Cytotoxic Flavonoids from the Leaves and Twigs of Murraya Tetramera.

Cytotoxic flavonoids of Murraya tetramera were investigated in this study. A novel flavonoid and twelve known flavonoids, including seven flavones (1-7), three flavanones (8-10), and three chalcones (11-13) were isolated from the leaves and twigs of Murraya tetramera. Chemical structures were elucidated by NMR combined with MS spectral analysis, and the new compound (6) was confirmed as 3',5'-dihydroxy-5,6,7,4'-tetramethoxyflavone. Furthermore, all the isolated flavonoids were evaluated for their cytotoxicities against murine melanoma cells (B16), and human breast cancer cells (MDA-MB-231) by CCK-8 assay. Among them, compounds 7, 13, and 5 exhibited potent cytotoxic activities against B16 cell lines (IC50 = 3.87, 7.00 and 8.66 µg/mL, respectively). Compounds 5, 13, and 12 displayed potent cytotoxicities against MDA-MB-231 cell lines (IC50 = 3.80, 5.95 and 7.89 µg/mL, respectively). According to the correlation of the structure and activity analysis, 5-hydroxyl and 8-methoxyl substituents of the flavone, 8-methoxyl substituent of the flavanone, and 3',5'-methoxyl substituents of the chalcone could be critical factors of the high cytotoxicity. The results indicated that the active flavonoids have potential to be developed as leading compounds for treating cancers.

Brd4 participates in epigenetic regulation of the extinction of remote auditory fear memory.

BACKGROUND: Inaccurate fear memories can be maladaptive and potentially portrait a core symptomatic dimension of fear adaptive disorders such as post-traumatic stress disorder (PTSD), which is generally characterized by an intense and enduring memory for the traumatic events. Evidence exists in support of epigenetic regulation of fear behavior. Brd4, a member of the bromodomain and extra-terminal domain (BET) protein family, serves as a chromatin "reader" by binding to histones in acetylated lysine residues, and hence promotes transcriptional activities. However, less is known whether Brd4 participates in modulating cognitive activities especially memory formation and extinction. Here we provide evidence for a role of Brd4 in modulation of auditory fear memory. Auditory fear conditioning resulted in a biphasic Brd4 activation in the anterior cingulate cortex (ACC) and hippocampus of adult mice. Thus, Brd4 phosphorylation occurred 6 h and 3-14 days, respectively, after auditory fear conditioning. Systemic inhibition of Brd4 with a BET inhibitor, JQ1, impaired the extinction of remote (i.e., 14 days after conditioning) fear memory. Further, conditional Brd4 knockout in excitatory neurons of the forebrain impaired remote fear extinction as observed in the JQ1-treated mice. Herein, we identified that Brd4 is essential for extinction of remote fear in rodents. These results thus indicate that Brd4 potentially plays a role in the pathogenesis of PTSD.

Systems pharmacology dissection of action mechanisms for herbs in osteoporosis treatment.

Objective: Osteoporosis has become the biggest cause of non-fatal health issue. Currently, the limitations of traditional anti-osteoporosis drugs such as long-term ill-effects and drug resistance, have raised concerns toward complementary and alternative therapies, particularly herbal medicines and their natural active compounds. Thus, this study aimed to provide an integrative analysis of active chemicals, drug targets and interacting pathways of the herbs for osteoporosis treatment. Methods: Here, we introduced a systematic pharmacology model, combining the absorption, distribution, metabolism, and excretion (ADME) screening model, drug targeting and network pharmacology, to probe into the therapeutic mechanisms of herbs in osteoporosis. Results: We obtained 86 natural compounds with favorable pharmacokinetic profiles and their 58 targets from seven osteoporosis-related herbs. Network analysis revealed that they probably synergistically work through multiple mechanisms, such as suppressing inflammatory response, maintaining bone metabolism or improving organism immunity, to benefit patients with osteoporosis. Furthermore, experimental results showed that all the five compounds (calycosin, asperosaponin VI, hederagenin, betulinic acid and luteolin) enhanced osteoblast proliferation and differentiation in vitro, which corroborated the validity of this system pharmacology approach. Notably, gentisin and aureusidin among the identified compounds were first predicted to be associated with osteoporosis. Conclusion: Herbs and their natural compounds, being characterized as the classical combination therapies, might be engaged in multiple mechanisms to coordinately improve the osteoporosis symptoms. This work may contribute to offer novel strategies and clues for the therapy and drug discovery of osteoporosis and other complex diseases.

