Sumac (Rhus coriaria L.) fruit: essential oil variability in Iranian populations

Sumac (Rhus coriaria L.), recognized in Iran and other areas of the Middle East as a very popular flavoring spice, contains a wide range of medicinally active components including organic acids, phenolic acids, flavonoids, anthocyanins, hydrolyzable tannins and terpenoids. In the present study, for the first time the variation of the essential oil compositions in R. coriaria fruits, collected from fourteen different locations in Iran, was assessed. A significant variability in the essential oil content was observed among the investigated populations (ranging from 0.04 to 0.19% (v/w)). GC-FID and GC–MS analyses of the essential oils identified a total of fifty-seven components. (E)-Caryophyllene (5.9–50.3%), n-nonanal (1.8–23.3%), cembrene (1.9–21.7%), α-pinene (0.0–19.7%), (2E,4E)-decadienal (2.4–16.5%) and nonanoic acid (0.0–15.8%) were identified as the main constituents of the essential oils, depending on the populations. The highest amounts of the mentioned components were identified in the essential oil of Tovrivar, Torbat jam, Qom, Kashmar, Torbat jam and Yazd populations, respectively. According to principal component (PCA) and cluster analyses (CA) the studied populations grouped into five different chemotypes: i.e., chemotype I ((E)-caryophyllene), chemotype II ((E)-caryophyllene/α-pinene), chemotype III ((E)-caryophyllene/cembrene), chemotype IV (nonanoic acid/cembrene), chemotype V (n-nonanal/(2E,4E)-decadienal). Such variability in essential oil compositions of Iranian sumac provides possibility to select populations with specific aroma profiles for domestication, breeding and industrial applications and suggests the effective in situ and ex situ conservation strategies for all populations and chemotypes of R. coriaria.