Essential Oils from Different Parts of Magnolia laevifolia: Chemical Constituents and Insecticidal Activities against Liposcelis bostrychophila.

Many synthetic pesticides were used to control a severe storage pest, booklouse (Liposcelis bostrychophila). However, considering the environmental impact, plant secondary metabolites were acceptable alternatives. An endemic plant, Magnolia laevifolia, has a significant and unique odour, so its essential oil (EO) could be an option for bio-pesticide development. This study extracted EOs from leaves, flowers, carpels and seeds of M. laevifolia. The common and major compound of EOs was isocapnell-9-en-8-one, which was present at 17.7 to 91.6 % in these four parts. We found no regular pattern in the composition of EO in terms of parts and collection time according to principal component analysis. The contact and repellent activities of EOs against the booklouse were then conducted. Leaves and flowers' EOs collected in the flowering stage had the best contact toxicity. The percent repellency values of the EOs from different parts of M. laevifolia reached above 80 % after 2 and 4 h exposure at 63.17 nL/cm2 , with the same levels as DEET (p<0.05). It was shown that parts of plants and collecting time could influence the insecticidal activities of M. laevifolia EOs against booklouse, but collecting time played a significant decisive role in the contact test.

Metabolic Dysfunction-Associated Fatty Liver Disease Increases the Risk of Gastroesophageal Reflux Symptoms.

OBJECTIVE: The present study aimed to explore the relationship between metabolic dysfunction-associated fatty liver disease (MAFLD) and gastroesophageal reflux symptoms (GERS). METHODS: The present study was a cross-sectional observational study. The study population was 3002 subjects from a single hospital who underwent a health checkup from September 1, 2019, to December 31, 2020. The diagnosis of MAFLD was based on the diagnosis of fatty liver in the subject by ultrasound or computed tomography (CT) and the presence of one of the following conditions: overweight or obesity (body mass index [BMI] ≥ 23), type 2 diabetes mellitus, and metabolic abnormalities. The subjects were divided into the GERS group (n = 305) and the non-GERS group (n = 2697) based on the presence or absence of GERS, based on the GerdQ score. RESULTS: The prevalence of MAFLD was significantly higher in the GERS group than in the non-GERS group (p = 0.001). In the univariate analysis of risk factors for GERS, MAFLD was identified as a risk factor for GERS (OR 1.5; 95% CI 1.176-1.913; p = 0.001). With adjustment of confounding factors such as BMI, waist circumference, lipid levels, and blood pressure, the correlation between MAFLD and GERS was attenuated but still significant (OR 1.408; 95% CI 1.085-1.826; p = 0.010). CONCLUSION: MAFLD might be an independent risk factor for GERS.

A taxonomic revision of the genus Conidiobolus (Ancylistaceae, Entomophthorales): four clades including three new genera.

The genus Conidiobolus is an important group in entomophthoroid fungi and is considered to be polyphyletic in recent molecular phylogenies. To re-evaluate and delimit this genus, multi-locus phylogenetic analyses were performed using the large and small subunits of nuclear ribosomal DNA (nucLSU and nucSSU), the small subunit of the mitochondrial ribosomal DNA (mtSSU) and the translation elongation factor 1-alpha (EF-1α). The results indicated that the Conidiobolus is not monophyletic, being grouped into a paraphyletic grade with four clades. Consequently, the well-known Conidiobolus is revised and three new genera Capillidium, Microconidiobolus and Neoconidiobolus are proposed along with one new record and 22 new combinations. In addition, the genus Basidiobolus is found to be basal to the other entomophthoroid taxa and the genus Batkoa locates in the Entomophthoraceae clade.

Generation and application of patient-derived xenograft models in pancreatic cancer research.

