Antibacterial activities of Turkish pollen and propolis extracts against plant bacterial pathogens Esin Basim a, * , Hu ¨ seyin Basim b , Musa O ¨ zcan c a Department of Plant Production, Korkuteli Vocational School, University of Akdeniz, 07800 Antalya, Turkey b Department of Plant Protection, Faculty of Agriculture, University of Akdeniz, 07058 Antalya, Turkey c Department of Food Engineering, Faculty of Agriculture, University of Selc ¸uk, 42031 Konya, Turkey Received 7 March 2005; accepted 3 August 2005 Available online 22 September 2005 Abstract The ‘‘in vitro’’ antibacterial activities of Turkish pollen and propolis extracts were investigated against 13 different species of agricul- tural bacterial pathogens including Agrobacterium tumefaciens, A. vitis, Clavibacter michiganensis subsp. michiganensis, Erwinia amylo- vora, E. carotovora pv. carotovora, Pseudomonas corrugata, P. savastanoi pv. savastanoi, P. syringae pv. phaseolicola, P. syringae pv. syringae, P. syringae pv. tomato, Ralstonia solanacearum, Xanthomonas campestris pv. campestris and X. axonopodis pv. vesicatoria. Among the tested bacteria, A. tumefaciens was the most sensitive one to 1/5 concentration of pollen extract, and the sensitivity of the bacteria followed the sequence A. tumefaciens > P. syringae pv. tomato, X. axonopodis pv. vesicatoria > E. amylovora, P. corrugata, R. solanacearum, X. campestris pv. campestris > A. vitis, C. michiganensis subsp. michiganensis > E. carotovora pv. carotovora, P. savas- tanoi pv. savastanoi, P. syringae pv. phaseolicola > P. syringae pv. syringae. P. syringae pv. phaseolicola was the most sensitive one to 1/10 concentration of propolis extract, and the sensitivity of the bacteria followed the sequence P. syringae pv. phaseolicola > P. savastanoi pv. savastanoi, P. corrugata, R. solanacearum > E. carotovora pv. carotovora, P. syringae pv. syringae, E. amylovora, A. tumefaciens, A. vitis, C. michiganensis subsp. michiganensis, P. syringae pv. tomato, X. campestris pv. campestris, X. axonopodis pv. vesicatoria. The least active concentrations towards the tested bacteria were 1/100 of the pollen extract and 1/1000 of the propolis extract. This study is the first report on the antibacterial activities of pollen and propolis against the plant pathogenic bacteria. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Propolis; Pollen extract; Plant pathogenic bacteria; Antibacterial activity 1. Introduction Propolis, or bee glue, is a brownish resinous material collected by worker bees from the leaf buds of numerous tree species like birch, poplar, pine, alder, willow and palm. In order to manufacture propolis, bees may also use mate- rial actively secreted by plants, or exuded from wounds in plants (lipophylic material on leaves, mucilages, gums, res- ins, lattices, etc.). The term propolis derives from the Greek pro (for Ôin front ofÕÔat the entrance toÕ) and polis (Ôcommu- nityÕ or ÔcityÕ) and means a substance in defence of the hive. Bees mix the original propolis with beeswax and b-glucosi- dase they secrete during the propolis collection. The result- ing material is used by bees to seal holes in the hives, exclude draught, protect against external invades and mum- mify their carcasses. Up to now, more than 180 compounds, mainly polyphenols, have been identified as constituents of propolis. New compounds have also been isolated from Bra- zilian (3,5-dipreny-4-hydroxycinnamic acid) and Chinese (octacosanol) samples of propolis (Castaldo & Capasso, 2002). Pollen is a fine, powder-like material produced by flower- ing plants and gathered by bees. Pollens are the male repro- ductive cells of flowers. Flower pollens, ‘‘beesÕ primary food’’ source, contain concentrations of phytochemicals 0260-8774/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jfoodeng.2005.08.027 * Corresponding author. Fax: +90 242 6435005. E-mail address: ebasim@yahoo.com (E. Basim). www.elsevier.com/locate/jfoodeng Journal of Food Engineering 77 (2006) 992–996