In the UK, GPs and Vets have been warned to cut back on use of antibiotics as the threat of antibiotic resistance grows ever closer, while in some developing countries, antibiotics are scarce and local people rely on knowledge of medicinal qualities of plants. Some scientists are focusing on a different area - to prove the antibiotic qualities of some natural alternatives which have traditionally been used in medicine. Here are some of the studies that scientists have worked on to prove how effective natural alternatives could be.
Honey possesses different qualities depending on where the bees live and harvest nectar. Its antibiotic resistance has long been used to treat wounds and sores, and also possesses anti-fungal and anti-viral properties. A study in 2014 examined the effect of the antimicrobial activities of honey. The study took 5 types of Manuka honey (from New Zealand), found in different areas and compared the effects against both antibiotic-resistant and -sensitive Staphylococcus aureus, a bacteria found in the nasal passages of humans, which has been implicated in a number of nasty infections, including impetigo, food poisoning, toxic shock syndrome and cellulitis. The scientists concluded that a concentration of 50% of honey showed an inhibitory effect against a number of bacteria. Honey which contained a high concentration of Unique Manuka Factor or UMF showed a bacterial effect against all the bacteria tested, but some of the local honey could only inhibit the bacteria. The effectiveness of the different types of honey depended on the honey type and the concentration administered.
Honey should not be fed to babies under 12 months of age. There has not yet been any effective bacterial resistance against the antibiotic resistance qualities of honey.
Almasaudi, S.B., et al., Antimicrobial effect of different types of honey on Staphylococcus aureus, Saudi Journal of Biological Sciences, September 2017, Vol.24:6, pp: 1255-1261
Garlic is a member of the alliaceae family, and has traditionally been used in both cuisine and medicinal fields. Many studies have proven its properties, including anti-viral, anti-fungal and antimicrobial, when using both fresh and freeze-dried garlic extracts. The plant is a hardy perennial, which can be grown in a number of different environments. Planting the individual clove of a garlic bulb will enable it to grow a full bulb and all the cloves of the bulb will have the same genetic make-up. Garlic can cause adverse effects as well as beneficial ones: it can cause an upset stomach, a platelet dysfunction leading to excessive bleeding post-surgery and or an epidural hematoma, where blood fills the epidural space spontaneously. It can also cause allergic reactions.
The scientists aimed to evaluate whether garlic can be relied upon to combat certain infections, including S.aureus and E.coli, both of which are beginning to develop resistant strains. Four different solvents: water, ethanol, chloroform and petroleum, were used to extract the bioactive compound from garlic and the antibiotic activity of the original sample was used to evaluate the compounds. The scientists found that water was the best compound, followed by ethanol, chloroform then petroleum. E.coli bacteria were more sensitive to garlic than S.areus, but garlic proved an effective antibacterial agent.
Wolde,T., Kuma,H., Trueha, K., Yabeker, A., Anti-Bacterial Activity of Garlic Extract against Human Pathogenic Bacteria, Pharmacovigil June 2018, 6.1
A plant that has been identified as possessing more than average antibiotic qualities has been Cytisus striatus or Portuguese broom, a plant found throughout the Iberian Peninsula on heathland, and chosen because it showed strong activity against ciprofloxacin and erythromycin which protected against MRSA, a bacteria which can cause serious and life-threatening infections.
The scientists examined a number of different extracts from the plant which had proven antimicrobial activity. They isolated those extracts which proved most potent against the bacteria and then aimed to isolate the compounds which caused the potency. Different parts of the plant exhibited different antibiotic qualities. Extracts from the leaf were the most potent against the bacteria, the flower extract worked only against certain S.aureus strains, while the twig extract showed no antibiotic activity against any of the strains. Separating out the compounds wnnabled the scientists to find three that offered antimicrobial activity against all S.aureous strains, but separating the compounds out is not easy due to the number of combinations available. More work is needed, but this experiment suggests that it may be possible to find compounds that could re-energise the ability of anti-microbial drugs, negating the effects of resistance to antibiotics.
Simoes, M., et al., Looking to nature for a new concept in antimicrobial treatments: isoflavonoids from Cytisus striatus as antibiotic adjuvants against MRSA, June 2017, Scientific Reports 7, Article no: 3777