OBJECTIVE: Pancreatic ductal adenocarcinoma cancer (PDAC) is one of the leading causes of cancer-related death worldwide. Hence, the development of effective anti-PDAC therapies is urgently required. Patient-derived xenograft (PDX) models are useful models for developing anti-cancer therapies and screening drugs for precision medicine. This review aimed to provide an updated summary of using PDX models in PDAC. DATA SOURCES: The author retrieved information from the PubMed database up to June 2019 using various combinations of search terms, including PDAC, pancreatic carcinoma, pancreatic cancer, patient-derived xenografts or PDX, and patient-derived tumor xenografts or PDTX. STUDY SELECTION: Original articles and review articles relevant to the review's theme were selected. RESULTS: PDX models are better than cell line-derived xenograft and other models. PDX models consistently demonstrate retained tumor morphology and genetic stability, are beneficial in cancer research, could enhance drug discovery and oncologic mechanism development of PDAC, allow an improved understanding of human cancer cell biology, and help guide personalized treatment. CONCLUSIONS: In this review, we outline the status and application of PDX models in both basic and pre-clinical pancreatic cancer researches. PDX model is one of the most appropriate pre-clinical tools that can improve the prognosis of patients with pancreatic cancer in the future.

Ecdysone oxidase and 3-dehydroecdysone-3ß-reductase contribute to the synthesis of ecdysone during early embryonic development of the silkworm.

Maternal ecdysteroids regulate a variety of cellular processes during early embryonic development of insects, yet little is known about the genes involved in the biosynthesis of these hormones. In this study, we found that ecdysone oxidase (EO) gene, which encodes an enzyme to catalyze ecdysone (or 20-hydroxyecdysone, 20E) to 3-dehydroecdysone (3DE), was highly expressed in the mature ovaries of the domestic silkworm, Bombyx mori. B. mori EO (BmEO) was localized in the cytoplasm around the yolk granules of oocyte. Furthermore, the down-regulated expression of the BmEO gene using RNA interference could not affect normal development of the female silkworm, but lower the 20E titer and hatching rate of its offspring. Rescue experiments by injecting the product (3DE) of BmEO can significantly elevate the 20E level and hatching rate of the BmEO RNAi offspring. Meanwhile, during embryonic stage, the down-regulating expression of 3DE-3ß-reductase, which can reduce 3DE into ecdysone, also lowered the 20E titer. Taken together, our results prove that 3DE can be synthesized from ecdysone in maternal ovary yolk granules, and then the maternal 3DE is converted into active ecdysone during the early embryonic development of offspring. Thus, our findings reveal a new pathway to explain the origin of high 20E level before the formation the prothoracic gland in the silkworm.

Contact and Repellant Activities of Zerumbone and Its Analogues from the Essential Oil of Zingiber zerumbet (L.) Smith against Lasioderma serricorne.

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), ß-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.

Transcription factor E74A affects the ecdysone titer by regulating the expression of the EO gene in the silkworm, Bomby mori.

The formation of ecdysone pulse in insects is synergistically controlled by its biosynthesis and degradation. Previous studies have revealed the feedback regulation of the prothoracic gland (PG) activity to affect the hormone synthesis. However, the molecular regulatory mechanism of the ecdysone degradation is still unclear. In this study, we showed that ecdysone oxidase (EO) gene encoding a hormone metabolism enzyme was also induced by hormone itself in the domestic silkworm, Bombyx mori. Furthermore, luciferase reporter, chromatin immunoprecipitation and electrophoretic mobility shift assays showed that ecdysone inducible transcription factor E74A could bind to the cis-regulatory elements of the EO gene. Then, down-regulating the expression of the E74A by RNA interference (RNAi) decreased the expression of the EO gene and caused a higher ecdysone titer compared with the control. Thus, our results demonstrated a new feedback regulation degradation (EO) pathway controlled by ecdysone itself through transcription factor E74A, expanding the knowledge about the regulatory system that determines the formation of ecdysone pulse.

Repellence of the main components from the essential oil of Glycosmis lucida Wall. ex Huang against two stored product insects.

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 ß-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.

Chemical Composition of Essential Oils from Zanthoxylum bungeanum Maxim. and Their Bioactivities against Lasioderma serricorne.

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.

Chemical Constituents and Insecticidal Activities of Ajania fruticulosa Essential Oil.

