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Two new polyacetylene thiophenes, echinopsacetylenes A and B (1 and 2), were isolated from the roots of Echinops transiliensis. The structures of 1 and 2 were elucidated on the basis of spectroscopic analyses and chemical transformations. Echinopsacetylenes A (1) is the first natural product possessing an α-terthienyl moiety covalently linked with another thiophene moiety. Echinopsacetylenes B (2) is the first natural thiophene conjugated with a fatty acid moiety. Echinopsacetylene A (1) showed toxicity against the Formosoan subterranean termite (Coptotermes formosanus).

Several lines of evidence suggest that insect repellent molecules reduce mosquito-host contacts by interacting with odorants and odorant receptors (ORs), thereby ultimately affecting olfactory-driven behaviours. We describe the molecular effects of 10 insect repellents and a pyrethroid insecticide with known repellent activity on two highly specific Aedes aegypti (Diptera: Culicidae) ORs, AaOR2 + AaOR7 and AaOR8 + AaOR7, exquisitely sensitive to key mosquito attractants indole and (R)-(-)-1-octen-3-ol, expressed in oocytes of Xenopus (Anura: Pipidae). Our study demonstrates that insect repellents can both inhibit odorant-evoked currents mediated by ORs and independently elicit currents in the absence of odorants. All of the repellents had effects on one or both ORs; most of these compounds were selective inhibitors and showed a high degree of specificity in their capacity to activate the two ORs. These results show that a range of insect repellents belonging to structurally diverse chemical classes modulate the function of mosquito ORs through multiple molecular mechanisms., (Published 2011. This article is a U.S. Government work and is in the public domain in the USA.)

An investigation of the Indian folk remedy plant Jatropha curcas L., was performed to identify the constituents responsible for the mosquito biting deterrent activity of the oil. J. curcas seed oil is burned in oil lamps in India and parts of Africa to repel biting insects, primarily mosquitoes. The seed oil was thoroughly analyzed by 1H NMR, 13C NMR, high-performance liquid chromatography-refractive index, and gas chromatography-flame ionization detection to identify the constituents in the oil. Identified constituents, both free fatty acids and triglycerides, were evaluated for activity in Aedes aegypti (L.) (Diptera: Culicidae) biting deterrent assays. Furthermore, an oil condensation trap was used to demonstrate that free fatty acids or triglycerides are partially volatilized during the combustion process. These compounds were found to be responsible for the biting deterrency of the burned oil. Specifically, oleic, palmitic, linoleic, and stearic acids were all active at 25 nmol/cm2 above that of solvent control in Ae. aegypti biting deterrent assays. Oleic, palmitic, and linoleic acids were all more active than stearic acid in the same bioassay. Evaluation of the triglycerides containing each of these fatty acids revealed that tripalmitin, tristearin, trilinolein, and triolein all demonstrated significant activity above a solvent control at 10 microg/cm2, whereas tripalmitin was the most active. Due to literature reports suggesting larvicidal activity of the oil, J. curcas seed oil and its free fatty acid constituents also were evaluated against 1-d-old Ae. aegypti larvae up to 500 ppm. Oleic acid was the only fatty acid having larvicidal activity against 1-d-old Ae. aegypti larvae, with an LD50 of 47.9 ppm.

Callicarpenal (1), a natural terpenoid isolated from American beautyberry (Callicarpa americana), has shown significant repellent activities against mosquitoes, ticks and imported fire ants. Here we report our efficient synthetic approach to this natural product, and preliminary results of the mosquito biting-deterrent effects of callicarpenal as well as its synthetic precursors and related C(8)-epimers. The synthetic strategy allows rapid access to various epimers and analogues of the natural product that can be used to explore its structure-activity relationship and optimize its biological properties.

Peppermint ( Mentha × piperita L.) and spearmints ('Scotch' spearmint, M. × gracilis Sole, and 'Native' spearmint, Mentha spicata L.) are widely grown essential oil crops in more northern latitudes; however, there is limited information on how harvest time and drying influence peppermint and spearmint yield, oil composition, and bioactivity, when grown south of the 41st parallel. In this 2-year study, the effects of harvest time and drying on the yield, oil composition, and bioactivity of peppermint ('Black Mitcham' and 'B90-9'), 'Scotch' spearmint, and 'Native' spearmint were evaluated. Peppermint oil from the dried material had higher menthol and eucalyptol concentrations. Menthone in both peppermint cultivars decreased from harvest 1 (late June) to harvest 5 (late August) or 6 (early September), whereas menthol increased. (-)-Carvone in spearmints accumulated early, before flowering, allowing for early harvest. Oil yields from the dried spearmint biomass reached the maximum at harvest 3 (mid-July). The essential oil compositions of the four mint genotypes were similar to that of 11 commercially available oils, suggesting that these genotypes can be grown in the hot, humid environment of the southeastern United States. The antioxidant activities (ORAC(oil) values) of the essential oils were 4372, 1713, 1107, and 471 μmol of TE L(-1) for 'Scotch' spearmint, 'Native' spearmint, peppermint, and Japanese cornmint ( Mentha canadensis ), respectively. The oils of the four mint genotypes did not affect ruminal fermentation in vivo, and did not exhibit antimicrobial, antileishmanial, or antimalarial activity at levels that would warrant bioassay-directed fractionation in a drug-discovery screening program. Specifically, the oils did not show greater than 50% growth inhibition against Leishmania donovani , Plasmodium falciparum clones D6 and W2, Candida albicans , Escherichia coli , Pseudomonas aeruginosa , Cryptococcus neoformans , Mycobacterium intracellulare , or Aspergillus fumigates at 50 μg mL(-1).

