Chemical variability and antioxidant activities among Pinus halepensis Mill. essential oils provenances, depending on geographic variation and environmental conditions

Variability in chemical composition and antioxidant activities of Pinus halepensis Mill. essential oils, collected from ten different bioclimatic areas in Algeria was investigated. The impact of geographic variation and environmental conditions on this variability was studied by using canonical correspondence analysis. GC and GC-MS analyses showed that α-pinene (7.6-22.3%), myrcene (10.5-24.1%), p-cymene (8.7-14.6%), (Z)-β-caryophyllene (15.6-27.4%) and caryophyllene oxide (0-12.5%) are the major components. Hierarchical cluster, principal component and canonical correspondence analyses showed that the investigated provenances essential oils are divided into three groups. The first group (S1-S5) was characterized by caryophyllene oxide, related to elevated areas in dolomitic soils that are wet during summer and being strongly dependent on continentality index. The second group (S6, S7) was characterized by p-cymene and occupied areas in limestone soils that are relatively dry during summer. The third group of provenances (S8-S10) was characterized by α-pinene and was strongly related to the bioclimatic factors affecting hydric balance in plants and soils. Based on the four DPPH, reducing power, β-carotene bleaching and chelating ability tests, the investigated essential oils highlighted important antioxidant activities. The highest antioxidant activities were exhibited by the first group (S1--S5). P. halepensis essential oil can be used as an alternative additive in foods, pharmaceuticals and cosmetic preparations instead of the toxic synthetic antioxidants, taking into account the importance of geographical origin of the provenances and the growing conditions, which significantly affect the essential oil composition and their antioxidant activities.