Traditional Medicinal Plant Extracts and Natural Products with Activity against Oral Bacteria: Potential Application in the Prevention and Treatment of Oral Diseases

Oral diseases are major health problems with dental caries and periodontal diseases among the most important preventable global infectious diseases. Oral health influences the general quality of life and poor oral health is linked to chronic conditions and systemic diseases. The association between oral diseases and the oral microbiota is well established. Of the more than 750 species of bacteria that inhabit the oral cavity, a number are implicated in oral diseases. The development of dental caries involves acidogenic and aciduric Gram-positive bacteria (mutans streptococci, lactobacilli and actinomycetes). Periodontal diseases have been linked to anaerobic Gram-negative bacteria (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Given the incidence of oral disease, increased resistance by bacteria to antibiotics, adverse affects of some antibacterial agents currently used in dentistry and financial considerations in developing countries, there is a need for alternative prevention and treatment options that are safe, effective and economical. While several agents are commercially available, these chemicals can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining. Hence, the search for alternative products continues and natural phytochemicals isolated from plants used as traditional medicines are considered as good alternatives. In this review, plant extracts or phytochemicals that inhibit the growth of oral pathogens, reduce the development of biofilms and dental plaque, influence the adhesion of bacteria to surfaces and reduce the symptoms of oral diseases will be discussed further. Clinical studies that have investigated the safety and efficacy of such plant-derived medicines will also be described

In silico investigation of lactone and thiolactone inhibitors in bacterial quorum sensing using molecular modeling

In the present study, the origin of the anti-quorum sensing (QS) activities of several members of a recently synthesized and in vitro tested class of lactone and thiolactone based inhibitors were computationally investigated. Docking and molecular dynamic (MD) simulations and binding free energy calculations were carried out to reveal the exact binding and inhibitory profiles of these compounds. The higher in vitro activity of the lactone series relative to their thiolactone isosteres was verified based on estimating the binding energies, the docking scores and monitoring the stability of the complexes produced in the MD simulations. The strong electrostatic contribution to the binding energies may be responsible for the higher inhibitory activity of the lactone with respect to the thiolactone series. The results of this study help to understand the anti-QS properties of lactone-based inhibitors and provide important information that may assist in the synthesis of novel QS inhibitors

Faecal microbiota of individuals with autism spectrum disorder

Many children with autistic spectrum disorders (ASDs) suffer from gastrointestinal problems such as diarrhoea, constipation and abdominal pain. Such symptoms may be due to a disruption of the indigenous gut microbiota promoting the overgrowth of potentially pathogenic micro-organisms. These observations have stimulated investigations into possible abnormalities of intestinal microbiota in autistic patients. The purpose of the present study was to determine if a relationship exists between ASD severity (mild – severe) and GI microbial populations. The faecal microbiota of 22 male and 6 female participants with ASDs (aged 7 ± 6 years) were analyzed by standard microbial culture methods and compared within-group (based on ASD severity) and with a standard laboratory reference range. Comparisons between children with mild ASD and those with moderate to severe ASD, as well as comparisons to a neurotypical control group previously reported, revealed that no significant differences appear to exist in the composition of the gut microbiota. Nevertheless, examination of each individual’s gut microbial composition showed 10 cases of unusual findings witch means 1out of 3 cases have unusual microbiota. Our data do not support consistent GI microbial abnormalities in ASD children, but the findings do suggest that aberrations may be found in a minority subset of ASD children. Further studies are required to determine the possible association between the microbiota and gastrointestinal dysfunctions in a subset of children with both ASD and gastro-intestinal problems

Evaluation of biogenic amines in the faeces of children with and without autism by LC-MS/MS

Previous researchers have postulated that gastrointestinal bacteria may contribute to the development and maintenance of Autism Spectrum Disorders (ASD). There is evidence based on quantitative evaluation of the gastrointestinal bacterial population in ASD that this is unlikely and an alternate mechanism will be examined where the bacteria may contribute to the development of ASD via their metabolic products and the role of biogenic amines (BAs) will be investigated. In humans, BAs influence a number of physiological processes via their actions as neurotransmitters, local hormones and gastric acid secretion. Various amines have been implicated in several medical conditions such as schizophrenia and colon cancer. To date, the relationship between BAs and autism has not been explored. This study has been designed to identify differences (and/or similarities) in the level of Bas in faecal samples of autistic children (without gastrointestinal dysfunction: n = 14; with gastrointestinal dysfunction; n = 21) and their neurotypical siblings (n = 35) by LC-MS/MS. Regardless of the diagnosis, severity of ASD and gastrointestinal dysfunction there were no significant differences found between the groups. The findings suggest that BAs in the gastrointestinal tract do not play a role in the pathophysiology of gastrointestinal dysfunction associated with ASD

Phytochemicals from traditional medicinal plants used in the treatment of diarrhoea: modes of action and effects on intestinal function

Medicinal plants have been used as traditional treatments for numerous human diseases for thousands of years. Diarrhoeal diseases continue to be a major cause of morbidity and mortality throughout the world and there is renewed interest in the discovery of novel compounds that can be used to fight these diseases. Numerous studies have validated the traditional use of antidiarrhoeal medicinal plants by investigating the biological activity of extracts of such plants, which have antispasmodic effects, delay intestinal transit, suppress gut motility, stimulate water adsorption or reduce electrolyte secretion. Of the numerous phytochemicals (such as alkaloids, tannins, flavonoids and terpenes) present in active extracts, tannins and flavonoids are thought to be responsible for antidiarrhoeal activity by increasing colonic water and electrolyte reabsorption. Others act by inhibiting intestinal motility. As some of the active ingredients are potentially toxic, there is a need to evaluate the safety of plant preparations. A few clinical trials have evaluated the safety and tolerability of traditional and herbal medicine preparations used to treat diarrhoea and generally indicate that minimal side effects are observed. However, with the increased popularity of plant-derived and herbal medicines in Western society, the benefits and potential dangers of these medicines must be considered

Traditional plants and herbal remedies used in the treatment of diarrheal disease: mode of action, quality, efficacy, and safety considerations

This chapter investigates methods used in the evaluation of bioactivity of medicinal plants (including antibacterial activity, antiprotozoal activity, antihelminthic activity, antiviral activity and antidiarrheal activity); traditional medicinal plants used in the treatment of diarrhea that display antimicrobial activity; traditional medicinal plants used in the treatment of diarrhea that display antidiarrheal activity; a phytochemical analysis, identification of active plant components, and mechanism of action of medicinal plants used in the treatment of diarrhea; and the quality, efficacy, and safety considerations of traditional medical plants used in the treatment of diarrheal disease

Medicinal plants of Australia: Melaleuca Alternifolia for the production of tea tree oil

Abstract not available

Genetic reassortment and interspecies transmission of rotaviruses

Abstract not available

Removal of contaminating bacteria from computers by disinfection and hand sanitation

Letter to the editor on a study conducted to test the efficacy of hand sanitation and disinfection of hand contact surfaces of computers (keyboards and mice) in reducing the number of viable bacteria, thereby decreasing the potential health risk of shared computer terminals