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The objective of this work was to investigate the chemical compositions of the essential oil (EO) extracted from Senecio scandens by hydrodistillation and their insecticidal activities against Tribolium castaneum, Lasioderma serricorne and Liposceis bostrychophila. The chemical profile of the EO were analyzed by gas chromatography–mass spectrometry (GC-MS), and 20 compounds were identified which accounted for 88.03% of the total EO. Five major compounds identified in the EO were assayed against the three stored product insects. The EO showed strong contact toxicity to T. castaneum (LD50 = 18.01 μg/adult), L. serricorne (LD50 = 20.11 μg/adult) and L. bostrychophila (LD50 = 72.14 μg/cm2). Among all compounds, geraniol showed the contact toxicity against L. serricorne and L. bostrychophila with LD50 values of 15.82 μg/adult and 26.64 μg/cm2. The EO and its five chemical compounds also exhibited different level of potential repellence to the three stored product insects.

To exploit botanical insecticides and decrease the damage to crops by stored insects, we analyzed the chemical composition of essential oils derived from celery (Apium graveolens L.) seed and root....

Synthetic insecticides, a traditional tool to avoid the reduction of stored-product due to insects, have emerged a serious of hazards to the environment for years, therefore, botanicals have entered people’s vision. This work aimed to present the essential oil composition of Melaleuca bracteata, and the contact as well as repellent activities against three stored-product insects, i.e. Lasioderma serricorne (Coleoptera: Ptinidae), Tribolium castaneum (Coleoptera: Tenebrionidae), and Sitophilus oryzae (Coleoptera: Curculionidae). For determining the composition, the analysis was performed by GC/FID and GC/MS. Among 11 identified compounds, the principal compounds were methyl eugenol (88.52 %) and methyl cinnamate (7.90 %). The essential oil demonstrated contact toxicity against L. serricorne, T. castaneum, and S. oryzae which LD50 values were 3.2, 22.6, and 20.4 μg/adult, respectively. Methyl cinnamate was more effective than methyl eugenol. The repellent activity indicated that essential oil and major compositions of M. bracteata were effective against L. serricorne and T. castaneum, but no use for S. oryzae. In the contact assay, L. serricorne showed more sensitivity, however, in repellency assay, T. castaneum was susceptible. We seek to provide a new application of the popular ornamental plant, M. bracteata, and offer an alternative material to botanical insecticides development.

The objective of this work was to analyze the essential oil from Atalantia guillauminii fruits in China and evaluate their chemical compositions, insecticidal and repellent activities against Tribolium castaneum and Lasioderma serricorne adults. The essential oil was obtained by hydro-distillation and its yield was 0.12% (V/W). All together 25 chemical compositions were identified by GC-FID and GC-MS, and the main chemical compositions were D-limonene (41.8%), β-pinene (10.9%) and selina-3,7(11)-diene (6.8%). The bioactivity of the obtained essential oil and its two main compositions (D-limonene and β-pinene) was investigated by fumigation, contact and repellent activity bioassay. The essential oil and its two main compositions all showed significant fumigant toxicity, contact toxicity and repellent activity against two target insects. These results suggest that the essential oil and its two main compositions have potential to be developed as natural insecticides and repellents for the control of stored product insect pests.

Apiaceae L. contains many potential plants as repellent and insecticidal resources. However, Ligusticum applied in the stored insect control is still under-evaluated. Hence, the chemical composition and bioactivities of five Ligusticum plants with abundant resources were investigated in this study against Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae), and Liposcelis bostrychophila (Psocoptera: Liposcelididae). The contact toxicity was found 24 h after treatment with Ligusticum pteridophyllum, Ligusticum ajanense, Ligusticum chuanxiong, Ligusticum thomsonii, and Ligusticum jeholense essential oils (LD50 = 87.99, 44.01, 21.53, 125.37, and >50% μg/adult; 89.82, 93.51, 28.42, 105.55, and 50.16 μg/adult; 7.87, 308.62, 67.82, and 195.06 μg/cm2, respectively). The five plants’ essential oils possessed poor fumigant toxicity against three target insects at the highest concentration. Moreover, all analyzed oils have good repellent activity in a dose-dependent manner. In conclusion, the tested oils have the potential to be developed as contact and repellent agents in protecting the stored products.

In order to develop more environmentally benignant insecticides, the Ligusticum pteridophyllum Franch. rhizomes essential oil and supercritical fluid (SFE-CO2) extract were obtained by two published techniques, hydrodistillation and SFE-CO2. The chemical components of this two tested samples were identified by using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID). Repellent activity and contact toxicity of the obtained samples and myristicin against the adults of Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae), and Liposcelis bostrychophila (Psocoptera: Liposcelididae) were compared. Nineteen components were identified in the SFE-CO2 extract. Twelve components were identified in the L. pteridophyllum rhizomes essential oil. SFE-CO2 extract exhibited higher contact toxicity against T. castaneum, L. serricorne, and L. bostrychophila (LD50 = 69.60 μg/adult, 14.58 μg/adult, and 1.69 μg/cm2, respectively) than that of L. pteridophyllum rhizomes essential oil (LD50 = 87.99 μg/adult, 89.82 μg/adult, and 7.87 μg/cm2, respectively). Besides, myristicin (LD50 = 36.46 μg/adult) showed superior contact toxicity against T. castaneum than that of the L. pteridophyllum rhizomes essential oil and SFE-CO2 extract. It possessed potentially practical significance to develop L. pteridophyllum rhizomes into plant pesticide or repellent agent for these stored insect controls.

The insecticidal and repellent activities of the essential oil (EO) from Atalantia buxifolia leaves were evaluated against three stored product insects, including Tribolium castaneum, Lasioderma se...

The essential oil (EO) from leaves of Mentha piperita was extracted by hydrodistillation. Twenty-one chemical components, accounting for 97.5% of the total oil, were determined by GC-MS and GC-FID. The major chemical components included menthol (41.6%), L-menthone (24.7%), isomenthol (6.3%), and limonene (5.0%). The bioactivity of the obtained EO and its two major components against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults were evaluated by fumigation, contact, and repellent activity bioassay. The EO showed significant fumigation and contact toxicity against T. castaneum (LC50 = 18.1 mg/L air and LD50 = 2.9 μg/adult, respectively), L. serricorne (LC50 = 68.4 mg/L air and LD50 = 12.6 μg/adult, respectively), and L. bostrychophila (LC50 = 0.6 mg/L air and LD50 = 49.8 μg/adult, respectively) adults. Meanwhile, the repellent effect of the EO on T. castaneum and L. serricorne adults was comparable to that of the positive control at the highest tested concentration. Menthol and L-menthone were two major components in total oil. Among them, L-menthone exhibited significant insecticidal activity on target insects, and menthol showed notable repellent effects. The results indicated that the EO of M. piperita leaves and two tested components have potential to be developed as natural insecticides and repellents for the control of stored product insect pests. Graphical abstract.