Phytotoxic microbial metabolites produced by certain phytopathogenic fungi and bacteria, and a group of phytotoxic plant metabolites including Amaryllidacea alkaloids and some derivatives of these compounds were evaluated for algicide, bactericide, insecticide, fungicide, and herbicide activities in order to discover natural compounds for potential use in the management and control of several important agricultural and household structural pests. Among the various compounds evaluated: i) ophiobolin A was found to be the most promising for potential use as a selective algicide; ii) ungeremine was discovered to be bactericidal against certain species of fish pathogenic bacteria; iii) cycasin caused significant mortality in termites; iv) cavoxin, ophiobolin A, and sphaeropsidin A were most active towards species of plant pathogenic fungi; and v) lycorine and some of its analogues (1-O-acetyllycorine and lycorine chlorohydrate) were highly phytotoxic in the herbicide bioassay. Our results further demonstrated that plants and microbes can provide a diverse and natural source of compounds with potential use as pesticides.

Crude extracts from over 16 species of plants from the family Convolvulaceae were evaluated for phytotoxic activity against Agrostis stolonifera (bentgrass) and Lactuca sativa (lettuce) at 1000 microg/mL. Ethanol extracts of Dicranostyles ampla Ducke were among the most active of those species tested. Systematic bioassay-guided fractionation of the ethanol extract of the aerial parts from this species was performed to identify specifically the phytotoxic compounds. Two phytotoxic flavonoids, dihydromyricetin (1) and myricetin-3-O-alpha-rhamnoside or myricetrin (2), were found to be responsible for much of the activity of the extract as a whole in the A. stolonifera and L. sativa bioassay. In a Lemna paucicostata bioassay, 1 and 2 had no activity at 100 microM.

Natural toxins are a source of new chemical classes of pesticides, as well as environmentally and toxicologically safer molecules than many of the currently used pesticides. Furthermore, they often have molecular target sites that are not exploited by currently marketed pesticides. There are highly successful products based on natural compounds in the major pesticide classes. These include the herbicide glufosinate (synthetic phosphinothricin), the spinosad insecticides, and the strobilurin fungicides. These and other examples of currently marketed natural product-based pesticides, as well as natural toxins that show promise as pesticides from our own research are discussed.

An Aedes aegypti larval toxicity bioassay was performed on compounds representing many classes of natural compounds including polyacetylenes, phytosterols, flavonoids, sesquiterpenoids, and triterpenoids. Among these compounds, two eudesmanolides, alantolactone, and isoalantolactone showed larvicidal activities against Ae. aegypti and, therefore, were chosen for further structure-activity relationship study. In this study, structural modifications were performed on both alantolactone and isoalantolactone in an effort to understand the functional groups necessary for maintaining and/or increasing its activity, and to possibly lead to more effective insect-control agents. All parent compounds and synthetic modification reaction products were evaluated for their toxic activities against Ae. aegypti larvae and adults. Structure modifications included epoxidations, reductions, catalytic hydrogenations, and Michael additions to the alpha,beta-unsaturated lactones. None of the synthetic isomers synthesized and screened against Ae. aegypti larvae were more active than isoalantolactone itself which had an LC(50) value of 10.0 microg/ml. This was not the case for analogs of alantolactone for which many of the analogs had larvicidal activities ranging from 12.4 to 69.9 microg/ml. In general, activity trends observed from Ae. aegypti larval screening were not consistent with observations from adulticidal screening. The propylamine Michael addition analog of alantolactone was the most active adulticide synthesized with an LC(50) value of 1.07 microg/mosquito. In addition, the crystal structures of both alantolactone and isoalantolactone were determined using CuK(alpha) radiation, which allowed their absolute configurations to be determined based on resonant scattering of the light atoms.

The tremendous increase in crop yields associated with the 'green' revolution has been possible in part by the discovery and utilization of chemicals for pest control. However, concerns over the potential impact of pesticides on human health and the environment has led to the introduction of new pesticide registration procedures, such as the Food Quality Protection Act in the United States. These new regulations have reduced the number of synthetic pesticides available in agriculture. Therefore, the current paradigm of relying almost exclusively on chemicals for pest control may need to be reconsidered. New pesticides, including natural product-based pesticides are being discovered and developed to replace the compounds lost due to the new registration requirements. This review covers the historical use of natural products in agricultural practices, the impact of natural products on the development of new pesticides, and the future prospects for natural products-based pest management.

