Insecticidal and repellant activities of polyacetylenes and lactones derived from Atractylodes lancea rhizomes.

During a screening program for new agrochemicals from Chinese medicinal herbs and local wild plants, the petroleum ether (PE) extract of Atractylodes lancea (Thunb.) rhizomes was found to possess repellent and contact activities against Tribolium castaneum adults. Bioactivity-directed chromatographic separation of PE extract on repeated silica-gel columns led to the isolation of two polyacetylenes, atractylodin and atractylodinol (1 and 2, resp.), and two lactones, atractylenolides II and III (3 and 4, resp.). The structures of the compounds were elucidated based on NMR spectra. The four isolated compounds were evaluated for their insecticidal and repellent activities against T. castaneum. Atractylodin exhibited strong contact activity against T. castaneum adults with a LD50 value of 1.83 µg/adult. Atractylodin and atractylenolide II also possessed strong repellenct activities against T. castaneum adults. After 4-h exposure, >90% repellency was achieved with atractylodin at a low concentration of 0.63 µg/cm(2) . The results indicated that atractylodin (1) and atractylenolide II (3) have a good potential as a source for natural repellents, and 1 has the potential to be developed as natural insecticide.

[Study on chemical constituents from Schisandra chinensis stem].

OBJECTIVE: To separate and identify the chemical constituents from the stem of Schisandra chinensis. METHODS: Various chromatographic techniques were used to separate and purify the chemical constituents from 95% ethanol extraction of the stem of Schisandra chinensis. Their structures were elucidated based on the physico-chemical properties and spectral data. RESULTS: Ten compounds were obtained and elucidated as (+)-deoxyschizandrin (1), γ-schizandrin (2), wuweizisu C (3), gomisin N (4), schizandrin (5), anwuweizic acid (6), (-)-dihydroguaiaretic acid (7), tetradecanoic acid (8), ß-sitosterol (9) and daucosterol (10). CONCLUSION: Compounds 6-8 are obtained from the stem of Schisandra chinensis for the first time.

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.