The essential oils (EOs) from aerial parts of Saussurea amara (L.) DC. (SAEO) and Sigesbeckia pubescens Makino (SPEO) were analyzed for their chemical composition by GC-MS, and their repellent activities against adults of the red flour beetle, Tribolium castaneum Herbst, as well as the booklouse, Liposcelis bostrychophila Badonnel, were evaluated for the first time. Results of GC-MS analysis indicated that both SAEO and SPEO were characterized by high content of sesquiterpenoids (relative content > 70%) including oxygenated sesquiterpenoids. The two oil samples and their major component caryophyllene oxide exerted beneficial repellent effects on T. castaneum and L. bostrychophila at 2 and 4 h post-exposure. At 4 h post-exposure, the PR value of caryophyllene oxide could still reach 92% (class V) against T. castaneum at minimum testing concentration of 3.15 nL/cm2, and this compound was observed to result in the greatest repellency (PR = 100%) against L. bostrychophila at 12.63 nL/cm2. This work confirmed the potent repellent efficacy of SAEO and SPEO for controlling pest damage and suggested their potential to be developed into botanical repellents.

Thymus quinquecostatus Celak. of the Lamiaceae family has a long history of dual use of medicine and food with high economic value, and has been proved to have good antioxidative, antimicrobial, and antidiabetic activities. Essential oil (EO) extracted from the aerial part of T. quinquecostatus was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC/MS) and GC. Totally 45 compounds were identified accounting for 98.5 % of the EO. The major constituents of the EO were linalool (52.003 %), borneol (10.911 %) and anethole (5.325 %). Fumigant, contact and repellent activity of T. quinquecostatus essential oil (EO) against Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma Serricorne (Coleoptera: Anobiidae), Liposcelis bostrychophila (Psocoptera: Liposcelididae) were evaluated in this work. T. quinquecostatus EO and three major constituents showed varying degrees of insecticidal and repellent activities to three stored-product insects. Anethole stated the best fumigant and contact activity than others did to all three insect species. EO and compounds showed general repellent activity against three target insects. This work suggests that the EO of T. quinquecostatus has promising potential to be developed into botanical pesticides and repellents controlling pest damage in warehouses and grain stores.

BACKGROUND: Several species of Verbenaceae have been widely used in medicine, and some species of Verbenaceae have been observed good insecticidal activity, such as Lantana camara and Vitex negundo. There is no report about repellent activity of Clerodendrum bungei Steud. (C. bungei) against stored product insects. The chemical composition of C. bungei essential oil (EO) were identified, repellent activity of methanol extract, EO of C. bungei and two main components of EO against T. castaneum, L. serricorne and L. bostrychophila were evaluated for the first time. RESULTS: EO of C. bungei was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS) and GC. A total of 25 components of the C. bungei EO were identified. The principal compounds in the EO were myristicin (75.0%), 2,2,7,7-Tetramethyltricyclo[6.2.1.0(1,6)]undec-4-en-3-one (4.1%) and linalool (3.4%). Results of bioassays indicated that C. bungei EO exerted strong repellent activity against three target insects. As main constituents, myristicin and linalool also had certain repellency. CONCLUSION: This work suggests that the EO of C. bungei has promising potential to develop into botanical repellents for the control of pest damage in warehouses and grain stores. GRAPHICAL ABSTRACT: [Image: see text]

To develop botanical pesticides and repellents against stored-product insects, the chemical composition and insecticide properties of the essential oil from Citrus medica L. var. sarcodactylis Swin...

Essential oils (EOs) extracted from leaves (EL) and fruit pericarp (EFP) of Zanthoxylum planispinum var. dintanensis were analyzed for their chemical composition by GC-MS technique and evaluated for their fumigant, contact toxicity and repellency against three stored-product insects, namely Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults. Results of GC-MS analysis manifested that EL and EFP of Z. planispinum var. dintanensis were mainly composed of oxygenated monoterpenes. Major components included linalool, sylvestrene and terpinen-4-ol. The obvious variation observed between two oil samples was that EL contained 2-dodecanone (11.52%) in addition to the above mentioned components, while this constituent was not detected in EFP. Bioassays of insecticidal and repellent activities were performed for EL, EFP as well as some of their individual compounds (linalool, terpinen-4-ol and 2-dodecanone). Testing results indicated that EL, EFP, linalool, terpinen-4-ol and 2-dodecanone exhibited potent insecticidal and repellent activities against the three target insects selected. Among the three individual compounds, 2-dodecanone was significantly toxic to T. castaneum (LD50 = 5.21 μg/adult), L. serricorne (LD50 = 2.54 μg/adult) and L. bostrychophila (LD50 = 23.41 μg/cm2) in contact assays and had beneficial repellent effects on L. serricorne at 2 and 4 h post-exposure. The anti-insect efficacy of Z. planispinum var. dintanensis EO suggests it has potential to be used as botanical insecticide or repellent to control pest damage in warehouses and grain stores.

The objective of this work was to analyze four essential oils (EOs) from Rhododendron species in China and evaluate their repellent activity against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila adults. These four EOs from Rhododendron species, including R. capitatum, R. przewalskii, R. mucronulatum, and R. micranthum, were obtained by hydrodistillation. Major components of four EOs were identified as sesquiterpenoids by GC-MS. The relatively high components included cedrene (22.20%), borneol (36.64%), 4-(2,3,4,6-tetramethylphenyl)-3-buten-2-one (27.74%), and germacrene D (27.60%). Repellent activity of EOs from Rhododendron species was investigated against T. castaneum, L. serricorne, and L. bostrychophila adults for the first time. In this study, EOs had demonstrated their repellent activities against three stored-product insects in 2- and 4-h exposure. The above results can not only provide comprehensive utilization of plant resources of Rhododendron genus but also establish a very good perspective of novel application to control stored-product insects.

Chemical investigation of fungus Pochonia chlamydosporia strain 170, derived from rice fermentation sediment samples, afforded seven radicicol analogues, including two new compounds, monocillin VI (1) and monocillin VII (2), and five known compounds, monocillin II (3), monorden D (4), monocillin IV (5), monocillin V (6), and pochonin M (7). The structures of compounds 1-7 were established primarily by analysis of nuclear magnetic resonance data, and the absolute configurations of the secondary alcohol in compounds 1 and 2 were assigned by the modified Mosher method. All seven compounds have modest antibacterial activities, with a minimal inhibitory concentration (MIC) of 25.6 μg/mL for compounds 1 and 3-7 and 51.2 μg/mL for compound 2, on inhibition of the growth of the plant pathogen Xanthomonas campestris (the positive control ampicillin showed a MIC value of 12.8 μg/mL), indicating that the fungus has the potential to control bacterial disease. The biosynthetic gene cluster and putative biosynthetic pathways of these radicicol analogues in the P. chlamydosporia genome were proposed. These findings increase our knowledge of the chemical potential of P. chlamydosporia and may allow us to better utilize the fungus as a biological control agent.