The major chemical components in the venom of red imported fire ants, Solenopsis invicta Buren, are 2-methyl-6-alkyl or alkenyl piperidines. After isolating the extracts of poison glands and whole worker bodies with column chromatography, we obtained fractions containing a mixture of six piperideine alkaloids. Reduction of those samples using NaBH(4) in ethanol generated piperidine alkaloids found in the fire ant poison gland, resulting in both the cis- and the trans-piperidine alkaloids. The mass spectra and gas chromatographic behavior of most piperidine alkaloids from fire ant venom have been well-characterized, which significantly facilitated the identification of these piperdeine compounds. On the basis of the mass spectra and profiles of NaBH(4) reduction products, we identified these alkaloids as 2-methyl-6-tridecenyl-6-piperideine, 2-methyl-6-tridecyl-6-piperideine, 2-methyl-6-pentadecenyl-6-piperideine, 2-methyl-6-pentadecyl-6-piperideine, 2-methyl-6-heptadecenyl-6-piperideine, and 2-methyl-6-heptadecyl-6-piperideine. To our knowledge, this is the first time that these piperideine alkaloids have been reported in red imported fire ant poison glands.

Callicarpenal (=13,14,15,16-tetranorclerod-3-en-12-al=[(1S,2R,4aR,8aR)-1,2,3,4,4a,7,8,8a-octahydro-1,2,4a,5-tetramethylnaphthalen-1-yl]acetaldehyde; 1) has previously demonstrated significant mosquito bite-deterring activity against Aedes aegypti and Anopheles stephensi in addition to repellent activity against host-seeking nymphs of the blacklegged tick, Ixodes scapularis. In the present study, structural modifications were performed on callicarpenal (1) in an effort to understand the functional groups necessary for maintaining and/or increasing its activity and to possibly lead to more effective insect control agents. All modifications in this study targeted the C(12) aldehyde or the C(3) alkene functionalities or combinations thereof. Mosquito biting deterrency appeared to be influenced most by C(3) alkene modification as evidenced by catalytic hydrogenation that resulted in a compound having significantly less effectiveness than 1 at a test amount of 25 nmol/cm2. Oxidation and/or reduction of the C(12) aldehyde did not diminish mosquito biting deterrency, but, at the same time, none of the modifications were more effective than 1 in deterring mosquito biting. Toxicities of synthesized compounds towards Ae. aegypti ranged from an LD50 value of 2.36 to 40.11 microg per mosquito. Similarly, LD95 values ranged from a low of 5.59 to a high of 104.9 microg.

Bioassay-guided fractionation of the chloroform extract from the roots of Angelica sinensis led to isolation and characterization of (Z)-ligustilide using direct-bioautography with Colletotrichum species. The structure of (Z)-ligustilide was confirmed by (1)H and (13)C NMR spectroscopy and GC/MS. (Z)-Ligustilide deterred the biting of two mosquito species more effectively than DEET. Three different A. sinensis accessions and one Angelica archangelica root oil were evauated by GC and GC/MS, and the dominant component in A. sinensis was 61-69% (Z)-ligustilide. Two other prominent compounds in A. sinensis oils were 5.7-9.8% (E)-3-butylidene phthalide and 1.5-2.3% (Z)-3-butylidene phthalide. The main constituents that comprised A. archangelica oil were monoterpene hydrocarbons such as 24.5% alpha-pinene, 13.8% delta-3-carene, 10.1% beta-phellandrene, 8.8% p-cymene, 8.4% limonene, and 6.3% sabinene. Phthalides and monoterpene hydrocarbons were determined to be good systematic markers or chemical fingerprints for A. sinensis and A. archangelica root oils. Chemical fingerprinting by GC/MS of A. sinensis also confirmed the misidentification of one A. archangelica sample sold in the Chinese market.

Camphorweed, Heterotheca subaxillaris (Lam.) Britt. & Rusby, has a camphor-like odor, and its leaf surfaces contain glandular trichomes of the type shown to contain high levels of isoprenoids in other species. Borneol (1), the phytotoxic calamenene-type sesquiterpenes (2-5, 9-11), and methylated flavones (12-15) were isolated from the dichloromethane rinsate of camphorweed aerial tissues. The strongest plant growth inhibitor against Agrostis stolonifera and Lactuca sativa seedlings, as well as duckweed (Lemna pausicostata), was 2-methoxy-calamenene-14-carboxylic acid (2). Esterification of calamenene carboxylic acids decreased their biological activity.

Bioautography of extracts of the fruiting bodies of the basidiomycete Gomphus floccosus (Schw.) Singer indicated the presence of fungitoxic compounds in the ethyl acetate fraction against the plant pathogens Colletotrichum fragariae, Colletotrichum gloeosporioides, and Colletotrichum acutatum. Bioassay-guided fractionation of this fraction resulted in the isolation of the bioactive fatty acids (9 S,10 E,12 Z)-9-hydroxy-10,12-octadecadienoic acid (1), (9 E,11 Z)-13-oxo-9,11-octadecadienoic acid (2), and (10 E,12 E)-9-oxo-10,12-octadecadienoic acid (3). These three oxylipins were further evaluated for activity against a greater range of fungal plant pathogens (C. fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and Phomopsis viticola) in in vitro dose-response studies. Phomopis species were the most sensitive fungi to these compounds. At 120 h of treatment, the IC50 values for compounds 1, 2, and 3 for P. obscurans were 1.0, 4.5, and 23 microM, respectively, as compared to 1.1 microM for the captan positive control.

