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Isolation of insecticidal constituents from the essential oil of Ageratum houstonianum Mill. against Liposcelis bostrychophila Badonnel.

1. Introduction

Botanical pesticides have the advantage of providing novel modes of action against insects that can reduce the risk of cross-resistance as well as offering new leads for the design of target-specific molecules. During the screening program for new agrochemicals from Chinese medicinal herbs and wild plants, essential oil of Ageratum houstonianum (Family: Compositae) aerial parts was found to possess strong insecticidal toxicity against the booklice, Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelidae). A. houstonianum is an annual erect ornamental shrub of 30-70 cm height. It is commonly known as floss flower and native to southeastern Mexico, Central America. Now it is cultured as an ornamental flower and also naturalized as an invasive weed in Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Jiangsu, Nanhai Zhudao, Shandong, Sichuan, Taiwan, Yunnan, and Zhejiang Province, China [1]. The whole plant of A. houstonianum is used medicinally in traditional Chinese medicine to clear away heat and toxic materials. People in Central America (Ecuador) use this plant as an antiphlogistic to relieve swelling and pain in the throat [1].

In the previous reports, various flavonoids, triterpenoids, steroids, pyrrolizidine alkaloids, and benzofuran derivatives (chromenes) have been isolated and identified in the plant [2-7]. The chemical composition of the essential oil of A. houstonianum has been studied previously [8-14]. It is reported that essential oil and extracts derived from the aerial parts (leaves) of A. houstonianum exhibit antifungal, antimicrobial, acaricidal, and mosquitocidal activity as well as repellency against mosquitoes [11-19]. However, a literature survey has shown that there is no report on insecticidal and repellent activity of the essential oil of A. houstonianum against L. bostrychophila. The present research was therefore undertaken to investigate the chemical constituents and insecticidal and repellent activity of the essential oil against the booklice for the first time and to isolate active constituent compounds from the essential oil.

2. Materials and Methods

2.1. Plant and Essential Oil Extract. Fresh aerial parts of A. houstonianum (15 kg) at flowering stage were harvested from Lishui City (27.54[degrees]N latitude and 119.20[degrees]E longitude, Zhejiang Province, China) in August 2013. The plant was identified, and a voucher specimen (CMH-Xiongercao-Zhejiang-201308) was deposited at the herbarium of Department of Entomology, China Agricultural University. The sample was airdried and ground to powder using a grinding mill (Retsch Muhle, Haan, Germany) and was subjected to hydrodistillation using a modified Clevenger-type apparatus for 6h and extracted with n-hexane. Anhydrous sodium sulphate was used to remove water after extraction. Essential oils were stored in airtight containers in a refrigerator at 4[degrees]C for subsequent experiments.

2.2. Oil Isolation and Fractionation. The essential oil (25 mL) was chromatographed on a silica gel (Merck 9385, 1,000 g) column by gradient elution with a mixture of solvents (n-hexane, n-hexane-ethyl acetate, and acetone). Fractions of 500 mL were collected and concentrated at 40[degrees]C, and similar fractions according to TLC profiles were combined to yield 16 fractions. Fractions (8-9, 11-12) that possessed contact toxicity, with similar TLC profiles, were pooled and further purified by preparative silica gel column chromatography (PTLC GF254, 300-400 mesh, Qingdao Haiyang Chemical Group Corp., China) with petroleum ether-acetone (10: 2, v/v) to obtain the pure compound for determining structure as precocene I (1, 1.3 g, 7-methoxy-2,2-dimethylchromene, Figure 1) and 3-precocene II (2, 1.9 g, 6,7-dimethoxy-2,2-dimethyl-2-chromene, Figure 1). The spectra data of the two compounds matched with previous report [20].

2.3. Gas Chromatography-Mass Spectrometry (GC-MS). Analyses of volatile constituents were determined using an Agilent 5973 GC-MS system operating in the EI mode at 70 eV (equipped with a 30 m HP-5MS column (0.25 mm x 30 m x 0.25 [micro]m) and coated with 5% phenylmethylpolysiloxane using a HP-5MS (df = 0.25 [micro]m) (Agilent J&W Scientific, USA)). The temperature program used for the analysis was as follows: initial temperature at 60[degrees]C, held for 1 min, ramped at 4[degrees]C/min to 290[degrees]C, and held for 0.5 min. Helium was the carrier gas at 1.0mL/min; the sample (1 [micro]L 1/100, v/v, in acetone) was injected in the split mode (1: 10). The injector and detector temperatures were performed at 230[degrees]C and 300[degrees]C, respectively. Most constituents were identified by gas chromatography by comparison of their retention indices with those of the literature or with those of authentic compounds available in our laboratories. The retention indices were determined in relation to a homologous series of n-alkanes ([C.sub.8]-[C.sub.24]) under the same operating conditions. Further identification was made by comparison of their mass spectra with those stored in NIST 05 and Wiley 275 libraries or with mass spectra from the literature [21].

