Insecticidal effect of phthalides and furanocoumarins from Angelica acutiloba against Drosophila melanogaster

Insecticidal activity of Angelica acutiloba extract and its constituents was investigated and compared with that of rotenone. Bioassay-guided isolation of the chloroform extract of A. acutiloba against larvae of Drosophila melanogaster afforded two phthalides, (Z)-butylidenephthalide (1) and (Z)-ligustilide (2), and two furanocoumarins, xanthotoxin (3) and isopimpinellin (4). The structures of these compounds were established by spectroscopic analysis. The isolated compounds 1, 2, 3, and 4 exhibited LC(50) values of 0.94, 2.54, 3.35, and 0.82 micromol/mL of diet concentration against larvae of D. melanogaster, respectively. Against both sexes (males/females, 1:1) of adults (5-7 days old), compound 1 showed the most potent activity with a LD(50) value of 0.84 microg/adult. Compound 1 is a more active insecticide than rotenone (LD(50) = 3.68 microg/adult) and has potential as a novel insect control agent. However, compound 2 was inactive against adults. The structure-activity relationship of phthalides isolated indicated that the aromaticity appeared to play an important role in the activity of both larvae and adults. To determine the insecticide mode of action for acute adulticidal activity, acetylcholinesterase (AChE) inhibitory activity was also investigated in vitro, and the result indicated that the acute adulticidal activity of compounds 3 and 4 was due to the inhibition of AChE.     

Biologically active components against Drosophila melanogaster from Podophyllum hexandrum

In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, a dichloromethane extract of Podophyllum hexandrum was found to give an insecticidal activity against larvae of Drosophila melanogaster Meigen. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as podophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays for insecticidal activity, 1 showed a LC(50) value of 0.24 micromol/mL diet against larvae of D. melanogaster and a LD(50) value of 22 microg/adult against adults. Acetylpodophyllotoxin (1A), however showed slight insecticidal activity in both assays, indicating that the 4-hydroxyl group was an important function for enhanced activity of 1.     

Insecticidal sesquiterpene from Alpinia oxyphylla against Drosophila melanogaster

In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, an MeOH extract of Alpinia oxyphylla was found to possess insecticidal activity against larvae of Drosophila melanogaster Meigen. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation and identified as nootkatone (1) by GC, GC-MS, and (1)H and (13)C NMR spectroscopy. In bioassays for insecticidal activity, 1 showed an LC(50) value of 11.5 micromol/mL of diet against larvae of D. melanogaster and an LD(50) value of 96 microg/adult against adults. Epinootkatol (1A), however, showed slight insecticidal activity in both assays, indicating that the carbonyl group at the 2-position in 1 was the important function for enhanced activity of 1.     

Acaricidal activity of butylidenephthalide identified in Cnidium officinale rhizome against dermatophagoides farinae and dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The acaricidal activity of materials derived from the rhizome of Cnidium officinale against adults of Dermatophagoides farinae and Dermatophagoides pteronyssinus was examined using direct contact application and fumigation methods and compared with that of benzyl benzoate and N,N-diethyl-m-toluamide (DEET). The active constituent of the Cnidium rhizome was identified as butylidenephthalide by spectroscopic analyses. Responses varied with dose. On the basis of 24-h LD(50) values, the acaricidal activity of butylidenephthalide (6.77 microg/cm(2)) against D. farinae adults was comparable to that of benzyl benzoate (8.54 microg/cm(2)). Very low activity was observed with DEET (37.59 microg/cm(2)). Against D. pteronyssinus adults, butylidenephthalide (6.46 microg/cm(2)) and benzyl benzoate (6.68 microg/cm(2)) were equitoxic. DEET (17.98 microg/cm(2)) was relatively inactive. The typical poisoning symptom of butylidenephthalide was lethargy of treated mites, leading to death without knockdown, whereas benzyl benzoate and DEET caused death following uncoordinated behavior. In a fumigation test with both mite species, butylidenephthalide was much more effective in closed containers than open ones. Naturally occurring C. officinale rhizome-derived materials merit further study as potential house dust mite control agents or lead compounds.     

