## 1 Introduction  
The word propolis is derived from the Greek, \"pro\" meaning \"at the entrance of\" and \"polis\" meaning \"city\"; it is a substance produced by bees in order to protect the bee's larvae, honey stores and combs from microbial infections [1, 2]. According to the Mexican Official Standard [3], propolis is the natural product produced by the bees. It consists of resinous substances collected and processed by forage bees from the vegetation surrounding the apjur. With a resinous appearance, its color can vary depending on its floral origin and range from red, reddish-yellow, dark-yellow, brownish-green, brown or black, with a bitter and slightly spicy flavor. Bees produce propolis to use it as a thermal insulation material, sealing cracks present in the hive. This helps to control humidity and temperature inside the hive, soften the internal walls and protect the hive against microbial infections, as well as to mummify dead bees inside the hive [4].  
Propolis is composed of 50% resins and vegetable balm, 30% beeswax, 5% pollen and 10% essential oils, among other organic compounds, mainly primary and secondary plant metabolites, such as amino acids, vitamins, minerals, phenolic compounds, terpenoids, tannins and alkaloids [5]. Nearly 300 chemical compounds have been identified. These compounds are not necessarily present in all propolis, because their presence dependsmainly on the botanical and geographical origin, the species of bee and the harvest season, as well as of various environmental factors [6; 7; 8]. In general, propolis contains flavonoids, terpen, phenols and their esters, sugars, alcohols, ketones, hydrocarbons, amino acids, vitamins and minerals [7].  
Since ancient times, propolis has been used in traditional medicine for the treatment of various conditions in human and animal health. Today propolis is consumed in various parts of the world, due to its health benefits, among which are antiseptides, antimicrobials (antibacterial, antifungal, antiprotozoan and antiviral), spasmolity, anti-inflammatory, anesthetics, antioxidants, antidiabetic, antiulcer, antimutagenic, anticancer, immunomodulatory and antihepatotoxic, in addition, it is excellent for the treatment of skin burns and oral health care [9; 10; 11]. Phenolic compounds are those mainly responsible for antioxidant activity, due to their ability to capture free radicals with the formation of more stable molecules [2]. Furthermore, flavonoids and phenolic acids exert a strong antimicrobial activity [12; 13; 14]. For many years, tincture has been the traditional way to use propolis (alcohol extraction); however, in order to obtain a pure propolis's extract, various extraction methodologies have been developed [4]. Ultrasound-assisted extraction is one of the most promising methods due to extraction time, yield and profitability [15]. On the other hand, ultrasound can be an excellent alternative for the recrystallization of honey, without affecting quality parameters [16]. In addition to reducing the size of the crystals and the content of products of the Maillard reaction, the honeys treated with the ultrasound increase the content of bioactive compounds, consequently, an improvement in their functional properties, mainly due to the liberation of bioactive compounds from the crystallized honey matrix [17].  
The aim of the present investigation was to determine the content of phenols and flavonoids and the antioxidant and antimicrobial activities of ethanolic extracts of propolis's obtained by ultrasound or maceration in a simulated in vitro digestion.