The insecticidal activity and chemical constituents of the essential oil from Ajania fruticulosa were investigated. Twelve constituents representing 91.0% of the essential oil were identified, and the main constituents were 1,8-cineole (41.40%), (+)-camphor (32.10%), and myrtenol (8.15%). The essential oil exhibited contact toxicity against Tribolium castaneum and Liposcelis bostrychophila adults with LD50 values of 105.67 µg/adult and 89.85 µg/cm(2) , respectively. The essential oil also showed fumigant toxicity against two species of insect with LC50 values of 11.52 and 0.65 mg/l, respectively. 1,8-Cineole exhibited excellent fumigant toxicity (LC50  = 5.47 mg/l) against T. castaneum. (+)-Camphor showed obvious fumigant toxicity (LC50  = 0.43 mg/l) against L. bostrychophila. Myrtenol showed contact toxicity (LD50  = 29.40 µg/cm(2) ) and fumigant toxicity (LC50  = 0.50 mg/l) against L. bostrychophila. 1,8-Cineole and (+)-camphor showed strong insecticidal activity to some important insects, and they are main constituents of A. fruticulosa essential oil. The two compounds may be related to insecticidal activity of A. fruticulosa essential oil against T. castaneum and L. bostrychophila.

Chemical Constituents and Activity of Murraya microphylla Essential Oil against Lasioderma serricorne.

The chemical composition, contact and repellent activities of the essential oil from Murraya microphylla branches and leaves against Lasioderma serricorne adults were determined and six compounds from the essential oil were isolated as well. The essential oil of M microphylla obtained by hydrodistillation was analyzed by gas chromatography-mass spectrometric (GC-MS) analysis; 22 compounds were identified. The main constituents of the essential oil included ß-caryophyllene (18.0%), α-pinene (13.8%), spathulenol (9.5%), α-humulene (6.0%), γ-elemene (5.1%) and zingiberene (4.6%), followed by α-cadinol (3.9%) and caryophyllene oxide (3.8%). Six of these compounds were isolated and fully identified as α-pinene, ß-caryophyllene, α-humulene, caryophyllene oxide, spathulenol and α-cadinol. L. serricorne adults had different sensitivities to the crude essential oil and isolated compounds. α-Humulene exhibited the strongest contact activity against L. serricorne, showing an LD50 value of 13.1 µg adult(-1). However, spathulenol, the crude essential oil and α-cadinol showed stronger contact activity against L. serricorne than caryophyllene oxide and ß-caryophyllene. The essential oil, α-humulene and spathulenol showed comparable repellency against L. serricorne adults at 2 h after exposure, relative to the positive control, DEET. The results demonstrate that the essential oil and isolated compounds exhibited important contact and repellent activities against L. serricorne. Thus, they could become potential natural insecticides or repellents for control of insects in stored products.

Repellant and insecticidal activities of shyobunone and isoshyobunone derived from the essential oil of Acorus calamus rhizomes.

CONTEXT: It was found that the essential oil of Acorus calamus rhizomes showed insecticidal activity. AIM: The aim of this study was to determine the chemical composition of the essential oil from A. calamus rhizomes, evaluate insecticidal and repellant activity against Lasioderma serricorne (LS) and Tribolium castaneum (TC), and to isolate any insecticidal constituents from the essential oil. MATERIALS AND METHODS: Essential oil from A. calamus was obtained by hydrodistillation and analyzed by gas chromatography (GC) flame ionization detector and GC-mass spectrometry. The insecticidal and repellant activity of the essential oil and isolated compounds was tested using a variety of methods. RESULTS: The main components of the essential oil were identified to be isoshyobunone (15.56%), ß-asarone (10.03%), bicyclo[6.1.0]non-1-ene (9.67%), shyobunone (9.60%) and methylisoeugenol (6.69%). Among them, the two active constituents were isolated and identified as shyobunone and isoshyobunone. The essential oil showed contact toxicity against LS and TC with LD50 values of 14.40 and 32.55 µg/adult, respectively. The isolated compounds, shyobunone and isoshyobunone also exhibited strong contact toxicity against LS adults with LD50 values of 20.24 and 24.19 µg/adult, respectively, while the LD50 value of isoshyobunone was 61.90 µg/adult for TC adults. The essential oil, shyobunone and isoshyobunone were strongly repellent (98%, 90% and 94%, respectively, at 78.63 nL/cm(2), after 2 h treatment) against TC. CONCLUSION: The essential oil, shyobunone and isoshyobunone possessed insecticidal and repellant activity against LS and TC.

