Essential oil from Cymbopogon citratus (DC) Stapf: a promising natural product against Malassezia spp

This study evaluated the sensitivity of Malassezia spp. strains, the etiologic agent of pityriasis versicolor, to essential oil from Cymbopogon citratus. The chemical composition of the essential oil was analysed by GC-MS, and the major constituents were: geraniol (52.80%), neral (36.65%) and myrcene (3.73%). The minimum inhibitory concentration (MIC) of C. citratus essential oil on to 22 strains of Malassezia spp. were determined by agar dilution technique in the presence and absence of ergosterol (50-250 ìg/mL) and sorbitol (0.8 M). Increased MIC values in the presence of ergosterol indicate an effect on fungal membrane, and the higher MIC values in the presence of sorbitol indicate a mechanism of action on thecell wall. The MIC ranged from 0.31 to 1.25 ìL/mL and it increased fourfold in the presence of ergosterol, regardless of concentration tested; and this fact was most likely related to the occurrence of the oil and exogenous ergosterol complexes. No change in MIC values in the presence of sorbitol was found. The sedata infer that C. citratus essential oil causes an effect on Malassezia spp. plasma membrane synthesis by binding to ergosterol. This study contributes to the development of new antifungal drugs, especially against Malassezia spp.

Base neurofisiológica para compreensão da dor crônica através da acupuntura / Neurophysiologic basis to understand chronic pain through acupuncture

JUSTIFICATIVA E OBJETIVOS: Os efeitos neurobiológicos da acupuntura, que atua também sobre os neurotransmissores relacionados com a dor e a depressão, qualificam o método como útil e adequado na terapêutica da dor crônica. O objetivo deste estudo foi ascender à questão do tratamento das dores crônicas pela acupuntura fazendo uma revisão bibliográfica sobre o assunto.CONTEÚDO: A acupuntura tem recebido grande destaque na mídia nas últimas décadas como uma modalidade terapêutica alternativa aos tratamentos convencionais. Estudo de neurofisiologia revela que através da inserção de agulhas há estimulação de fibras sensitivas A, de condução mais rápida (mielínica) e C, de condução mais lenta (amielínica) as quais levam os estímulos até o corno posterior da medula e este ascende pelo trato espinotalâmico. As fibras do tipo A, em especial as fibras A-beta são responsáveis pela percepção mais fina (tato) e as fibras do tipo C pela condução da dor, em especial de característica difusa e em queimação. A reação fisiológica mais extensivamente pesquisada na acupuntura tem sido a liberação de substâncias no cérebro conhecidas como endorfinas, que pertencem a um subtipo de neuropeptídio chamado de opioides endógenos que é parte integral do mecanismo natural de supressão da dor. CONCLUSÃO: Este estudo permitiu compreender a importância de conhecer os potenciais efeitos da acupuntura nos processos dolorosos crônicos, pois estar ciente dos meios de inibir os processos excitatórios dolorosos e estimular as ações moduladoras e inibitórias é fundamental para planejar o tratamento direcionado para os fatores responsáveis pela presença e manutenção da dor crônica.

BACKGROUND AND OBJECTIVES: Neurobiological effects of acupuncture, which also acts on pain and depression-related neurotransmitters, qualify such method as useful and adequate to treat chronic pain. This study aimed at evaluating the treatment of chronic pain with acupuncture through a literature review on the subject.CONTENTS: Acupuncture has been widely spread by the media in recent years as an alternative therapeutic modality to conventional treatments. Neurophysiologic studies show that through needle insertions there is stimulation of sensory A fibers, of faster conduction (myelinic) and of C fibers, of slower conduction (unmyelinated) which transmit stimuli to posterior bone marrow horn and from there they ascend through the spinothalamic tract. Type-A fibers, especially A beta fibers, are responsible for the finer perception (touch) and type-C fibers are responsible for pain conduction, especially diffuse and burning pain. Most extensively researched physiologic reaction in acupuncture has been the release of substances in the brain, known as endorphins, which belong to a neuropeptide subtype called endogen opioids, which are integral part of natural pain suppression mechanism. CONCLUSION: This study showed the importance of knowing potential acupuncture effects on chronic painful processes because it is fundamental to be aware of means to inhibit painful excitatory processes and to stimulate modulating and inhibiting actions to plan the treatment directed to factors responsible for chronic pain presence and persistence.