Continuous use of synthetic insecticides increases environmental contamination and resistance in many species. Botanical insecticides, such as essential oil, were considered to be suitable alternatives due to multiple modes of action and low mammalian toxicity. Haplophyllum dauricum is a overlooked plant for the control of stored-product insects. Five essential oils (EOs) from Haplophyllum dauricum collected in October and November, rich in pinene, were extracted and evaluated on anti-insect activity against two stored-product insects, Tribolium castaneum (Coleoptera: Tenebrionidae) and Lasioderma serricorne (Coleoptera: Anobiidae). The lethal doses (LD50 and LD90), lethal concentrations (LC50 and LC90) and percentage repellency (PR) were evaluated. The GC-MS analysis showed that pinene (α-pinene and β-pinene) were major constituent of the EOs (54.61% and 57.33% in fruits, 46.80% in stems + leaves, and 30.57% in leaves), followed by β-phellandrene (14.49% and 21.34% in fruits and leaves), 3-carene (26.84% in leaves) and limonene (15.77%, 11.09%, 12.40%, 7.59%, and 6.24% in five EOs, respectively). Five EOs and selected major compounds provided promising fumigant, contact and repellent activity against T. castaneum and L. serricorne. The EO of stems + leaves collected in October showed the strongest contact toxicity on T. castaneum (LD50 = 20.21μg/adult), as well as fumigant and contact toxicity on L. serricorne (LC50 = 17.17 mg/L air, LD50 = 25.46 μg/adult). All the five EOs exhibited effective repellent activity (PR>80%) against T. castaneum. The results highlight that the EOs from H. dauricum have a promising potential as eco-friendly botanical insecticides.

The essential oil was extracted from the roots of Valeriana officinalis L. by hydrodistillation. The qualitative and quantitative analysis of its chemical constituents was conducted on GC-MS and GC-FID in this study. Seventeen compounds were detected and the major constituents included bornyl acetate (48.2%) and camphene (13.8%). The toxic and repellent effects of the essential oil and its two major constituents were evaluated on Liposcelis bostrychophila and Tribolium castaneum. The results of bioassays indicated that the essential oil showed the promising fumigant and contact toxicity against L. bostrychophila (LC50 = 2.8 mg/L air and LD50 = 50.9 μg/cm2, respectively) and the notable contact effect on T. castaneum (LD50 = 10.0 μg/adult). Meanwhile, the essential oil showed comparable repellent effect on T. castaneum at all testing concentrations. Bornyl acetate and camphene also exhibited strong fumigant and contact toxicity against both species of pests (LC50 = 1.1, 10.1 mg/L air and LD50 = 32.9, 701.3 μg/cm2 for L. bostrychophila; > 126.3, 4.1 mg/L air, and 66.0, 21.6 μg/adult for T. castaneum). Bornyl acetate and camphene showed moderate repellent effect on T. castaneum and conversely showed attractant effect on L. bostrychophila. This work highlights the insecticidal potential of V. officinalis, which has been noted as a traditional medicinal plant.

The aim of this research was to determine the chemical constituents and toxicity of the oil derived from Alpinia katsumadai seeds against Tribolium castaneum, Liposcelis bostrychophila and Lasioder...

In this work, the essential oils (EO) were extracted from seven typical Chinese herbs, and their repellent and contact toxicities against Tribolium castaneum adults (red flour beetles) were evaluated. The experimental results showed that the above EOs presented the various levels of repellent and contact toxicities. The EOs extracted from A. lancea and A argyi of the Compositae (Asteraceae) family presented obvious repellent effects (Repellency Percentage > 90% at 3.15 nL/cm2 after 4 h exposure) and strong contact toxicity with LD50 values of 5.78 and 3.09 μg/adult respectively. Based on literature researches and screening results, the EO from A. lancea was analyzed by GC-MS and chosen for further identification of bioactive components. Altogether 59 chemical components were identified and 17 of them were recognized as sesquiterpene compounds, accounting for 57.8% of the total weight of the EO. From the identified sesquiterpenes, three individual compounds (β-eudesmol, hinesol, valencene) were selected for the laboratory bioassays of the toxicity against red flour beetles. It was found that all the three compounds expressed some repellent effects. Although β-eudesmol (31.2%) and hinesol (5.1%) were identified as main constituents and had been considered to be symbolic characteristics of high medicinal value, valencene (0.3%) showed strong repellent property which could be comparable to that of DEET (N, N‑diethyl‑3‑methylbenzamide), a powerful commercial pesticides, and it had best toxicity with LD50 values of 3.25 (μg/adult) in the contact test. This work may provide toxicity evidence of seven common herbs against red flour beetles, add the information for the development and comprehensive utilization of A. lancea, and will contribute to the application of grain preservation.

One new sesquiterpene (α-iso-cubebenol acetate, 8), together with 9 known compounds (1-7, 9, 10) were isolated from the stems of Schisandra chinensis (Turcz.) Baill. by repeated silica gel column c...

The essential oil was obtained from the aerial parts of Pogostemon cablin by hydrodistillation. The chemical compounds of P. cablin essential oil were analyzed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Eight compounds were totally identified and accounted for 92.4% of the oil. Patchoulol was the major component (51.1%), followed by phloroacetophenone (23.5%) and β-patchoulene (7.3%). The essential oil and its two major compounds patchoulol and phloroacetophenone were evaluated for their contact and repellent activities against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results of bioassays indicated that the essential oil and patchoulol had great contact toxicity against three species of insects. Meanwhile, the essential oil and patchoulol showed great repellent activities against T. castaneum and L. bostrychophila but were mildly repellent to L. serricorne. Phloroacetophenone exhibited neither contact nor repellent activity against any of these target insects. This work emphasized the promising potential of P. cablin to control insect pests during storage.

