The purpose of this study was to investigate the protective effect on oxidative stress induced PC12 cells, and volatile flavor composition of essential oils derived from medicinal plant seeds- Gossypium hirsutum L. (G. hirsutum), Coix lachryma-jobi (C. lachryma-jobi) and Oenothera biennis (O. biennis). The essential oils were obtained by the solvent (hexane) extraction method from the seeds. The essential oils of the seeds were analyzed by the solid-phase micro-extraction gas chromatography mass spectrometry (SPME-GC/MS). The major compounds of G. hirsutum, C. lachryma-jobi and O. biennis were cyclonexanol (16.65%), β-asarone (14.29%) and ylangene (50.01%). The DPPH radical scavenging activity (IC50) was the highest value of 8.52 mg/mL in the O. biennis. Additionally, IC50 values of G. hirsutum and C. lachryma-jobi were 26.76 mg/mL and 36.81 mg/mL. For the oxidative stress on PC12 cells, we treated with hydrogen peroxide (H2O2). The pretreatment of oxidative stress induced PC12 cells with all the essential oils preserved or increased their cell viability and G. hirsutum and O. biennis attenuated the ROS generation (by 68.75% and 56.25% vs. H2O2 control). The results of this study suggest that the essential oils derived from medicinal plant seeds could be used as valuable back data as a natural essential oil material to prevent neurodegenerative diseases by protecting neuro-cells.

Miticidal and repellent activity of twenty plant essential oils against the adults of two spotted spider mites, Tetranychus urticae, were examined. Sandalwood oil was the most potent one in mortality, whereas clary sage oil exhibited the greatest repellent activity. On those twenty essential oils tested, no apparent correlation between toxicity and repellency was observed. The chemical compositions of sandalwood and clary sage oils were identified via GC/MS analyses. The major constituents of sandalwood oils were sesquiterpene compounds, whereas the major ones for clary sage oil were monoterpenes. Among the major components in clary sage oil, linalyl acetate was not only the most abundant constituent, but also the most responsible one for its repellent activity against the adults of the two spotted spider mites. Nevertheless, the combination of seven major constituents of clary sage oil showed lesser repellent activity than the original essential oil did, implying the presence of interactions between the major and minor constituents affecting the overall repellent activity of the crude oil.

톱다리개미허리노린재는 최근 농약사용 횟수의 증가로 천적이 사라지면서 전국적으로 크게 발생을 하고 있다. 톱다리개미허리노린재는 년 2~3회 발생하며 포장 잔재물이나 포장 주위의 잡초 등에서 성충으로 월동한 후 다음 해 봄 기주작물인 콩과 작물, 과수작물, 곡류작물에 피해를 주는데 이중 콩이 가장 적합한 먹이원이며 피해가 가장 크다. 콩의 열매 성숙 초기 즉 착협기에 일어나는 톱다리개미허리노린재에 의한 섭식 피해가 수확량에 직접적인 영향을 주기 때문이다. 본 실험은 톱다리개미허리노린재에 대한 기피제 개발 목적으로 미나리과 식물체정유인 아조완 정유와 그 성분들의 톱다리개머허리노린재 성충 및 약충에 대한 기피 활성을 실험실내에서 four-arms olfactometer를 이용하여 조사하였다. 아조완 정유를 1.25 mg의 농도에서 처리했을 때 성충 수컷 89% 및 암컷 성충 90%가 기피를 보였다. 4령 약충의 경우, 성충과 같은 농도로 처리했을 때 73%의 기피 활성이 나타났다. 아조완 정유의 기피 활성 물질을 확인하기 위해 GC-MS로 정유를 분석하였고 12종의 정유 성분을 확인하였다. 12종의 아조완 정유성분들 중 각 성충 수컷과 암컷, 4령 약충에서 1 mg 농도로 처리했을 때 thymol과 carvacrol이 100%의 강한 기피 활성을 보였다. 아조완 정유와 정유성분들은 톱다리개미허리노린재의 집합페로몬 트랩과 같이 “push and pull”전략에 활용이 가능할 것으로 판단된다.

본 연구에서는, 20종의 식물정유를 이용하여 점박이응애 성충에 대한 살비활성 및 기피활성을 확인하였다. 살비활성 평가에서는 샌달우드 오일이, 기피활성 평가에서는 클라리 세이지 오일이 가장 높은 효과를 나타내었고, 평가에 사용한 20종의 식물정유간에는 살비활성과 기피활성간 의 상관관계가 매우 낮게 나타났다. 높은 활성을 나타낸 정유들의 혼합시험에서는, 거의 대부분의 조합이 서로간에 저해효과를 갖는 것으로 확인되었다. 샌달우드 및 클라리 세이지 오일의 구성성분은 GC/MS 분석을 통해 확인하였으며, 샌달우드는 세스퀴터펜류가, 클라리 세이지 오일은 모노 터펜류가 주종을 이루었다. 클라리세이지 오일의 구성성분 중에서는 linalyl acetate가 가장 높은 함량을 갖고 있을 뿐만 아니라, 해당정유가 기피효과를 갖는 주된 효능물질임을 확인하였다.

