Industrial Crops and Products 37 (2012) 34–40 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me pag e: www.elsevier.com/locate/indcrop Variation in chemical composition and biological activities of two species of Opuntia flowers at four stages of flowering Imène Ammar a , Monia Ennouri a,b,∗ , Bassem Khemakhem c , Thabèt Yangui d , Hamadi Attia a a Alimentary Analysis Unit, National Engineering School of Sfax, BPW 3038, Sfax, Tunisia b Higher Institute of Applied Sciences & Technology of Mahdia, Sidi Messaoud 5111 Mahdia, Tunisia c Laboratory of Plant Biotechnology, Department of Biology, Faculty of Sciences of Sfax, BP 1171, 3000 Sfax, Tunisia d Laboratory of Environmental Bioprocess, Center of Biotechnology of Sfax, BP1177, 3018 Sfax, Tunisia a r t i c l e i n f o Article history: Received 6 May 2011 Received in revised form 13 September 2011 Accepted 23 November 2011 Available online 7 January 2012 Keywords: Opuntia ficus indica Opuntia stricta Flower Chemical composition Flowering stage a b s t r a c t The chemical composition of hexane extracts from flowers belonging to two species of prickly pear, Opuntia ficus-indica (L.) Miller and Opuntia stricta (Haw.) Haworth has been studied by gas chromatography–mass spectrometry in four developmental stages of flower: vegetative, initial flower- ing, full flowering, and post-flowering stages. Remarkable differences were noted between the flowers’ compositions. The main compounds were carboxylic acid (28–97%), terpenes (0.2–57%), esters (0.2–27%), and alcohols (<1.8%). The study of the biological activities showed that extracts were active in vitro towards four bacteria and two fungal strains. It exhibited remarkable activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Antioxidant activity of the flowers extracts was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method. Our findings demonstrate the interest of Opuntia flowers extract as a source of bioactive substances and its potential preservative use in food. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Opuntia ficus-indica (L.) Miller and Opuntia stricta (Haw.) Haworth belongs to the Cactaceae family and the order Centrosper- mae. These plants grow wild in arid and semi-arid regions, where the production of more succulent food plants is severely limited. O. ficus-indica species has gradually attained economic importance of the international scientific community, through FAO, also con- tributes to the diffusion of this cultivation (Galati et al., 2002). Many uses of cactus pear fruit and cladodes are reported (Hoffmann, 1980). Cladodes have been investigated as a possi- ble treatment for gastritis, hyperglycemia, ateriosclerosis, diabetes, and prostatic hypertrophy (Frati-Munari et al., 1990; Hegwood, 1990; Palevitch et al., 1993). Cladodes are also highly used for the food industry; they have been studied for their gelling properties (Sepúlveda et al., 2007) and they are also considered as a source of fiber and color in the formulation of cake (Ayadi et al., 2009). The fruits are used for the manufacture of food products such as juices (Espinosa et al., 1973; Ennouri et al., 2006), alcoholic ∗ Corresponding author at: Alimentary Analysis Unit, National Engineering School of Sfax, BPW 3038, Sfax, Tunisia. Tel.: +216 98 278 684; fax: +216 74 221 160. E-mail address: monia.ennouri@enis.rnu.tn (M. Ennouri). beverage (Bustos, 1981), jam (Sawaya et al., 1983), natural liquid sweetener (Saenz et al., 1996).The flower was little studied because of their limited bloom duration and in addition to that the diffi- culty to get them. They generally appear on one-year-old cladodes. The color of the Opuntia flower is generally yellow, but there are also orange, pink, purple, red, white or mottled flowers (Anderson, 2001). Floral development from bud to anthesis requires between 21 and 75 days (Grant and Grant, 1979; Barbera et al., 1992; Nieddu and Spano, 1992).Opuntia flower is useful in numerous fields; such as traditional medicines thanks to its effect which are defined as depurative and in particularly diuretic and relaxant of renal excre- tory tract. The valorization of natural resources such as plant extracts and products of plant secondary metabolism, particularly used by the popular tradition is for a great interest. In fact, plant extracts have attracted a great deal of scientific interest due to their poten- tial as a source of natural antioxidants and biologically active compounds, such as antibacterial, antifungal and insecticidal sub- stances (Celiktas et al., 2007). The nutritional and pharmacological benefits of the different parts of the prickly pear, in addition to its increasing importance at industrial level motivated our investigation on the chemical content of the flowers which are less known. In the literature few reports are focused on Opuntia flowers. Bergaoui et al. (2007) 0926-6690/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2011.11.027