The essential oil extracted from roots and rhizomes of Ligusticum jeholense Nakai et Kitagawa was investigated for its chemical composition by GC-MS analysis, and evaluated for its contact toxicity and repellency against Tribolium castaneum and Lasioderma serricorne, along with some of its individual components. The essential oil was rich in aromatics (65.34%) with low molecular weight. Major components included sedanolide (33.95%), 3-butylidenephthalide (18.76%), spathulenol (8.90%) and myristicin (6.76%). The results of bioassays indicated that the essential oil of L. jeholense and 3-butylidenephthalide possessed significant repellent activities against T. castaneum at 2 and 4 h post-exposure. Meanwhile, 3-butylidenephthalide had potent contact toxicity against L. serricorne (LD50 = 13.64 µg/adult). The minor component n-butylbenzene in the oil was highly toxic to T. castaneum (LD50 = 23.99 µg/adult) and L. serricorne (LD50 = 7.86 µg/adult) in contact assays, but failed to repel these beetles at all testing concentrations. Spathulenol and myristicin exerted good insecticidal and repellent effects on the two target insects. This work suggests that the essential oil of L. jeholense has promising potential for development as natural insecticide or repellent to control pest damage in warehouses.

In this work, we investigated the chemical constituents of hydrodistillation essential oil from the aerial parts of Artemisia frigida Willd. All together 14 components were identified by GC-MS. Moreover, we tested the fumigant and contact activities of the essential oil and its five major individual compounds (terpinen-4-ol, verbenone, camphene, α-terpineol and α-terpinyl acetate) against Liposcelis bostrychophila, Lasioderma serricorne and Tribolium castaneum. In fumigant toxicity tests, α-terpineol possessed the strongest activity (LC50 = 3.27 mg/L air) against L. serricorne. Terpinen-4-ol exhibited the strongest activity (LC50 = 0.08 and 3.74 mg/L air respectively) against L. bostrychophila and T. castaneum. As for contact toxicity, terpinen-4-ol and α-terpinyl acetate exhibited fair toxicity against L. bostrychophila (LD50 = 33.10 and 31.80 µg/cm2 respectively) and L. serricorne (LD50 = 8.62 and 8.87 µg/adult respectively), and camphene possessed the strongest activity (LD50 = 5.13 µg/adult) against T. castaneum. The results indicated that A. frigida essential oil and its individual compounds had the potential to be developed as natural fumigants and insecticides for control of these three stored-product insects.

The natural and ecologically safe control of stored product insects has gained considerable attention in modern society. In this study of further searching for botanical pesticides from wild-growing plant, the contact toxicity and repellency towards Tribolium castaneum and Liposcelis bostrychophila were assessed for the essential oil (EO) from Ostericum viridiflorum. The EO was distilled from aboveground parts of O. viridiflorum and checked by gas chromatography-mass spectrometry. Twenty-two compounds were identified and the main components were β-caryophyllene (24.3%), α-humulene (21.0%), apiol (10.2%), and carotol (2.5%). For bioactivity tests, results indicated that the EO and its two main compounds (β-caryophyllene and α-humulene) all showed potent contact toxicity towards L. bostrychophila with LD50 values of 44.52 μg/cm2, 74.11 μg/cm2, and 118.56 μg/cm2, respectively. The EO and the two main compounds also exhibited comparable repellency towards T. castaneum and L. bostrychophila. The results evidenced the EO of O. viridiflorum aboveground parts and its major compounds could be considered for the development of eco-friendly botanical insecticides and repellents in controlling stored product insects.

Three lignans (1–3) and three butanolides (4–6) were isolated from the lipophilic extract of theCinnamomum camphorastem bark. The six compounds were identified as (-)-sesamin (1), 9α-hydroxysesamin (2), 9β-hydroxysesamin (3), obtusilactone A (4), isoobtusilactone A (IOA, 5), and isomahubanolide (6) from their spectroscopic data. Four (1, 2 and 5, 6) of them were evaluated for their repellent and feeding deterrent activities againstTribolium castaneum. In this work, the three butanolides (4–6) were confirmed to exist inC. camphorafor the first time. Results of bioassays indicated that (-)-sesamin (1), IOA (5), and isomahubanolide (6) displayed certain repellent activities againstT. castaneumat 78.63, 15.73, and 3.15 μg/cm2at 2 h after exposure. Among the three compounds, (-)-sesamin (1) and IOA (5) exerted stronger effects and maintained longer duration of repellency. Furthermore, IOA (5) and isomahubanolide (6) showed good feeding deterrent activity againstT. castaneum. IOA (5) was still potently active at low concentrations with the feeding deterrence index (FDI) ranging from 42.85% to 50.66% at 15–1500 ppm. This work provides some evidence for explaining antiinsect properties of the nonvolatile fraction of theC. camphorastem bark and helps promote the development and comprehensive utilization of this tree species.

The extract from Cinnamomum cassia Presl bark was obtained with supercritical CO2 fluid extraction (SFE). Chemical components of the SFE extract were characterized by GC-MS spectrometry. The repellency and contact toxicity of the SFE extract were evaluated against the adults of Tribolium castaneum and Lasioderma serricorne along with those of its two main compounds. The results of GC-MS analysis indicated that 33 volatile constituents were identified from the extract. The main components included trans-cinnamaldehyde (32.1%), 3,3-dimethylhexane (10.6%) and 2,4-di-tert-butylphenol (7.9%). Testing results showed that the SFE extract had potent contact toxicity against T. castaneum and L. serricorne with LD50 values of 3.96 and 23.89 μg/adult, respectively. LD50 values of trans-cinnamaldehyde against T. castaneum and L. serricorne were 5.78 and 3.24 μg/adult, respectively. Additionally, percentage repellency values of the SFE extract and trans-cinnamaldehyde against T. castaneum and L. serricorne were rather high (PR = 100% and PR > 90%, respectively) at 78.63 and 15.73 nL/cm2 at 2 h post-exposure. 2,4-Di-tert-butylphenol showed some repellency against both beetle species. Considering its insecticidal and repellent effects, the SFE extract from C. cassia bark might be used in integrated pest management programs for T. castaneum and L. serricorne.

The essential oils (EOs) extracted from Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Benth. leaves are screened to evaluate their contact toxicity and repellency towards Tribolium castaneum (Coleoptera: Tenebrionidae), Lasioderma serricorne (Coleoptera: Anobiidae) and Liposcelis bostrychophila (Psocoptera: Liposcelididae) adults. The EOs are obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The principal components in the E. lenticellata EO are identified to be caryophyllene oxide (28.5%), β-caryophyllene (23.1%), β-elemene (14.5%), and β-cubebene (4.7%), while the main components of the E. rutaecarpa EO are α-pinene (39.4%), β-elemene (13.5%), α-ocimene (7.6%), and α-selinene (4.0%). These two kinds of EOs and their individual compounds all showed different levels of contact toxicity and repellent activity against three stored-product insects.

