What do you know about Bee Propolis?
Propolis is in no way a new discovery. The use of propolis goes back to ancient times, at least to 300 BC, and it has been used as a medicine in local and popular medicine in many parts of the world, both internally and externally. Egyptians, Greeks and Romans reported the use of propolis for its general healing qualities and for the cure of some lesions of the skin. Propolis has always been reputed as an anti-inflammatory agent and to heal sores and ulcers. Ancient Egyptians used it to embalm their dead, and more recently it was used during the Boer War for healing wounds and tissue regeneration (Ghisalberti, 1979). However, its use continues today in remedies and personal products, and the list of preparations and uses is endless. It is still one of the most frequently used remedies in the Balkan States (Bankova, 2005a), and it has only been in the last decades that scientists have investigated its constituents and biological properties.
Propolis has attracted researchers’ interest in the last decades because of several biological and pharmacological properties, such as immunomodulatory, antitumor, antimicrobial, anti-inflammatory, antioxidant, among others (Bankova et al., 2000). Besides, propolis-containing products have been intensely mar-keted by the pharmaceutical industry and health-food stores (Banskota et al., 2001). The ethnopharmacological approach, combined with chemical and biological methods, may provide useful pharmacological leads. Thus, this review aimed to discuss its chemical composition and plant sources as well as to discuss some mechanisms of action of this bee product on the immune system and against tumor cells.
Propolis is a resinous material collected by bees from bud and exudates of the plants, which is transformed in the presence of bee enzymes. Its color varies from green, red to dark brown. Propolis has a characteristic smell and shows adhesive properties because it strongly interacts with oils and proteins of the skin. In general, propolis in nature is composed of 30% wax, 50%resin and vegetable balsam, 10% essential and aromatic oils, 5% pollen, and other substances (Burdock, 1998).
Etymologically, the Greek word propolis means pro, for or in defense, and polis, the city, that is “defense of the hive”. Bees use it to seal holes in their honeycombs, smooth out internal walls as well as to cover carcasses of intruders who died inside the hive in order to avoid their decomposition. Propolis also protects the colony from diseases because of its antiseptic efficacy and antimicrobial properties (Salatino et al., 2005).
After its administration to mice or to humans propolis does not seem to have side effects (Kaneeda and Nishina, 1994; Sforcin et al., 1995, 2002b; Jasprica et al., 2007). According to Burdock (1998) propolis is non-toxic, and its DL50 ranges from 2 to 7.3 g/kg in mice. This author suggested that the safe concen-tration for humans could be 1.4 mg/kg and day, or approximately 70 mg/day. After treatment of rats with different concentrations of propolis (1, 3 and 6 mg/kg/day), different extracts (water or ethanol) and varying the time of administration (30, 90 and 150 days) no significant alterations in total lipids, triglycerides, cholesterol, HDL-cholesterol concentrations, nor in AST and LDH specific activities were observed (Mani et al., 2006). The body weight of rats was measured in all these protocols, and propolis administration did not induce alterations in their weight. Cuesta et al. (2005) have not observed either mortality or growth rate alteration after daily intake of propolis in the diet during 6 weeks.
Although few in number, some cases of propolis allergy and contact dermatitis have been reported (Hausen et al., 1987; Hegyi et al., 1990; Silvani et al., 1997; Callejo et al., 2001), differently from the common allergy to honey, which contains allergens derived from flowers. Beekeepers usually show sen-sitivity to propolis (Rudeschko et al., 2004; Gulbahar et al., 2005). Ethanol and water extracts of propolis possess anti-allergic action, inhibiting histamine release in rat peritoneal mast cells (Miyataka et al., 1998). However, in higher concentrations (300 g/ml), propolis directly activated mast cells, promoting inflammatory mediators release, what could be linked to allergic processes in propolis-sensitive individuals (Orsi et al., 2005b).
Propolis antimicrobial property has been widely investigated, and several authors have demonstrated its antibacterial action (Grange and Davey, 1990; Kujumgiev et al., 1999; Sforcin et al., 2000; Orsi et al., 2005c, 2006b; Scazzocchio et al., 2006). Fernandes et al. (2001) investigated the antibacterial action of propolis produced by Africanized honeybees, comparing with that produced by the stingless bees (subfamily Meliponinae). Propolis produced by Partamona sp. and Melipona sp. had a similar activity to that produced by Apis mellifera.