2.4. NMR Analysis. [sup.1]H nuclear magnetic resonance (NMR) spectra were recorded on Bruker ACF300 (300 MHz ([sup.1]H)) and AMX500 (500 MHz ([sup.1]H)) instruments using deuterochloroform (CD[Cl.sub.3]) as the solvent with tetramethylsilane (TMS) as the internal standard. Electron impact mass spectra (EIMS) were determined on a Micromass VG7035 mass spectrometer at 70 eV (probe).

2.5. Insects. L. bostrychophila was obtained from laboratory cultures in the dark in incubators at 28-30[degrees]C and 70-80% r.h. and was reared on a 1:1:1 mixture, by mass, of milk powder, active yeast, and flour. All containers housing insects and the Petri dishes used in experiments were made escape proof with a coating of polytetrafluoroethylene (Fluon, Blades Biological, UK). Adult insects used in all the experiments were about one week old.

2.6. Contact Toxicity. Contact toxicity of the oil against the booklice was measured as described by Zhao et al. [22]. The filter paper with 3.5 cm in diameter (Whatman) was treated with 150 [micro]L of the solution (2.0%, 2.4%, 2.9%, 3.5%, 4.2%, and 5.0% in acetone). The treated filter paper after being treated with solid glue (Glue Stick, Jong Ie Nara Co., Ltd., Hong Kong) was placed in a Petri dish (3.5 cm in diameter) and 10 booklice were put on the filter paper. The plastic cover with holes was put and all the Petri dishes were kept in incubators at 27-29C, 70-80% r.h. for 24 h and mortality of insects was observed. Acetone was used as controls and pyrethrum extract was used as a positive control. Pyrethrum extract (25% pyrethrin I and pyrethrin II) was purchased from Fluka Chemie (Buchs, Switzerland).

2.7. Repellent Activity. A commercial repellent, dimethyl phthalate, was purchased from Aladdin-Reagent Company (Shanghai) and used as a positive control. The essential oil and isolated compounds were diluted in acetone to four concentrations (6.4, 3.2 1.6, and 0.8 nL/[cm.sup.2]). Filter paper (6 cm in diameter) was cut in half and 150 [micro]L of each concentration was applied separately to half of the filter paper as uniformly as possible with a micropipette. The other half (control) was treated with 150 [micro]L of absolute acetone. Both the treated half and the control half were then air dried to evaporate the solvent completely (10 sec). A full disc was carefully remade by attaching the tested half to the negative control half with tape. Each remade filter paper after being treated with solid glue was placed in a Petri dish and 20 insects were released in the center of each filter-paper disc and a cover was placed over the Petri dish. Five replicates were used and the experiment was repeated for three times. Counts of the insects present on each strip were made after 2 h and 4 h. The percent repellency of the oil/compounds was then calculated using the formula

PR (%) = [(Nc - Nt)/(Nc + Nt)] x 100, (1)

where Nc was the number of insects present in the negative control half and Nt was the number of insects present in the treated half.

The averages were then categorised according to the following scale [23, 24] as shown in Table 1.

2.8. Data Analysis. The observed mortality data were corrected for control mortality using Abbott's formula. The results from all replicates in contact toxicity were subjected to Probit analysis using PriProbit Program V1.6.3 to determine [LD.sub.50] and [LD.sub.90] values [25]. The percentage repellency data were subjected to an arcsine square-root transformation before ANOVA and Tukey's tests.

