Effect of drying temperature on the yield and phytochemical quality of the essential oil of pepper rosemary (Lippia origanoides Kunth) and of clove basil (Ocimum gratissimum L.) / Efeito da temperatura de secagem no rendimento e na qualidade fitoquímica do óleo essencial de alecrim-pimenta (Lippia origanoides Kunth) e de alfavaca (Ocimum gratissimum L.)

Among medicinal species, Lippia origanoides Kunth and Ocimum gratissimum L. stand out for its recognized therapeutic value associated with the medicinal properties of their essential oils. Drying is a critical point in post-harvest processing of medicinal plants for the conservation of bioactive compounds. This work aimed to evaluate the effect of drying temperature on the essential oil’s yield and phytochemical quality extracted from leaves of O. gratissimum and L. origanoides. The medicinal species were grown in an organic system and their leaves were harvest and immediately dried at 40, 50 and 60 °C. The essential oils were extracted from the leaves by hydrodistillation in Clevenger apparatus. There was detected a difference (P <0.01) in the essential oil yield of O. gratissimum with the increase in the drying temperature, being 1.35% (40 °C), 0.83% (50 °C) and 0.45% (60 °C) ). In L. origanoides there was detected a difference (P <0.01) in the essential oil yield only between 40 °C (3.4%) and 60 °C (2.84%). The increase of drying temperature reduced the levels of the major constituents of O. gratissimum (eugenol, germacrene D and caryophyllene oxide), but did not change the levels of the major constituents of L. origanoides (thymol, trans-caryophyllene and para-cymene). Considering that the increase of the drying temperature promote a reduction in the essential oil yield of both medicinal species and also in the major constituents concentration in O. gratisssimum, it is essential to select the correct drying temperature to guarantee the best yield and the phytochemical quality of the essential oil to ensure therapeutic efficacy. Here, we conclude that the best drying temperature to the essential oil’s yield and phytochemical quality is 40 °C for O. gratissimum and 40 or 50 °C for L. origanoides

Effect of drying temperature on yield and phytochemical quality of essential oil extracted from Mikania laevigata (Guaco) leaves / Efeito da temperatura de secagem sobre o rendimento e qualidade fitoquímica de óleo essencial extraído de folhas de Mikania laevigata (Guaco)

Mikania laevigata Sch. Bip. ex Baker, Asteraceae, commonly known as the guaco, is medicinal species native to Brazil. Among the critical points of post-harvest processing of medicinal species, the drying temperature must be considered, because its can interfere in the yield and phytochemical quality of plant material, and, consequently, in the therapeutic action. The effect of the drying temperature was evaluated on the yield and phytochemical quality of the essential oil extracted from M. laevigata leaves. The cultivation was carried out in an organic system and using the select genotype (Cenargen) for this region. The leaves were harvested and immediately submitted to drying process at 40, 50 and 60 °C. The essential oils were extracted by hydrodistillation in Clevenger apparatus and the chemical constituents was evaluated using gas chromatography coupled to the mass spectrophotometer (CG-MS). There was a reduction in the essential oil yield (p <0.05) with increasing drying temperature. However, at 60 ºC there was a higher concentration of coumarin to which the bronchodilator and expectorant action is attributed. Therefore, we recommended dry the M. laevigata leaves at 60 ºC to obtain the highest coumarin content and guarantee the bronchodilator and expectorant therapeutic effect

Lettuce and lemon balm intercropping: crops productivity, yield and phytochemical quality of lemon balm’s essential oil / Consórcio entre alface e melissa: produtividade das culturas, teor e qualidade fitoquímica do óleo essencial de melissa

Intercropping is a recommended to conserve the agroecosystem balance, but identifying which species in the intercropping benefit each other is a challenge. The aim of this study was to evaluate the viability and effect of spacing between plants in the intercropping of lettuce with lemon balm on the yield and phytochemical quality of lemon balm essential oil. Lettuce was harvested at 41 days after transplanting (DAT) and fresh and lemon balm was harvested at 69 DAT. Equivalent Area Index (EAI) was used to evaluate the intercropping between lemon balm and lettuce, which has proven feasible, since the EAI were higher than 1.0. The yield of the two species intercropped was not significantly different from that obtained in the monocropping and there was no reduction in the essential oil content. There was also an increase in the major constituents of the lemon balm essential oil

Effect of drying temperature on the yield and phytochemical quality of the essential oil of mint (Mentha x villosa Huds.) / Efeito da temperatura de secagem no rendimento e na qualidade fitoquímica do óleo essencial de hortelã (Mentha x villosa Huds.)

A hortelã (Mentha x villosa Huds.) consta na Relação Nacional de Plantas Medicinais de Interesse ao SUS (RENISUS) devido ao reconhecimento de suas propriedades medicinais, dentre elas a atividade antiparasitária. Dentre as etapas do processamento pós-colheita de plantas medicinais, destaca-se a secagem como etapa crítica e essencial para a conservação dos compostos bioativos vegetais. Desta forma, objetivou-se avaliar o efeito da temperatura de secagem sobre o rendimento e a qualidade fitoquímica do óleo essencial extraído de folhas de hortelã. Realizou-se o cultivo em sistema orgânico em Oratórios, Minas Gerais, Brasil. Os ramos de hortelã foram colhidos e as folhas destacadas e submetidas à secagem em estufa de circulação forçada de ar a 40, 50 e 60 °C. A extração do óleo essencial foi feita por hidrodestilação em aparelho Clevenger, e para identificação dos constituintes químicos utilizou-se a cromatografia gasosa acoplada ao espectrofotômetro de massas (CG-MS). Constatou-se redução (P<0,001) do rendimento do óleo essencail com o aumento da temperatura de secagem das folhas. Não houve alteração do teor  de óxido de piperitona (OP) (78 %), composto majoritário ao qual se atribui a atividade antiparasitária, nas temperaturas de secagem testadas. Entretato, observou-se maior diversidade de constituintes químicos identificados no óleo essencial obtido de  folhas submetidas a secagem a 50 ºC. Os resultados contribuem para orientação de produtores no prcessamento pós-colheita das folhas de Mentha x villosa Huds visando a qualidade fitoquímica do óleo essencial e seu uso terapêutico como antiparasitário