Essential oil from Artemisia annua aerial parts: composition and repellent activity against two storage pests.

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.

Antrodan Alleviates High-Fat and High-Fructose Diet-Induced Fatty Liver Disease in C57BL/6 Mice Model via AMPK/Sirt1/SREBP-1c/PPARγ Pathway.

Non-alcoholic fatty liver disease (NAFLD) and -steatohepatitis (NASH) imply a state of excessive fat built-up in livers with/or without inflammation and have led to serious medical concerns in recent years. Antrodan (Ant), a purified ß-glucan from A. cinnamomea has been shown to exhibit tremendous bioactivity, including hepatoprotective, antihyperlipidemic, antiliver cancer, and anti-inflammatory effects. Considering the already well-known alleviating bioactivity of A. cinnamomea for the alcoholic steatohepatitis (ASH), we propose that Ant can be beneficial to NAFLD, and that the AMPK/Sirt1/PPARγ/SREBP-1c pathways may be involved in such alleviations. To uncover this, we carried out this study with 60 male C57BL/6 mice fed high-fat high-fructose diet (HFD) for 60 days, in order to induce NAFLD/NASH. Mice were then grouped and treated (by oral administration) as: G1: control; G2: HFD (HFD control); G3: Ant, 40 mgkg (Ant control); G4: HFD+Orlistat (10 mg/kg) (as Orlistat control); G5: HFD+Ant L (20 mg/kg); and G6: HFD+Ant H (40 mg/kg) for 45 days. The results indicated Ant at 40 mg/kg effectively suppressed the plasma levels of malondialdehyde, total cholesterol, triglycerides, GOT, GPT, uric acid, glucose, and insulin; upregulated leptin, adiponectin, pAMPK, Sirt1, and down-regulated PPARγ and SREBP-1c. Conclusively, Ant effectively alleviates NAFLD via AMPK/Sirt1/CREBP-1c/PPARγ pathway.

[Identification of Fel Serpentis and its adulterants with specific PCR method].

The study aims at developing a convenient and specific method for the identification of Fel Serpentis DNA. The methods of Fel Serpentis genomic DNA purification were tested and optimized, four pairs of specific primers for the amplification of COⅠ, Cyt b and 16S were designed. Then the best pair of primers were selected according to the specificity and efficiency. The DNA fragment about 400 bp was amplified from 20 kinds of Fel Serpentis, whereas no DNA fragment was amplified from other animal samples under the same condition. This method is specific,accurate and reproducible, which provides a useful tool for the quality control of Fel Serpentis.

Ultrasound-Guided Oblique Sub-Costal Transversus Abdominis Plane Block as the Principal Anesthesia Technique in Peritoneal Dialysis Catheter Implantation and Plasma Ropivacaine Concentration Evaluation in ESRD Patients: A Prospective, Randomized, Double-Blinded, Controlled Trial.

BACKGROUND: The ultrasound-guided transversus abdominis plane (TAP) block is generally used for analgesia but not for anesthesia. A TAP block has a partial analgesic effect on the parietal peritoneum in abdominal surgeries. We hypothesized that an ultrasound-guided oblique subcostal TAP block, used as the principal anesthesia technique, could provide a better anesthetic effect on peritoneum stimulation in peritoneal dialysis catheter (PDC) implantation in end-stage renal diseases (ESRD) patients than local anesthetic infiltration (LAI). METHODS: End-stage renal disease patients undergoing PDC implantation were randomized into 3 groups: LAI Group, unilateral TAP group (Uni-TAP Group) and bilateral TAP group (Bi-TAP Group). A 40-mL dose of 0.25% ropivacaine was used for the regional block (LAI or TAP). The quality of anesthesia, visual analogue scale (VAS) of pain, cumulative rescuing sufentanil consumption, and venous plasma ropivacaine concentrations were compared among the 3 groups. RESULTS: Sixty-nine patients were enrolled, and higher 'Satisfied' anesthesia rates from nephrologists and patients were recorded in the 2 TAP groups, compared with the LAI Group. Significantly lower VAS scores were observed in the Uni-TAP Group at a majority of time points compared with the LAI Group. Less cumulative rescuing sufentanil was used in the 2 TAP groups (2.5 ± 2.7 and 3.0 ± 2.8 µg, respectively) compared with the LAI Group (5.8 ± 2.6 µg, p < 0.05). The median peak venous plasma ropivacaine concentrations were below the reported toxic threshold in all 3 groups. CONCLUSIONS: As the principal anesthesia technique, an ultrasound-guided unilateral oblique subcostal TAP block with 40 mL of 0.25% ropivacaine provided better anesthetic effect in PDC implantations in ESRD patients than LAI.