3. Results and Discussion

3.1. Essential Chemical Composition. The yellow essential oil yield of A. houstonianum was 0.67% (v/w based on dry weight) while the density of the concentrated essential oil was 0.90 g/mL. A total of 35 components from the essential oil of A. houstonianum were identified, accounting for 97.92% of the total oil. Precocenes only represented 2 of the 35 compounds, corresponding to 75.89% of the whole oil, while 18 of the 35 constituents were sesquiterpenoids (20.61% of the crude essential oil) (Table 2). The major constituents of A. houstonianum essential oil were precocene II (62.68%), precocene I (13.21%), and [beta]-caryophyllene (7.92%). The results are similar to the previous reports [8-14] although there are some variations in chemical composition of the essential oils of A. houstonianum. For example, the essential oil of A. houstonianum leaves harvested from Cameroon contained precocene I and precocene II in almost similar amounts (32% and 24%, resp.) [8]. However, the essential oil of A. houstonianum flowers collected from Cameroon mainly contained precocene I (48.01%), precocene II (36.55%), and [beta]-caryophyllene (8.37%) [12]. Precocene II (43.99%), precocene I (23.34%), and [beta]-caryophyllene (9.18%) were identified as major constituents of the essential oil of A. houstonianum harvested from Jammu Region of India [9]. In another report [10], precocene II (52.64%), precocene I (22.45%), and pcaryophyllene (9.66%) represented the major constituents in the essential oil of A. houstonianum aerial parts also collected from India.

3.2. Contact Toxicity. The essential oil of A. houstonianum aerial parts exhibited contact toxicity against L. bostrychophila with an [LC.sub.50] value of 50.8 [micro]g/[cm.sup.2] (Table 3). Precocene II ([LC.sub.50] = 30.4 [micro]g/[cm.sup.2]) exhibited stronger acute toxicity than precocene I ([LC.sub.50] = 64.0 [micro]g/[cm.sup.2]) against the booklice. Precocene II shows almost 2 times stronger toxicity than the oil while precocene I exhibits less toxicity than the oil. Thus it seems that contact toxicity of the oil maybe mainly attributed to precocene II. However, compared with the positive control, pyrethrum extract ([LC.sub.50] = 18.99 [micro]g/[cm.sup.2]), A. houstonianum essential oil, and precocene II showed 2.7 and 1.6 times less toxicity to L. bostrychophila, respectively. When compared with the other essential oils in the previous studies using the same bioassay, the essential oil of A. houstonianum exhibited stronger or the same level of acute toxicity against the booklice, for example, essential oils of Acorus calamus [26], Artemisia rupestris and A. frigida [24, 27], Curcuma wenyujin [28], Foeniculum vulgare [22], and Valeriana jatamansi [29].

3.3. Repellent Activity. The essential oil of A. houstonianum showed strong repellent activity (Class V) against the booklice at a concentration of 1.6 nL/[cm.sup.2] and higher concentration after 4 hr of exposure (Table 4). Moreover, the essential oil of A. houstonianum still exhibited the same level (class IV) of repellent activity against the booklice as commercial repellent, dimethyl phthalate, at a concentration of 0.8 nL/[cm.sup.2] after 4 hr of exposure. Precocene I possessed the same strong repellency against the booklice, while precocene II exhibited class IV repellent activity at a concentration of 1.6 nL/[cm.sup.2] after 4 hr of exposure. Compared with commercial repellent, dimethyl phthalate, precocene I showed the same level of repellent activity against the booklice, while precocene II exhibited less active at lower concentrations (0.8 nL/[cm.sup.2] and 1.6 nL/[cm.sup.2]) (Table 4).

This study demonstrates that the essential oil of A. houstonianum had contact toxicity and repellent activity to the booklice. Furthermore, the two isolated constituent compounds, precocene II and precocene I, also exhibited insecticidal and repellent activity against L. bostrychophila. In the previous studies, precocene II and precocene I demonstrated to inhibit the synthesis of juvenile hormone in a number of insects. Consequently, this inhibition can disturb the embryonic development, induce premature metamorphosis, decrease the reproductive potential, and affect the insect behavior including the antifeedant and repellent effect [19, 30-35]. The above findings suggest that the essential oil and the two isolated constituent compounds show a potential to be developed as possible natural insecticides/repellents for the control of grain storage insects. It seems that this plant is quite safe to human consumption because it has been used as a medicinal herb for clearing away heat and toxic materials [1]. However, A. houstonianum is reported to be toxic to grazing animals, causing liver lesions [36]. Moreover, no information on toxicity of the essential oil and the isolated constituents to human were available. Thus, to develop a practical application for the essential oil and the isolated constituents as novel natural insecticides, further research into the safety of the essential oil/compounds to humans is needed. Additional studies on the development of formulations are also necessary to improve the efficacy and stability and to reduce cost.

