IC(50) values of 63.5, 81.2, 92.1 and 30.5 micro g/mL respectively. Cytotoxic effect of the extracts of Tinospora smilacina was investigated in vitro using ATP-based luminescence assay and the results showed no cytotoxic effect on cell lines of skin fibroblasts (1BR3), human Caucasian hepatocyte carcinoma (Hep G2) and human Caucasian promyelocytic leukaemia (HL-60). This paper also describes the results of fractionations and bioassay guided chemical studies, suggesting that the anti-inflammatory activity is due to triterpene-fatty acid esters and free fatty acids.

Five coumarins and two flavonoid glycosides are reported from Philotheca pinoides of which one, 3-(3-hydroxy-3-methylbut-1-enyl)-7,8-dimethoxycoumarin, appears to be novel. HPLC analysis of extracts of a number of other Philotheca species revealed that 5,7-dioxygenated-6,8-prenylated coumarins were present in P. apiculata, P. coccinea, P. deserti, P. pachyphylla, P. rhomboidea, P. thryptomenoides and P. gardneri, but not in P. nodiflora, P. pinoides, P. sericea, P. spicata, P. tomentella or P. woganensis. An analysis of the distribution of coumarins demonstrate that Geleznowia verrucosa is chemically indistinguishable from many species of Philotheca section Philotheca, whereas Philotheca section Erionema is more variable. Typical avicennol type coumarins have been found in the Boronieae only in Philotheca section Philotheca, in Geleznowia and in one species of Asterolasia. Coumarins that characterise Philotheca section Philotheca are not currently known from Eriostemon s.s., and sympatric genera such as Phebalium and Drummondita.

Examination of the leaf exudate of the South African species Aloe littoralis by reversed-phase HPLC revealed the presence of two major metabolites. The identification of the two compounds without isolation was attempted by HPLC-NMR based on separation using a C18 column eluting with a deuterium oxide:acetonitrile solvent gradient and an inverse HPLC-NMR probe. For each compound, one-dimensional proton spectra, and two-dimensional homonuclear COSY and TOCSY, and heteronuclear HSQC and HMBC, spectra were collected. On the basis of the data obtained, the metabolites were characterised as 10-hydroxyaloin B and deacetyllittoraloin.

The aerial parts of Phebalium clavatum yielded eight new 3-prenylated coumarins, phebaclavin A-H (1-8). Their structures were established on the basis of their NMR and mass spectral data. In addition, seven known compounds were also isolated, including two 8-geranyloxy linear furocoumarins previously obtained from Phebalium tuberculosum ssp. megaphyllum, included in the same section of the genus.

The aerial parts of Halfordia kendack (Rutaceae) have yielded the known alkaloid trans-erioaustralasine ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'beta,2'beta-epoxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one) together with four new alkaloids. The latter were characterised by spectroscopic methods as trans-deacetoxyerioaustralasine ([rel]-1-methyl-4.8'-epoxy-3-(1'beta,2'beta-epoxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one), trans-deacetoxyerioaustralasine hydrate ([rel]-1-methyl-4.8'-epoxy-3-(1'alpha,2'alpha-dihydroxy-3'beta,4'alpha-para-;menthyl-3'-yl)quinolin-2-one), trans-erioaustralasine hydrate ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'alpha,2'alpha-dihydroxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one) and trans-1-epi-deacetoxyerioaustralasine hydrate ([rel]-1-acetoxymethyl-4.8'-epoxy-3-(1'beta,2'alpha-dihydroxy-3'beta,4'alpha-para-menthyl-3'-yl)quinolin-2-one).

Three flavones, 5,7-dihydroxy-2',3',4',5'-tetramethoxyflavone, 5,4'-dihydroxy-7,2',3',5'-tetramethoxyflavone, and 5,7,4'-trihydroxy-2',3',5'-trimethoxyflavone were isolated from the leaf exudate of Psiadia punctulata, together with the previously reported 5-hydroxy-7,2',3',4',5'-pentamethoxyflavone and 5,7,3'-trihydroxy-2',4',5'-trimethoxyflavone. The two phenylpropenoids, Z-docosyl-p-coumarate and E-docosyl-p-coumarate were also isolated. The structures were determined on the basis of spectroscopic evidence.

The stem bark of Albizia gummifera has yielded four triterpenes, lupeol, lupenone, vitalboside-A (1) and vitalboside-A 2'-methylglucuronate (2), the last of which appears to be novel.

A C19 metabolite has been isolated from the methanol extract of the roots of Chiococca alba and characterized as a new nor-seco-pimarane, to which we have given the trivial name merilactone (1). The structure and relative stereochemistry of 1 was established by spectral data interpretation.

