Repellent, Insecticidal and Antimicrobial Activities of Leaf Essential Oils from Three Eucalyptus Species

Abstract

Developing effective and eco‐friendly antimicrobials and pesticides has become a highly important issue. The repellent, insecticidal and antimicrobial activity of essential oils (EOs) isolated by hydrodistillation from dried leaves of the three Eucalyptus species (E. cloeziana, E. umbellata and E. benthamii) were investigated. During GC/MS analysis, α‐pinene (47.36 %), 1,8‐cineol (38.53 %) and α‐pinene (35.31 %) were identified as major components of E. cloeziana, E. umbellata and E. benthamii, respectively. The EOs from E. cloeziana exhibited the longest effective protection time (465 min, at 50.0 % w/w) for humans among the EOs studied. The effective protection time was 30 min and 300 min at concentrations of 12.5 % (w/w) and 25.0 % (w/w), respectively. Fumigating insecticidal activity of EOs from three Eucalyptus species was tested by airtight fumigation in conical flask, which indicated that essential oils had a highly and rapidly insecticidal activity on Culex pipiens quinquefasciatus. The antimicrobial activity of EOs was evaluated by using disc diffusion and agar dilution methods. There was no significant difference in the antibacterial activity of EOs from E. cloeziana and E. umbellate and they had the same MICs (20 mL/L) on Staphylococcus aureus, Salmonella typhi, Bacillus subtilis and Escherichia coli. E. benthamii had the worst microbial inhibitory effect among the three Eucalyptus essential oils and the MIC value for the test species is 40 mL/L except for Rhodotorula Harrison (10 mL/L).

Identification of Bioactive Compounds against Aedes aegypti (Diptera: Culicidae) by Bioassays and in Silico Assays

“…The C. winterianus essential oil had as its most abundant constituents trans‐ geraniol (28.81 %), followed by citronellal (22.98 %), which were also the most abundant compounds reported in other studies [16,17] . Eucalyptus globulus essential oil obtained only seven compounds, mostly constituted by eucalyptol (82.94 %), as demonstrated in other studies, where this chemical compound was found in a significant variety of plant species [6] …”

“…Among the repellent types, synthetic ones have become a public health concern due to adverse effects on its users and selection of repellent resistant insect populations [5] . The N,N‐diethyl‐3‐methylbenzamide (DEET) has historically been the most effective repellent, but research on its toxicity and safety indicates that it can penetrate the skin, causing risks to human health [6] . In face of such risks, several studies with natural plant products have been conducted, mainly because these compounds are biodegradable and cause less damage to health and the environment [7,8] …”

Chemical Composition and Cytotoxic Activity of Eucalyptus torquata Luehm. and Eucalyptus salmonophloia F. Muell. Trunk Bark Essential Oils against Human SW620 and MDA‐MB‐231 Cancer Cell Lines

“…Eucalyptus leaves are well‐known for their richness in EOs that are largely used for their therapeutic virtues as well as for other commercial purposes such as in the food, flavor, and perfumery industries [12] . Leaf EOs have a wide range of biological activities, including antioxidant, [13] antimicrobial, [14,15] insecticidal, [16,17] and herbicidal [18] . They also have significant hypoglycemic [19] and anticancer effects [20,21] .…”

Atividade antimicrobiana e inseticida do óleo essencial de Piper amalago L. (Piperaceae) / Antimicrobial and insecticidal activity of the essential oil of Piper amalago L. (Piperaceae)

“…Todavia, a composição química dos óleos essenciais de Piper spp. apresenta variações interespecíficas (regionais) que se alternam de acordo com o local de coleta ou intraespecíficas, como a sazonalidade 8 O uso de inseticidas e repelentes naturais, vem sendo estudado nos últimos anos, pois são menos prejudiciais ao meio ambiente e aos seres humanos do que os sintéticos, além da menor resistência dos insetos 3,10 . Assim, no presente trabalho, foram analisadas a atividade antimicrobiana e inseticida bem como o efeito repelente no óleo essencial de P. amalago (OEPA) em um cultivo no Estado do Paraná, Brasil.…”