The influence of seasonal and circadian variations on the content and chemical composition of essential oil from Aristolochia cymbifera Mart & Zucc

Essential oil production is sensitive to various environmental factors, such as seasonality and time of collection. The time of year when a secondary metabolite is collected is one of the most important factors in determining the amount and sometimes the nature of the active constituents, which are not always constant [1]. There are also a growing number of studies to show that the composition of plant secondary metabolites can vary considerably during the day/night cycle; for example, circadian variations in the concentrations of essential oils and alkaloids have been previously describe [2]. Knowing how these factors influence metabolite production is important in the agronomic management and harvesting of medicinal plants [3]. Among the main secondary compounds reported from the genus Aristolochia are aristolochic acids, aristolactams, alkaloids, monoterpenes, sesquiterpenes, diterpenes and triterpenes [4]. Although the terpenes of this genus have been widely studied, there are no reports on the influence of environmental factors over their production, especially in the species A. cymbifera. The present study was aimed at evaluating seasonal and circadian variability in the concentration and chemical composition of essential oil from A. cymbifera. Leaves and branches of A. cymbifera were collected during different seasons and times of day, to determine the concentration and chemical composition of volatile oils. Chemical analyses showed high concentrations of sesquiterpene hydrocarbons (24.0% to 62.3%). There was an interaction between the seasonal and circadian variations that influenced the contents of essential oil and monoterpene hydrocarbons, with higher concentrations being observed in September (0.24; 0.23 and 0.19%). For bicyclogermacrene, the major constituent (13.66%), there was also an interaction between these factors; in addition, there were greater relative concentrations of bicyclogermacrene (28.06; 44.12 and 28.75%) during the month of March.

Keywords: Monoterpenes, sesquiterpenes, Aristolochiaceae

References:

[1] Gobbo-Neto, L.; Lopes, N. P.; Químa Nova. 2007, 30, 374.

[2] Angelopoulou, D.; Demetzos, C.; Perdetzoglou, D.; Biochemistry Systematic Ecology. 2002, 30, 198.

[3] Fonseca, M.C.M.; Casali, V.W.D.; Barbosa, L.C.A.; Revista Brasileira de Plantas Medicinais. 2007, 9, 75.

[4] Kumar, V.; Poonam; Prasad, A.K.; Parmar, V.S.; Natural product reports. 2003, 20, 565.