A large number of naturally occurring and synthetic benzoquinones were evaluated for activity against the Formosan subterranean termite, Coptotermes formosanus, with potential use in termite control. Among these bioactive naturally occurring benzoquinones are 2-methyl-5-isopropyl-1,4-benzoquinone, 2-methoxy-6-pentyl-1,4-benzoquinone, 2,3-dimethoxy-5-methyl-6-(3-methyl-2-butenyl)-1,4-benzoquinone, 2,3-dimethoxy-5,6-dimethyl-1,4-benzoquinone, and 2,3-dichloro-5,6-dimethyl-1,4-benzoquinone. All five of these compounds demonstrated 100% mortality against C. formosanus by day 11 at a concentration of 1% (wt/wt) or less. In general, benzoquinones with one or two hydrophobic groups on the 5 and/or 6 positions of the quinone ring along with one or two group(s) on the opposite side of the ring, at the 2 and/or 3 position, led to high rates of mortality against C. formosanus. Quantitative structure-activity relationship (QSAR) studies showed no correlation between lipophilicity (calculated log P) and mortality for the entire group of nonhalogenated benzoquinones. A correlation was observed between C-6 chain length and day 3 percent mortality for 2,3-dimethoxy-5-methyl-6-substituted aliphatic benzoquinones where short chain lengths resulted in higher mortality.

Callicarpenal and intermedeol are two insect-repellent terpenoids isolated from leaves of American beautyberry (Callicarpa americana L.; Verbenaceae) and Japanese beautyberry (Callicarpa japonica Thunb.). The repellency of these two terpenoids against workers of red imported fire ants, Solenopsis invicta Buren, black imported fire ants, Solenopsis richteri Forel, and a hybrid of these two species was evaluated using digging bioassays. In a multiple choice digging bioassay using two colonies from each species and their hybrid, callicarpenal showed significant repellency at concentration as low as 50 ppm against both red imported fire ant colonies and 6.25 ppm against all black imported fire ant and hybrid colonies. Intermedeol showed significant repellency at concentration as low as 1.50 ppm against both red imported fire ant colonies and 6.25 ppm against all black imported fire ant and hybrid colonies. In total, 15 colonies, five colonies from each species and the hybrid, were tested on callicarpenal and intermedeol at 50 ppm in a two-choice digging bioassay. Both callicarpenal and intermedeol showed repellency against all colonies, and intermedeol showed significantly greater repellency than callicarpenal against both species and their hybrid.

A study was conducted to evaluate the effect of cut on biomass productivity, oil content, composition, and bioactivity of Ocimum basilicum L. (cvs. German and Mesten) and Ocimum sanctum L. (syn. O. tenuiflorum L.) (cv. Local) in Mississippi. Yields of basil herbage and essential oil were high and comparable to those reported in the literature. Essential oil content of O. basilicum cv. German varied from 0.40 to 0.75%, the oil content of cv. Mesten varied from 0.50 to 0.72%, and the oil content of cv. Local (of O. sanctum) ranged from 0.17 to 0.50% in air-dried basil. Herbage and essential oil yields of cvs. German and Mesten of O. basilicum increased with the second and then again with the third cut, whereas herbage and oil yields of cv. Local of O. sanctum increased with the third cut relative to the previous cuts. Overall, essential oil yields were 115, 123, and 51 kg/ha for the cvs. German, Mesten, and Local, respectively. The major oil constituents of cvs. German and Mesten (of O. basilicum) were (-)-linalool (30-40%) and eugenol (8-30%), whereas the major oil constituents of cv. Local (of O. sanctum) were eugenol (8-43%) and methylchavicol (15-27%). Essential oils from both species grown in Mississippi showed in vitro activity against Leishmania donovani (IC50 = 37.3-49.6 microg/mL), which was comparable to the activity of commercial oil (IC50 = 40-50 microg/mL). Minor basil oil constituents (+)-delta-cadinene, 3-carene, alpha-humulene, citral, and (-)- trans-caryophyllene had antileishmanial activity, whereas other constituents were ineffective. None of the oil was cytotoxic to mammalian cells.

A field experiment was conducted to assess yield, oil content, and composition of 38 genotypes of sweet basil ( Ocimum basilicum L.). Overall, biomass yields were high and comparable to those reported in the literature. However, basil genotypes differed significantly with respect to oil content and composition. Oil content of the tested accessions varied from 0.07% to 1.92% in dry herbage. On the basis of the oil composition, basil accessions were divided into seven groups: (1) high-linalool chemotype [19-73% (-)-linalool], (2) linalool-eugenol chemotype [six chemotypes with 28-66% (-)-linalool and 5-29% eugenol], (3) methyl chavicol chemotype [six accessions with 20-72% methyl chavicol and no (-)-linalool], (4) methyl chavicol-linalool chemotype [six accessions with 8-29% methyl chavicol and 8-53% (-)-linalool], (5) methyl eugenol-linalool chemotype [two accessions with 37% and 91% methyl eugenol and 60% and 15% (-)-linalool], (6) methyl cinnamate-linalool chemotype [one accession with 9.7% methyl cinnamate and 31% (-)-linalool], and (7) bergamotene chemotype [one accession with bergamotene as major constituent, 5% eucalyptol, and <1% (-)-linalool]. Our results demonstrated that basil could be a viable essential oil crop in Mississippi. The availability of various chemotypes offers the opportunity for production of basil to meet the market requirements of specific basil oils or individual compounds such as (-)-linalool, eugenol, methyl chavicol, methyl cinnamate, or methyl eugenol.

