Chemical composition and fumigant effect of essentialoil of Lippia sidoides Cham. and monoterpenes against Tenebrio molitor (L.) (coleoptera: tenebrionidae)

Abstract

The chemical composition of Lippia sidoides essential oils obtained by hydrodistillation was characterized and quantified by GC/MS and their insecticidal activity by fumigation test was assayed against Tenebrio molitor. Moreover, the toxicity of monoterpenes carvacrol, 1,8-cineol and thymol were also evaluated when applied alone or in binary (1:1) or tertiary (1:1:1) mixture. The essential oil of L. sidoides has as major constituents carvacrol (31.68%), -cymene (19.58%), 1,8-cineole (9.26%) and -terpinene (9.21%), from a 21 compounds identified, being 92.53% of total. Both compounds have insecticidal activity against T. molitor, being the degree of toxicity of carvacrol > 1,8-cineole > L. sidoides essential oil > thymol, and its respectively LC 50 at 24h were 5.53; 5.71; 8.04 and 14.71 µL/L air. When the different mixture of carvacrol, 1,8-cineole and thymol was assayed against T. molitor, the synergism among them was observed. For the mixture of carvacrol:1,8-cineole LC 50 was 5.34 µL/L air; carvacrol:thymol 7.67 µL/L air; 1,8-cineole:thymol 7.51 µL/L air and carvacrol:1,8-cineole:thymol 6.34 µL/L air. Mainly, the monoterpene thymol had a synergic effect, which increased the toxicity of carvacrol and 1,8-cineole, both in binary mixture like carvacrol:thymol and 1,8-cineole:thymol.Index terms: "Alecrim pepper", mealworm, natural compound, toxicity, synergism. RESUMOA composição química do óleo essencial de Lippia sidoides obtido por hidrodestilação foi caracterizada e quantificada por GC/MS, bem como sua atividade inseticida por teste de fumigação foi avaliada sobre Tenebrio molitor. Além disso, a toxicidade dos monoterpenos carvacrol, 1,8-cineol e timol, também foi avaliada quando esses compostos foram aplicados isoladamente, ou em misturas binárias (1:1), ou terciárias (1:1:1). O óleo essencial de L. sidoides tem como principais constituintes o carvacrol (31,68%), ñ-cimeno (19,58%), 1,8-cineol (9,26%) e -terpineno (9,21%), em 21 compostos identificados, sendo 92,53% do total. Termos para indexação: Alecrim pimenta, bicho-da-farinha, produto natural, toxicidade, sinergismo.

Atividade fungitóxica in vitro dos óleos essenciais de Lippia sidoides Cham., Cymbopogon citratus(D.C.) Stapf. e de seus constituintes majoritários no controle de Rhizoctonia solani e Sclerotium rolfsii

“…Constituintes químicos dos óleos essenciais e os respectivos teores expressos em porcentagem. Lima et al (2011), constataram a presença do carvacrol (31,68%), ρ-cimeno (19,58%), 1,8-cineol (9,26%) e o γ-terpineno (9,21%) como constituintes majoritários do óleo essencial de plantas nativas da região de Itumirim, MG.…”

Secondary metabolites from endophytic fungus from Lippia sidoides Cham.

“…(Verbenaceae), also known as "rosemary pepper" is an aromatic plant of popular medicinal use found in the Caatinga region of the Brazilian Northeast (Santos et al, 2016). It presents insecticidal activity against Tenebrio molitor (Lima et al, 2011) and larvae of Aedes aegypti (Lima et al, 2013) and acaricide against Tetranychus urticae Koch (Soares et al, 2016). When tested against different pathogenic bacteria, such as Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli (Ratnaweera et al, 2015) and different fungi and yeasts, including Candida albicans (Premjanu et al, 2016), it demonstrated a strong antimicrobial action.…”

Insecticidal activity of citronella grass essential oil on Frankliniella schultzei and Myzus persicae

“…In this respect, the use of essential oils for controlling insects has obtained satisfactory results (SOARES et al, 2008;LIMA et al, 2009;LIMA et al, 2011). Essential oil from Cymbopogon winterianus Jowitt, popularly known as citronella grass, has an acaricide (OLIVO et al, 2008) and repellent effect (LABINAS; CROCOMO, 2002).…”