Throughout our semester of studying plant physiology, most of the class covered processes of normal plant functions that involved anything from development, growth, and reproduction. These processes are complex and directly involve numerous elements and compounds from the environment that are modified and used in intrinsic metabolic systems. These compounds are called primary metabolites. These metabolites can be anything from sucrose to ethanol to lactic acid to cellulose, and can serve vital purposes in the world -- such as in agriculture by providing the populations with fuel, food, and fiber.
In addition to primary metabolites, secondary metabolites are also present in our world. They function differently than primary metabolites in the way that they are produced through modification of primary metabolite synthases and are not required for the functioning of a plant ("Primary and Secondary Metabolites,” 2015). Yet, they can also serve important roles in plant ecosystems, such as attracting pollinators, giving a plant its color, or even defense against predators. Secondary metabolites, such as opioids, antibiotics, growth factors, and pigments, can aid in human uses, or they can serve as nasty reminders - such as urushiol, the allergenic component of poison ivy. Urushiol is a secondary metabolite of great interest due to its storage, synthesis, and release, as well as its human and environmental impacts.
Poison ivy is a member of the Anacardiaceae family. Its members include cashews, sumac, and mangos, all of which contain urushiol as well (Aguilar-Ortigoza, 2003). Poison ivy’s history in North America dates back to the early 17th century, and possibly even before that. The first published records of poison ivy in North America date to 1609 in Captain John Smith’s writings about the New World after his voyage from England (Armstrong and Epstein, 2011). Despite this fact, urushiol was first isolated quite recently in the 1920’s by a Japanese chemist named Rikou Majima (Boyd and Rucker, 2013). He named urushiol after the term urushi, the Japanese name for lacquer tree, due to its coloring. Urushiol is colorless until the allergen is exposed to oxygen in the air, and then turns a dark brown or black color - which gives it the same coloring as lacquer that is used for finishing wood (Boyd and Rucker, 2013).