Antifeedant and insecticide properties of a limonoid from Melia azedarach (Meliaceae) with potential use for pest management

In the course of screening for novel naturally occurring insecticides from plants, the activity of the fruit extract of the Argentinian Melia azedarach L. (Meliaceae) and its recently described limonoid meliartenin were investigated. The antifeedant activity of the fruit extract was tested on a variety of herbivore and granivorous insects through choice tests. Sixteen of 17 species belonging to three orders consume significantly less food when treated with the extract. The bioactivity of the isolated active compound meliartenin and its interchangeable isomer 12-hydroxiamoorastatin (1) was further studied. In choice tests, compound 1 inhibited feeding of Epilachna paenulata Germ. (Coleoptera, Coccinellidae) larvae, with an ED(50) value of 0.80 microg/cm(2), comparable to that of azadirachtin (2) and lower than that of toosendanin (3) (0.72 and 3.69 microg/cm(2), respectively), both compounds used for comparison purposes. In no-choice tests, E. paenulata larvae reared on food treated with 1 or 2 ate less, gained less weight, and suffered greater mortality rates than control larvae. The activity of compound 1 was comparable to that of 2, with LD(50) values of 0.76 and 1.24 microg/cm(2), respectively, at 96 h. Shorter LT(50) values were recorded for 1 at 4 and 1 microg/cm(2) in comparison with 2. Thus, M. azedarach fruit extract and its active principle have interesting potential for use in pest control programs.     

Evaluation of insecticidal activity of diterpenes and lignans from Aristolochia malmeana against Anticarsia gemmatalis

The insecticidal activity of hexane extracts from the roots and leaves of Aristolochia malmeana was evaluated against Anticarsia gemmatalis larvae by topical application. Extract from the roots was the most active and caused 50% mortality in larvae at 308.4 microg/microL. From this extract, a clerodane diterpene, (-)-kolavenic acid, and three lignans, (-)-kusunokinin, (-)-hinokinin, and (8 S,8' R,9 S)-cubebin, were isolated by chromatography and partition procedures and then evaluated for their insecticidal activities either individually or in pairs. (-)-Kusunokinin showed higher activity against A. gemmatalis (LD10=9.3, LD50=230.1 microg/microL) than the crude extract, and its activity was dose-dependent, whereas the other constituents did not exhibit any significant activity. Together with (-)-kusunokinin and (-)-hinokinin, (-)-copalic acid, (-)-2-oxokolavenic acid, (-)- ent-6-beta-hydroxy-copalic acid, (8 R,8' R,9 R)- and (8 R,8' R,9 S)-cubebins, (-)-fargesin, and (-)-phillygenin were isolated from the hexane extract of the leaves. The compounds were identified on the basis of spectroscopic analysis.     

Antifungal chalcones and new caffeic acid esters from Zuccagnia punctata acting against soybean infecting fungi

The crude methanolic extract of Zuccagnia punctata was active toward the fungal pathogens of soybean Phomopsis longicolla and Colletotrichum truncatum. Assay guided fractionation led to the isolation of two chalcones, one flavanone and a new caffeoyl ester derivative as the compounds responsible for the antifungal activity. Another new caffeoyl ester derivative was isolated from the antifungal chloroform extract but proved to be inactive against the soybean infecting fungi up to 50 microg/mL     

Acaricidal activity of Paeonia suffruticosa root bark-derived compounds against Dermatophagoides farinae and Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The acaricidal activities of materials derived from the root bark of Paeonia suffruticosa against adults of Dermatophagoides farinae and Dermatophagoides pteronyssinus were examined using direct contact and fumigation bioassays and compared with those of benzyl benzoate, dibutyl phthalate, and N,N-diethyl-m-toluamide (deet), widely used acaricides. The active constituents of Paeonia root bark were identified as paeonol and benzoic acid by spectroscopic analyses. On the basis of 24-h LD50 values, the acaricidal activities of paeonol (7.82 microg/cm3) and benzoic acid (6.58 microg/cm3) against adult D. farinae were comparable to that of benzyl benzoate (7.72 microg/cm3) but higher than those of deet (36.34 microg/cm3) and dibutyl phthalate (33.92 microg/cm3). Against adult D. pteronyssinus, the acaricidal activities of paeonol (7.08 microg/cm3) and benzyl benzoate (7.22 microg/cm3) were comparable to that of benzyl benzoate (7.14 microg/cm3). Deet and dibutyl phthalate were less effective. In fumigation tests with both mite species, paeonol and benzoic acid were much more effective in closed containers than open ones, indicating that the effect of these compounds was largely a result of action in the vapor phase. Neither benzyl benzoate, deet, nor dibutyl phthalate exhibited fumigant toxicity. Paeonia root bark-derived materials, particularly paeonol and benzoic acid, merit further study as potential acaricides or lead compounds for the control of D. farinae and D. pteronyssinus.     