Essential Oil of Amomum maximum Roxb. and Its Bioactivities against Two Stored-Product Insects.

Amomum maximum Roxb. is a perennial herb distributed in South China and Southeast Asia. The objective of this work was to analyze the chemical constituents and assess insecticidal and repellent activities of the essential oil from Amomum maximum fruits against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel). The essential oil was obtained by hydrodistillation and analyzed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. The main components of the essential oil were identified to be ß-pinene (23.39%), ß-caryophyllene (16.43%), α-pinene (7.55%), sylvestrene (6.61%) and ç-cadinene (4.19%). It was found that the essential oil of A. maximum fruits possessed contact and fumigant toxicities against T. castaneum adults (LD50 = 29.57 µg/adult and LC(50) = 23.09 mg/L air, respectively) and showed contact toxicity against L. bostrychophila (LD(50) = 67.46 µg/cm(2)). Repellency of the crude oil was also evaluated. After 2 h treatment, the essential oil possessed 100% repellency at 78.63 nL/cm(2) against T. castaneum and 84% repellency at 63.17 nL/cm(2) against L. bostrychophila. The results indicated that the essential oil of A. maximum fruits had the potential to be developed as a natural insecticide and repellent for control of T. castaneum and L. bostrychophila.

Repellent activity of Glycosmis plant extracts against two stored product insects / Actividad repelente de extractos de plantas Glycosmis contra dos insectos de productos almacenados

In the present study, the repellent activities of the leaf and/or stem crude extracts of Glycosmis lucida Wall. ex Huang, G. craibii var. glabra, G. craibii Tanaka, G. oligantha Huang, G. pentaphylla (Retz) Correa. and G. esquirolii (Levl.) Tanaka were analyzed by using assays on petri dishes against Tribolium castaneum and Liposcelis bostrychophila. The leaf and stem extracts of G. lucida, G. craibii var. glabra, G. craibii Tanaka, G. oligantha and G. esquirolii possessed significant repellent activities against T. castaneum, the same level repellent with the positive control, DEET. However, the extracts of G. pentaphylla, no repellency but some insect attractant was observed. Moreover, they also showed repellent activities against L. bostrychophila. These results indicate that extracts from G. lucida and G. oligantha leaf could be a source of novel repellent against insects.

En el presente estudio, las actividades repelentes de la hoja y/o tronco de los extractos crudos de Glycosmis lucida Wall. ex Huang, G. craibii var. glabra, G. craibii Tanaka, G. oligantha Huang, G. pentaphylla (Retz) Correa y G. esquirolii (Levl.) Tanaka se analizaron mediante el uso de ensayos en placas de Petri contra Tribolium castaneum y Liposcelis bostrychophila. Los extractos de las hojas y tallo de G. lucida, G. craibii var. glabra, G. craibii Tanaka, G. oligantha y G. esquirolii poseían actividades repelentes significativas contra T. castaneum, el mismo nivel repelente del control positivo, el DEET. Sin embargo, los extractos de G. pentaphylla, no se observó la repelencia pero sí actividad atrayente de insectos. Por otra parte, también se mostraron las actividades repelentes contra L. bostrychophila. Estos resultados indican que los extractos de hojas de G. lucida y G. oligantha podrían ser una fuente de repelente contra los insectos.

Chemical Composition and Bioactivities of the Essential Oil from Etlingera yunnanensis against Two Stored Product Insects.