Five compounds, including three that are novel, were isolated from the stems of Paramignya griffithii (Rutaceae). Two new and one known prenylated flavanones were characterized as 3′,4′-dihydroxy-7-methoxy-8-(3-methylbut-2-enyl)-furano(4″,5″:6,5)-flavanone, 3′,4′-dihydroxy-7-methoxy-8-(3-methylbut-2-enyl)-2″-(1-hydroxy-1-methylethyl)-furano (4″,5″:6,5)-flavanone and amoradicin. In addition, a triterpene, 3-oxo-tirucalla-7,24-diene-21-al, and a novel chromene, 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran, were identified.

Twelve compounds have been isolated from the aerial parts of Eriostemon rhomboideus , six of which are novel. The novel compounds have been characterised as the flavones, 3,5,7,8,3′,4′-hexahydroxyflavone-3- O -β-glucopyranoside-7-methyl ether and 3,5,7,8,3′,4′,-hexahydroxyflavone-3- O -(6- p -coumaroyl)-β-glucopyranoside-7-methyl ether, the 2-alkylbenzopyrans, 5,7-dihydroxy-2-heptacosanylbenzopyran-4-one and 2ξ,5,7-trihydroxy-2-heptacosanyl-2,3-dihydrobenzopyran-4-one, glyceryl-1-tetracosanoate and the coumarin, isobaisseoside-3′- p -coumarate {esculetin-7- O -(3- p- coumaroyl-6-α-rhamnopyranosyl)-β-glucopyranoside}. The known compounds were eriostoic acid, eriostemoic acid, hesperidin, sitosterol-3- O -β-glucopyranoside and a mixture of catechin and epicatechin. The chemotaxonomic importance of the isolation of a coumarin glycoside is noted.

Oxytetracycline is a polyketide antibiotic made by Streptomyces rimosus. From DNA sequencing, the gene product of otcD1 is deduced to function as a bifunctional cyclase/aromatase involved in ring closure of the polyketide backbone. Although otcD1 is contiguous with the ketoreductase gene, they are located an unusually large distance from the genes encoding the “minimal polyketide synthase” of the oxytetracycline gene cluster. A recombinant, disrupted in the genomic copy ofotcD1, made four novel polyketides, all of shorter chain length (by up to 10 carbons) than oxytetracycline. All four novel structures contained the unusual carboxamido group, typical of oxytetracycline. This implies that the carboxamido group is present at the start of biosynthesis of oxytetracycline, a topic that has been debated in the literature. Loss of the cyclase protein has a profound influence on the length of polyketide chain assembled, implying that OtcD1 plays a greater role in the overall integrity of the quaternary structure of the polyketide complex than hitherto imagined.

Three new partially acetylated derivatives of 1-O-dodecanyl-alpha-L- rhamnopyranosyl-(1--3)-alpha-L-rhamnopyranosyl-(1--3)-alpha-L- rhamnopyranoside and three partially acetylated derivatives of 1-O-dodecanyl-alpha-L-rhamnopyranosyl-(1--3)- alpha-L-rhamnopyranosyl-(1--3)-alpha-L-rhamnopyranosyl-(1--4)- alpha-L-rhamnopyranoside, one of them new, have been isolated from the mature leaves of Cleistopholis patens (Annonaceae). Their structures, elucidated by using COSY, COSY-LR, TOCSY and FAB mass spectrometry, have been characterised as cleistrioside-2, -3, -4 and cleistetroside-1, -2 and -6. From the same source, shikimic acid was also isolated.

A bioassay-guided technique has been used to isolate anti-inflammatory compounds from the dried rhizomes of Polygonum bistorta, for structural identification. Anti-inflammatory activity was detected using the carrageenan-induced rat paw oedema. Two compounds were isolated which significantly suppressed the inflammatory response. Spectral data from EIMS and NMR together with some physical characteristics revealed the identities of the two active compounds as 5-glutinen-3-one and friedelanol. The results indicate that these two compounds largely account for the anti-inflammatory actions of the rhizomes of P. bistorta.

Two novel compounds, the lignan, (+)-2- (3,4-dimethoxyphenyl)-6-(3,4-dihydroxyphenyl)-3,7-dioxabicyclo [3,3,0]octane, and the coumarin, (+)-7-(3-methyl-4-carboxybutanoxy)umbelliferone methyl ester, have been isolated from the aerialparts of Melicope hayesii . The known compounds, eudesmin, kobusin, N - p -coumaroyltyramine, N -methyl-2-pyrrolidinone, umbelliferone and 7- (3-methylbut-2-enoxy)umbelliferone were alsoobtained. Their structures were determined by extensive NMR studies.

