Phytotoxic, DPPH scavenging, insecticidal activities and essential oil composition of Achillea vermicularis, A. teretifolia and proposed chemotypes of A. biebersteinii (Asteraceae)

Previous reports on folk medicinal uses and insecticidal activity of the genus Achillea prompted us to investigate selected Achillea species in our ongoing biological activity screening of Asteraceae family. Three Achillea species A. biebersteinii Afan. (collected from two different locations), A. vermicularis Trin. and A. teretifolia Willd. essential oils were investigated for their phytotoxic, DPPH scavenging and insecticidal activities against Sitophilus granarius as well as their chemical compositions. Seventy compounds were identified in A. biebersteinii oil from Mt. Ararat sample representing 91.9% of the oil; sixty one compounds were identified in the oil from Mt. Dumluca sample representing 90.1% of the oil. Main components of the first sample from Mt. Ararat were 1,8-cineole 30.6%; piperitone 28.9%; camphor 11.7% and second sample from Mt. Dumluca were 1,8-cineole 31.1%; camphor 14.4%; α-thujone 12.9%; p-cymene 4.6%; β-thujone 3.4%; borneol 3.4%. Essential oil of A. vermicularis from Turkey was investigated for the first time and 61 components were identified representing 92.2% of the oil. Main components of the oil were 1,8-cineole 29.2%, camphor 25.8%, borneol 5.2%, piperitone 4.5% and camphene 3.8%. Fifty seven compounds were identified representing 76.6% of A. teretifolia oil. Main components of the oil were 1,8-cineole 15.9%, borneol 8.1%, camphor 7.0%, T-cadinol 5.9%, trans-nerolidol 5.1%, terpinen-4-ol 5.0% and caryophyllene oxide 3.9%. All of the tested oils showed low fumigant toxicity to Lemna minor, highest activity was observed for the A. biebersteinii collected from Mt. Ararat (29.95 ± 1.30%) when compared with other samples. DPPH scavenging activities of the oils were investigated at various concentrations and incubation time. Highest DPPH scavenging activity was observed for A. teretifolia (89.92 ± 0.49%) oil at 20 mg/mL concentration when 60 min. incubation time was employed. When compared with positive control α-tocopherol (96.59 ± 0.90%) at same conditions A. teretifolia and A. vermicularis essential oil showed considerable DPPH scavenging activity. All of the essential oils tested showed high insectidal contact toxicity against S. granarius. Highest contact toxicity was observed for A. biebersteinii collected from Mt. Ararat (100.00 ± 0.00%) at 0.2 μL/mL concentration when compared with the other oil samples. However tested essential oils showed low insecticidal fumigant toxicity against S. granarius. Highest fumigant toxicity was observed for A. biebersteinii collected from Mt. Ararat (36.64 ± 0.12%) when compared with other samples. Additionally variation in the essential oil composition of both A. biebersteinii samples and previously reported literature was observed and chemotypes were proposed according to agglomerative hierarchical cluster analysis. Similarly variation of A. teretifolia essential oil in present work and previous literature was observed. This is the first report on the essential oil composition of A. vermicularis from Turkey. The phytotoxic, DPPH scavenging and insecticidal activities of these species look promising as potential biopesticides.