Chemical Ecology
Supercritical operates in the area of chemical ecology, which is the study of the interactions between organisms and their environment, specifically the role that chemical compounds play in these interactions. Chemical ecology explores how these compounds, called semiochemicals, are used in plant communication, defence, reproduction, immune responses and other biological processes. Semiochemicals are sometimes referred to as “infochemicals” or “chemical messengers” as they convey important information between individuals of the same species or even between different species. Semiochemicals are understood to play a crucial role in various ecological and behavioral processes. For example, semiochemicals can be used to attract or repel pests. By understanding the chemical signals used by various pests, chemical ecologists can develop more effective pest control strategies that are less harmful to the environment than traditional pesticides. Â
Semiochemicals are products of the plants metabolism which are not directly involved in the growth and development processes and are also called secondary metabolites and have a wide range of chemical structures, such as alkaloids, terpenoids, flavonoids, and phenolic compounds.
One of the main functions of plant secondary metabolites (semiochemicals) is to serve as chemical defences against herbivores and pathogens. For example, many plants produce metabolites which are bitter and toxic compounds that can deter insects and other herbivores from feeding on the plant. Some secondary metabolites have also been shown to have antimicrobial, antifungal and antiviral properties which can protect the plant from infections caused by bacteria, fungi and viruses.
Plant secondary metabolites also have important medical applications. For example, metabolites such as morphine and quinine, are used as drugs for human health. Various plant secondary metabolites have been used for centuries in traditional medicine for a range of purposes, such as pain relief, wound healing, and as anti-inflammatory agents. In conclusion, plant secondary metabolites are an important area of research, with the potential for many applications in ecology, medicine, and agriculture.
Terpenes
A large class of semiochemicals (secondary metabolites) are volatile organic compounds (VOC’s), which are used by plants to communicate both above and below ground. Plant derived VOC’s exist in a variety of forms the most diverse group of which are the volatile terpenes. Terpenes are thought to be built up from isoprene, a hydrocarbon consisting of five carbon atoms attached to eight hydrogen atoms (C5H8) and are synthesized by plants through the same metabolic pathways that produce other important plant chemicals. The term terpene is often extended to the terpenoids, which are oxygenated derivatives of these hydrocarbons.
Terpenes are responsible for the characteristic smells and flavours of many different herbs, fruits, and flowers. There are over 20,000 known terpenes, and various terpenes have been used for centuries in traditional medicine, aromatherapy, and food flavouring. They are now also being studied for their potential therapeutic benefits. Some terpenes, such as limonene and pinene, have been found to have anti-inflammatory, analgesic, and anti-anxiety effects, while others, such as linalool and myrcene, have been shown to have sedative and relaxing properties.
More recently, terpenes (and terpenoids) are also being recognised as playing important roles in the way in which plants mediate their interactions with other plants (within and between species), insects (pests, pollinators, beneficial predatory insects) and pathogens. This area is a major focus of Supercriticals research.
For recent reviews on this topic see:
Boncan et.al (2020) “Terpenes and Terpenoids in Plants: Interactions with Environment and Insects” International Journal of Molecular Sciences 2020, 21, 7382
Rosenkranz, M., Chen, Y., Zhu, P., and Vlot, A. (2021) “Volatile Terpenes – mediators of plant to plant communication” The Plant Journal 108: 617-631.