Two novel prenylated flavones, 3,5,4′-trihydroxy-8,3′-dimethoxy-7- (3-methylbut-2-enoxy)flavone and 3,5,8,4′-tetrahydroxy-7,3′-dimethoxy-6- (3-methylbut-2-enyl)flavone have been isolated from the aerial parts of Melicope micrococca (Rutaceae) together with the known compounds, quercetin 3- O - β - d -glucopyranoside, isorhamnetin 3- O -rutinoside, the acridone alkaloid arborinine, sitosterol 3 β - O -glucopyranoside (daucosterol) and 5- O -methyl- myo -inositol (sequoyitol). The structures of all compounds were elucidated by spectroscopic methods.

Through insecticidal bioassay-guided fractionation and isolation, five isobutylamides 1-5 were isolated from n-hexane and EtOAc extracts of the aerial parts of Dinosperma erythrococca (Rutaceae). The structures of compounds 1-5 were established through 1D and 2D NMR. Compounds 1-3 were identified as erythrococcamides A-C and represent two novel classes of isobutylamide. Compounds 4-5 were identified as N-(2-hydroxy-2-methylpropyl)-6-phenyl-2(E), 4(E)-hexadienamide (4)1,2 and N-(2-methylpropyl)-6-phenyl-2(E), 4(E)-hexadienamide (5),1,3 respectively. Compound 1 showed lethal activity against the housefly (Musca domestica) (kill EC50 = 20.2 ppm) and the tobacco budworm (Heliothis virescens) (kill EC50 = 74.2 ppm). Compound 4 showed lethal activity against H. virescens at 500 ppm, while compound 5 showed lethal activity against M. domestica at 500 ppm.

Investigation of the ethyl acetate extract of the stem bark of Uvaria mocoli resulted in the isolation of the novel retrodihydrochalcone 2-hydroxy-4,5,6-trimethoxydihydrochalcone together with the known flavonoids 2′-hydroxy-4′,6′-dimethoxychalcone, 2′-hydroxy-4′,5′,6′-trimethoxychalcone, 5,7-dimethoxyflavanone and 5,7,8-trimethoxyflavanone, the oxoaporphines lysicamine, liriodenine and isomoschatoline, benzoic acid and a mixture of sitosterol and stigmasterol. All the compounds were identified by analysis of their spectral data.

8-formamido-2-(4-hydroxy-3-methoxyphenyl)-2,2a,5,6-tetrahydro-3H-furo[2,3,4-kl][3]benzazocine-3,7(4H)-dione (named: moschamide), a novel alkaloid, has been isolated from the seeds of Centaurea moschata (Compositae). The structure of this compound has been determined primarily by extensive 1D and 2D NMR spectroscopic analysis, notably, 1H, 13C PENDANT, COSY45, NOESY, HMBC and HMQC.

From the aerial parts of Bosistoa selwynii (Rutaceae) four novel prenylated acetophenones were isolated and identified as pyranoselwynone (5-hydroxy-6-acetyl-{6,6-dimethyl-5ξ-hydroxy-4,5-di-hydropyrano}-[3,2-h]-2,2-dimethylbenzopyran), selwynone (5,7-dihydroxy-6-acetyl-8-(3-methylbut-2-enyl)-3,4-dihydro-2,2-dimethyl-3ξ-hydroxypyran), furanoselwynone (5-hydroxy-6-acetyl-{5-[1-hydroxy-1-methylethyl]-4,5-dihydro-furano}-[3,2-h]-2,2-dimethylpyran), and isofurano-selwynone (7-hydroxy-8-acetyl-{5-[1-hydroxy-1-methylethyl]-4,5-dihydrofurano}-[3,2-f]-2,2-dimethylpyran). Other compounds isolated were a series of eight acridone alkaloids (reported on previously), the coumarins scopoletin and braylin and the triterpenes lupeol and β-amyrin. The structures of the new acetophenones were elucidated on the basis of NMR spectral data.

From the stem bark of Millettia usaramensis subsp. usaramensis four new 12a-hydroxyrotenoids with the unusual trans B/C ring junction ((+)-12a-epimillettosin, (+)-usararotenoid-A, (+)-12-dihydrousararotenoid-A, and (+)-usararotenoid-B), a new α-hydroxydihydrochalcone (α,4,2′-trihydroxy-4′-O-geranyldihydrochalcone), a new isoflavone, (norisojamicin), and a new cinnamyl alcohol derivative (4-O-geranylcinnamyl acetate) have been isolated and characterized. In addition, the known compounds 4′-O-geranylisoliquiritigenin, isoliquiritigenin, barbigerone, jamaicin and maximaisoflavone-G were identified. The structures were determined on the basis of spectroscopic evidence and chemical transformations.

