ABSTRACT
Natural products have been used for thousands of years in folk medicine for several purposes. Among them, honey has attracted increased interest in recent years due to its antimicrobial activity against a wide range of pathogenic microorganisms (Table 4.1). Various studies attribute the antibacterial, antifungal, anti-inammatory, antiproliferative, and anticancer potentiating properties to honey (Skiadas and Lascaratos 2001). Approximately 70% of bacteria that cause infections in hospitals are resistant to at least one of the antibiotics most commonly used to treat infections. This antibiotic resistance is driving up health care costs, increasing the severity of disease and the fatality of certain infections. Sepsis is another serious medical condition resulting from severe inammatory response to systemic bacterial infections (Martin et al. 2003). More desirably, honey has the capacity to bind bacterial endotoxin and neutralize bacterium-induced inammatory response. Because of the dual capability to kill bacteria and neutralize endotoxins, this antimicrobial natural product holds great promise as a new class of antimicrobial and antisepsis agent (Finaly and Hancock 2004). The major antimicrobial properties are correlated to
Introduction .............................................................................................................. 37 Antimicrobial Properties of Honey .......................................................................... 39
Physicochemical Properties of Honey ................................................................ 39 Phytochemical Properties of Honey ....................................................................40 Variation in Honey Potency and Bacterial Susceptibility ................................... 41 Antiviral Properties of Honey ............................................................................. 43 Antifungal Properties of Honey .......................................................................... 43
Anti-Inammatory Properties of Honey .................................................................. 43 Inammation: Physiologic Overview .................................................................. 43 Role of Honey in Preventing and Curing Inammation ...................................... 45
Antioxidant Properties of Honey ............................................................................. 47 Botanical Origin and Antioxidant Activities of Honey ............................................48 Antioxidant in Honey Adds Health Benets ............................................................ 49 Immunomodulatory Properties of Honey ................................................................ 49 References ................................................................................................................ 51
the hydrogen peroxide (H2O2) level, which is determined by relative levels of glucose oxidase and catalase (Weston et al. 2000), whereas the nonperoxide factors that contribute to honey’s antibacterial and antioxidant activity are lysozyme, phenolic acids, and avonoids (Snowdon and Cliver 1996). Apart from antibacterial properties, honey also plays a therapeutic role in wound healing and the treatment of eye and gastric ailments. This is partly due to its antioxidant activity (Gheldof et al. 2002), because some of these diseases have been recognized as being a consequence of free radical damage (Aljadi and Kamaruddin 2004). Topical application of growth factors to wound has shown good capability to speed up tissue repair in animal models (Mustoe et al. 1991; Pierce et al. 1992). Moreover, human recombinant platelet-derived growth factor (PDGF), which directly interferes and favors the repair process, has given good results in the healing of diabetic patient ulcers (Pierce et al. 1992; Steed 1998). However, they are high-cost dressings that are not affordable to most patients who have chronic ulcers (Mendonça and Coutinho-Netto 2009). It is also to be mentioned that infection is important for the treatment of
TABLE 4.1 Infection Caused by Bacterial Pathogens That Are Sensitive to the Antibacterial Activity of Honey
an infected wound. Therefore, different types of medicated collagen dressings with antibiotics have been developed (Lee et al. 2002). It is well established that honey has antibacterial activity in vitro, and clinical case studies have shown that application of honey to severely infected cutaneous wounds is capable of improving the healing process (Moore et al. 2001). Health care professionals are aware that wound dressings should be judged on effectiveness, safety, and cost. As such, honey that is to be used for medicinal purposes has to be free of residual herbicides, pesticides, heavy metals, and radioactivity. It also has to be sterilized by γ-radiation to prevent wound infection (wound botulism). Furthermore, glucose oxidase in honey has to be controlled during processing to maintain the potency for infection prevention without doing harm to the wound tissues. Besides these primary conditions, the application of honey should be easy (Bogdanov 1996; Molan and Allen 1996; Emsen 2007). Understanding the scientic basis of the anti-inammatory properties of honey could potentially lead to the development of novel therapeutic agents with a view to rationalizing and optimizing its use for wound therapy. Topical application of cytokines such as interleukin (IL)-8, although not very effective, or other agents such as emu oil (Politis and Dmytrowich 1998; Li et al. 2004), which inhibits proin-ammatory cytokine production, has been shown experimentally to promote wound healing. Ointments that contain enzymatic agents such as DNase and collagenase are used to promote wound debridement (Hebda et al. 1990). However, these drugs used in clinical practice have low efcacy in healing of chronic wounds (Mendonça and Coutinho-Netto 2009). Modern hydrocolloid wound dressings are presently favored as moist dressing, although such wound dressings are expensive. Foams, gels, and alginates are also available for treating chronic wounds. Although moist wound care enhances the healing process through tissue regrowth, such moist conditions favor the growth of infecting bacteria.