Systematic bioassay-guided fractionation of the methylene chloride extract of the roots from Ligularia macrophylla was performed to identify both phytotoxic and antifungal compounds. Four phytotoxic eremophilanes (furanoeremophilan-14beta,6alpha-olide, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane, eremophil-7(11)-ene-12,8alpha;14beta,6alpha-diolide, and 3alpha-angeloyloxybakkenolide A) and two antifungal fatty acids (linoleic acid and alpha-linolenic acid) were isolated. The X-ray crystal structure determination of 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane is reported here for the first time. All four eremophilanes substantially inhibited growth of the monocot Agrostis stolonifera (bentgrass) while demonstrating little activity against the dicot Lactuca sativa (lettuce) at 1000 microM. In a dose-response screening of all compounds for growth inhibitory activity against Lemna paucicostata, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane was the most active with an IC50 of 2.94+/-0.16 microM. This compound also caused the greatest reduction of photosynthetic electron flow; however, its mode of action remains to be determined. Evaluation of isolated compounds for activity against the Formosan subterranean termite, Coptotermes formosanus, is also reported. At a concentration of 0.5% (wt/wt), 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane significantly reduced the consumption of filter paper by C. formosanus.

Callicarpenal (13, 14, 15, 16-tetranor-3-cleroden-12-al) and intermedeol [(4S,5S,7R,10S)-eudesm-11-en-4-ol], isolated from American beautyberry, Callicarpa americana (Lamiaceae), were evaluated in laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, Ixodes scapularis, and lone star tick, Amblyomma americanum. A strip of organdy cloth treated with test solution was doubly wrapped (treatment on outer layer) around the middle phalanx of a forefinger and ticks released on the fingertip. Callicarpenal and intermedeol, at 155 nmole/cm(2) cloth repelled 98 and 96% of I. scapularis nymphs, respectively. Dose response tests with I. scapularis nymphs showed no difference in repellency among callicarpenal, intermedeol and Deet (N,N-diethyl-3-methylbenzamide), however, SS220 ((1S,2'S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide) was significantly more repellent than the other compounds. Callicarpenal, at 155 nmole/cm(2 )cloth, repelled 100 and 53.3% of I. scapularis nymphs at 3 and 4 h, respectively, after the cloth was treated, whereas intermedeol repelled 72.5% of I. scapularis nymphs 3 h after treatment. In comparison with the results obtained with I. scapularis, callicarpenal, intermedeol, Deet and SS220 were less effective against A. americanum. Only intermedeol and SS220 repelled significantly more A. americanum than ethanol controls at 155 nmole compound/cm(2) cloth. At 1,240 nmole/cm(2 )cloth, callicarpenal and intermedeol repelled 20 and 40% of A. americanum nymphs.

Over 220 crude extracts from repositories generated from plants native to Greece and Kazakhstan were evaluated for termiticidal activity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Emerging from this screening effort were bioactive extracts from two Greek species (Echinops ritro L. and Echinops spinosissimus Turra subsp. spinosissimus) and extracts from two Kazakhstan species (Echinops albicaulis Kar. & Kir. and Echinops transiliensis Golosh.). Fractionation and isolation of constituents from the most active extracts from each of the four species has been completed, resulting in the isolation of eight thiophenes possessing varying degrees of termiticidal activity. 2,2':5',2"-Terthiophene and 5'-(3-buten-1-ynyl)-2,2'-bithiophene demonstrated 100% mortality against C. formosanus within 9 days at 1 and 2 wt% concentrations respectively. In addition, all but two of the eight compounds tested were significantly different from the solvent controls in the filter paper consumption bioassay., (Copyright 2006 Society of Chemical Industry.)

Extracts from 30 plants of the Greek flora were evaluated for their antifungal activity using direct bioautography assays with three Colletotrichum species. Among the bioactive extracts, the dichloromethane extract of the radix of Echinops ritro (Asteraceae) was the most potent. Bioassay-guided fractionation of this extract led to the isolation of eight thiophenes. Antifungal activities of isolated compounds together with a previously isolated thiophene from Echinops transiliensis were first evaluated by bioautography and subsequently evaluated in greater detail using a broth microdilution assay against plant pathogens Colletotrichum acutatum, Colletotrichum fragariae, Colletotrichum gloeosporioides, Botrytis cinerea, Fusarium oxysporum, Phomopsis viticola, and Phomopsis obscurans. 5'-(3-Buten-1-ynyl)-2,2'-bithiophen (1), alpha-terthienyl (2), and 2-[pent-1,3-diynyl]-5-[4-hydroxybut-1-ynyl]thiophene (5) at 3 and 30 microM were active against all three Colletotrichum species, F. oxysporum, P. viticola, and P. obscurans.

