• Natural antibiotics are substances of plant origin endowed with antibacterial effects.
• They are a useful tool to complement the body's natural defences, although it is important to use them after consulting a doctor.
• Natural antibiotics include commonly used culinary herbs (such as garlic and onion), as well as traditionally medicinal herbs and fungal species.

Among the tools available to us for promoting human health, natural antibiotics represent a precious resource. To understand their importance, we must start from the strict meaning of "antibiotic" — a drug aimed at neutralising bacterial infections. From this concept we then arrive at that of antibiotic resistance, the phenomenon by which the bacteria responsible for disease become stronger in relation to the antibiotic drug. In our era, antibiotics are the indispensable tool for managing bacterial infections of any severity. However, the incorrect and excessive use of these drugs has led to the development of resistant bacteria, reducing the effectiveness of conventional therapies. In this context, there arises a necessary search for alternative antibiotics derived from the natural world.

Natural antibiotics: what do we mean?

Natural antibiotics are represented by plant extracts with documented, or presumed, antibacterial activity. These are biologically active substances of various kinds, including essential oils and polyphenols. In a more or less complex way, these components define the "phytochemical" profile of each plant and act synergistically to produce certain effects (such as the antibacterial one).

The available scientific evidence provides promising data on various botanical species, although in some cases the results are only preliminary. Research is nonetheless progressing towards its objectives, providing ever more suitable tools.

In many instances, the plant resources in question are commonly used plants, such as the most widespread culinary herbs. The pharmaceutical and herbal industry, moreover, offers various products with specific formulations, drawing on more or less well-established scientific knowledge.

Preventing and treating infectious diseases with natural antibiotics

Fatigue, stress and poor diet are common causes of an inefficient immune system. Indeed, those who fall ill are already in a state of weakness, which makes it easier for infections to take hold. The issue is not so much avoiding contact with microbes — which is almost impossible — but rather trying to keep our defences always ready and prevent pathogens from finding a favourable environment in which to multiply.

Natural antibiotics can prove to be a valuable tool for prevention and treatment, also acting as a support for our defences. Plant resources, in fact, provide synergistic components capable of acting as antioxidants and immune stimulants as well. The herbal and pharmaceutical industry is very active in this regard, proposing more or less effective solutions depending on the case. Importantly, however, these do not dispense with medical supervision, since each condition requires a precise and carefully considered treatment. Furthermore, a "natural remedy" is not always synonymous with a "harmless remedy" and, certainly, cannot replace specific antibiotic drug therapies where these are necessary. Self-medication, in short, is always wrong, as well as potentially harmful.

The best natural antibiotics

As regards botanical sources of natural antibiotics, the scientific literature contains a great deal of data. Certain plant-derived substances, in particular, display interesting properties.

1. Aloe vera

Classified among perennial herbaceous plants, Aloe vera has long been the subject of numerous phytotherapeutic studies. Among the beneficial properties attributed to aloe, its antimicrobial ones stand out, having been assessed in several laboratory investigations. In particular, its antibacterial efficacy against various pathogen species has been documented, including Staphylococcus aureus and Escherichia coli. Currently, aloe juice and its bioactive components are included in the formulation of various supplements. These are aimed, for example, at managing urinary tract infections, also making use of aloe's mild anti-inflammatory activity. Its antioxidant and antifungal potential, also documented, against Candida species is likewise noteworthy. Given its content of aloin, a substance known for its laxative effects, it is advisable to avoid aloe preparations of dubious origin.

2. Grapefruit seed extract

Grapefruit seed extract has preservative properties, to the extent that it finds effective use in food preservation. Specifically, its antiviral, antibacterial, antifungal and antiparasitic potential has been demonstrated, attributed to the polyphenolic components of the plant extract. Closely linked to its antimicrobial activity, the antioxidant property is a further characteristic. More recent is the evidence on anti-biofilm activity, and therefore on the ability of grapefruit seed extracts to reduce the formation of true bacterial aggregates. Grapefruit seed extract lends itself to the formulation of supplements in liquid or capsule form. These are used for preventive purposes, to support the immune defences, as well as for curative purposes against infections of the oral cavity and the gastrointestinal tract.

3. Propolis

Propolis is a resin that bees collect and process for the protection of their hives. Long studied for its presumed beneficial properties, propolis boasts interesting antimicrobial activity. Several experiments have suggested its rather broad potential against multiple types of bacteria. Among these, some are classified as pathogens of the respiratory tract. These effects are associated with the phenolic substances contained in the resin and their related synergistic effect. A wide range of propolis-based products are available on the market, such as spray preparations for upper respiratory tract infections or tablet supplements for intestinal infections. Also worth noting are propolis honey and hydroalcoholic solutions, intended mainly for minor infections of the oral cavity. In addition to its antimicrobial effects, propolis boasts antioxidant and soothing properties, which are undoubtedly beneficial to its effectiveness.

4. Tea tree oil

Melaleuca alternifolia, or tea tree, is a shrub belonging to the Myrtaceae family. Several laboratory studies have demonstrated its antimicrobial potential, linking it to the plant's essential oils. These, in particular, appear to act on various viral, bacterial, fungal and parasitic pathogens. Regarding their effects on bacteria, tea tree oils act on several species, both damaging them and inhibiting their multiplication (at lower concentrations). Food supplements based on tea tree oil exploit both its antimicrobial component and its anti-inflammatory effect, which represents an additional property of the plant. The formulations in question are aimed at a variety of applications, depending on the infection to be prevented or treated (mycoses, cystitis, mouth ulcers, etc.).