Mosquitocidal, nematicidal, and antifungal compounds from Apium graveolens L. seeds

The methanolic extract of Apium graveolens seeds was investigated for bioactive compounds and resulted in the isolation and characterization of mosquitocidal, nematicidal, and antifungal compounds sedanolide (1), senkyunolide-N (2), and senkyunolide-J (3). Their structures were determined by 1H and 13C NMR spectral methods. Compounds 1-3 gave 100% mortality at 25, 100, and 100 microg mL(-1), respectively, on the nematode, Panagrellus redivivus. Compound 1 showed 100% mortality at 50 microg mL(-1) on nematode, Caenorhabditis elegans, and fourth-instar mosquito larvae, Aedes aegyptii. Also, it inhibited the growth of Candida albicans and Candida parapsilasis at 100 microg mL(-1). Compounds 2 and 3 were isolated for the first time from A. graveolens. This is the first report of the mosquitocidal, nematicidal, and antifungal activities of compounds 1-3.     

New mosquito larvicidal tetranortriterpenoids from Turraea wakefieldii and Turraea floribunda

The crude methanol extracts of the root barks of Turraea wakefieldii and Turraea floribunda were found to show mosquito larvicidal activity against third-instar larvae of Anopheles gambiae sensu stricto. Four new limonoids comprising a vilasininoid 1 and three havanensinoids 2-4 were isolated from the chloroform fractions of the methanol extracts of T. wakefieldii and T. floribunda, respectively. The structures of the compounds were elucidated by NMR spectroscopy. Compounds 1, 2, and 4 had LD50 values of 7.1, 4.0, and 3.6 ppm, respectively, and were more potent than azadirachtin, which had an LD50 value of 57.1 ppm when tested against larvae of A. gambiae.     

Bioactive compounds and 1,3-Di[(cis)-9-octadecenoyl]-2-[(cis,cis)-9, 12-octadecadienoyl]glycerol from Apium graveolens L. seeds

Bioassay-directed isolation and purification of the hexane extract of Apium graveolens L. seeds led to the characterization of three compounds: beta-selinene (1), 3-n-butyl-4,5-dihydrophthalide (2) and 5-allyl-2-methoxyphenol (3). The structures of these compounds were established by using (1)H and (13)C NMR spectral methods. Compounds, 1-3 demonstrated 100% mortality on fourth-instar Aedes aegyptii larvae at 50, 25, and 200 microg mL(-)(1), respectively, in 24 h. Also, 2 inhibited the growth of Candida albicans and Candida kruseii at 100 microg mL(-)(1). It inhibited both topoisomerase-I and -II enzyme activities at 100 microg mL(-)(1). Compound 2 displayed 100% mortality at 12.5 and 50 microg mL(-)(1), respectively, when tested on nematodes, Panagrellus redivivus and Caenorhabditis elegans. The triglyceride, 1,3-di[(cis)-9-octadecenoyl]-2-[(cis,cis)-9, 12-octadecadienoyl]glycerol (4) and 3 were isolated for the first time from A. graveolens seeds, although 4 was not biologically active.     

Acute, sublethal, antifeedant, and synergistic effects of monoterpenoid essential oil compounds on the tobacco cutworm, Spodoptera litura (Lep., Noctuidae)

Monoterpenoids (terpenes and biogenically related phenols) commonly found in plant essential oils were tested for acute toxicity via topical application to tobacco cutworms (Spodoptera litura Fab.). The most toxic among 10 such compounds was thymol (LD(50) = 25.4 microg/larva) from garden thyme, Thymus vulgaris. The compounds were then tested for sublethal effects, specifically inhibition of larval growth after topical application of low doses. Among 6 compounds tested, an LD(10) dose reduced growth by 20% on average 3 days after administration. Feeding deterrence was determined using a cabbage leaf disk choice test. The most deterrent compound was thymol, with a DC(50) of 85.6 microg/cm(2) leaf disk area. Because minor constituents in complex essential oils have been suggested to act as synergists, binary mixtures of the compounds were tested for synergy vis à vis acute toxicity and feeding deterrence. trans-Anethole acted synergistically with thymol, citronellal, and alpha-terpineol, in terms of both acute toxicity and feeding deterrence. On the basis of these findings, several complex mixtures were developed and tested as leads for effective control agents. Candidate mixtures demonstrated good synergistic effects. The observed LD(50) of mixture 3 was 40.6 microg/larvae compared to an expected value of 74.6 microg/larvae. The result of this research is a proprietary product suitable for commercial production.     