Essential oils obtained from many plants showed various kinds of insecticidal properties; some of them have been considered as alternative insecticides for pest control. The present study was aimed at determining the chemical composition of the essential oil from the roots of Bupleurum bicaule Helm, as well as evaluating the contact and repellent activities of the oil and four identified compounds against Lasioderma serricorne and Liposcelis bostrychophila adults. The essential oil was extracted by hydrodistillation, and its components were analyzed by gas chromatography-mass spectrometry (GC-MS). 26 components were determined and the main compounds included trans-2-isopropylbicyclo[4.3.0]non-3-en-8-one (25.9%), 4,5-dimethyl-1,2,3,6,7,8,8a,8b-octahydrobiphenylene (23.5%), and 1,4-dimethoxy-2-tert-butylbenzene (4.3%). It was found that the essential oil exhibited contact toxicity against L. serricorne (LD50 = 11.91 μg/adult), but the contact toxicity against L. bostrychophila could not be observed. The essential oil also showed strong repellent activity against L. serricorne with percent repellency of 100% at 78.63 nl/cm2. Four chemical compounds, 1,4-dimethoxy-2-tert-butylbenzene, bornyl acetate, (2E,4E)-2,4-nonadienal, and β-bisabolene, exhibited various levels of bioactivities. The experimental results indicated that the essential oil of B. bicaule and its individual compounds could be used in insecticidal and repellent strategies for stored product insects.

The Amomum villosum essential oil was obtained from hydrodistillation and was investigated by GC-MS. The main constituents were bornyl acetate (51.6%), camphor (19.8%), camphene (8.9%) and limonene (6.2%). Insecticidal toxicity of the essential oil was evaluated in this study. It showed that the essential oil possessed contact toxicity against Tribolium castaneum and Lasioderma serricorne (LD50 = 32.4 and 20.4 μg/adult). Three monoterpenoids camphor, camphene and limonene showed strong fumigant toxicity against T. castaneum (LC50 ＜ 2.3, LC50 ＝ 6.2 and 6.2 mg/L air). In addition, repellency of the essential oil was also evaluated. Data showed that the essential oil and all four compounds had repellent activity against T. castaneum and L. serricorne at high concentration (78.63 nL/cm2). But with the decrease of concentration, they showed a different degree of attractant properties.

Nineteen compounds were isolated from Ajania potaninii, including one sulfur paraffin (1), one monoterpene (6), one lactone (3), one aliphatic acid (15), two sterols (8 and 10), one triterpenes (13), one alkaloid (18), eleven flavonoids (2, 4, 5, 7, 9, 11, 12, 14, 16 and 17) and one cyclic amide (19). All of these compounds were obtained from A. potaninii for the first time. This is the first report of N-nonanemercaptan (1), 3-hydroxy-5-decanolide (3), cirsiliol (5), 1,2,4-trihydroxy-p-mentane (6), 6-methoxytricin (7), eriodictyol (11), pectolinarigenin (12), 3,3′-di-O-methylquercetin (14), tetradecanoic acid (15), lappaconitine (18) and 1,1′,1″,1‴,1‴'-tricontane lactam (19) from the genus Ajania. The occurrence of compounds 18 and 19 in A. potaninii warrants further study.

Murraya alata Drake is a shrub that is distributed in the underwood of sandy areas near sea level in China and Vietnam. Twenty-two compounds were isolated from the leaves and stems of M. alata, including six new coumarins (6, 8–10, 17, 19) named muralatins L–Q. The structures were identified on the base of NMR and MS spectral analysis. Furthermore, the repellent activity against Tribolium castaneum was tested for fourteen isolated compounds. A statistic model-grey relational analysis was introduced to evaluate repellent activity directly based on relative correlation degree. This statistical analysis was suitable for complex problems of multiple indexes. The testing compounds exhibited various repellent activities against T. castaneum. Among them, compounds 1 (meranzin), 2 (phebalosin) and 16 (muralatin K) showed significant repellent activity against T. castaneum with ri values of 0.7047, 0.6990 and 0.6884, respectively, comparable to that of the positive control, N, N-diethyl-3-methylbenzamide (DEET, ri = 0.7013). The optimal compounds might be considered as potential leading compounds for the development of natural repellents.

The contact toxicity and repellent activities of the essential oil extracted from the rhizomes of Zingiber zerumbet (L.) Smith (Zingiberaceae) was evaluated against cigarette beetles (Lasioderma serricorne). The essential oil obtained by hydrodistillation was investigated by GC-FID and GC-MS. The main constituents of the essential oil were zerumbone (40.2%), α-caryophyllene (8.6%), humulene epoxide II (7.3%), camphene (5.9%) and fenchene (4.7%). Zerumbone and its analogues totally are accounting for 60.3% of the essential oil. It was found that the essential oil possessed contact toxicity against L. serricorne adults with a LD50 value of 48.3 µg/adult. α-Caryophyllene (LD50 = 13.1 µg/adult) exhibited stronger contact toxicity against L. serricorne than humulene oxide (LD50 = 31.2 µg/adult), β-caryophyllene (LD50 = 35.5 µg/adult) and zerumbone (LD50 = 42.4 µg/adult). Moreover, α-caryophyllene possessed strong repellent activity (Class IV and V, respectively) against the beetles at 78.63 nL/cm2, after 2 and 4 h treatment. The results indicate that zerumbone and its analogues might be developed into natural insecticides or repellents for control of cigarette beetles, but their bioactivities are affected by their structures.

The objective of this study was to analyze six essential oils fromZanthoxylumgenus (family Rutaceae) in China and evaluate their repellent activities againstTribolium castaneumandLasioderma serricorneadults. Six essential oils fromZanthoxylumgenus, includingZ. armatum,Z. dimorphophyllum,Z. dimorphophyllumvar.spinifolium,Z. piasezkii,Z. stenophyllum,andZ. dissitum,were obtained by hydrodistillation and their yields were ranging from 0.02% to 0.53%. Totally, there were 39 chemical components revealed by GC-MS. Among them, some components with high relative content existed in more than threeZanthoxylumspecies. For instance, bothδ-cadinene (1.21%–17.15%) and spathulenol (0.36%–10.19%) appeared in essential oils ofZ. dimorphophyllum,Z. piasezkii,Z. stenophyllum,andZ. dissitumwhich were found to have higher content of sesquiterpenoids. The repellent activities of six essential oil samples againstT. castaneumandL. serricorneadults were investigated for the first time. Data demonstrated that sixZanthoxylumspecies had much stronger repellent activities againstT. castaneumthanL. serricorneadults, especially in 2 hours after exposure. The results indicate that these six essential oils fromZanthoxylumhave significant potential to be developed into natural repellents to control insects in grains, food, and traditional Chinese medicinal materials.