The insecticidal activities of 13 Lamiaceae plant oils and their components against adult German cockroaches, Blattella germanica L. (Blattodea: Blattellidae), were evaluated using fumigant and contact bioassay. Among the tested oils, basil, pennyroyal, and spearmint showed the strongest insecticidal activities against adult B. germanica. Insecticidal activity of pennyroyal was 100% against male B. germinica at 1.25 mg concentration in fumigant bioassay. Basil and spearmint revealed 100% and 100% insecticidal activity against male B. germinica at 5 mg concentration, but their activities reduced to 80% and 25% at 2.5 mg concentration, respectively. In contact toxicity bioassy, basil, pennyroyal, and spearmint oils exhibited 100%, 100%, and 98% mortality against female B. germanica at 1 mg/♀, respectively. Among the constituents identified in basil, pennyroyal and spearmint oils, insecticidal activity of pulegone was the strongest against male and female B. germanica.

Assessments were made of fumigant and contact toxicities of 6 Myrtaceae plant essential oils (EOs) and their components against spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). Median lethal dose (LD50;mg/L) values of Leptospermum citratum EO for fumigant activity were 2.39 and 3.24 for males and females, respectively. All tested EOs except Kunzea ambigua EO exhibited effective contact toxicity. LD50(μg/fly) values for contact toxicity of manuka and kanuka were 0.60 and 0.71, respectively, for males and 1.10 and 1.23, respectively, for females. β-Triketone fractions, composed of flavesone, isoleptospermone and leptospermone, exhibited efficient activity with the LD50 values of 0.13–0.37and0.22–0.57μg/fly for males and females, respective

Insect growth regulators (IGRs) are attractive pest control agents due to their high target specificity and relative safety to the environment. Recently, plants have been shown to synthesize IGRs that affect the insect juvenile hormone (JH) as a part of their defense mechanisms. We identified several JH agonists (JHAs) and antagonists (JHANs) from plant essential oil compounds using a yeast two-hybrid system transformed with the Aedes aegypti JH receptor as a reporter system. They showed high mosquitocidal activities with relatively low LC50 values and caused retardation of ovarian development in female mosquitoes. While the JHAs increased the expression of JH-induced gene, the JHANs caused reduction in the expression of the same gene. The compounds identified in this study could provide insights on the plant-insect interactions and may be useful for the development of novel IGR insecticides.

We evaluated the larvicidal activity of 12 Apiaceae plant essential oils and their components against the Asian tiger mosquito, Aedes albopictus, and the inhibition of acetylcholine esterase with their components. Of the 12 plant essential oils tested, ajowan (Trachyspermum ammi), caraway seed (Carum carvi), carrot seed (Daucus carota), celery (Apium graveolens), cumin (Cuminum cyminum), dill (Anethum graveolens), and parsley (Petroselinum sativum) resulted in >90% larval mortality when used at 0.1 mg/mL. Of the compounds identified, α-phellandrene, α-terpinene, p-cymene, (-)-limonene, (+)-limonene, γ-terpinene, cuminaldehyde, neral, (S)-+-carvone, trans-anethole, thymol, carvacrol, myristicin, apiol, and carotol resulted in >80% larval mortality when used at 0.1 mg/mL.

We evaluated the repellent activity of 12 Apiaceae plant essential oils and their components against male and female adult German cockroaches, Blattella germanica, to find new natural repellents. Of the plant essential oils tested, ajowan (Trachyspermum ammi) and dill (Anethum graveolens) essential oils showed the most potent repellent activity against male and female adult German cockroaches. Of the compounds identified, carvacrol, thymol, and R-(-)-carvone showed >80% repellent activity against male and female adult German cockroaches at 0.2 mg/L air concentration. S-(+)-Carvone, (+)-dihydrocarvone, and terpinen-4-ol showed >70% repellent activity against male and female adult German cockroaches at 0.8 mg/L air concentration. Our results indicated that Apiaceae plant essential oils and their constituent have good potential as natural repellents against adult German cockroaches.

