A herbal mouthwash selectively killed off bad bacteria in the mouth while preserving the good strains, according to a new study. It suggests an alternative to conventional mouthwashes, which were found to kill indiscriminately and damage gum tissue.
Evidence is growing about the health-giving properties of good oral bacteria. Prior research has linked disturbances in the oral microbiome to depression, anxiety, autism spectrum disorder, Parkinson’s disease, dementia, and schizophrenia. So it makes sense that we would want to hold on to good mouth bacteria and rid ourselves of the not-so-good.
A new study led by the Rutgers School of Dental Medicine has examined the effect of using a commercially available herbal mouthwash on oral bacteria, compared with conventional mouthwashes such as PerioGard and Listerine, and found that one is clearly better for maintaining the microbiome.
“It’s a paradigm shift,” said Georgios Kotsakis, the school’s assistant dean for clinical research and the study’s corresponding author. “We’re moving from eradicating all bacteria to focusing on selectivity. We want to keep the good bacteria alive while targeting the bad.”
The herbal mouthwash the researchers tested was StellaLife VEGA Oral Rinse, which, according to the website, contains the active ingredients azadirachta, calendula, echinacea, and plantago “in homeopathic dilution.” Homeopathic dilution is a process in which a substance is diluted with alcohol or distilled water before being vigorously shaken. The belief is that highly diluted substances can stimulate the body to heal itself. Against this product, the researchers tested 0.12% chlorhexidine gluconate mouthwash (sold as Savacol, Peridex, or PerioGard) and Listerine Cool Mint mouthwash. Saline was used as a control.
Each of the mouthwashes was applied to specific oral bacterial cultures – Streptococcus oralis, Streptococcus gordonii, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis – and bacterial growth was assessed. The effectiveness of the mouthwashes was also tested against biofilms, bacterial communities encased in a self-produced slimy substance that adheres to surfaces and can provide resistance to antibiotics and the immune system. And, finally, the mouthwashes were assessed for their damage to human gum cell cultures.
StellaLife’s oral rinse exhibited a selective antimicrobial action. It inhibited disease-causing bacteria F. nucleatum and P. gingivalis but spared beneficial bacteria S. oralis, S. gordonii, and V. parvula. In contrast, the chlorhexidine and Listerine mouthwashes killed both harmful and helpful microbes indiscriminately. In lab models of bacterial species, the homeopathic oral rinse reduced harmful bacteria while maintaining a biofilm of normal, healthy bacteria. In more complex biofilms from real clinical samples, the herbal wash effectively disrupted bad biofilms and reduced pathogenic bacteria compared to chlorhexidine and Listerine.
When the products were tested on human gum cells, chlorhexidine caused significant cell death, and Listerine caused moderate damage. StellaLife showed minimal toxicity, preserving cell structure and viability, suggesting it was more compatible with human tissues.
“These good bacteria have important functions,” Kotsakis said. “They synergize with your tissues. They actually kill some of the bad bacteria themselves.”
There are limitations to the study. Most results are from controlled laboratory models, not live human subjects, so real-world conditions may differ. And while biofilm volume and viability were measured, the detailed bacterial composition post-treatment wasn’t evaluated by, say, DNA sequencing. Also, the exact way that StellaLife’s oral rinse selectively kill pathogens and spares good bacteria remains unclear. Finally, the experiments mostly covered hours to days; long-term effects on the oral microbiome weren’t assessed.
Despite these limitations, the study’s findings are instructive. They suggest a move away from a scorched-earth, carpet-bombing approach to oral hygiene, such as that provided by conventional mouthwashes, to one that is more selective and protective of good oral bacteria.
“Randomized clinical trials are the next step,” said Kotsakis. He offered this piece of advice: “If you’re brushing and flossing like a dentist – regularly and perfectly – you may not need a mouthwash, but in reality, even the best of us can miss some surfaces during cleaning at home.”
The study was funded by StellaLife and was published in the journal Frontiers in Oral Health.
Source: Rutgers University
