Zoonotic Diseases and Phytochemical Medicines for Microbial Infections in Veterinary Science: Current State and Future Perspective

Shin, Bora; Park, Woojun

In a previous study, we found that 4-hydroxybenzaldehyde as an adjuvant, which cannot be used as carbon source in A. baumannii, showed synergistic effects with only amphenicol antibiotics by increasing the antibiotic influx through a 4hydroxybenzoate transporter (69) . In particular, capsaicin is an active component of Capsicum plants (chili peppers) used as food ingredients and has been used for medicinal purposes since ancient times. Owing to its various pharmacological properties, including anti-cancer and beneficial cardiovascular and gastrointestinal tract effects, capsaicin has recently received attention to focus research into its antibacterial and anti-viral effects (55) . Its antibacterial effects have been reported against several foodborne pathogens, such as S. aureus, Helicobacter pylori, and P. aeruginosa (55, 56) . Intestinal bacteria can perform reactions that transform more complex plant phenols into simple phenol metabolites (51) . In addition, phenolic acid can control the number of microorganisms in the intestine. Gallic acid and caffeic acid have been reported to suppress the growth of Clostridium and Bacteroides species in intestinal microbiome (51) . In fact, phytomedicines, in particular Triticum aestivum L. and Theobroma cacao L., have been used in zoos to treat gastrointestinal pain and diarrhea in African elephants (Loxodonta africana) and crab-eating macaques (70) . Especially, cocoa beans have historically been used as a treatment for diarrhea, and the mode of action of cocoa-related flavonoids, i.e., inhibition of salt and water secretion, has been demonstrated in vitro (57) . The effective use of plant extracts with antimicrobial, antioxidant, and immune-boosting effects in combination with antibiotics can work synergistically and may provide a solution for management of antibiotic-resistant bacteria in veterinary science.