New bioactive chalcones in propolis from El Salvador

Propolis (bee glue) is a resinous hive product collected by bees from plant exudates. It is widely used in medicine, cosmetics and food industry (Marc ucci 1995; Matsuda 1994), due to its versatile biological activities. These include antimicrobial, fungicidal, antiviral, immunostimulating, cytostati c and radical-scavenging activities (Marcucci, 1995; Krol et al., 1996). Fo r a long period, investigations on propolis were focused on samples origina ting from the. temperate zones (Ghisalberti, 1979; Marcucci, 1995). However , the chemical composition of bee glue depends on the flora at the site of collection and varies at different geographic locations (Bankova et al., 20 00). For this reason the composition of tropical propolis is quite differen t form propolis from temperate regions. Recently, tropical propolis has bec ome a subject of increasing interest for chemists and biologists (Banskota et al., 2000a, Marcucci and Bankova, 1999; Valcic et al., 1999, Bankova et al., 1998). It turned out to be a source of new biologically active compoun ds (Banskota et al., 2000b; Claus et al., 2000, Hirota et al., 2000; Kimoto et al., 1998). In this paper we report the isolation and characterization of two new chalcones from propolis originating from El Salvador, Central Am erica, and their biological activity.