The chemical constituents of the essential oil extracted from Artemisia anethoides and the bioactivities of essential oil against Tribolium castaneum and Lasioderma serricorne were investigated. The main components of the essential oil were 1,8-cineole (36.54%), 2-isopropyl-5-methyl-3-cyclohexen-1-one (10.40%), terpinen-4-ol (8.58%), 2-isopropyltoluene (6.20) and pinocarveol (5.08%). The essential oil of A. anethoides possessed contact and fumigant toxicities against T. castaneum adults (LD50 = 28.80 μg/adult and LC50 = 13.05 mg/L air, respectively) and against L. serricorne (LD50 = 24.03 μg/adult and LD50 = 8.04 mg/L air, respectively). The crude oil showed repellent activity against T. castaneum and L. serricorne. Especially, the percentage repellency of essential oil was same level with DEET (positive control) against T. castaneum. The results indicated that the essential oil of A. anethoides had the potential to be developed as insecticide and repellent for control of T. castaneum and L. serricorne.

In this work, the essential oil (EO) and supercritical CO2 fluid extract (SF extract) of four Valerianaceae plants (Valeriana officinalis L., Valeriana officinalis L. var. latifolia Miq., Valeriana jatamansi Jones and Nardostachys chinensis Bat.) were chemically characterized. GC-MS analysis identified 74 compounds, representing 35.2%–82.4% of the total EOs and SF extracts. The EO was dominated by low-molecular-weight components while the SF extract was rich in fatty acids. Bornyl acetate and camphene were the characteristic compounds in EO and SF extracts. The efficacy of six extracts against three stored-product insects was investigated. In contact assays, V. officinalis exhibited strongest toxicity to red flour beetle (LD50 = 10.0 μg/adult), and V. jatamansi EO was the most active one against the cigarette beetle (LD50 = 17.6 μg/adult), while V. officinalis var. latifolia EO showed outstanding efficacy against the booklouse (LD50 = 40.2 μg/cm2). Binary mixtures of two major compounds (camphene and bornyl acetate) were assessed for the contact toxicity to the red flour beetle. Additive effect existed in the natural proportion of V. officinalis, and synergism was observed in that of V. officinalis var. latifolia. This work confirmed the insecticidal efficacy of the species of the Valerianaceae family, and it would offer some information for the development of botanical insecticide.

As a medicinal plant, Artemisia annua is widely distributed in China. The purpose of this work was to analyze the chemical composition of essential oil from A. annua aerial portions, as well as to assess its repellent activity against Lasioderma serricorne and Tribolium castaneum adults. GC-FID and GC-MS analyses enabled the identification of 15 components representing 90.1% of the essential oil. The main components included artemisia ketone (70.6%), α-caryophyllene (5.1%) and germacrene D (3.8%). The essential oil was found to possess considerable ability to repel the two storage pests. This paper provided some evidence for the exploitation and utilization of A. annua resources as a natural repellent.

In this work, the essential oils (EOs) of Alpinia zerumbet (Pers.) Burtt. et Smith were extracted from different organs (stems, leaves, flowers and fruits). The GC-MS analysis showed that two isomers m-cymene and o-cymene distributed totally diverse among different organs: m-cymene were relatively rich in the EOs from stems, flowers and fruits (7.1, 11.3 and 6.6%, respectively), but absent in the EO from leaves; o-cymene was predominant in the EO from leaves (14.9%), but missing in the EOs from other organs. A. zerumbet EOs from different organs, as well as seven characteristic compounds (m-cymene, o-cymene, camphene, eucalyptol, linalool, camphor, and borneol) showed varying degrees of insecticidal and repellent activities to Tribolium castaneum and Liposcelis bostrychophila. o-Cymene exhibited stronger fumigant and contact toxicity than m-cymene did to both insect species, suggesting that the relative position of methyl and isopropyl on benzene ring would influence the insecticidal activity. Positive correlation between relative content of camphor and LC50 value to T. castaneum was significant, while fumigant and contact toxicity of EOs appeared to be negatively correlated with the content of m-cymene.

A screening of Chinese medicinal herbs and wild plants for agrochemicals was carried out; the essential oil of Glycosmis lucida leaves was found to possess significant repellent activity against Tribolium castaneum and Liposcelis bostrychophila. It was found that the main components included elixene (19.81%), spathulenol (10.68%), anethole (12.05%), verbenone (10.32%) followed by β-caryophyllene (6.87%). The essential oil, anethole and verbenone were strongly repellent against T. castaneum (96, 86 and 94%, respectively, at 15.73 nL cm−2) and L. bostrychophila (100, 68 and 72%, respectively, at 31.58 nL cm−2) after a 2h treatment. The results indicate that anethole and verbenone had the potential to be developed as natural repellents for control of stored product insects.

Two essential oil samples were obtained from the pericarp of Zanthoxylum bungeanum with the methods of hydrodistillation (HD) and supercritical fluid CO2 extraction (SFE), their chemical components were identified, and their bioactivities against Lasioderma serricorne adults were evaluated. In the process of testing, the two samples showed significant bioactivities against Lasioderma serricorne adults. For an example, the SFE-sample expressed relatively stronger fumigant toxicity on Lasioderma serricorne adults (LC50 = 3.99 μg/mL air) than that of the HD-sample (LC50 = 12.54 μg/mL air). According to GC-MS analysis, the chemical components between two samples were different. The major chemical components for HD included linalool (25.99%), limonene (19.34%), linalyl anthranilate (12.22%), 4-terpinenol (10.49%), eucalyptol (6.53%) and α-terpineol (5.02%), while for SFE included nonanoic acid (21.43%), γ-terpinene (14.51%), eucalyptol (13.45%), α-terpineol (5.83%) and caryophyllene oxide (5.48%). The results showed that different chemical components result in different bioactivities. This work provides theoretical basis for traditional Chinese concept of antagonistic storage, and it also provides important information for the development and comprehensive utilization of Zanthoxylum bungeanum.

