RESUMEN
AIMS: This study aimed to evaluate in vitro individual and combined antifungal activity of propolis extract (PE) and oregano essential oil (OEO) against Penicillium allii, causal agent of blue mould disease. The chemical characterization of both products was also included. METHODS AND RESULTS: Chromatographic analysis of PE and OEO confirmed the presence of bioactive compounds. The antifungal susceptibility assays showed that PE and OEO were highly active against the mycelial growth and conidial germination of P. allii. PE and OEO MICs were 12·5 and 1·5 µl ml-1 , respectively. The MFCs of these products were 50 and 3·1 µl ml-1 , respectively. PE acted mainly through diffusion, while OEO acted by a mixed contribution of vapour and diffusion. Synergism and additive effect between both products were found in some combination ratios. CONCLUSION: PE and OEO, both natural products with different chemical composition, have a strong antifungal activity against P. allii and show a favourable interaction causing synergism. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study indicated the potential use of PE combined with OEO as a non-conventional strategy towards the formulation of a biofungicide to control blue mould disease in garlic seed-cloves.
Asunto(s)
Ascomicetos , Ajo , Aceites Volátiles , Origanum , Penicillium , Própolis , Syzygium , Aceites Volátiles/farmacología , Extractos Vegetales/farmacología , Própolis/farmacología , SemillasRESUMEN
One of the most common insect pests is Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), which affects different food commodities. A new effective approach for the management of insect pests is the development of new formulations based on essential oils (EO). However, few works informed about the relationship between insecticidal activity of EO or essential oils loaded polymeric nanoparticles (EOPN) and post-application temperature. In our work, palmarosa [Cymbopogon martinii (Roxb.) Watson], geranium (Geranium maculatum L.), and peppermint (Mentha piperita L.) oils were formulated in a polyethylene glycol 6000 matrix to obtain EOPN. Geranium and palmarosa EOPN had sizes of 259 and 191 nm, respectively; the encapsulation efficiency (EE) was close to 90%, and the samples were monodisperse. The sizes from peppermint EOPN were around 380 nm, with an EE of 72%, and were polidisperse. In a contact toxicity bioassay, the insecticidal effect of the oils was increased by all EOPN, with palmarosa oil being the most toxic. In addition, the oils and their nanoparticles showed a significantly negative temperature coefficient when applied by contact. In a fumigant bioassay, just palmarosa and peppermint EOPN enhanced the oil activity and palmarosa EO and EOPN showed the highest toxic effect. In this case, the EO and EOPN insecticidal activity was unaffected by environmental temperature variation.
Asunto(s)
Insecticidas/farmacología , Mariposas Nocturnas/efectos de los fármacos , Nanopartículas/química , Aceites Volátiles/farmacología , Extractos Vegetales/farmacología , Animales , Cymbopogon/química , Parasitología de Alimentos , Geranium/química , Control de Insectos , Insecticidas/química , Aceites Volátiles/química , Extractos Vegetales/química , Polímeros/química , TemperaturaRESUMEN
Over the last years, nanotechnology has contributed to the development of new botanical insecticides formulations based on essential oils (EO), which are safe for the human health and the environment. Nanoemulsions (NEs) can enhance the bioactivity of the EO to prevent the premature volatility and degradation of the active ingredients. In our work, geranium EO (Geranium maculatum L.) was used to develop micro and nanoemulsions adding Tween 80 as surfactant. For NEs formulation, ultrasound was applied and the physicochemical and ultrasound parameters were optimized: oil: surfactant ratioâ¯=â¯1:2, ultrasound powerâ¯=â¯65â¯W, sonication timeâ¯=â¯2â¯min, cyclesâ¯=â¯30 on/20 off and ultrasonic probe distanceâ¯=â¯3.7â¯cm. The NEs obtained had 13.58â¯nm and polydisperse index (PDI) values of 0.069. They were stored at 25⯰C and were stable for 60â¯days. The present study also demonstrated the potential of NEs to enhance the toxicity of geranium EO against larvae of Culex pipiens pipiens (EO LC50â¯=â¯80.97â¯ppm, NEs LC50â¯=â¯48.27â¯ppm) and Plodia interpunctella (EOâ¯+â¯ß-cypermethrin LD50â¯=â¯0.16⯵g larvae-1, NEsâ¯+â¯ß-cypermethrin LD50â¯=â¯0.07⯵g larvae-1). Overall, our findings pointed out that NEs can increase twofold the insecticidal efficacy of EO, and thus, they can be considered further for the development of botanical insecticides.
Asunto(s)
Dípteros/efectos de los fármacos , Emulsiones/química , Insecticidas/farmacología , Lepidópteros/efectos de los fármacos , Nanotecnología , Aceites Volátiles/química , Aceites Volátiles/farmacología , AnimalesRESUMEN
Essential oils (EO) from peppermint, palmarosa, geranium, lavender and rosemary were tested against the German cockroach, Blatella germanica L. (Blattaria: Blatellidae). Peppermint and palmarosa oils were the most effective and were included in a polyethylene glycol 6000 matrix to obtain EO loaded polymeric nanoparticles (EOPN). The physicochemical analyses indicated that, at 7 days postformulation, peppermint EOPN had sizes of 380 nm, the loading efficiency (LE) was 72.25% and the polydispersity index (PDI) was >0.4 (polydisperse sample). Palmarosa EOPN had sizes of 191 nm; LE was 89.75% and PDI was <0.25 (monodisperse sample). Peppermint and palmarosa EOPN enhanced the lethal and sublethal effects of the EO on B. germanica. These results suggest that the newly developed nanoinsecticides could be successfully used to control German cockroach.