Natural Antibiotic: Definition and Application

Antibiotic resistance is now a major health problem. In 2013, more than nine million people worldwide died from bacterial infections. Interest in the field of research and development of new antibiotics has declined in recent years due to increasing antibiotic resistance and rising deaths. Natural products have become a source of inspiration for the design of new antibiotics due to their complex structure and unique antibacterial function. In-depth study of the complexity of antibiotic compounds and mining of natural products is expected to open up new ways to deal with the bacterial resistance crisis.

What are natural antibiotics?

Natural antibiotics are substances derived from natural sources such as plants, herbs, actinomycetes, fungi and even certain minerals that have the ability to inhibit or destroy bacteria. These substances were used in traditional medicine for hundreds of years before the advent of modern synthetic antibiotics and continue to play an important role in alternative and complementary therapies. The antibacterial activity of plants is affected by the type and concentration of the compounds contained in them. The most common phytochemicals with antibacterial activity include phenols, polyphenols, terpenes, essential oils, alkaloids, lectins, and polypeptides, and mixtures of them. Between 1986 and 2006, more than 100 antimicrobial agents were approved for clinical use, 75 of which were of plant origin.

Compared to synthetic antibiotics, which often specialize in specific pathways or structures of bacteria, natural antibiotics have a broader range of actions. They work by damaging bacterial cell membranes, inhibiting key enzyme activity, or impeding protein synthesis. Due to the complexity of the structure of natural antibiotics, it is more difficult for bacteria to develop resistance to them, which makes the value of natural antibiotics more and more prominent in the increasingly serious problem of antibiotic resistance. Natural antibiotics are commonly found in herbal extracts, essential oils, teas and nutritional supplements, and are also suitable for the topical treatment of skin wounds and ulcer infections.

Schematic presentation of the main mechanisms of antibacterial action of natural compounds. (Pancu, D. F., 2021)

What is the strongest natural antibiotic for humans?

Identifying the strongest natural antibiotic for humans involves considering several factors, including the type of infection, the bacterial strain involved, and the overall health of the individual. There are some natural antibiotics that are effective for humans and all can be used for bacterial infection.

Garlic: Allicin is the main active compound in garlic and is responsible for most of its antibacterial activity. It is effective against a variety of bacterial strains, including multidrug-resistant ones. Allicin kills bacteria by blocking enzymes critical to energy production (ethanol dehydrogenase, acetyl-CoA synthetase, and acetokinase) that maintain cell structure. In addition, allicin can stop the growth of bacteria and fungi by blocking the formation of biofilms, which are the source of most persistent infections in the human body.

Tea tree oil: Tea tree oil is extracted from the tea tree plant (Melaleuca alternifolia) and is a broad-spectrum antibiotic used on the skin. It is an active ingredient in many preparations used to treat skin infections. Some of the compounds in tea tree oil, called monoterpenes (terpinene-4-ol, linalool, alpha-pinene and alpha-terpinol) are responsible for antimicrobial resistance. Monopterpenes block energy production (cellular respiration) and damage the outer layer (membrane) of bacterial and fungal cells.

Tea tree oil is effective against bacteria that cause skin infections, acne, pneumonia, food poisoning and more. Some strains include Staphylococcus (Staphylococcus aureus and Staphylococcus epidermidis), Propionibacterium pemphigus, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella, and Escherichia coli. In a clinical trial of 236 hospitalized patients, a cream and body wash containing tea tree oil (10% and 5% tea tree oil, respectively) used for 5 days helped clear antibiotic-resistant Staphylococcus aureus skin infections.

Oregano oil: The antibiotic and antifungal activity of oregano oil comes from two compounds, carvacrol and thymol. Thymol and carvacrol destroy extracellular bacteria (membranes) and kill cells.

In a clinical trial of 40 patients recovering from surgical wounds, oregano oil ointment reduced the contamination of wounds by Staphylococcus aureus, thus aiding the healing process. In test tubes, Mexican oregano oil, along with thyme and mustard oil, was effective against three bacteria (Listeria monocytogenes, Staphylococcus aureus and Salmonella enteritidis). Thymol and carvacrol also have antifungal, antiviral, and antiparasitic activities.