In this work, we investigated the chemical constituents of the essential oil extracted from the leaves of Rhododendron thymifolium and their insecticidal and repellent activities against Liposcelis bostrychophila and Tribolium castaneum. 14 chemical components were identified from the essential oil and included germacrone (20.83%), γ-elemene (11.10%), selina-3,7(11)-diene (6.18%), α-oxobisabolene (5.39%), β-sesquiphellandrene (2.44%), β-elemenone (35.17%), Z,Z,Z-1,5,9,9-tetramethyl-1,4,7,-cycloundecatriene (3.64%) and 1-(4-ethylphenyl)-3-methyl-pyrazol-(4H)-one (2.91%). Among them, the first five components were isolated and identified. The results showed that the essential oil and five pure compounds possessed the obvious repellent activity and various levels of contact activities against the two species of stored insects. The essential oil possessed the contact toxicity (LD50 = 19.63 μg/cm2) which was quite close to the toxicity of positive control pyrethrins (LD50 = 18.72 μg/cm2) against L. bostrychophila. The five pure compounds might individually or together effect the contact toxicity of the essential oil against L. bostrychophila. The essential oil possessed the contact toxicity (LD50 = 29.82 μg/adult) against T. castaneum, but only germacrone revealed strong contact toxicity (LD50 = 0.97 μg/adult), which was comparable with the toxicity of pyrethrins (LD50 = 0.24 μg/adult) among five compounds against T. castaneum. The existence of germacrone might be one of the key elements which affected the contact toxicity of R. thymifolium essential oil against T. castaneum. The insecticidal and repellent activities of essential oil and five compounds were evaluated, the results provide a basis of the development and utilization in the future for control of insects.

The essential oil obtained by hydrodistillation from Alpinia kwangsiensis rhizomes was investigated by GC-MS. A total of 31 components representing 92.45% of the oil were identified and the main compounds in the oil were found to be camphor (17.59%), eucalyptol (15.16%), β-pinene (11.15%) and α-pinene (10.50%). These four compounds were subsequently isolated and the essential oil and four isolated compounds exhibited potent insecticidal activity against Lasioderma serricorne adults. During the assay, it was shown that the essential oil exhibited both potential contact (LD50 = of 24.59 μg/adult) and fumigant (LC50 = of 9.91 mg/L air) toxicity against Lasioderma serricorne. The study revealed that the insecticidal activity of the essential oil can be attributed to the synergistic effects of its diverse major components, which indicates that oil of Alpinia kwangsiensis and its isolated compounds have potential to be developed into natural insecticides to control insects in stored grains and traditional Chinese medicinal materials.

Murraya genus (family Rutaceae) has been widely used as local traditional medicines in East Asia. The chemical composition of essential oils extracted from six Murraya species and their repellent activity against Tribolium castaneum was investigated. From the samples of Murraya tetramera , Murraya euchrestifolia , Murraya koenigii , Murraya kwangsiensis , Murraya exotica , and Murraya alata , essential oils were obtained by hydrodistillation and their yields were various from 0.03 to 0.23%. All together 36 components were identified by GC–MS from the essential oils samples. The constituents with relatively higher contents included α-cedrene (4.22–21.82%), β-caryophyllene (8.15–27.73%), γ-elemene (4.38–12.65%), γ-selinene (3.80–21.09%), α-selinene (2.60–10.68%), α-zingiberene (2.08–12.68%), spathulenol (3.08–11.80%), caryophyllene oxide (1.58–10.59%), β-eudesmol (1.33–25.32%), etc. Moreover, eight compounds, which were recognized as significant components in the essential oils of M. tetramera , and M. kwangsiensis , were isolated and they were identified as α-terpinene, β-caryophyllene, α-caryophyllene, alloaromadendrene, spathulenol, β-eudesmol, camphene and caryophyllene oxide. The repellent activity against T. castaneum was tested for all the six samples of essential oils and eight isolated compounds. The testing samples exhibited a variety of repellent activity against T. castaneum . Among them, the essential oils of two species ( M. tetramera and M. kwangsiensis ) and three isolated compounds (alloaromadendrene, spathulenol and caryophyllene oxide) showed the fair repellent activity with relatively higher yields of contents. They might be considered as potential materials for the development of natural repellents for control of insects in stored products. Meanwhile, cluster analysis was performed using the collectives of data which were obtained in the process of the experiments. It was found that the characteristics of the repellent activity against T. castaneum could be related to the chemical composition of the essential oils. There were some interesting senses brought out as well. Such as, the repellent activity of the essential oils would not be depend on the contents of individual bioactive compound, and the existence of some compounds might affect the repellent activity of the essential oils.

Antifeedant activities of the methanol extracts from Zanthoxylum bungeanum , Zanthoxylum schinifolium , Zanthoxylum armatum and Zanthoxylum dissitum were assessed on Tribolium castaneum adults. It was found that the methanol extract of stem bark of Z. schinifolium had the highest antifeedant activity at 41.12% (antifeedant index). Based on bioactivity-guided fractionation, six benzophenanthridines norchelerythrine ( 1 ), decarine ( 2 ), 8-hydroxy-9-methoxy-2,3-(methylenedioxy) benzophenanthridine ( 3 ), 6-hydroxydihydrochelerythrine ( 4 ), 6-methoxy-7-hydroxydihydrochelerythrine ( 5 ) and oxychelerythrine ( 6 ) were isolated from the stem barks of Z. schinifolium . And their antifeeding activities were also evaluated against T. castaneum . All of them exhibited strong antifeeding activity in a concentration-dependant manner with EC 50 of 62.67, 66.97, 151.39, 96.72, 141.61 and 192.32 ppm, respectively. The six bioactive compounds from the stem bark of Z. schinifolium might be used as antifeedants against T. castaneum .

Five new sulphur-containing amides (2, 5–8) and three known analogue compounds (1, 3–4) were isolated from the leaves of Glycosmis lucida which were collected in Yunnan province, China. Their structures were elucidated with NMR spectroscopy and mass spectrometry. The compounds were identified as N-(p-hydroxyphenethyl)-3-(methylsulfonyl)-propenamide (1), N-[2-(4- hydroxyphenyl)-ethyl]-3-methanesulfonyl-N-methyl-propionamide (2), methylgerambullin (3), methylisogerambullone (4), methylgerambullindiol (5), N-{2-[4-(6,7-hydroxy-3,7-dimethyl-oct- 2-enyloxy)-phenyl]-ethyl}-3-methanesulfonyl-N-methyl-acrylamide (6), N-{2-[4-(6,7-dihydroxy- 3,7-dimethyl-oct-2-enyloxy)-phenyl]-ethyl}-3-methanesulfonyl-N-methyl-propionamide (7), (E)-N-{2-[4-(6-hydroxy-7-dimethyl-oct-2-enyloxy)-phenyl]-ethyl}-3-methanesulfinyl-N-methyl- acrylamide (8). Feeding deterrent activities of these surphur-containing derivatives against Tribolium castaneum were assayed for the first time. Compound 2, 3, 6 possessed significant feeding deterrent activities against T. castaneum adults (EC50 = 311.6, 244.9 and 108.3 ppm, respectively). These results demonstrated that some sulphur-containing amides are promising candidates as insect antifeedant agents.