Bioassay-guided fractionation of the hexane/ethyl acetate/water (H/EtOAc/H2O) crude extract of the aerial parts of Haplophyllum sieversii was performed because of preliminary screening data that indicated the presence of growth inhibitory components against Colletotrichum fragariae, Colletotrichum gloeosporioides, and Colletotrichum acutatum. Fractionation was directed using bioautographical methods resulting in the isolation of the bioactive alkaloids flindersine, anhydroevoxine, haplamine, and a lignan eudesmin. These four compounds were evaluated for activity against C. fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, and Phomopsis obscurans in a dose-response growth-inhibitory bioassay at 50.0, 100.0, and 150.0 microM. Of the four compounds tested, flindersine demonstrated the highest level of antifungal activity. Additionally, flindersine, eudesmin, and haplamine were screened against the freshwater phytoplanktons Oscillatoria perornata, Oscillatoria agardhii, Selenastrum capricornutum, and Pseudanabaena sp. (strain LW397). Haplamine demonstrated selective inhibition against the odor-producing cyanobacterium O. perornata compared to the activity against the green alga S. capricornutum, with lowest observed effect concentration values of 1.0 and 10.0 microM, respectively.

Essential oil extracts from Callicarpa americana and Callicarpa japonica were investigated. Bioassay-guided fractionation of C. americana extracts using the yellow fever mosquito, Aedes aegypti, led to the isolation of alpha-humulene, humulene epoxide II, and intermedeol and a newly isolated terpenoid (callicarpenal). Similar work involving C. japonica resulted in the isolation of an additional compound, spathulenol, as well as the four compounds isolated from C. americana. Structure elucidation was performed on all isolated compounds using a combination of gas chromatography-mass spectrometry-electron ionization, high-resolution liquid chromatography-MS-electrospray ionization, and one- and two-dimensional NMR experiments. Heretofore, 13,14,15,16-tetranorclerodane, callicarpenal, has never been identified from natural sources. Complete (1)H and (13)C NMR assignment data are provided for this compound. In bite deterrent studies, spathulenol, intermedeol, and callicarpenal showed significant repellent activity against A. aegypti and Anopheles stephensi.

seco-Hinokiol (1), a new abietane diterpenoid, has been isolated from the leaves of Rosmarinus officinalis. Its structure was elucidated on the basis of extensive spectroscopic analysis. To our knowledge, this is the fourth report of a seco-abietane having been isolated. In addition, methyl carnosate (4) was synthesized from carnosic acid (3), and detailed NMR spectroscopic data are provided to clarify previous literature reports.

Over four-hundred crude extracts from 202 plant species distributed among 131 plant families were evaluated for their bioactivity against brine shrimp (Artemia salina). Activity was determined for both the organic (CH2Cl2:MeOH) and aqueous extracts against A. salina in a 96 well-plate assay. Of the greater than four-hundred extracts tested, 21 organic and 6 aqueous extracts demonstrated potent cytotoxic activity (LC50 = < 100 microg/ml). Three of these organic extracts (Crateva religiosa, Diospyros dichrophylla, and Olax subscorpioidea) were chosen for chemical investigations due to their high activity and a lack of prior investigations. Chemical analysis of these extracts resulted in the isolation of oleanolic acid (1) and 4-epi-hederagenin (2) from C. religiosa, isodiospyrin (3) from D. dichrophylla, and santalbic acid (4) from O. subscorpioidea.

Pure analytical standards for the major saponins present in processed soy products, the group B saponins (soyasaponins I, II, III and IV), were isolated in mg quantities by a combination of processing, precipitation/re-solubilisation, TLC and preparative HPLC. These standards were determined to be pure by LC-ESI/MS analysis and NMR. The standards were used to perfect a facile analytical HPLC method using spectrometric detection to determine the percent composition of the group B soyasaponins in various products from processing of soybean.

Abstract. Tuberculosis (TB), mainly caused by Mycobacterium tuberculosis, is the leading killer among all infectious diseases worldwide and is responsible for more than two million deaths annually. For over thirty years no antitubercular agents with new mechanisms of action have been developed. The recent increase in the number of multi-drug resistant clinical isolates of M. tuberculosis has created an urgent need for the discovery and development of new antituberculosis leads. This review covers recent reports on plant-derived terpenoids that have demonstrated moderate to high activity in in vitro bioassays against M. tuberculosis. In this review, mono-, sesqui-, di- and triterpenes, and sterols, their structural analogs and semisynthetic derivatives will be discussed, with particular emphasis on the structural features essential for antimycobacterial activity.

Chondropsin D (2), a new 37-membered-ring macrolide lactam, was isolated as a minor constituent of an aqueous extract of the marine sponge Chondropsis sp. This sponge sample had previously been the source of chondropsins A (1) and B, two novel polyketide-derived macrolides with potent cytotoxic activity. The structure of 2 was initially deduced from analysis of spectral data. This assignment was supported by the observation that chondropsin A (1), which contains a 35-membered macrocyclic ring, could be converted to chondropsin D (2) by a base-catalyzed intramolecular transesterification reaction. Rearrangement of the methylated derivative of chondropsin A (3) to the corresponding methylated analogue of chondropsin D (4) confirmed the structure of 2.

