Please cite this article in press as: Pluempanupat, S., et al., Laboratory evaluation of Dalbergia oliveri (Fabaceae: Fabales) extracts and isolated isoflavonoids on Aedes aegypti (Diptera: Culicidae) mosquitoes. Ind. Crops Prod. (2012), http://dx.doi.org/10.1016/j.indcrop.2012.09.006 ARTICLE IN PRESS G Model INDCRO-6340; No. of Pages 6 Industrial Crops and Products xxx (2012) xxx–xxx Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me page: www.elsevier.com/locate/indcrop Laboratory evaluation of Dalbergia oliveri (Fabaceae: Fabales) extracts and isolated isoflavonoids on Aedes aegypti (Diptera: Culicidae) mosquitoes Sujittra Pluempanupat a , Nutchaya Kumrungsee b , Wanchai Pluempanupat c , Kotchamon Ngamkitpinyo c , Warinthorn Chavasiri a , Vasakorn Bullangpoti b , Opender Koul d,∗ a Natural Products Research Unit, Department of Chemistry, Faculty of Science and Center for Petroleum Petrochemicals, and Advanced Materials, Chulalongkorn University, Bangkok 10330, Thailand b Biopesticides Toxicology Speciality Research Unit, Zoology Department, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand c Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science Kasetsart University, Bangkok 10900, Thailand d Insect Biopesticide Research Centre, 30 Parkash Nagar, Jalandhar 144003, India a r t i c l e i n f o Article history: Received 14 May 2012 Received in revised form 4 August 2012 Accepted 7 September 2012 Available online xxx Keywords: Burma rosewood Dalbergia oliveri Aedes aegypti Larval control Isoflavonoids a b s t r a c t We explored the potential of Burma rosewood, Dalbergia oliveri in dengue fever vector control by evalu- ating various extracts as larvicides and growth disruptors of Aedes aegypti Linnaeus (Diptera: Culicidae) under laboratory conditions. Third instars and pupae of the mosquito were tested using WHO guide- lines. Highest larvicidal effect was obtained with dichloromethane and hexane extracts (LC 50 = 289.1 and 325.3 ppm, respectively) within 24 h post-treatment. However, toxicity was about 1.78-fold more in dichloromethane extracts than hexane extract, if treatment was given for longer duration of 48 h (LC 90 = 5048.5 ppm for hexane and 2848.1 ppm for dichloromethane extracts, respectively). In these treat- ments moderate inhibition of pupation was also seen with some larvae staying as 4th stage larvae for 8 days before dying. There were no significant differences in the sex ratio of emerged adults compared with the controls. Dichloromethane extract, being most active, was subjected to sequential chemical separation to obtain series of isoflavonoids. Three compounds (+)-medicarpin, formononetin and (±)- violanone were identified as active larvicides of Ae. aegypti. Significant pupal mortality was observed with dichloromethane extract treatment of 1–3 h old pupae after 48 h post-treatment (LC 50 = 1004.5 ppm). Isoflavonoid medicarpin (LC 50 = 296.72 ppm) was most active compound against pupae. Eclosion inhi- bition (EI) was also observed in pupae treated with dichloromethane extract (EI 50 of 668.7 ppm). Thus, naturally occurring larvicides can be particularly effective where larval habitats are readily identifiable. Results obtained should be of value in the search for new natural larvicidal compounds from other extracts as well and represent the first report of this plant species being used to control a mosquito vector. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Over 40% of the world’s populations in some 100 countries are exposed to varying degrees of vector borne diseases like malaria, dengue, chikungunya, filariasis, Japanese encephalitis, and visceral leishmaniasis that result in thousands of deaths annually (El Hag et al., 1999; Dhiman et al., 2010). Aedes aegypti (Diptera: Culicidae) is the principal vector which transmits dengue fever and dengue hemorrhagic fever. It is also reported to infect more than one hun- dred million people every year in more than 110 countries in the tropics (Halstead, 2000). Factors that may cause outbreaks include ∗ Corresponding author. Tel.: +91 981 5666657; fax: +91 181 2274336. E-mail addresses: fsciwcp@ku.ac.th (W. Pluempanupat), warintho@yahoo.com (W. Chavasiri), fscivkb@ku.ac.th (V. Bullangpoti), okoul@airtelmail.in, okoul@koulresearch.org (O. Koul). an increase in vector breeding sites, migration of infected peo- ple into a vector-rich area, populated with susceptible individuals, arrival of new efficient vectors, breakdown of vector control meas- ures and resistance of the vectors to insecticides. Pesticides are known to cause environmental pollution and they are biomagnified through food chain, and have been demonstrated as being toxic to non-target organisms, with residual effects and resistance by their indiscriminate use. Hence, an effort is required to find alternative method to replace or reduce the use of chemical pesticides. The search for new strategies or natural products to control destruc- tive insects and 144 vectors of diseases is desirable, due to the prevalent occurrence of vector resistance to synthetic insecticides and the problem of toxic nonbiodegradable residues contaminating the environment and undesirable effects on nontarget organisms (Jantan et al., 2005). Botanical phytochemicals with mosquitocidal potential are now recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to 0926-6690/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2012.09.006