The chemical composition of the essential oil of Etlingera yunnanensis rhizomes and its contact and repellent activities against Tribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel) were investigated. The essential oil obtained from E. yunnanensis rhizomes with hydrodistillation was performed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. The main components of the essential oil were identified to be estragole (65.2%), ß-caryophyllene (6.4%), 1,8-cineole (6.4%), limonene (5.2%), and α-pinene (2.4%). It was found that the essential oil of E. yunnanensis rhizomes possessed contact toxicity against T. castaneum and L. bostrychophila (LD50 = 23.33 µg/adult and LD50 = 47.38 µg/cm², respectively). Estragole, 1,8-cineole, and limonene exhibited stronger contact toxicity (LD50 values of 20.41, 18.86, and 13.40 µg/adult, respectively) than ß-caryophyllene (LD50 = 41.72 µg/adult) against T. castaneum adults. Estragole possessed stronger contact toxicity (LD50 = 30.22 µg/cm²) than ß-caryophyllene, 1,8-cineole, and limonene (LD50 values of 74.11, 321.20, and 239.62 µg/adult, respectively) against L. bostrychophila adults. Repellency of the crude oil was also evaluated. The essential oil and constituents possessed strong repellent activity against T. castaneum adults. The four individual constituents showed weaker repellent activity than the essential oil against L. bostrychophila adults. The results indicated that the essential oil of E. yunnanensis rhizomes and the individual constituents had the potential to be developed as a natural insecticide and repellent for the control of T. castaneum and L. bostrychophila.

Chemical Composition and Bioactivity of Essential Oil of Atalantia guillauminii against Three Species Stored Product Insects.

The toxic and repellent activities of the essential oil extracted from the leaves of Atalantia guillauminii Swingle were evaluated against three stored product insects, red flour beetles (Tribolium castaneum), cigarette beetles (Lasioderma serricorne) and booklice (Liposcelis bostrychophila). The essential oil obtained by hydrodistillation was investigated by GC-MS. The main constituents of the essential oil were ß-thujene (27.18%), elemicin (15.03%), eudesma-3, 7(11)-diene (9.64%), followed by (-)-4-terpeniol (6.70%) and spathulenol (5.25%). The crude oil showed remarkable contact toxicity against T. castaneum, L. serricorne adults and L. bostrychophila with LD50 values of 17.11, 24.07 µg/adult and 55.83 µg/cm(2) respectively and it also displayed strong fumigant toxicity against T. castaneum, L. serricorne adults with LC50 values of 17.60 and 12.06 mg/L respectively, while weak fumigant toxicity against L. bostrychophila with a LC50 value of 16.75 mg/L. Moreover, the essential oil also exhibited the same level repellency against the three stored product insects, relative to the positive control, DEET. At the same concentrations, the essential oil was more repellent to T. castaneum than to L. serricorne. Thus, the essential oil of A. guillauminii may be potential to be developed as a new natural fumigant/repellent in the control of stored product insects.

Insecticidal Constituents of Essential Oil Derived from Zanthoxylum armatum against Two Stored-Product Insects.

In the course of our search for natural bioactive chemicals and investigations on their insecticidal activities from some medicinal plants growing in China, the essential oil derived from the twigs of Zanthoxylum armatum (Rutaceae) was found to possess strong insecticidal activities against two stored-product insects, Lasioderma serricorne and Tribolium castaneum. A total of 32 constituents of the essential oil were identified by GC and GC-MS analysis, and it revealed (E)-anethole (20.5%), 1,8-cineole (14.0%), 2-tridecanone (12.5%), limonene (9.0%) and piperitone (8.0%) as major components, followed by ß-phellandrene (6.3%), ß-pinene (5.1%) and 4-terpineol (4.4%). From the essential oil, five compounds were isolated and identified as (E)-anethole, 1,8-cineole, 2-tridecanone, limonene and piperitone. The results of insecticidal bioassays showed that the essential oil of Z. armatum exhibited strong fumigant toxicity towards L. serricorne and T. castaneum with LC50 values of 13.83 and 4.28 mg/L air, respectively, and also possessed contact toxicity against two insect species with LD50 values of 18.74 and 32.16 µg/adult, respectively. Among the active compounds, piperitone performed the strongest fumigant toxicity against L. serricorne (LC50 = 1.21 mg/L air) and contact toxicity against T. castaneum (LD50 = 3.16 µg/adult). 1,8-Cineole, limonene and piperitone showed similar fumigant toxicity against T. castaneum with LC50 values of 5.47, 6.21 and 7.12 mg/L air, respectively. Meanwhile, L. serricorne was the most sensitive to 2-tridecanone (LD50 = 5.74 µg/adult) in the progress of contact toxicity assay.