[Psoralen inhibits RAW264.7 differentiation into osteoclasts and bone resorption by regulating CD4+T cell differentiation].

This paper aimed to investigate whether psoralen inhibits the differentiation and bone resorption by regulating CD4+T cell differentiation in RANKL-induced osteoclastogenesis in RAW264.7 cells, and elucidate its mechanism for osteoporosis. CD4+T cells were isolated from spleen cells of Balb/c mice by immunomagnetic separation method. The cells were divided into blank control group and psoralen group. The cells were cultured in 24-well plates and cultured for 3 days, and then they were collected for co-culture experiments after 4 days. Co-culture experiments were divided into RAW264.7 cell group, psoralen+RAW264.7 cell group, without psoralen treatment of CD4+T cells+RAW264.7 cell group, psoralen treatment of CD4+T cells+RAW264.7 cell group. After 5 days of co-culture, TRAP staining was used to detect the number of osteoclasts, and after 8 days of co-culture, bone resorption was evaluated by toluidine blue staining. The expressions of RORγt, Foxp3, IL-17, TNF-α, TGF-ß and IL-10 in CD4+T cells and osteoclast differentiation-related genes MMP-9, TRAP and Cat-K were detected by Real-time polymerase chain reaction (RT-PCR); ELISA kit was used to detect IL-17, TNF-α, TGF-ß and IL-10 and other cytokines levels. Our data confirmed that the psoralen significantly promoted the expression of Foxp3, TGF-ß and IL-10 in CD4+T, and inhibited the expression of RORγt, IL-17 and TNF-α in CD4+T, the CD4+T cells without treatment by psoralen can significantly promote RANKL-induced differentiation of RAW264.7 to osteoclasts, and psoralen treatment of CD4+T can significantly inhibit RANKL-induced RAW264.7 osteoclast differentiation and bone resorption. Taken together, psoralen inhibits the differentiation and bone resorption of RAW264.7 into osteoclasts by promoting the development of CD4+ CD25+ Treg/Th17 balance in CD4+T cells to CD4+CD25+T.

Fumigant and repellent activities of essential oil extracted from Artemisia dubia and its main compounds against two stored product pests.

The major chemical constituents of the essential oil extracted from Artemisia dubia wall. ex Bess. (Family: Asteraceae) were found as terpinolene (19.02%), limonene (17.40%), 2,5-etheno[4.2.2]propella-3,7,9-triene (11.29%), isoelemicin (11.05%) and p-cymene-8-ol (5.93%). Terpinolene and limonene were separated as main components from the essential oil. The essential oil showed fumigant toxicity against Tribolium castaneum and Liposcelis bostrychophila with LC50 values of 49.54 and 0.74 mg/L, respectively. The essential oil and isolated compounds of A. dubia showed repellency activities against both insects. Terpinolene and limonene showed the fumigant toxicity against T. castaneum. Terpinolene showed obvious fumigant toxicity against L. bostrychophila. The results indicated that the essential oil of A. dubia had potential to be developed into natural insecticides for controlling stored product pests.

The active component screening of Anoectochilus roxburghii and the functional study on inhibition of melanogenesis in zebrafish.