Background: Combining topotecan with other cytotoxics has been problematic due to marrow suppression. A phase I trial was initiated to identify the optimal sequence and maximum-tolerated dose of topotecan in combination with paclitaxel and carboplatin., Patients and Methods: Patients with advanced cancer and performance status ECOG < or = 2. The starting dose was paclitaxel 175 mg/m2 day 1, carboplatin AUC 6.0 day 1, and topotecan 0.5 mg/m2 daily day 1-5 (early sequence). The next course of paclitaxel and carboplatin administration was delayed to day 5 (late sequence). Treatment was repeated every three weeks. After determining maximum-tolerated dose without cytokines, granulocyte colony-stimulating factor (G-CSF) was added and further dose escalation was pursued., Results: Fifty-one patients were entered; men: women ratio 30:21. Dose-limiting toxicity (DLT) for the early sequence was neutropenia at doses paclitaxel mg/m2/carboplatin AUC 5/topotecan mg/m2 (PCT) 175/5/0.75 for four to five days. DLT for the late sequence was neutropenia at PCT doses of 175/5/ 1.0 for four days. G-CSF 5 microg/kg subcutaneously starting day 6 permitted further topotecan dose escalation. After adding G-CSF, late sequence DLT was neutropenia at doses 175/5/1.25 for four days. Forty-six patients were evaluable for response and of those, there were thirteen partial responses., Conclusions: The late sequence resulted in less toxicity and was better tolerated. The early sequence maximum-tolerated dose (MTD) was 175/6/0.5 for five days. The late sequence MTD was PCT 175/5/0.75 for five days. The late sequence MTD with G-CSF was 175/5/1.0 for four days. The recommended phase II PCT dose is the late sequence 175/5/1.0 for four days with G-CSF.

Two new 3,6-epidioxy-7,10-tetrahydrofurano C(26) unsaturated fatty acids, stolonic acids A (1) and B (2), were isolated from a previously undescribed ascidian species, Stolonica sp. collected off the Maldive Islands in the Indian Ocean. The structures and relative stereochemistry of 1 and 2 were determined using conventional spectroscopic methods. Both compounds exhibited antiproliferative activity against selected human melanoma and ovarian tumor cell lines, with IC(50) values of approximately 0.05-0.1 microg/mL.

In a bioassay-guided search for antimycobacterial natural products from higher plants, we have chemically investigated the methanol extract of aerial parts of Ajuga remota Benth. (Labiatae) for its active constituent(s). Bioactive chromatographic fractions of the crude extract provided the known triterpene ergosterol-5,8-endoperoxide plus the diterpenes clerodin, ajugarin-I, and ajugarin-II, which had been previously isolated from A. remota. This is the first report on the isolation of ergosterol-5,8-endoperoxide from this plant. The above compounds were tested in a radiorespirometric bioassay for activity against Mycobacterium tuberculosis. Ergosterol-5,8-endoperoxide showed a minimum inhibitory concentration (MIC) of 1 microgram/ml, while ergosterol-5,8-endoperoxide acetate, ergosterol, and ergosta-5,7,9(11),22-tetraen-3 beta-ol gave MICs of 8 micrograms/ml, > 128 micrograms/ml, and 128 micrograms/ml, respectively. Clerodin, ajugarin-I, and ajugarin-II were inactive with MICs of > 128 micrograms/ml.

In a bioassay guided search for antimycobacterial compounds from higher plants, the root extracts of Elecampane (Inula helenium L.; Asteraceae) and Sweet Coneflower (Rudbeckia subtomentosa Pursh.; Asteraceae) were chemically investigated for their active constituents. Chromatographic fractions of root extracts of l. helenium, which exhibited significant activity against Mycobacterium tuberculosis, provided the known eudesmanolides alantolactone, isoalantolactone, and 11 alpha H, 13-dihydroisoalantolactone. Peracid epoxidation of alantolactone and isoalantolactone provided 5 alpha-epoxyalantolactone and 4(15) alpha-epoxyisoalantolactone, respectively and oxidation of alantolactone with OsO4 gave 11,13-dihydroxyalantolactone. Active fractions from R subtomentosa contained the known alloalantolactone and 3-oxoalloalantolactone. The structures of the above compounds were established by spectroscopic methods including 1D and 2D NMR techniques as well as spectral comparison with previously reported data. The molecular structure of 5 alpha-epoxyalantolactone was determined by single crystal X-ray diffraction. Eleven natural and semisynthetic eudesmanolides were tested in a radiorespirometric bioassay for activity against M. tuberculosis. 5 alpha-Epoxyalantolactone and encelin from Montanoa speciosa showed minimum inhibitory concentrations (MICs) of 8 and 16 micrograms ml-1, respectively. Alantolactone, isoalantolactone and its 4 alpha, 15-epoxide, 1,2-dehydro-3-epi-isotelekin and alloalantolactone gave MICs of 32 micrograms ml-1. All other compounds showed MIC values of 128 micrograms ml-1 or higher.

In a bioassay-guided search for antimycobacterial compounds from higher plants, we have chemically investigated methanolic extracts of seeds of Melia volkensii. Chromatographic fractions provided two new euphane (20R)-type triterpenoids. The structures of the new compounds, 12beta-hydroxykulactone (1) and 6beta-hydroxykulactone (2), were elucidated by 1D and 2D NMR (13C, 1H, 1H-1H COSY, HMQC, HMBC, and NOESY spectra) and FABMS studies and shown to be hydroxyl derivatives of kulactone (3). Also isolated was the known kulonate (4). In a radiorespirometric bioassay against Mycobacterium tuberculosis, compounds 1, 2, and 4 exhibited minimum inhibitory concentrations of 16, 4, and 16 microg/mL, respectively.