Contact Toxicity and Repellency of the Essential Oil of Dictamnus dasycarpus Roots from China against Two Stored-Product Insects.

During our screening program for new agrochemicals from traditional medicinal herbs, Dictamnus dasycarpus was found to possess contact toxicity and repellent activity against the cigarette beetle Lasioderma serricorne and the booklouse Liposcelis bostrychophila. The essential oil obtained by hydrodistillation of D. dasycarpus roots was characterized by GC-FID and GC/MS analyses, and the main components identified were syn-7-hydroxy-7-anisylnorbornene (1, 49.9%), 1,3,4,5,6,7-hexahydro-2H-inden-2-one (2, 11.6%), 5,6-diethenyl-1-methylcyclohexene (3, 7.4%), and 3,9-dimethyltricyclo[4.2.1.1(2,5)]dec-3-en-9-ol (4, 6.35%). The D. dasycarpus root oil exhibited strong contact toxicity against L. serricorne adults and L. bostrychophila, with LD50 values of 12.4 µg/adult and 27.2 µg/cm(2), respectively. Moreover, the essential oil also showed strong repellency against both stored-product insects tested.

Contact toxicity and repellency of the essential oil from Mentha haplocalyx Briq. against Lasioderma serricorne.

The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Mentha haplocalyx was investigated by GC-FID and GC/MS analyses. In sum, 23 components, representing 92.88% of the total oil composition, were identified, and the main compounds were found to be menthol (59.71%), menthyl acetate (7.83%), limonene (6.98%), and menthone (4.44%). By bioassay-guided fractionation (contact toxicity), three compounds were obtained from the essential oil and identified as menthol, menthyl acetate, and limonene. The essential oil and the three isolated compounds exhibited potent contact toxicity against Lasioderma serricorne adults, with LD50 values of 16.5, 7.91, 5.96, and 13.7 µg/adult, respectively. Moreover, the oil and its isolated compounds also exhibited strong repellency against L. serricorne adults. At the lower concentrations tested and at 2 h after exposure, menthol showed even significantly stronger repellency than the positive control DEET. The study revealed that the bioactivity properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components, which indicates that the M. haplocalyx oil and its isolated compounds have potential for the development as natural insecticides and/or repellents to control insects in stored grains and traditional Chinese medicinal materials.

Chemical Composition and Insecticidal Activity of Essential Oils from Zanthoxylum dissitum Leaves and Roots against Three Species of Storage Pests.

This work aimed to investigate chemical composition of essential oils obtained from Zanthoxylum dissitum leaves and roots and their insecticidal activities against several stored product pests, namely the cigarette beetle (Lasioderma serricorne), red flour beetle (Tribolium castaneum) and black carpet beetle (Attagenus piceus). The analysis by GC-MS of the essential oils allowed the identification of 28 and 22 components, respectively. It was found that sesquiterpenoids comprised a fairly high portion of the two essential oils, with percentages of 74.0% and 80.9% in the leaves and roots, respectively. The main constituents identified in the essential oil of Z. dissitum leaves were δ-cadinol (12.8%), caryophyllene (12.7%), ß-cubebene (7.9%), 4-terpineol (7.5%) and germacrene D-4-ol (5.7%), while humulene epoxide II (29.4%), caryophyllene oxide (24.0%), diepicedrene-1-oxide (10.7%) and Z,Z,Z-1,5,9,9-tetramethyl-1,4,7-cycloundecatriene (8.7%) were the major components in the essential oil of Z. dissitum roots. The insecticidal activity results indicated that the essential oil of Z. dissitum roots exhibited moderate contact toxicity against three species of storage pests, L. serricorne,T. castaneum and A. piceus, with LD50 values of 13.8, 43.7 and 96.8 µg/adult, respectively.