Chapter 9: Natural Products in the Oral Cavity and Biological Dark Matter

While the principles of complexity and reductionism in assessing the effects of natural products has been discussed in previous chapters, there are some examples of situations where local and systemic effects are linked. One of these is the oral cavity where the balance of microbial species has also been linked to a range of extra-oral effects including cardiovascular disease, Alzheimer’s disease and others. One aspect of the oral cavity is the existence of ultrasmall bacteria which are unable to exist without the presence of larger bacteria. The former are referred to as epibionts. Their role is, in some particular aspects, unclear and they have been referred to as biological dark matter, by analogy with cosmological dark matter. One aspect of their activity seems to be an effect on the production of quorum sensing molecules. These are molecules by which bacteria control aspects of their growth and proliferation including biofilm formation. By considering what is known (and unknown) with regard to the oral microbiome, it is possible to develop a better understanding of the system through a combination of observation and hypothesis testing. This leads to a wider discussion of natural product chemistry, persistence and metaphysics.