Zanthoxylum species and volatile oils have shown to have insect resistance. The present work was conducted to find alternative botanical source with significant activity on storage pests control. Chemical examination of Zanthoxylum dimorphophyllum Hemsl. var. spinifolium Rehder et E. H. Wilson stem bark has led to fifteen coumarins, which including two were novel compounds named 6-(2′,3′-dihydroxy-3′-methylbutyl)-7-hydroxyl-8-(3″-methyl-2″-butenyl)-2H-1-benzopyran-2-one (7) and 6-(2′-hydroxyl-3′-methyl-3′-butenyl)-7-methoxyl-8-(3″-methyl-2″-butenyl)-2H-1-benzopyran-2-one (8). All the chemical structures were elucidated on the basis of nuclear magnetic resonance spectroscopy and high resolution electrospray ionization mass spectrometry analysis. Additionally, dose-dependent feeding deterrent activities of fifteen coumarins against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) were evaluated scientifically. Among them, compound 12 (phellopterin) exhibited stronger feeding deterrent activity (EC50 = 64.00 ppm) than the positive control, toosendanin. While, compound 11 (imperatorin) displayed the same level of feeding deterrent activity as the positive control with median effect concentration of 73.10 ppm. The relationship between chemical structure and effectiveness showed that compounds with epoxy structure or isopentenyl group exhibited higher feeding deterrent activities and might have potential to be developed into novel feeding deterrent reagents or potential lead compounds on storage insect prevention and control.

Spices are popular commodities with highly edible and medicinal values. At ancient times, people took advantage of spices to prevent insect infestation and mold erosion in stored-products. The Lauraceae family offers abundant raw materials as spices and plants from this family have widely biological activities. Here, the essential oils (EOs) of four spice plants from the Lauraceae, namely Cinnamomum burmannii, Cinnamomum migao, Litsea pungens and Laurus nobilis were analyzed for their chemical composition by GC–MS. The EOs and some of their individual components mainly monoterpenoids were evaluated for their bioactivities against stored-product insects. Three modes of action were selected: fumigant, contact toxicity and repellent activity. Target insects were adults of Tribolium castaneum and Liposcelis bostrychophila. Results of GC–MS analysis denoted that the chemical composition of EOs from these spice plants had certain similarity and diversity. All the EOs were rich in monoterpenoids, and the major components were limonene, sabinene, linalool, eucalyptol, borneol, α-terpineol, 4-terpinenol, α-terpinyl acetate, β-caryophyllene, spathulenol and 1,2,3,4-tetramethylbenzene. The results of bioassays indicated that all the EOs were toxic and repellent to T. castaneum and L. bostrychophila. Common monoterpenoids limonene, sabinene, linalool, eucalyptol, borneol, α-terpineol, 4-terpinenol and α-terpinyl acetate showed different levels of insecticidal or repellent activities against the two insect species. Among these monoterpenoids, borneol had no fumigant toxicity, but possessed contact toxicity and beneficial repellency at the concentration range of 63.17-2.53 nL/cm2 against L. bostrychophila. Sabinene and α-terpineol were significantly repellent to T. castaneum within the testing concentration range of 78.63-3.15 nL/cm2. Furthermore, β-caryophyllene (sesquiterpenoids) and 1,2,3,4-tetramethylbenzene (aromatics) were also assessed. β-caryophyllene exhibited contact toxicity and repellency against T. castaneum and L. bostrychophila. 1,2,3,4-tetramethylbenzene was toxic to these target insects in fumigant and contact assays. This work provides some evidence for explaining insecticidal and repellent activities of several spices from the Lauraceae based on individual active substances. It suggests that these spice EOs have promising potential to serve as bio-insecticides and green repellents for controlling pest damage in warehouses and grain stores.

The speciation of a methanolic extract of Zanthoxylum armatum stem bark has enabled the isolation and characterization of 11 known lignans. Among them, five compounds (6, 8–11) are reported in this plant for the first time. All of the chemical structures were elucidated on the basis of NMR spectral analysis. Additionally, their antifeedant activities against Tribolium castaneum were evaluated scientifically. Among them, asarinin (1), with an EC50 of 25.64 ppm, exhibited a much stronger antifeedant activity than the positive control, toosendanin (EC50 = 71.69 ppm). Moreover, fargesin (2), horsfieldin (3), and magnolone (10), with EC50 values of 63.24, 68.39, and 78.37 ppm, showed almost the same antifeedant activity as the positive control. From the perspective of structure-effectiveness relationship, compounds with the chemical group of methylenedioxy exhibited higher antifeedant activities and have potential to be developed into novel antifeedants or potential lead compounds to protect food and crops in storage.

To develop natural product resources to control cigarette beetles (Lasioderma serricorne), the essential oil from Artemisia lavandulaefolia (Compositae) was investigated. Oil was extracted by hydrodistillation of the above-ground portion of A. lavandulaefolia and analyzed using gas chromatography-mass spectrometer (GC-MS). Extracted essential oil and three compounds isolated from the oil were then evaluated in laboratory assays to determine the fumigant, contact, and repellent efficacy against the stored-products' pest, L. serricorne. The bioactive constituents from the oil extracts were identified as chamazulene (40.4%), 1,8-cineole (16.0%), and β-caryophyllene (11.5%). In the insecticidal activity assay, the adults of L. serricorne were susceptible to fumigant action of the essential oil and 1,8-cineole, with LC50 values of 31.81 and 5.18 mg/L air. The essential oil, 1,8-cineole, chamazulene, and β-caryophyllene exhibited contact toxicity with LD50 values of 13.51, 15.58, 15.18 and 35.52 μg/adult, respectively. During the repellency test, the essential oil and chamazulene had repellency approximating the positive control. The results indicated that chamazulene was abundant in A. lavandulaefolia essential oil and was toxic to cigarette beetles.

A nuclear magnetic resonance- (NMR-) based metabolomics method was used to identify differential metabolites of methanol extracts obtained from six parts of Peganum harmala L. (P. harmala), namely, the root, stem, leaf, flower, testa, and seed. Two multivariate statistical analysis methods, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA), were combined to clearly distinguish among the P. harmala samples from the six different parts. Eleven differential components were screened by the PLS-DA loading plot, and the relative contents were calculated by univariate analysis of variance. Chemometric results showed significant differences in the metabolites of the different parts of P. harmala. The seeds contained large amounts of harmaline, harmine, and vasicine compared to other organs. The acetic acid, proline, lysine, and sucrose contents of the roots were significantly higher than those of the other parts. In the testa, the vasicine, asparagine, choline, and 4-hydroxyisoleucine contents were clearly dominant. The obtained data revealed the distribution characteristics of the metabolomes of the different P. harmala parts and provided fundamental knowledge for the rational development of its medicinal parts.