Echinacea: While the exact composition of echinacea varies from species to species, the main components are carbohydrates, caffeic acid, and protein (glycoprotein).

Echinacea reduces the symptoms of bacterial infection by blocking the release of inflammatory markers such as cytokines. The mechanism of antibacterial action is not clear. Echinacea is effective in reducing the growth of a variety of bacterial strains, such as Streptococcus pyogenes, Haemophilus influenzae, Legionella pneumophila, and Propionibacterium acnes. Echinacea blocks the growth of a variety of fungal strains and protects mouse cells from deadly infections.

Manuka honey: The main active antibiotic ingredient in Manuka honey is a compound called pyruvaldehyde. Another ingredient in honey is propolis, which contains flavonoids (such as galangin and pinocembrin), phenolic acids, and esters that may help boost the immune system. Manuka honey is also rich in glucose oxidase, an enzyme that converts glucose into hydrogen peroxide, which has antibacterial properties. Another compound, glucolactone, lowers the pH of honey and has natural antibacterial properties.

Cinnamon: Two compounds, cinnamaldehyde and eugenol, are responsible for the antibacterial and antiviral properties of cinnamon.

Turmeric: Curcumin is the most active compound in turmeric. In test tubes, it blocks bacterial biofilms that cause urinary tract infections, such as E. coli, Pseudomonas aeruginosa, Proteus mirabilis, and Proteus mirabilis. Curcumin also interferes with bacterial intercellular communication (quorum sensing) and prevents the production of important compounds (pyocyanin and acylhomoserinolactone). Curcumin also disrupts the activity of proteins involved in survival in the fungus (ATPase activity, ergosterol and protease). Curcumin inhibits hepatitis C virus replication (via the PI3K /Ak pathway).

Some antibiotics at BOC Sciences

Antibiotic production services at BOC Sciences

What is the strongest natural antibiotic for tooth infection?

Garlic: Garlic extracts may help treat swollen gums and prevent tooth decay because they can kill oral pathogens in test tubes, such as: Porphyromonas gingivalis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans. Allicin inhibits the germination of spores and the growth of fungi (Candida albicans, Cryptococcus, Aspergillus and Saccharomyces cerevisiae) in test tubes. Candida can infect the lining of the mouth and cause an inflammatory disease called denttitis or oral candidiasis. In 2 clinical trials conducted on 96 people with the disease, garlic extract (used as a mouthwash or toothpaste) showed similar effects to the antifungal drugs nystatin and clotrimazole.

Oregano oil: Thymol and carvacrol stop the growth of bacteria that cause tooth decay (Streptococcus mutans) and, in tests on rats, protected them from gum disease.

Turmeric: In a cellular study, the ginger compound killed three of the bacteria that cause gum disease: Porphyromonas gingivalis, Porphyromonas pulposus and Prevotella intermedia.

Cloves: The main component of cloves, eugenol, fights a variety of candida genera and can be used to treat oral candida infections (oral candidiasis) as well as inflammation and soreness caused by denture use (denture stomatitis).

What is the strongest natural antibiotic for UTI?

Urinary tract infections (UTIs) are a common health concern, especially for women. Among natural antibiotics, cranberry extract is well-known for preventing bacterial adhesion to the urinary tract lining, thus reducing the likelihood of infection. But if is for preventive that serve cranberry anyway.

Oregano oil is proving to be a powerful natural antibiotic for treating UTIs. The powerful antimicrobial effect, especially by carvacrol, helps in removal of E. coli and most common reason for UTIs. Moreover, garlic has also been found to be effective in curing UTIs due to it generalised antibacterial effects.

Reference

1. Pancu, D. F., et al. Antibiotics: conventional therapy and natural compounds with antibacterial activity-a pharmaco-toxicological screening. Antibiotics. 2021, 10(4): 401.