Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.

RESUMEN Introducción: El melanoma es un tumor maligno de estirpe melanocítica que constituye el sexto cáncer más frecuente en la población general y tiene una alta capacidad para producir metástasis. Aproximadamente el 95% de los melanomas primarios pertenecen a cuatro tipos clínico-patológicos: extensivo superficial, nodular, lentigo maligno y lentiginoso acral. El 5% restante corresponde a variantes menos frecuentes entre las que se encuentra el melanoma amelanótico, que representa entre el 0.4-27.5% de los casos de este subgrupo. Objetivo: Presentar un caso de un melanoma amelanótico, como una variante que puede acompañar a cualquier otro tipo clínico de melanoma, en este caso a uno de tipo nodular,lesión que, debido a su disminución o ausencia de pigmento, puede conducir a errores diagnósticos que inciden en la demora en el tratamiento y reducen la sobrevida de los pacientes que lo padecen. Caso Clínico: Se presenta el caso de un paciente de sexo masculino de 75 años que acude por presentar una lesión tumoral exofítica en la frente, de aproximadamente un año de evolución. Al examen físico se observa la lesión tumoral cupuliforme, eritematosa y brillante, que bajo dermatoscopio de luz polarizada muestra un patrón vascular polimorfo a predominio de vasos lineales gruesos. Se plantean varios diagnósticos diferenciales entre los que se destacan: carcinoma basocelular, granuloma piógeno, linfoma y metástasis cutáneas; se realiza una toma de muestra para biopsia y técnicas de tinción con inmunohistoquímica, que confirman el diagnóstico de melanoma, se decide exéresis de la tumoración con márgenes y seguimiento multidisciplinario del caso. Conclusiones: Las variantes hipo/amelanóticas del melanoma son poco frecuentes y su diagnóstico presenta dificultades que suelen generar demoras que influyen en el tratamiento y pronóstico de la enfermedad. La dermatoscopía se presenta como una herramienta sumamente útil que puede aumentar la sospecha diagnóstica de estos tumores, aunque el estudio histopatológico continúa siendo el patrón de referencia para el diagnóstico, así como para el abordaje terapéutico y seguimiento ulteriores.

ABSTRACT Introduction: Melanoma is a malignant melanocytic tumor that constitutes the sixth most frequent cancer in the general population and has a high capacity to produce metastasis. Approximately 95% of primary melanomas belong to four clinicopathological types: extensive superficial, nodular, lentigo maligna, and acral lentiginous. The remaining 5% correspond to less frequent variants, among which is amelanotic melanoma, that represents between 0.4-27.5% of the cases in this subgroup. Objective: To present a case of an amelanotic melanoma, as a variant that can accompany any other clinical type of melanoma, in this case a nodular type, a lesion that, due to its decrease or absence of pigment, can lead to diagnostic errors that affect the delay in treatment and reduce the survival of patients who suffer from it. Clinical Case: The case of a 75-year-old male patient who presents with an exophytic tumor lesion on the forehead of approximately one year of evolution. Physical examination reveals a bright, erythematous, dome-shaped tumor which shows a polymorphous vascular pattern with a predominance of thick linear vessels under a polarized light dermatoscope. Several differential diagnoses are proposed, among which the following stand out: basal cell carcinoma, pyogenic granuloma, lymphoma, and skin metastases; a sample is taken for biopsy and staining techniques with immunohistochemistry, which confirm the diagnosis of melanoma, it is decided to excise the tumor with margins and multidisciplinary follow-up of the case. Conclusions: The hypo / amelanotic variants of melanoma are rare and their diagnosis presents difficulties that usually generate delays that influence the treatment and prognosis of the disease. Dermoscopy is presented as an extremely useful tool that can increase the diagnostic suspicion of these tumors, although the histopathological study continues being the gold standard for diagnosis, as well as for the therapeutic approach and subsequent follow-up.