4. Conclusion

This study indicates that the essential oil of A. houstonianum aerial parts and its isolated constituent compounds have potential for development into natural insecticides and repellents for control of insects in stored grains.

http://dx.doi.org/10.1155/2014/645687

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Acknowledgments

The authors are grateful to Dr. QR Liu, College of Life Sciences, Beijing Normal University, Beijing, China, for identification of Chinese medicinal herb. This work was funded by the Special Fund for Agro-Scientific Research in the Public Interest (Grant no. 201003058).

References

[1] Y. Lin and Y. L. Chen, Flora Reipublicae Popularis Sinicae, vol. 74, Science Press, Beijing, China, 1985, http://www.efloras.org/ florataxon.aspx?flora_id=2&taxonjd=200023022.

[2] H. Wiedenfeld and A. Andrade-Cetto, "Pyrrolizidine alkaloids from Ageratum houstonianum Mill," Phytochemistry, vol. 57, no. 8, pp. 1269-1271, 2001.

[3] R. Siebertz, P. Proksch, V Wray, and L. Witte, "A benzofuran from Ageratum houstonianum," Phytochemistry, vol. 27, no. 12, pp. 3996-3997, 1988.

[4] M. Breuer, H. Budzikiewicz, R. Siebertz, and P. Proksch, "Benzofuran derivatives from Ageratum houstonianum," Phytochemistry, vol. 26, no. 11, pp. 3055-3057, 1987.

[5] L. Quijano, J. S. Calderon, F. G. Garibay, E. Escobar, and T. Rios, "Further polysubstituted flavones from Ageratum houstonianum," Phytochemistry, vol. 26, no. 7, pp. 2075-2078, 1987

[6] L. Quijano, J. S. Calderon, F. Gomez G, E. Escobar, and T. Rios, "Octasubstituted flavones from Ageratum houstonianum," Phytochemistry, vol. 24, no. 5, pp. 1085-1088, 1985.

[7] L. Quijano, J. S. Calderon, F. Gomez, and T. Rios, "Two polymethoxyflavones from Ageratum houstonianum," Phytochemistry, vol. 21, no. 12, pp. 2965-2967, 1980.

[8] C. Menut, G. Lamaty, P. H. A. Zollo, J. R. Kuiate, and J. M. Bessiere, "Aromatic plants of tropical Central Africa--part X: chemical composition of the essential oils of Ageratum houstonianum mill. and Ageratum conyzoides L. From Cameroon," Flavour and Fragrance Journal, vol. 8, no. 1, pp. 1-4, 1993.

[9] S. Chandra, A. K. Shahi, P. Dutt, and A. Tava, "Essential oil composition of Ageratum houstonianum Mill. from Jammu region of India," Journal of Essential Oil Research, vol. 8, no. 2, pp. 129-134, 1996.

[10] N. P. Kurade, V. Jaitak, V. K. Kaul, and O. P. Sharma, "Chemical composition and antibacterial activity of essential oils of Lantana camara, Ageratum houstonianum and Eupatorium adenophorum," Pharmaceutical Biology, vol. 48, no. 5, pp. 539-544, 2010.

[11] E. T. Pamo, F. Tendonkeng, J. R. Kana et al., "A study of the acaricidal properties of an essential oil extracted from the leaves of Ageratum houstonianum," Veterinary Parasitology, vol. 128, no. 3-4, pp. 319-323, 2005.

[12] T. E. Pamo, F. Tendonkeng, J. R. Kana, G. Tenekeu, L. A. Tapondjou, and V. K. Payne, "The acaricidal effect of the essential oil of Ageratum houstonianum Mill. flowers on ticks (Rhipicephalus lunulatus) in Cameroon," South African Journal of Animal Sciences, vol. 34, no. 1, pp. 244-247, 2004.

[13] G. S. S. Njateng, J. R. Kuiate, D. Gatsing, J. D. Tamokou, R. S. Mouokeu, and V. Kuete, "Antidermatophytic activity and dermal toxicity of essential oil from the leaves of Ageratum houstonianum (Asteraceae)," Journal of Biological Sciences, vol. 10, no. 5, pp. 448-454, 2010.