5. Garlic

Known to everyone for its aromatic role in cooking, Allium sativum, or garlic, possesses marked medicinal properties. It is a rich source of phytochemical compounds capable of acting on multiple aspects of health, including glycaemic control and liver health. Its antimicrobial properties, directed against bacterial, parasitic and fungal infections, are also worth highlighting. Among the bioactive components involved in these effects are, specifically, substances known as allicin and quercetin. Laboratory investigations have shown bactericidal effects of garlic on staphylococci, Escherichia coli and even the bacterium Pseudomonas aeruginosa, which is known for antibiotic resistance. Given its strong olfactory component, garlic does not lend itself to direct consumption — or at least not in quantities sufficient to produce preventive and/or curative effects. As a result, there is no shortage of dedicated food supplements obtained from plant extracts.

6. Thyme

Among antibacterial remedies, thyme also features, classified in botany as Thymus vulgaris and belonging to the Lamiaceae family. It is a perennial aromatic species, readily available in our geographical area too. By virtue of its essential oil content and, in particular, its thymol, this species is associated with certain beneficial properties for humans, such as antispasmodic and antibacterial effects. Its antimicrobial potential has also been demonstrated by dedicated experimental studies, which have highlighted its effects on well-known bacterial species such as Staphylococcus aureus. Components extracted from thyme are marketed in the form of essential oil, mother tincture and tablet preparations.

7. Onion

The common kitchen onion (Allium cepa) is an unlikely source of beneficial properties, such as antioxidant and anti-inflammatory ones, but also antihypertensive, antidiabetic and antitumour effects. Antimicrobial — and antibacterial in particular — activities also count among the favourable effects for human health. Plant extracts of onion have been tested on various bacterial pathogens, such as bacilli and staphylococci, proving active thanks to certain flavonoids they contain, such as kaempferol and quercetin. In herbal medicine, preparations based on Allium cepa are numerous and produced for various preventive and curative purposes. References to respiratory and urinary infections are not uncommon in this regard.

8. Sage

Sage is known in botany as Salvia officinalis and belongs, like thyme, to the Lamiaceae family. It is a herb highly valued in the culinary world, although it can also boast medicinal potential. Among its best-known applications is the management of digestive complaints, but there is also evidence of its antimicrobial effects. These are attributed to the essential oils and other minor components, which act effectively in synergy. Certain laboratory experiments, specifically, have focused on the antifungal and antibacterial properties of these substances, highlighting effects on Staphylococcus aureus and the species Bacillus subtilis. A very widespread use of sage extracts concerns the treatment of minor mouth and throat infections. In this regard, herbal shops stock spray atomisers and dried leaves for preparing infusions.

9. Peppermint

Like sage, peppermint (Mentha piperita) is also used in cooking for its strong aromatic character. However, it is also a well-known phytotherapeutic remedy with antimicrobial effects. Documented through sector studies, its antibacterial activity has proved effective against various species, such as Escherichia coli. This property is attributed to the menthol contained in the plant.

In herbal medicine, peppermint extracts are available as essential oil, hydroalcoholic extracts and dried leaves. The application of these products is aimed, generally speaking, at the treatment of mild upper respiratory tract infections.

10. Essential oils of bergamot, eucalyptus, geranium and lemon

The role of essential oils as natural antibiotics represents a substantial field of research.

Eucalyptus essential oils, and eucalyptol (or 1,8-cineole) in particular, are associated with important antibacterial and antioxidant properties. Studies conducted on this substance have highlighted its effects on certain respiratory tract pathogens, such as Streptococcus pneumoniae. Also noteworthy is the potential of bergamot (Citrus bergamia), an ancient fruit long known for the versatility of its essential oils. The most prevalent components, such as limonene, linalool and linalyl acetate, display a winning synergy against various pathogenic bacteria. The classic lemon (Citrus limon) likewise boasts essential oils with antiseptic and bactericidal potential. Among the standout components are limonene and beta-pinene. Perhaps less well known, the essential oils of geranium (genus Pelargonium) are composed mainly of geraniol and citronellol, and display antimicrobial activity. Among the pathogenic species susceptible to these essential oils is the well-known Staphylococcus aureus.

11. The medicinal mushrooms Reishi and Shiitake

Ganoderma lucidum, known above all as Reishi, and Lentinula edodes, known as Shiitake, are medicinal mushrooms widely used in the field of Eastern medicine. They are species containing bioactive components capable of promoting various aspects of health. In particular, they appear to exert immunomodulatory and antioxidant activities, as well as antitumour, anti-inflammatory and antimicrobial ones. With regard to this last property, the effects are attributed to particular substances (polysaccharides) present in fungal extracts, as well as to the synergy of multiple components. The evidence, which is limited to laboratory experiments, concerns various bacterial species, such as Bacillus cereus (for both mushrooms), Escherichia coli and Pseudomonas aeruginosa (for Reishi). Reishi and Shiitake supplements are available in the form of tablets, lozenges and capsules, and are used to provide support for the body's natural defences.

Faq

What is the most powerful natural antibiotic?
The data currently available associate antibiotic potential with several plants, including commonly used ones. Efficacy levels can vary depending on the concentrations taken, the methods of use, and the synergy of multiple components.

What can I use as a natural antibiotic?
There are many plant species with antibiotic properties. These include some plants widely used in cooking, such as garlic, onion and lemon, as well as some strictly phytotherapeutic derivatives, such as eucalyptus essential oils and tea tree oils. In any case, it is important to seek medical supervision and avoid self-medication.

What can I use instead of antibiotics?
The use of synthetic antibiotics, or natural antibiotics as an alternative to the former, is a decision that rests with the treating physician. It is never advisable to independently choose how to treat an infection.

How do I use garlic as an antibiotic?
In addition to dietary intake, the active compounds in garlic can be taken through specific formulations available in pharmacies and/or herbalist's shops. In any case, it is preferable to seek a doctor's advice.