Chemical Composition, Repellent Action, and Toxicity of Essential Oils from Lippia origanoide, Lippia. alba Chemotypes, and Pogostemon cablin on Adults of Ulomoides dermestoides (Coleoptera: Tenebrionidae).

The essential oils (EOs) from bioactive species can provide an alternative tool for the management of stored grain insects that is less environmentally damaging than synthetic chemicals. The aim of this study was to assess the repellent action and toxicity of EOs obtained from phellandrene-rich Lippia origanoides, carvone-rich Lippia alba, citral-rich L. alba, and Pogostemon cablin aerial parts on adults of Ulomoides dermestoides. These EOs were isolated by hydrodistillation and characterized by gas chromatography coupled to mass spectrometry (GC-MS). The repellency assay was carried out using the area preference method, and the toxicity evaluated utilizing a filter paper contact test. The major components (>10%) of the studied EOs were sabinene (16.9%), trans-ß-caryophyllene (18.6%) and α-humulene (10.1%) for phellandrene-rich L. origanoides EO; limonene (40.1%) and carvone (37.7%) for carvone-rich L. alba EO; geranial (24.5%), geraniol (19.0%), and neral (11.9%) for citral-rich L. alba EO; and α-guaiene (13.3%), α-bulnesene (15.7%), and patchoulol (35.3%) for P. cablin EO. All EOs displayed 100% repellency at a concentration of 16 µL/mL, with lower toxicity than that elicited by the commercial repellent DEET. EO concentrations up to 8 µL/mL did not induce any mortality on the beetle. These findings show that the EOs provide active and safe molecules for natural repellent formulations to prevent and control insect infestations of stored products.

The aqueous extract of Fridericia chica grown in northern Colombia ameliorates toxicity induced by Tergitol on Caenorhabditis elegans.

The aqueous extract of fallen leaves from Fridericia chica (Bonpl.) L.G. Lohmann is utilized as a remedy in communities at northern Colombia. Traditional uses include wound healing, gastrointestinal inflammation, leukemia and psoriasis, among others. The aims of this research were to evaluate the potential of the aqueous extract of fallen leaves of F. chica (AEFchica) to inhibit ethoxylated nonylphenol (Tergitol)-induced toxicity in Caenorhabditis elegans; and to identify its main components. The pharmacological properties of AEFchica was evaluated using a Tergitol-induced toxicity model in Caenorhabditis elegans. Lethality, locomotion, reproduction, and DAF-16 nuclear translocation were quantified. The chemical composition of AEFchica was carried out using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. AEFchica induced very little lethality on C. elegans (5.6%) even at high concentrations (10,000 µg/mL). The extract had no effect on locomotion impairing induced by ethoxylated nonylphenol. However, AEFchica (1000 µg/mL) abrogated Tergitol-induced mortality, recovering up to 53.3% of the nematodes from lethality induced by 10 mM Tergitol. Similarly, it also blocked Tergitol-dependent reproduction inhibition (82.1% recovery), as well as DAF-16 nuclear translocation (>95%), suggesting a prominent role on oxidative stress control. The chemical analysis indicated the presence of a great variety of molecules with known antioxidant, metabolic and immune modulator properties, such as hydroxylated methoxy flavones, N-methyl-1-deoxynojirimycin, and rehmaionoside A. In short, the aqueous extract of F. chica protects C. elegans from the deleterious effects of Tergitol on lethality, reproduction and oxidative stress involving DAF-16-mediated pathway. This extract is a promising source of bioactive phytochemicals for multi-target pharmacological purposes.

Microencapsulación de aceite esencial de tomillo (Thymus vulgaris) en matrices poliméricas de almidón de ñame (Dioscorea rotundata) modificado / Microencapsulation of thyme (Thymus vulgaris) essential oil in polymeric matrices based on modified yam (Dioscorea rotundata) starch

Los aceites esenciales son conocidos por sus numerosas actividades biológicas y organolépticas, pero su empleo suele verse limitado por su alta volatilidad y tendencia a degradarse. La microencapsulación es una estrategia válida para superar estos inconvenientes. En este trabajo se empleó almidón de ñame (D. rotundata), el cual fue sometido a procesos de hidrólisis y lipofilización, empleando anhídrido dodecenilsuccínico (DDSA); esto incrementó significativamente las capacidades captadora de aceite y emulsificante (tensoactiva) del almidón nativo, el cual se empleó para microencapsular aceite esencial de tomillo, que en estudios previos demostró potente actividad antibacteriana sobre las cepas involucradas en el desarrollo del acné. La microencapsulación se llevó a cabo por microparticulación lipídica sólida, seguida de emulsificación. Esta alcanzó una eficiencia superior al 98%, y el producto obtenido, desafiado en diversas pruebas, demostró capacidad de retener más del 90% del aceite esencial en condiciones de evaporación, evitando su oxidación y el cambio en su perfil de composición. Finalmente, las microcápsulas de aceites esenciales de tomillo, al ponerse en contacto con las bacterias del acné, mantuvieron su actividad bactericida. Los resultados de este trabajo aportan al desarrollo de formulaciones farmacéuticas, cosméticas y alimentarias estables y funcionales de aceites esenciales, al protegerlos de la evaporación y degradación.

Essential oils are known for their numerous biological and organoleptic activities, but their use is often limited by high volatility and tendency to degrade. Microencapsulation is a valid strategy to overcome these drawbacks. In this paper starch yam (D. rotundata) was used, which was subjected to hydrolysis processes and lipophilization using dodecenyl succinic (DDSA) anhydride, this significantly increased the scavenging capacity of oil and emulsifier (surfactant) of native starch, which was used to microencapsulate thyme essential oil, that in previous studies showed potent antibacterial activity on strains involved in the development of acne. Microencapsulation was conducted by microparticulation solid lipid, followed by emulsification. This reached an efficiency of over 98%, and the product obtained, challenged by various trials, demonstrated ability to hold more than 90% of essential oil under evaporation conditions, avoiding oxidation and change in composition profile. Finally, the microcapsules of essential oil of thyme at contact the acne bacteria, maintained its bactericidal activity. The results of this study contribute to the development of pharmaceutical, cosmetic and food formulations stable and functional based on essential oils, to protect degradation and evaporation.