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This study investigated the biological activity of essential oils (EOs) and their main components (caryophyllene and cuminol) against Tribolium castaneum larvae and Lasioderma serricorne adults. EOs were extracted from both flowers and leaves of Elsholtzia stauntoni. The results indicated that the EOs derived from both flowers and leaves, as well as their main components (caryophyllene and cuminol), exhibited contact activities with LD50 values of 35.11, 43.66, 15.44, and 26.05 µg/larva, respectively, against T. castaneum larvae. Moreover, they demonstrated obvious contact toxicities with LD50 values of 14.15, 11.18, 17.81, and 13.91 µg/adult, respectively, against L. serricorne adults. Additionally, EOs from both flowers and leaves exhibited fumigant activities against T. castaneum larvae (LC50 = 24.42 and 62.54 mg/L) and L. serricorne adults (LC50 = 15.26 and 24.29 mg/L). Furthermore, the EOs of flowers and leaves and their main components (caryophyllene and cuminol) remained significantly repellency to T. castaneum larvae and L. serricorne adults within the testing concentration range of 78.63-15.83 nL/cm2 after 12 h of exposure. These findings suggested that the EO from E. stauntoni and its two major components could potentially be developed as a natural insecticide for controlling T. castaneum larvae and L. serricorne adults. [ABSTRACT FROM AUTHOR]

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%), β-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 β-caryophyllene (LD50 = 41.72 μg/adult) against T. castaneum adults. Estragole possessed stronger contact toxicity (LD50 = 30.22 μg/cm2) than β-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. [ABSTRACT FROM AUTHOR]

Sixteen compounds were isolated from the leaves and stems of Murraya tetramera 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-1β,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. [ABSTRACT FROM AUTHOR]