What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

Question

So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I have heard it asserted that using antibacterials derived from plants would lessen the problem. One argument for the use of plants is that the bacteria from which we derive an antibiotic must themselves already be resistant to that antibiotic, meaning that the allele for resistance is already in the bacterial gene pool and when we exert a selection pressure by using the antibiotic, resistance will eventually appear among pathogenic species. Another argument I have heard is that plants can provide a lot of structurally diverse metabolites from which we might discover new classes of antibacterials. Is there anything else to this? (I know I have answered my own question to an extent, but I am wondering whether there are any other good reasons to look to plants for the next generation of antibacterial drugs). Thank you!

Answer 1

Interesting proposition. I think that the majority of natural products exist since, in nature, there is competition between two organisms for resources in a niche environment. Bacteria, viruses, and fungi infect plants and plants do their best to produce chemicals to deter or inhibit them. Likewise, the same bacteria and fungi make their own proteins and other molecules to deter the plants and each other for the same colonial surface. I think a lot of the natural products out there exist to make the plant unpalatable at least and immune to decay at best to every possible infection. Take the coniferous yews of the genus Taxus, they make compounds that inhibit mammalian mitotic spindle activity which we humans capitalized on for chemotherapy (paclitaxel). Lung tumors do not infect conifer trees, yet the tree made a compound that inhibits lung cancer growth. In many instances, it is the fungi and the bacteria coinciding ON a plant or animal that is responsible for the most diverse compounds. The sea sponges of the reef are notorious catalogs of structurally diverse compounds with unique pharmacologic activity. These compounds exist in their own little world of bacteria warfare (two different genera of bacteria fighting for an ecological niche), and we just capitalize on it and test them out.