The leaves of six of the seven species currently assigned to the Australian genus Bosistoa (Rutacea) have been examined. Major groups of metabolites isolated were flavones and flavanones, 1,3,5-oxygenated acridone alkaloids phloroglucinols and acetophenones, all of which are further modified by the addition of 5-carbon prenyl substituents. In a recent revision Bosistoa was divided into two groups and the distribution of flavonoid aglycones is found to coincide with Group II while species in Group 1 yield acridones, phloroglucinols and acetophenones. It is suggested that secondary metabolite production in Bosistoa is best rationalized by considering a central triketide or tetraketide which through either internal cyclization (phloroglucinols, acetophenones) or condensation with anthranilic acid (acridone alkaloids) or cinnamic acids (flavonoids) can give rise to all major groups of metabolites.

Some Astragalus species are used as forage for livestock and wild animals. Many species are used in folk medicine for their hepatoprotective, antioxidative, immunostimulant, and antiviral properties, whereas others are toxic, and in many cases the toxic principles can pass to humans through milk and meat. Three groups of chemicals have been described as pharmacologically active principles: polysaccharides, saponins and phenolics. In addition, three kinds of toxic principles have been reported: indolizidine alkaloids, aliphatic nitro compounds and selenium. © 1997 John Wiley & Sons, Ltd.

Biochemical and physiological changes in Gnaphalium luteo-album plants were analysed in response to two different irradiance levels of UV-B. Low irradiance treatments showed increases in stem elongation, in chlorophyll A and B and carotenoid contents, and in the absorbance of vacuolar phenolics. Significant increases were observed in the concentrations of two surface flavonols, calycopterin and 3′-methoxycalycopterin, which were identified for the first time in this species. By contrast, a third surface flavonol, gnaphaliin, decreased in amount. High irradiance treatments inhibited plant growth but still increases in surface flavonols were observed. Our results support the view that surface flavonols are produced by plants as a protective device to shield the leaf from damage by UV-B radiation. © 1997 Elsevier Science Ltd. All rights reserved

Leaves from four collections of Bosistoa pentacocca , two of the variety connaricarpa and one each of the type variety and var. dryanderensis , have been examined. In each, the major metabolite isolated was characterized as 2-(3,7-dimethyloct-2.5-dienyl)-6-(3-methylbut-2-enyl)phloroglucinol-1-acetate (trivial name pentacoccol). Four other pentacoccol derivatives were obtained as minor components, pentacoccol-5-methyl ether(from var. pentacocca and var. dryanderesis , 2,2-dimethyl-3ξ, 7-dihydroxy-5-acetoxy-6-(3,7-dimethyloct-2,5-dienyl-3,4-dihydrobenzo-[2 H ]-pyran (3′-hydroxydihydropyranopentacoccol from var. connaricarpa ), 2′-(1 -hydroxy-1-methylethyl)-4-acetoxy-5-(3,7-dimethyloct-2,5-dienyl)-6-hydroxybenzo-[2 H ]-furan (2′-(1-hydroxyosopropyl) furanopentacoccol from var. pentacocca and 4-acetoxy-5-(3,7-dimethyloct-2,5-dienyl)-6-hydroxybenzo-[2 H ]-furan (furanopentacoccol from var. dryanderensis . All compounds were identified on the basis of their spectroscopic data. © 1997 Elsevier Science Ltd. All rights reserved

Two known diterpenes, (ent)-2-oxokaur-16-en-18,19-diol (psiadin) and (ent)-kaur-16-en-2α,18,19-triol, and three novel diterpenes, (ent)-16β,17-dihydroxykauran-20-oic acid, 2-oxotrachyloban-18,19-diol and trachyloban-2β,6β,19-triol have been isolated from the leaf exudate of Psiadia punctulata. The structures of the diterpenes was established on the basis of spectroscopic analysis and previously published data on the known compounds.

The phytochemical analysis of two collections of a new species (SAC-2825), tentatively assigned as aff. Samadera bidwillii (Simaroubaceae), has yielded a limonoid (limonin), a quassinoid (2′-acetoxyglaucarubin), three alkaloids [2-(10′ξ-acetoxyundecanyl)-1-acetoxymethyl-4-quinolone, 1-methoxy-10-methyl-acridan-9-one and 1,8-dihydroxyacridan-9-one] and seven bicyclo-octane type lignans [(−)-sesamin, (−)-episesamin, fargesin, neofargesin, (−)-kobusin, (−)-epieudesmin and (−)-eudesmin]. The 4-quinolone alkaloid appears to be novel. The metabolites identified are collectively typical of the Rutales, but have a biosynthetic range never previously found together in a single species. Particularly noteworthy is the co-occurrence of limonoids and quassinoids in the same plant, which is currently unique to SAC-2825.