Biologically active carbazole alkaloids from Murraya koenigii

The bioassay guided fractionation of the acetone extract of the fresh leaves of Murraya koenigii resulted in the isolation of three bioactive carbazole alkaloids, mahanimbine (1), murrayanol (2), and mahanine (3), as confirmed from their (1)H and (13)C NMR spectral data. Compound 2 showed an IC(50) of 109 microg/mL against hPGHS-1 and an IC(50) of 218 microg/mL against hPGHS-2 in antiinflammatory assays, while compound 1 displayed antioxidant activity at 33.1 microg/mL. All three compounds were mosquitocidal and antimicrobial and exhibited topoisomerase I and II inhibition activities.     

Insect antifeedants from tropical plants: structures of dumnin and dumsenin

Two novel A-seco limonoids, dumnin and dumsenin, were isolated from the methanolic extract of Croton jatrophoides by bioassay-guided fractionation, and the structures were determined by nuclear magnetic resonance, circular dichroism, and mass spectrometry experiments. These compounds showed potent antifeedant activity (PC(50) 相似文献   

Acaricidal activity of clove bud oil compounds against Dermatophagoides farinae and Dermatophagoides pteronyssinus (Acari: Pyroglyphidae)

The acaricidal activity of clove (Eugenia caryophyllata) bud oil-derived eugenol and its congeners (acetyleugenol, isoeugenol, and methyleugenol) against adults of Dermatophagoides farinae and Dermatophagoides pteronyssinus was examined using direct contact application and fumigation methods and compared with those of benzyl benzoate and N,N-diethyl-m-toluamide (DEET). Responses varied according to compound, dose, and mite species. On the basis of LD(50) values, the compound most toxic to D. farinae adults was methyleugenol (0.94 microg/cm(2)) followed by isoeugenol (5.17 microg/cm(2)), eugenol (5.47 microg/cm(2)), benzyl benzoate (9.22 microg/cm(2)), and acetyleugenol (14.16 microg/cm(2)). Very low activity was observed with DEET (37.59 microg/cm(2)). Against D. pteronyssinus adults, methyleugenol (0.67 microg/cm(2)) was much more effective than isoeugenol (1.55 microg/cm(2)), eugenol (3.71 microg/cm(2)), acetyleugenol (5.41 microg/cm(2)), and benzyl benzoate (6.59 microg/cm(2)). DEET (17.85 microg/cm(2)) was least toxic. These results indicate that the lipophilicity of the four phenylpropenes plays a crucial role in dust mite toxicity. The typical poisoning symptom of eugenol and its congeners was a similar death symptom of the forelegs extended forward together, leading to death without knockdown, whereas benzyl benzoate and DEET caused death following uncoordinated behavior. In a fumigation test with both mite species, all four phenylpropenes were much more effective in closed containers than in open ones, indicating that the mode of delivery of these compounds was largely due to action in the vapor phase. Eugenol and its congeners merit further study as potential house dust mite control agents or as lead compounds.     

Acaricidal constituents isolated from Sinapis alba L. seeds and structure-activity relationships

Allyl isothiocyanate (AITC) and phenethyl isothiocyanate (PEITC) were isolated from Sinapis alba L. seeds and their effects against Dermatophagoides farinae and D. pteronyssinus were evaluated using the impregnated fabric disk method. The LD 50 values of their compounds and derivatives were then compared with those of a commercial acaricide, benzyl benzoate. On the basis of the LD 50 values against D. farinae, PEITC (0.21 microg/cm(2)) was the most toxic, followed by benzyl isothiocyanate (0.55 microg/cm(2)), phenyl isothiocyanate (1.09 microg/cm(2)), butyl isothiocyanate (1.24 microg/cm(2)), and AITC (1.36 microg/cm(2)); acetyl isothiocyanate (195.01 microg/cm(2)) was the least toxic. In addition, the acaricidal effects of AITC and PEITC against D. farinae were 7.4- and 47.8-fold greater than those of benzyl benzoate, respectively. Against D. pteronyssinus, PEITC was the most toxic (0.19 microg/cm(2)), followed by benzyl isothiocyanate (0.77 microg/cm(2)), phenyl isothiocyanate (1.37 microg/cm(2)), butyl isothiocyanate (1.50 microg/cm(2)), and AITC (2.88 microg/cm(2)); acetyl isothiocyanate (168.82 microg/cm(2)) was the least toxic. AITC and PEITC were 3.3- and 50.4-fold more active than benzyl benzoate against D. pteronyssinus, respectively. Taken together, these findings indicate that AITC, PEITC, and partial derivatives may be useful as preventive agents against dust mites. In addition, these results indicate that structure-activity is related to the aromatic structure, the number of carbon atoms, and the compounds hydrophobicity.     

