In a country so obsessed with the use of antibacterial soaps and hand sanitizers that contribute to the growing problem of antibiotic-resistant bacteria, some so-called “natural” products have shown to be effective against some common bacteria, viruses, and fungal organisms.
Plants, primarily herbs, have been claimed to have antibacterial properties for centuries; however, the evidence has been based on folklore and anecdotal evidence. Herbs have been used in the past for healing and medicinal purposes, but science-based evidence has been lacking. Is there any scientific evidence to support these claims? Surprisingly, there are some reports worth noticing.
At Kansas State University, researchers added cinnamon or no cinnamon to commercially pasteurized apple juice samples. They then added several bacteria such as Salmonella, Yersinia, and Staphyloccus species and viruses that commonly cause foodborne illnesses. The samples were then stored at either room or refrigerated temperatures. When they compared the samples, they observed that the cinnamon samples had fewer live organisms than in the cinnamon-free samples. Also the bacteria and viruses were killed in the juice at room temperature than when refrigerated.
The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections
Hospital-acquired infections and antibiotic-resistant bacteria continue to be major health concerns worldwide. Particularly problematic is methicillin-resistant Staphylococcus aureus (MRSA) and its ability to cause severe soft tissue, bone or implant infections. First used by the Australian Aborigines, Tea tree oil and Eucalyptus oil (and several other essential oils) have each demonstrated promising efficacy against several bacteria and have been used clinically against multi-resistant strains.
Several common and hospital-acquired bacterial and yeast isolates (6 Staphylococcus strains including MRSA, 4 Streptococcus strains and 3 Candida strains including Candida krusei) were tested for their susceptibility for Eucalyptus, Tea tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea and Sage oil with the agar diffusion test. Olive oil, Paraffin oil, Ethanol (70%), Povidone iodine, Chlorhexidine and hydrogen peroxide (H2O2) served as controls.
Large prevailing effective zones of inhibition were observed for Thyme white, Lemon, Lemongrass and Cinnamon oil. The other oils also showed considerable efficacy. Remarkably, almost all tested oils demonstrated efficacy against hospital-acquired isolates and reference strains, whereas Olive and Paraffin oil from the control group produced no inhibition.
As proven in vitro, essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species.
Journal of Cranio-maxillofacial surgery. Vol. 37, Oct. 2009, pgs. 392-397.
Louis Pasteur first studied the antiseptic properties of garlic in the 1880’s. Garlic was used to disinfect wounds before our modern antibiotics were discovered by Alexander Fleming in 1928. Garlic contains two sulfur compounds that is thought give antiseptic properties by blocking some enzymes that bacteria and viruses use to invade and damage host cells.
In my microbiology course, we added garlic to ground beef samples and found that less bacteria grew when compared to a sample of beef without garlic.
Antimicrobial activity of garlic against oral streptococci.
The antimicrobial activity of two garlic cloves’ (1: purple and 2: white) crude extracts against oral microbiota was evaluated in vitro (study 1) and in vivo (study 2). Study 1 consisted of the evaluation of minimum inhibitory (MIC) and bactericidal (MBC) concentrations against nine streptococci strains. In study 2, a 2.5% garlic (clone 2) solution was used as a mouthwash in a 5-week study by 30 subjects. Blood agar and Mitis Salivarius Bacitracin agar were inoculated with subjects’ saliva to quantify oral microorganisms and mutans streptococci. Study 1 showed that garlic inhibited the growth of several bacterial species. Study 2 showed that 2.5% garlic mouthwash solution had good antimicrobial activity against mutans streptococci and oral microorganisms. Maintenance of reduced salivary levels of streptococci was observed after 2 weeks at the end of mouthwash use. Unpleasant taste (100%), halitosis (90%) and nausea (30%) were reported by subjects after the end of the study. It was concluded that the garlic clones have antimicrobial properties in vitro against streptococci and anticariogenic properties against oral microorganism in spite of its adverse effects.
Int J Dent Hyg. 2007 May;5(2):109-15.
Bactericidal and anti-adhesive properties of culinary and medicinal plants against Helicobacter pylori.
AIM: To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H. pylori). METHODS: Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H. pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H. pylori to stomach sections. RESULTS: Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H. pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H. pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric, borage and parsley were able to inhibit the adhesion of H. pylori strains to the stomach sections. CONCLUSION: Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H. pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent alternative therapy for H. pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.
World J. Gastroenterol. 2005; 11:7499-507