Renoprotective Role of Natural Honey in the prevention of High Blood Pressure in Animal Model
Honey is a natural product produced from the nectar and exudation of plants by the honeybees, Apis mellifera (Alvarez-Suarez et al., 2010). The natural honey has been reported to contain about 200 substances, which consist of not only highly concentrated solution of sugars, but also the complex mixture of other saccharides, amino acids, peptides, enzymes, proteins, organic acids, polyphenols, carotenoidlike substances, vitamins, and minerals (Gheldof etal., 2002; Sato & Miyata, 2000; White, 1975).
Sugars are the main constituents of honey, comprising about 95% of its dry weight (Alvarez-Suarez et al., 2010). While glucose and fructose are the dominant constituents, about 25 different sugars have been detected (Doner, 1977; Siddiqui, 1970). The view by White (1975) has demonstrated that proteins in honey are mainly enzymes. Honey contains roughly 0.5% proteins (Alvarez-Suarez et al., 2010) and the protein contents in some honeys can be over 1 000 µg/g (Azeredo et al., 2003). Main enzymes include diastase, invertase, glucose oxidase and catalase. Although the content of amino acids in honey is relatively small, it has been found that almost all of physiologically essential amino acids are present in honey (Cotte et al., 2004; Hermosín et al., 2003). The primary amino acid is proline, contributing 50-85% of the total amino acids (Hermosín et al., 2003). The level of organic acids in honey is relatively low and about 18 organic acids have been detected (Nanda et al., 2003). Most of the acidity present in honey is added by honeybees (Echigo & Takenaka, 1974). Gluconic acid, the predominant honey organic acid, is the product of glucose oxidation, presenting at 50-fold higher levels than other acids (Cherchi et al., 1994). Investigations have shown that a wide range of trace elements are present in honey, including Al, Ba, Bi, Co, Cr, Mo, Ni, Pb, Sn, Ti, as well as minerals (Ca, Cu, Fe, K, Na, Mg, Mn, Zn) (Conti, 2000; Stocker et al., 2005), among them, the main mineral element is potassium while copper presents lowest amount (Nada et al., 2003). Vitamins such as thiamin (B1), riboflavin (B2), pyridoxine (B6), and ascorbic acid (C) have also been reported but their amount is very small in honey (Ball, 2007; Nada et al., 2003). When honey is treated with mild heat or prolonged storage, a compositional change can occur due to caramelization of the carbohydrates, the Maillard reaction, and decomposition of fructose in the acid medium of honey (Villamiel et al., 2001)
Phytochemicals are chemical substances naturally occurring in plants and many of them are now recognized to have health-promoting activity (Apostolidis et al., 2006; Liu, 2003; Liu, 2004; Sun et al., 2002; Vattem et al., 2005). Phenolic substances are the largest group of phytochemicals (King & Young, 1999). The plants containing phytochemicals might be used as a supply of the bees; thereby bioactive compounds can be transferred to honey. Studies have shown that honey contains great variation in contents of different phytochemicals according to floral sources and climatic conditions, which contribute to different characteristic colors, flavors, aromas, and bioactivities (Abu-Tarboush et al., 1993; Molan, 1996). As herbal medicines are derived from different plants, which can produce different therapeutic properties (Villegas et al., 1997), some honey derived from these specific plants may provide added value for health promotion. Honey produced by bees fed herbal extracts has shown greater antioxidant activity than normal honey (Rosenblat et al., 1997).