In an attempt to study the structural dependence of antimycobacterial activity of the guaianolide dehydrocostus lactone and its derivatives, m-chloroperoxybenzoic acid oxidations of dehydrocostus lactone (1a) were performed. Three new monoepoxides, one previously synthesized diepoxide, and two new diepoxides were obtained. Two of the monoepoxides are C-10 epimers (3a, 3b), while the 4(15)-monoepoxide (2) has the 4alpha-O-configuration. The known diepoxide (4a) contains a C-10 alpha-epoxide and a beta-epoxide at C-4. The diepoxides 4b and 4c, each with a C-4 alpha-epoxy group, differ in the configuration of the epoxide ring at C-10. Allylic oxidation of dehydrocostus lactone (1a) with selenium dioxide/tert-butyl hydroperoxide afforded the known 3-epizaluzanin C (1b). The relative configurations of compounds 1b-4c were established by 1D and 2D NMR techniques (1H, 13C, COSY, NOESY, HMQC, and HMBC) as well as comparison with literature data. The molecular structures of lactones 1b, 4a, and 4c were determined by single-crystal X-ray diffraction. In radiorespirometric bioassays against Mycobacterium tuberculosis and Mycobacterium avium, dehydrocostus lactone (1a) exhibited minimum inhibitory concentrations of 2 and 16 microgram/mL, respectively. In contrast, its monoepoxides (2, 3a, and 3b) and diepoxides (4a-c), as well as its hydrogenated derivatives and other analogues (1b, 1c, 5, and 6), showed significantly lower activities against M. tuberculosis.

The minimum inhibitory concentrations (MIC) against Mycobacterium tuberculosis and M. avium of parthenolide, costunolide, 1 (10)-epoxycostunolide and other germacranolide-type sesquiterpene lactones and derivatives were determined by use of a radiorespirometric bioassay. Structure-activity relationship studies with natural and semisynthetic sesquiterpene lactones suggested that the alpha-methylene-gamma-lactone moiety is an essential, but not sufficient, structural requirement for significant in vitro activity against M. tuberculosis and M. avium.

Two-hundred and thirty crude organic extracts from 118 plant species distributed among 10 families were evaluated for anti-mycobacterial activity. Activity was determined against Mycobacterium tuberculosis H(37)Rv and Mycobacterium avium using the BACTEC 460 radiorespirometric assay. At 100 μg/ml, twenty-four and ten of the extracts caused more than 95% inhibition of growth of M. tuberculosis and M. avium, respectively. The most active plant species (100% inhibition) were Borrichia frutescens, Solidago arguta, and Inula helenium against M. tuberculosis, Euthamia leptocephala against M. avium, and Erigeron strigosus and Magnolia acuminata against both mycobacteria., (Copyright © 1998 Gustav Fischer Verlag. Published by Elsevier GmbH.. All rights reserved.)

The crude methanol extract of the Kenyan shrub Leucas volkensii Gürke (Labiatae) displayed in a radiorespirometric bioassay antimycobacterial activity against Mycobacterium tuberculosis. Bioassay-guided fractionation of the crude extract led to the identification of (E)-phytol as the principal active component with a minimum inhibitory concentration (MIC) of 2 micrograms/ml, a value also observed for (3R,S,7R,11R)-phytanol, (Z)-phytol, and a commercially available 2:1 mixture of (E)- and (Z)-phytol. The derivatives (E)-phytol acetate, a mixture of the (2S,3S)- and (2R,3R)-isomers of (E)-phytol epoxide and (3R,S,7R,11R)-phytanic acid displayed lower activities with MICs of 8, 16, and > 128 micrograms/ml, respectively. Geraniol and farnesol, displayed MICs of 64 and 8 micrograms/ml, respectively. The activities of (E)-phytol, (Z)-phytol and (3R,S,7R,11R)-phytanol were found to be in the same range as ethambutol, a clinically useful drug with an MIC in the range 0.95-3.8 micrograms/ml.

In a bioassay-guided search for antimycobacterial compounds from higher plants of the southeastern United States, we have chemically investigated the sea daisy (Borrichia frutescens) from coastal marshes of Louisiana for their active constituents. Bioactive chromatographic fractions provided two new triterpenes, (24R)-24,25-epoxycycloartan-3-one (1) and (23R)-3-oxolanosta-8,24-dien-23-ol (4), and (3 alpha H, 24R)-24,25-epoxycycloartan-3-ol (3a). Compound 3a had been previously isolated as a mixture of C-24 epimers. The structures of 1, 3a, and 4 were established by spectroscopic methods and chemical transformations, and the molecular structures of 1 and 4 were determined by single-crystal X-ray diffraction. In a radiorespirometric bioassay against Mycobacterium tuberculosis, the epoxycycloartanes 1 and 3a exhibited minimum inhibitory concentrations of 8 micrograms/mL. In contrast, the lanostadiene-type triterpene 4 showed no significant inhibition at 128 micrograms/mL, as did the acetate 3b. Cytotoxicity for Vero cells gave IC50 values of 71.8, 39.8, and 103.6 micrograms/mL for triterpenes 1, 3a, and 4, respectively.