[14] S. Tennyson, K. Balaraju, K. Park, K. J. Ravindran, A. Eapen, and S. J. William, "In vitro antioxidant activity of Ageratum houstonianum Mill. (Asteraceae)," Asian Pacific Journal of Tropical Disease, vol. 2, no. 2, pp. S712-S714, 2012.

[15] S. Tennyson, K. J. Ravindran, A. Eapen, and S. J. William, "Effect of Ageratum houstonianum Mill. (Asteraceae) leaf extracts on the oviposition activity of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)," Parasitology Research, vol. 111, no. 6, pp. 2295-2299, 2012.

[16] S. Tennyson, J. Ravindran, A. Eapen, and J. William, "Repellent activity of Ageratum houstonianum Mill. (Asteraceae) leaf extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)," Asian Pacific Journal of Tropical Disease, vol. 2, no. 6, pp. 478-480, 2012.

[17] S. Tennyson, K. J. Ravindran, A. Eapen, and S. J. William, "Effect of Ageratum houstonianum Mill. (Asteraceae) leaf extracts on the oviposition activity of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae)," Parasitology Research, vol. 111, no. 6, pp. 2295-2299, 2012.

[18] J. Ravindran, T. Samuel, E. Alex, and J. William, "Adulticidal activity of Ageratum houstonianum Mill. (Asteraceae) leaf extracts against three vector mosquito species (Diptera: Culicidae)," Asian Pacific Journal of Tropical Disease, vol. 2, no. 3, pp. 177-179, 2012.

[19] W. S. Bowers, T Ohta, J. S. Cleere, and P. A. Marsella, "Discovery of insect anti juvenile hormones in plants," Science, vol. 193, no. 4253, pp. 542-547, 1976.

[20] A. Yaguchi, T. Yoshinari, R. Tsuyuki et al., "Isolation and identification of precocenes and piperitone from essential oils as specific inhibitors of trichothecene production by Fusarium graminearum," Journal of Agricultural and Food Chemistry, vol. 57, no. 3, pp. 846-851, 2009.

[21] R. P. Adams, Identification of Essential Oil Components by Gas Chromatography/Mass Spectroscopy, Allured, Carol Stream, Ill, USA, 2007

[22] N. N. Zhao, L. Zhou, Z. L. Liu, S. S. Du, and Z. W. Deng, "Evaluation of the toxicity of the essential oils of some common Chinese spices against Liposcelis bostrychophila," Food Control, vol. 26, no. 2, pp. 486-490, 2012.

[23] Z. L. Liu, M. Yu, X. M. Li, T. Wan, and S. S. Chu, "Repellent activity of eight essential oils of chinese medicinal herbs to Blattella germanica L," Records of Natural Products, vol. 5, no. 3, pp. 176-183, 2011.

[24] X. C. Liu, L. G. Zhou, Z. L. Liu, and S. S. Du, "Identification of insecticidal constituents of the essential oil of Acorus calamus rhizomes against Liposcelis bostrychophila badonnel," Molecules, vol. 18, no. 5, pp. 5684-5696, 2013.

[25] M. Sakuma, "Probit analysis of preference data," Applied Entomology and Zoology, vol. 33, no. 3, pp. 339-347, 1998.

[26] X. C. Liu, L. G. Zhou, Z. L. Liu, and S. S. Du, "Identification of insecticidal constituents of the essential oil of Acorus calamus rhizomes against Liposcelis bostrychophila badonnel," Molecules, vol. 18, no. 5, pp. 5684-5696, 2013.

[27] X. C. Liu, Y. Li, T. Wang, Q. Wang, and Z. L. Liu, "Chemical composition and insecticidal activity of essential oil derived from Artemisia frigida Willd. (Compositae) against two grain storage insects," Tropical Journal of Pharmaceutical Research, vol. 13, pp. 587-592, 2014.

[28] Z. L. Liu, N. N. Zhao, C. M. Liu, L. Zhou, and S. S. Du, "Identification of insecticidal constituents of the essential oil of Curcuma wenyujin rhizomes active against Liposcelis bostrychophila badonnel," Molecules, vol. 17, no. 10, pp. 12049-12060, 2012.