Twelve Lamiaceae plant essential oils (EOs) and their components were evaluated for their fumigant and contact toxicities. Inhibition of AChE by the major components of active EOs was also assessed. Strong fumigant toxicity was observed from EOs of Mentha piperita and Perilla frutescens. Menthone and menthol, and perilla aldehyde were identified as major components of the above two EOs, respectively. The LC50 (mg/L) values of M. piperita, P. frutescens, menthone, menthol and perilla aldehyde were 3.87, 2.44, 5.76, 1.88, and 0.99 against male, and 4.10, 3.31, 5.13, 1.94, and 1.15 against female, respectively. Strong contact toxicity was observed from the EOs of Satureja montana and Thymus zygis. Thymol and carvacrol were major components of these two EOs. The LD50 (μg/fly) values for contact toxicity of S. montana, T. zygis, thymol and carvacrol were 2.95, 2.93, 1.63, and 1.30 for male, and 4.59, 5.09, 2.68, and 2.60 for female, respectively. Among the five major components, perilla aldehyde showed most active inhibition activity against AChE of both sexes of SWD.

Six wooden plant essential oils (EOs; Illicium verum, Gaultheria fragrantissima, Bursea delpechiana,Croton anisatum, Cinnamomum cassia and Aniba rosaeodora) and their major compounds (trans-anethole, methyl salicylate, trans-cinnamaldehyde, linalool and linalyl acetate) identified from gas chromatography (GC) and GC-mass spectrometry were tested for adult repellence and pheromone antagonism using Y-tube essay and oviposition deterrent effect using no choice test against adzuki bean beetle (ABB), Callosobruchus chinensis L. EOs of I. verum and C. anisatum as well as their common major compound, trans-anethole were found effective repellents having high degree of pheromone antagonistic and oviposition deterrent activity. Methyl salicylate, the major compound of G. fragrantissima EO (which was only the pheromone antagonist) showed high degree of repellency, oviposition deterrence and pheromone antagonistic effect in higher concentration. From this study, EOs of I. verum and C. anisatum and their common major compound trans-anethole as well as the major compound of G. fragrantissima, methyl salicylate can be screened as eco-friendly management agents against C. chinensis in stored legumes if slow releasing formulations are prepared by future efforts.

Insect growth regulators (IGRs) are compounds that induce developmental anomalies such as premature molting or supernumerary larval stages. IGRs can be divided into 3 groups based on their mode of action, one of which is known as the juvenile hormone agonists (JHAs). Previously, we have developed a novel screening method which can identify juvenile hormone antagonists (JHANs) using a yeast-two hybrid system incorporating Aedes aegypti juvenile hormone receptor complex proteins (MET and FISC). It has been reported that plants may use IGRs in their defenses against insect herbivores. In this study, 171 plant essential oil samples were screened using the yeast-two hybrid system in order to identify JHAs and/or JHANs. Eight out of 171 samples, 4 JHA and 4 JHAN candidates, were selected and their insecticidal activities were investigated against A. aegypti larvae. They showed high levels of insecticidal activities, with LC50 values ranging from 11.2~21.4 ug/ml. These results indicate that plants do use JHAs and/or JHANs as a part of their defenses against insect herbivores. Also, JHAs and JHANs identified in this study could be exploited as effective biological control agents.

This study was conducted to determine the toxicity to adult Myzus persicae (Sulzer) and Aphis gossypii Glover of 88 plant essential oils and six experimental spray formulations containing bitter orange or marjoram oil was examined using the vapor-phase mortality and spray bioassays. Results were compared with those of two conventional insecticides deltamethrin and dichlorvos. As judged by 24 h LC50 values, bitter orange oil (0.0212 and 0.0192 mg/cm3) was the most active material, followed by marjoram, celeryseed, and cypress oils (0.0239-0.0508 and 0.0209-0.0542 mg/cm3). These essential oils were significantly less toxic than dichlorvos, respectively. These essential oils were consistently more toxic to adult M. persicae in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapor. Bitter orange oil and marjoram oil applied as 1% spray provided complete mortality toward two aphid species adults. Reasonable aphid control in greenhouses can be achieved by a spray formulation containing the 1% oil as potential contact-action fumigant.

Essential oils from 22 plant species were tested for their insecticidal activities against spotted wing drosophila (SWD), Drosophila suzukii Matsumura, using fumigation and contact bioassay. Responses varied with the essential oils, their constituents and concentrations. Strong fumigation activities were observed from the essential oils of wintergreen (Gaultheria fragrantissima), croton (Croton anisatum) and star anise (Illicium verum). Strong contact activities were observed in the essential oils of oriental sweetgum (Liquidambar orientalis), cassia (Cinnamomum cassia), damask rose (Rosa damascena) and sandalwood (Santalum album). The compositions of these selected essential oils were identified using gas chromatographymass spectrophotometer. The compounds identified were tested individually for their insecticidal activities against SWD. Responses varied by doses for each compound. The results showed that natural materials are as effective as synthetic pesticides.