Evaluation of the cytotoxicity, genotoxicity, mutagenicity, and antimutagenicity of propolis from Tucuman, Argentina

This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.     

Potential food additives from Carex distachya roots: identification and in vitro antioxidant properties

In the present study, the chemical composition and antioxidant properties of root methanol extract of Carex distachya Desf. (Cyperaceae) were assessed to use this plant as sources of food additives and nutraceuticals. The IC50 of the extract (4.2 microg/mL), derived from the DPPH radical scavenging capacity assay, was similar to those of ascorbic acid, alpha-tocopherol, and BHT. These results revealed a strong antioxidant activity because of the presence of an extraordinary quantity of bioactive phytochemicals. The phytochemical study of the root extract led to the isolation and identification of new and known polyphenols, most of them common constituents of plant foods. A total of 16 polyphenols, identified on the basis of spectroscopic data as 7 lignans, 4 phenylethanoids, 3 resveratrol derivatives, a monolignol, and a secoiridoid glucoside, were isolated. The tentative structural elucidation of the new metabolites 5'-O-beta-D-glucopyranosyloxy-3,3'-dimethoxy-7,9'-epoxylignan-4,8',9-triol and 3,5-bis-O-beta-D-glucopyranosyloxy-3'-methoxy-trans-stilben-4'-ol have been performed by a combined approach using ESI/TQ/MS techniques and 1D and 2D NMR experiments. All of the compounds have been tested for their antioxidant activity using six different antioxidant and radical scavenging tests. Interestingly, the extract contained high quantities of polyphenols, most of them reported as constituents of edible plants, such as grape and olive, suggesting that the methanol root extract of this plant could be used as a source of natural antioxidants useful as potential food additives.     

Toxicity of atractylon and atractylenolide III Identified in Atractylodes ovata rhizome to Dermatophagoides farinae and Dermatophagoides pteronyssinus

The acaricidal activity of materials derived from rhizome of Atractylodes ovata (Atractylodes macrocephala) toward adult Dermatophagoides farinae and Dermatophagoides pteronyssinus was examined using fabric-circle residual contact and vapor-phase toxicity bioassays. Results were compared with those of the currently used acaricides: benzyl benzoate, dibutyl phthalate, and N,N-diethyl-m-toluamide (Deet). The active principles of A. ovata rhizome were identified as the sesquiterpenoids, atractylenolide III (1) and atractylon (2), by spectroscopic analysis. In fabric-circle residual contact bioassays with adult D. farinae, atractylenolide III (LD50, 103.3 mg/m2) and atractylon (136.2 mg/m2) were five and four times more toxic than Deet and 1.7- and 1.3-fold more active than dibutyl phthalate, respectively, based on 24 h LD50 values. These compounds were less toxic than benzyl benzoate (LD50, 45.8 mg/m2). Against adult D. pteronyssinus, atractylenolide III (LD50, 73.8 mg/m2) and atractylon (72.1 mg/m2) were eight times more active than Deet and 2.5-fold more toxic than dibutyl phthalate. These compounds were slightly less effective than benzyl benzoate (LD50, 46.0 mg/m2). In vapor-phase toxicity tests with both mite species, atractylenolide III and atractylon were effective in closed but not in open containers. These results indicate that the effect of these sesquiterpenoids was largely a result of action in the vapor phase. Naturally occurring atractylenolide III and atractylon merit further study as potential house dust mite control agents or leads because of their great activity as a fumigant.     

Insect antifeedants from tropical plants II: structure of zumsin

A novel A-seco limonoid was isolated from methanolic extract of Croton jatrophoides and designated as zumsin. This compound showed potent antifeedant activity against two lepidopteran larvae, pink bollworm, Pectinophora gossypiella (PC(50) = 1 microg/cm(2), PC(95) = 8 microg/cm(2)), and fall armyworm, Spodoptera frugiperda (PC(50) = 2 microg/cm(2), PC(95) = 16 microg/cm(2)). The structure of zumsin was determined as 1 using a variety of spectroscopic methods including nuclear magnetic resonance, mass spectrometry, and circular dichroism. The structure consists of an A'-B trans-fused ring while dumsin (2), a constituent of the same source, maintains an A'-B cis-fused ring, and suggests two unique biosynthetic processes after A ring oxidative expansion.