As our posts so far have shown, even a domestic garden can supply many plants with interesting chemical compounds, but this time, let’s see how the professionals do it – Picture It… Chemistry goes outdoors to the University of Bristol Botanic Garden. (This is the Picture It… Chemistry contribution to the #ChemTravelCarnival suggested by Brandon Findlay over on Chemtips.)
In a departure from our usual format, Natalie has taken her camera to the University of Bristol Botanic Garden to focus on plants that have found medicinal and culinary uses. We plan to explore some of these in greater detail in the future, so for now there are many pictures and just a few links,* mostly to the relevant Wikipedia pages** for plants and key compounds, to get you interested.
The beds collecting representatives of different plant families hold, among many others, the Solanaceae, colloquially known as the Nightshade family, which contain both poisonous and very useful plants, not in the least the potato, Solanum tuberosum, tomatoes (Solanum lycopersicum) and the tomatillo (Physalis philadelphica), more of an exotic on this side of the pond, but an important part of the American bed. Our favourite chilli plants (Capsicum spp.) and the pretty but dangerous tobacco plant (Nicotiana tabacum) also belong to this family. Many of the members of this plant family contain potent alkaloids, a family of molecules with multiple medicinal uses.
Many of these plants were also in the Native American Foods bed (and I got better pictures there), along with these very pretty amaranths (Amaranthus sp.), grown for its seeds, but also a source of pigments, including the deep red amaranthine.
The Mediterranean bed showcases many of the aromatic herbs common to that climate, but also cultivated plants of great importance to agriculture, such as the common grape vine (Vitis vinifera), rich in anthocyanins (including chrysanthemin, covered in our post on rhubarb). The chemistry of natural phenols is rich and varied (as well as tasty and possibly even healthy).
The Botanic Garden also has a collection of herbs and plants used in Western medicine, including thyme (Thymus officinalis) and various mints (Menta spicata) and sages (Salvia officinalis). Thymol, 2-isopropyl-5-methylphenol, is one of the key chemicals in thyme leaves, giving rise to their flavour; it may also have antiseptic properties.
The garden’s variety is further extended by the evolutionary dell, showcasing very ancient plants (and a metal dinosaur sculpture). The Carboniferous Period section is particularly interesting, not in the least because these plants have become most of our oil and coal deposits, arguably forming the basis of many areas of modern synthetic chemistry.
There is also the Chinese Medicinal Herb Garden, containing gems like several species of Ginkgo biloba, a source of terpenic lactones including Ginkgolide and Bilobalide, but also a range of other plants important to Chinese Herbology, some more familiar (garlic chives, Allium tuberosum) than others (such as Cornus officinalis, Leonurus heterophyllus).
While the Botanic Garden is not large, it is certainly worth a visit, if nothing else to see the less familiar plants used in other parts of the world for both medicine and food. Normal service will resume in the next post…
Contributor: Natalie Fey
*Couldn’t log on to make molecules yesterday, computer said “No”…
**As good a starting point as any, but you should do further research, including in the relevant medical and chemical literature.