[29] X. C. Liu, L. Zhou, and Z. L. Liu, "Identification of insecticidal constituents from the essential oil of Valeriana jatamansi Jones against Liposcelis bostrychophila Badonnel," Journal of Chemistry, vol. 2013, Article ID 853912, 6 pages, 2013.

[30] M. A. Saleem and R. M. Wilkins, "Precocene-I: an anti-juvenile hormone, a potential 4th generation insecticide against a malathion-resistant strain of Oryzaephilus surinamensis (L.)," Pakistan Journal of Zoology, vol. 16, no. 2, pp. 195-201, 1984.

[31] M. A. A. Eid, M. S. Salem, and G. Z. Taha, "Effects of precocene II on morphogenesis of the desert locust Schistocerca gregaria," Biochemical Systematics and Ecology, vol. 16, no. 5, pp. 515-520, 1988.

[32] R. P. Srivastava and P. Proksch, "Insecticidal and antifeedant effects of compounds of plant origin against insect pests," Indian Journal of Plant Protection, vol. 21, no. 2, pp. 234-239, 1993.

[33] R. C. Saxena, M. Sharma, M. L. Kumar, S. K. Bansal, and D. Shrivastava, "Developmental effects of 6, 7-dimethoxy-2, 2-dimethyl chromene on the preimaginal stages of Anopheles stephensi," Proceedings of the Academy of Environmental Biology, vol. 3, no. 2, pp. 181-184, 1994.

[34] S. Srivastva and K. Kumar, "Precocene I and II induced metamorphosis in a noctuid moth, Spodoptera litura Fabr," Proceedings of the National Academy of Sciences, India B, vol. 67, no. 3-4, pp. 213-226, 1997

[35] W. E. Khafagi, "Effects of juvenile hormone I, precocene I and precocene II on the progeny of Microplitis rufiventris Kok. female when administered via its host, Spodoptera littoralis (Boisd.)," Journal of Applied Entomology, vol. 128, no. 1, pp. 6-10, 2004.

[36] M. Noa, L. M. Sanchez, and R. Durand, "Ageratum houstonianum toxicosis in Zebu cattle," Veterinary and Human Toxicology, vol. 46, no. 4, pp. 193-194, 2004.

Xiao Nan Lu, Xin Chao Liu, Qi Zhi Liu, and Zhi Long Liu

Department of Entomology, China Agricultural University, 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China

Correspondence should be addressed to Zhi Long Liu; zhilongliu@cau.edu.cn

Received 12 February 2014; Revised 27 May 2014; Accepted 28 May 2014; Published 15 June 2014

Academic Editor: Bhimapaka C. Raju

TABLE 1: The scale to be assign repellency of
the essential oil and its constituents.

Class   Percent repulsion (%)

0            0.01 to 0.1
I              0.1-20
II             20.1-40
III            40.1-60
IV             60.1-80
V             80.1-100

TABLE 2: GC-MS analysis of essential oil of
Ageratum houstonianum aerial parts.

No.          Compound           RI    Peak area (%)

1        [alpha]-Pinene *      939        0.19
2        [beta]-Pinene *       974        0.11
3            Sabinene          975        0.06
4        [beta]-Myrcene *      991        0.09
5      [beta]-Phellandrene     1030       0.18
6         1,8-Cineole *        1032       0.11
7           Linalool *         1094       0.32
8           Isoborneol         1160       0.18
9         4-Terpineol *        1177       0.07
10     [alpha]-Terpineol *     1189       0.11
11      Isobornyl acetate      1284       0.07
12       Bornyl acetate *      1287       0.43
13         Piperitenone        1338       0.27
14       [alpha]-Cubebene      1345       0.34
15     a-Terpineol acetate     1349       0.21
16          Eugenol *          1356       0.16
17           Copaene           1375       2.45
18       [beta]-Cubebene       1388       0.32
19      (Z)-Caryophyllene      1409       0.75
20    [beta]-Caryophyllene *   1420       7.92
21       [gamma]-Elemene       1433       0.11
22       [beta]-Gurjunene      1434       0.51
23    [alpha]-Caryophyllene    1454       0.25
24     (E)-[beta]-Famesene     1457       0.28
25         Precocene I         1467       13.21
26      [gamma]-Muurolene      1473       2.87
27         Germacrene D        1485       0.91
28      [alpha]-Muurolene      1495       0.13
29       [gamma]-Cadinene      1513       2.18
30       [delta]-Cadinene      1523       0.17
31       Cadine-1,4-diene      1532       0.22
32         Spathulenol         1578       0.09
33     Caryophyllene oxide     1583       0.23
34         Precocene II        1656       62.68
35       [beta]-Bisabolol      1673       0.88
         Total identified                 97.92
          Monoterpenoids                  1.26
         Sesquiterpenoids                 20.61
            Precocenes                    75.89
              Others                      0.16

RI, retention index on a HP-5MS column. * Identification by coinjection
of authentic compounds.