The aim of this study is to explore the active components of Anoectochilus roxburghii capable of inhibiting melanin formation using chemical separation and extraction and functional analysis. Anoectochilus roxburghii were extracted with alcohol and separated into three groups: the total extraction group, alcohol extracted group and alcohol precipitated group. Zebrafish embryos at 0.75 h post-fertilization were exposed to various concentrations of the three groups of extracts, and analyzed at 72 h, using semi-quantitative RT-PCR and in situ hybridization. The results showed that the alcohol extracts inhibit melanogenesis most significantly in the zebrafish embryos. The mRNAs of melanin-related genes, such as silv, tyr, tyrp1a, were down-regulated by the alcohol extracts spatially and temporally. The alcohol extracts also inhibited the activity of tyrosinase, a key enzyme in melanogenesis, in a dosage dependent manner. In addition, the alcohol extracts also display a remarkable inhibitory effect on melanin synthesis through down-regulation of mRNAs of melanin-related genes and tyrosinase activity in zebrafish embryos, in which a large amount of melanin has already been synthesized. Such inhibitory effect could be reversed after the withdrawal of the alcohol extracts. Our results showed that the alcohol extracts of Anoectochilus roxburghii can significantly inhibit zebrafish melanogenesis, supporting the notion that Anoectochilus roxburghii could potentially be used in the development and production of natural whitening products.

Methylation of transcription factor YY2 regulates its transcriptional activity and cell proliferation.

Yin Yang 1 (YY1) is a multifunctional DNA-binding transcription factor shown to be critical in a variety of biological processes, and its activity and function have been shown to be regulated by multitude of mechanisms, which include but are not limited to post-translational modifications (PTMs), its associated proteins and cellular localization. YY2, the paralog of YY1 in mouse and human, has been proposed to function redundantly or oppositely in a context-specific manner compared with YY1. Despite its functional importance, how YY2's DNA-binding activity and function are regulated, particularly by PTMs, remains completely unknown. Here we report the first PTM with functional characterization on YY2, namely lysine 247 monomethylation (K247me1), which was found to be dynamically regulated by SET7/9 and LSD1 both in vitro and in cultured cells. Functional study revealed that SET7/9-mediated YY2 methylation regulated its DNA-binding activity in vitro and in association with chromatin examined by chromatin immunoprecipitation coupled with sequencing (ChIP-seq) in cultured cells. Knockout of YY2, SET7/9 or LSD1 by CRISPR (clustered, regularly interspaced, short palindromic repeats)/Cas9-mediated gene editing followed by RNA sequencing (RNA-seq) revealed that a subset of genes was positively regulated by YY2 and SET7/9, but negatively regulated by LSD1, which were enriched with genes involved in cell proliferation regulation. Importantly, YY2-regulated gene transcription, cell proliferation and tumor growth were dependent, at least partially, on YY2 K247 methylation. Finally, somatic mutations on YY2 found in cancer, which are in close proximity to K247, altered its methylation, DNA-binding activity and gene transcription it controls. Our findings revealed the first PTM with functional implications imposed on YY2 protein, and linked YY2 methylation with its biological functions.

Role of early environmental enrichment on the social dominance tube test at adulthood in the rat.

RATIONALE: Environmental enrichment (EE) could influence brain plasticity and behavior in rodents. Whether the early EE may predispose individuals to a particular social hierarchy in the social dominance tube test (SDTT) at adulthood is still unknown. OBJECTIVE: The present study directly investigated the influence of EE on competitive success in the SDTT among adult rats. METHODS: Male rats were maintained in EE from postnatal days 21 to 35. Social dominance behavior was determined by SDTT, competitive food foraging test, and mate preference test at adulthood. IBA-1 expression in the hypothalamus was examined using immunohistochemistry and western blot. RESULTS: EE rats were prone to become submissive during a social encounter with standard environment (SE) rats in the SDTT. No difference was found in food foraging in the competitive food foraging test between SE and EE rats. Male EE rats were more attractive than the SE to the female rats in the mate preference test. IBA-1 expression was found to be decreased in the hypothalamus of EE rats compared to SE group. Infusion of a microglia inhibitor reduced percentage of forward in SE rats in the SDTT. Infusion of DNA methyltransferase inhibitor prevented the development of subordinate status in EE rats and restored the expression of IBA-1 in the hypothalamus. CONCLUSIONS: The results suggest that early EE did not lead to reduced social hierarchy in the male rat. However, EE caused a reduction in the percentage of forward in the SDTT, which might be associated with reduced number of microglia in the hypothalamus.

