Industrial Crops and Products 44 (2013) 618–621 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products jo ur nal homep age: www.elsevier.com/locate/indcrop Short communication Differential activity against aphid settling of flavones obtained from Clytostoma callistegioides (Bignoniaceae) Lucía Castillo a,b , Martina Díaz a , Azucena González-Coloma b , Carmen Rossini b,∗ a Laboratorio de Ecología Química, Departamento de Química Orgánica, Facultad de Química, Universidad de la República, General Flores 2124, CP 11800, Montevideo, Uruguay b Instituto de Ciencias Agrarias-CSIC, Serrano, 115 Dpdo-28006, Madrid, Spain a r t i c l e i n f o Article history: Received 6 July 2012 Received in revised form 5 September 2012 Accepted 10 September 2012 Keywords: Clytostoma callistegioides Flavones Rhopalosiphum padi Myzus persicae Aphids a b s t r a c t Secondary metabolites from plants have been the source of various natural products with anti-insect properties; having some of them already reached the market. In recent years, the drawbacks related to the use of synthetic pesticides have triggered the need to find alternatives and brought about revitalization on bioprospecting programs. In that direction, this work presents the results of a study on a South American native species. The methanolic leaf extract of Clytostoma callistegioides (Bignoniaceae), was hydrolyzed with HCl, and sequentially subjected to Sephadex LH20 and HPLC procedures. Three flavones, not previ- ously obtained from this species, were identified by NMR and UV spectra: 4 ′ -Hydroxywogonin, Acacetin and Galangustin. Two important agricultural pests, Myzus persicae and Rhopalosiphum padi (Hemiptera: Aphididae), were studied in their reluctance to settling on leaf treated with these flavonoids, and the results are here reported in terms of a preference index (PI), calculated as PI = [(%C - %T)/(%C + %T)]; where %C and %T are the percentages of aphids settled on the treated and the control leaf pieces, respectively. While 4 ′ -Hydroxywogonin did not exhibit significant activity against neither of the aphids, Acacetin was active only against R. padi (PI = 0.3 ± 0.1). Further, Galangustin exhibited a better deterrence activity on the settling of both aphids (PI = 0.4 ± 0.1 and 0.8 ± 0.1 for M. persicae and R. padi respectively). © 2012 Elsevier B.V. All rights reserved. 1. Introduction One of the present biggest challenges that confront the planet is the need to raise yields of primary production, consistently to the increase of world population. This has generated an increase in the use of conventional pesticides to control pest damages in crops. The use of classical pesticides produces effective results in the short term, but it has several drawbacks, such as the develop- ment of resistance and the adverse environmental effects (Gilbert, 2012). The latest trend in agricultural production calls therefore for the implementation of alternatives to the use of conventional pesticides (Isman, 2006). As a part of the search for options to the use of synthetic pesti- cides, our group has been extensively working in a bioprospecting program looking for potential botanical pesticides in Uruguay’s flora. Species from different families have been tested against several insect pests (Castillo et al., 2009). Among these species, ∗ Corresponding author at: General Flores 2124, CP 11800, Montevideo, Uruguay. Tel.: +598 29242535; fax: +598 29241906. E-mail addresses: lcastillo@fq.edu.uy (L. Castillo), martinadiaz@fq.edu.uy (M. Díaz), azu@ica.csic.es (A. González-Coloma), crossini@fq.edu.uy (C. Rossini). ethanolic extracts from three Bignoniaceae species, Clytostoma cal- listegioides, Macfadyena unguis-cati and Dolychandra cinanchoides, exhibited promising potential as they were non-toxic to the hon- eybee Apis mellifera, but deterred settling of aphids (Myzus persicae and Rhophalosiphum padi) and feeding by a Cucurbitaceae specialist (Epilachna paenulata) (Castillo et al., 2009). The interactions of Bignoniaceae species with insects have been extensively studied when mediated by iridoids, the most common secondary metabolites of the family, according to Bowers’ inves- tigations (Bowers and Puttick, 1986; Bowers, 2003). Iridoids are efficient plant defences against herbivory in some cases (El-Naggar and Doskotch, 1980; Bernays and De Luca, 1981; Chan et al., 1986; Puttick and Bowers, 1988; de la Fuente et al., 1994), but they can also act as kairomones enabling herbivores to find their host plants (Stephenson, 1982). Few other defensive metabolites have been characterized from members of Bignoniaceae. These include naph- thoquinones and quinones (Grace et al., 1989; McDaniel, 1992; Xu et al., 2003; Kaushik and Saini, 2008) as well as fatty acids (Castillo et al., 2010). C. callistegioides, a native species from the south of South Amer- ica, is an ornamental vine advertised in nurseries as pest free. Ethanolic extracts from its leaves and vines strongly deterred sett- ling of M. persicae (Hemiptera: Aphididae). Besides, the leaf extract 0926-6690/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2012.09.012