TABLE 3: Contact toxicity of Ageratum houstonianum essential oil and
its isolated compounds against Liposcelis bostrychophila.

                    [LD.sub.50] ([micro]g/   [LD.sub.50] ([micro]g/
Treatment           [cm.sup.2]) (95% FL *)   [cm.sup.2]) (95% FL *)

Essential oil          50.8 (45.7-55.6)       176.3 (148.6-194.2)
Precocene I            64.0 (578-70.3)        211.9 (189.8-232.5)
Precocene II           30.4 (276-33.2)         105.8 (94.1-116.4)
Pyrethrum extract      19.0 (176-20.9)          68.5 (62.1-75.8)

                                           Chi-square
Treatment           Slope [+ or -] SD    ([chi square])

Essential oil       3.85 [+ or -] 0.36      10.98 **
Precocene I         7.19 [+ or -] 0.66      8.67 **
Precocene II        8.65 [+ or -] 0.81      7.45 **
Pyrethrum extract   2.21 [+ or -] 0.17      4.27 **

 * Fiducial limits, ** significant at P < 0.05 level.

TABLE 4: Repellency (PR) after two exposure times for Ageratum
houstonianum essential oil and its isolated compounds against
Liposcelis bostrychophila.

                                    2 hr (nL/[cm.sup.2]) *
Treatment
                            6.4                      3.2

Essential oil        93  [+ or -] 4 (a)   V   86  [+ or -] 9 (a)   V
Precocene I          96  [+ or -] 5 (a)   V   87  [+ or -] 4 (a)   V
Precocene II         97  [+ or -] 5 (a)   V   85  [+ or -] 8 (a)   V
Dimethyl phthalate   98  [+ or -] 4 (a)   V   91  [+ or -] 3 (a)   V

                                   2 hr (nL/[cm.sup.2]) *
Treatment
                            1.6                        0.8

Essential oil        82  [+ or -] 6 (a)   V    70  [+ or -] 8 (ab)   IV
Precocene I          84  [+ or -] 7 (a)   V    74  [+ or -] 9 (ab)   IV
Precocene II         79  [+ or -] 8 (a)   IV   67  [+ or -] 7 (b)    IV
Dimethyl phthalate   89  [+ or -] 4 (a)   V    81  [+ or -] 5 (a)    V

                                 4 hr (nL/[cm.sup.2]) *
Treatment
                            6.4                      3.2

Essential oil        86  [+ or -] 7 (a)   V   80  [+ or -] 6 (a)   V
Precocene I          91  [+ or -] 4 (a)   V   81  [+ or -] 6 (a)   V
Precocene II         89  [+ or -] 9 (a)   V   82  [+ or -] 7 (a)   V
Dimethyl phthalate   90  [+ or -] 4 (a)   V   85  [+ or -] 4 (a)   V

                                    4 hr (nL/[cm.sup.2]) *
Treatment
                             1.6                        0.8

Essential oil        71  [+ or -] 7 (b)    V    61  [+ or -] 6 (b)   IV
Precocene I          83  [+ or -] 5 (a)    V    70  [+ or -] 8 (ab)  IV
Precocene II         78  [+ or -] 5 (ab)   IV   63  [+ or -] 1 (b)   IV
Dimethyl phthalate   84  [+ or -] 4 (a)    V    77  [+ or -] 4 (a)   IV

* Means in the same column followed by the same letters do not differ
significantly (P > 0.05) in ANOVA and Tukey's tests. PR was subjected
to an arcsine square-root transformation before ANOVA and Tukey's
tests.
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Title Annotation:Research Article
Author:Lu, Xiao Nan; Liu, Xin Chao; Liu, Qi Zhi; Liu, Zhi Long
Publication:Journal of Chemistry
Article Type:Report
Date:Jan 1, 2014
Words:4395
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