Chemical composition and antifungal activity of Hyptis suaveolens (L. ) poit leaves essential oil against Aspergillus species

This study aimed to identify the constituents of the essential oil from Hyptis suaveolens (L.) leaves using a Gas Chromatograph -Mass Spectrometer and assess its inhibitory effect on some potentially pathogenic Aspergilli (A. flavus, A. parasiticus, A. ochraceus, A. fumigatus and A. niger). Eucaliptol (47.64 percent) was the most abundant component in the oil, followed for gama-ellemene (8.15 percent), beta-pynene (6.55 percent), (+)3-carene (5.16 percent), trans-beta-cariophyllene (4.69 percent) and germacrene (4.86 percent). The essential oil revealed an interesting anti-Aspergillus property characterized by a Minimum Inhibitory Concentration and Minimum Fungicidal Concentration of 40 and 80 µL/mL, respectively. The oil at 80 and 40 µL/mL strongly inhibited the mycelial growth of A. fumigatus and A. parasiticus along 14 days. In addition, at 10 and 20 µL/mL the oil was able to cause morphological changes in A. flavus as decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure suggesting fungal wall degeneration. These findings showed the interesting anti-Aspergillus property of H. suaveolens leaves essential oil supporting its possible rational use as alternative source of new antifungal compounds to be applied in the aspergillosis treatment.

Inhibitory effect of Cinnamomum zeylanicum Blume (Lauraceae) essential oil and beta-pinene on the growth of dematiaceous moulds

Dematiaceous moulds are pathogen microorganisms able to act as etiological agents of mycoses with different degrees of severity. This study evaluated the effectiveness of Cinnamomum zeylanicum Blume essential oil and beta-pinene in inhibiting the growth of various strains of dematiaceous moulds (Alternaria brassicola, Cladosporium herbarium, C. resinae, C. cladosporioides, Chaetomum globosum, Curvularia sp., Fonsecaea compacta, Piedraia hortae). Antimicrobial assays were led by determining the Minimum Inhibitory Concentration-MIC using the solid medium diffusion procedure and observing the interference of the MIC values on the mould radial mycelial growth along 14 days. MIC values found to C. zeylanicum essential oil oscillated between 63 and 125 µL/mL. beta-pinene showed MIC value of 125 µL/mL for the most mould strains, however C. resinae and C. globosum were resistant to it in all assayed concentrations. MIC values found to C. zeylanicum essential oil and beta-pinene presented intense fungicidal effect noted by a total inhibition of the mycelial growth of C. cladosporioides and F. compacta along 14 days of exposure. These results showed the intense antimould potential of C. zeylanicum essential oil and beta-pinene which could be regarded in a rational use in pharmaceutical formulations used to treat some mycoses, particularly, those caused by dematiaceous moulds.

Os fungos dematiáceos são microrganismos patogênicos capazes de agir como agentes etiológicos de micoses com diferentes graus de severidade. Este estudo avaliou a efetividade do óleo essencial de Cinnamomum zeylanicum Blume e beta-pineno em inibir o crescimento de várias cepas de fungos dematiáceos (Alternaria brassicola, Cladosporium herbarium, C. resinae, C. cladosporioides, Chaetomum globosum, Curvularia, Fonsecaea compacta, Piedraia hortae). Os ensaios antimicrobianos foram conduzidos através da determinação da Concentração Inibitória Mínima-CIM utilizando-se da técnica de difusão em meio sólido, bem como através da observação da interferência dos valores de CIM sobre o crescimento micelial radial fúngico ao longo de 14 dias. Os valores de CIM encontrados para o óleo essencial de C. zeylanicum oscilaram entre 63 e 125 µL/mL. beta-pineno apresentou um valor de CIM de 125 µL/mL para a maioria das cepas fúngicas, entretanto C. resinae e C. globosum mostraram-se resistentes a todas as concentrações ensaiadas. Os valores de CIM encontrados para C. zeylanicum e beta-pineno apresentaram intenso efeito fungicida notado por uma total inibição do crescimento micelial de C. cladosporioides e F. compacta ao longo de 14 dias de exposição. Estes resultados mostraram o intenso potencial antifúngico do óleo essencial de C. zeylanicum e beta-pineno, os quais poderiam ser considerados em um uso racional em formulações farmacêuticas utilizadas para a terapia de algumas micoses, particularmente, aquelas causadas por fungos dematiáceos.