Insecticidal activity of Tanacetum chiliophyllum (Fisch. & Mey.) var. monocephalum grierson extracts and a new sesquiterpene lactone

Abstract

Extracts from aerial parts and roots of Tanacetum L. (emend. Briq.) chiliophyllum (Fisch. & Mey.) var. monocephalum Grierson from Turkey were investigated for their DPPH scavenging activity and contact toxicity against Sitophilus granarius. The ethyl acetate extract of aerial parts yielded a new sesquiterpene lactone 1- epi-chiliophyllin ( 1) which is a derivative of the compound chiliophyllin previously isolated from T. chiliophyllum var. heimerlei. Also known compounds; neolupenyl acetate (lup-12-ene-3 β-acetate) ( 2), 4′,5,7-trihydroxy-3′,8-dimethoxyflavone ( 3), 4′,5,7-trihydroxy-8-methoxyflavone ( 4) were isolated together with ( 1). Structures of the compounds were determined by spectral methods including UV, IR, MS and 1D, 2D NMR. Highest contact toxicity against the stored granary products pest S. granarius was observed after 48 h (68.49 ± 0.67%). Highest DPPH scavenging activity observed for ethyl acetate extract of the roots at 10 mg/mL concentration (87.8 ± 0.84%). The DPPH scavenging activities of the pure flavonoids ( 3, 4) at 1 mg/mL concentration were unsignificant ( 3, 16.4 ± 0.16%; 4, 17.6 ± 0.82%) when compared with the positive controls α-tocopherol (91.7 ± 1.07%) and BHT (91.7 ± 0.37%) at the same concentration.