Chemical Constituents of Murraya tetramera Huang and Their Repellent Activity against Tribolium castaneum.

Sixteen compounds were isolated from the leaves and stems of Murrayatetramera Huang. Based on the NMR and MS spectral results, the structures were determined. It was confirmed that the isolated compounds included three new compounds (9, 10 and 13) and one new natural product (8), which were identified asmurratetra A (9), murratetra B (10), murratetra C (13) and [2-(7-methoxy-2-oxochromen-8-yl)-3-methylbut-2-enyl]3-methylbut-2-enoate (8), respectively. Meanwhile, the repellent activity against Tribolium castaneum was investigated for 13 of these isolated compounds. The results showed that the tested compounds had various levels of repellent activity against T. castaneum. Among them, compounds 1 (4(15)-eudesmene-1ß,6α-diol), 11 (isoferulic acid) and 16 (2,3-dihydroxypropyl hexadecanoate) showed fair repellent activity against T. castaneum. They might be considered as potential leading compounds for the development of natural repellents.

Bioactivities and Chemical Constituents of Essential Oil Extracted from Artemisia anethoides Against Two Stored Product Insects.

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.

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.

Regulation of Transcription Factor Yin Yang 1 by SET7/9-mediated Lysine Methylation.

Yin Yang 1 (YY1) is a multifunctional transcription factor shown to be critical in a variety of biological processes. Although it is regulated by multiple types of post-translational modifications (PTMs), whether YY1 is methylated, which enzyme methylates YY1, and hence the functional significance of YY1 methylation remains completely unknown. Here we reported the first methyltransferase, SET7/9 (KMT7), capable of methylating YY1 at two highly conserved lysine (K) residues, K173 and K411, located in two distinct domains, one in the central glycine-rich region and the other in the very carboxyl-terminus. Functional studies revealed that SET7/9-mediated YY1 methylation regulated YY1 DNA-binding activity both in vitro and at specific genomic loci in cultured cells. Consistently, SET7/9-mediated YY1 methylation was shown to involve in YY1-regulated gene transcription and cell proliferation. Our findings revealed a novel regulatory strategy, methylation by lysine methyltransferase, imposed on YY1 protein, and linked YY1 methylation with its biological functions.

[Effect of puerarin in Longmaining formula on pharmacokinetics-pharmacodynamics correlation in rats with myocardial ischemia].

To study the pharmacokinetics of puerarin in compound Longmaining(FFLMN) in normal rats and myocardial ischemia rats, and investigate its correlation with anti-myocardial ischemia effect of FFLMN. Models of myocardial ischemia rats were produced by subcutaneous injection of isoproterenol(ISO), then FFLMN extract solution was administered by gavage. Orbital sinus blood sampling was collected at different time points after gavage. HPLC-UV method was applied to determine the concentration of puerarin in plasma, and compare the difference in pharmacokinetics between normal rats and model rats after application of same dose of FFLMN. Meanwhile, microplate reader was used to determine IL-6 and SOD activities in plasma of different time points, and draw dose-effect curve. The results indicated that the pharmacokinetics of puerarin conformed to the two-compartment model in both normal group and myocardial ischemia model group. In the comparison of main pharmacokinetic parameters between two groups: AUC0-∞=(11.451±3.228) mg•h•L⁻¹,AUC0-t=(14.047±3.765) mg•h•L⁻¹, Cmax=(5.623±1.40) mg•L⁻¹ in normal group; AUC0-∞=(68.849±50.396 9) mg•h•L⁻¹, AUC0-t= (58.312±45.802) mg•h•L⁻¹,Cmax=(18.456±7.517) mg•L⁻¹ in treatment group. The SOD level was significantly increased and IL-6 concentration was significantly decreased in plasma, indicating that as compared with the normal group, puerarin in FFLMN had a higher plasma concentration, slower elimination rate and higher bioavailability. Therefore, puerarin concentration in plasma has correlation with the anti-myocardial ischemia effect of FFLMN, which could increase SOD level and inhibit the release of IL-6.

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.

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.