Sofia Pombal

The indiscriminate use of acaricides is a problem worldwide and has increased the selection of acaricide-resistant tick populations. The goal of this study was to evaluate the acaricide effects of two essential oils (from Schinus molle and Bulnesia sarmientoi) using the larval immersion test on three Rhipicephalus tick species. Rhipicephalus evertsi, Rhipicephalus appendiculatus and Rhipicephalus pulchelus ticks collected in Kenya, without history of acaricide exposure, were tested, as well as individuals from two populations of Rhipicephalus microplus (with or without history of acaricide exposure), for comparison. The sample most resistant to the treatments was a population of R. microplus with previous acaricide exposure, whereas the least tolerant sample was a strain of the same species that never had contact with acaricides (Porto Alegre strain). Interestingly, the field tick samples without previous acaricide exposure responded to essential oils with a mortality profile resembling that observed in the acaricide-resistant R. microplus field population, and not the susceptible Porto Alegre strain. The essential oil of B. sarmientoi and its two components tested (guaiol and bulnesol) caused the highest mortality rates in the tested species and are potential molecules for future studies on control methods against these species.

Carvone is one of the most versatile synthons in organic synthesis. It has been used as starting material for a huge number of organic syntheses of natural products with interesting biological activities. This manuscript communicates the antioxidant activity against superoxide of carvone and several derivatives.

The synthesis of the two 7,8-epoxides of carvone has been attained using organocatalysis in a two-step synthetic route through a bromoester intermediate. Among the different reaction conditions tested for the bromination reaction, moderate yields and diastereoselection are achieved using proline, quinidine, and diphenylprolinol, yielding the corresponding bromoesters that were transformed separately into their epoxides, obtaining the enantiopure products.

Carvone has corroborated its versatility as starting material for building blocks synthesis in organic chemistry, being achieved a new chiral lactone. It has been done a study on the antioxidant activity against superoxide of carvone and a chloro derivative that show the potent activity of the natural product (R)-carvone, 1.

Lavandula luisieri (Rozeira) Rivas-Martinez is an endemic aromatic Labiatae the Iberian Peninsula, common in semi-arid regions of southern Portugal and southwestern Spain, that produces an active antibacterial essential oil from the leaves and flowers. This work presents the study of the chemical variation in various stages of growth of leaves and flowers of L. luisieri. It has been found that the essential oils are mainly constituted by 1,8-cineol, camphor, linalool and trans-α-necrodil acetate. It was also studied the total phenol content and the antioxidant activity on leaves and flowers. The ethanol extraction from de leaves contents the highest total phenol, important factor for the antioxidant activity of the plant, extract. It has been studied too, the antibacterial activity against Escherichia coli, Salmonella spp. and Staphylococcus aureus. In accordance with the obtained results, the antibacterial activities stand out against Staphylococcus, of the oil of L. luisieri (leaves and flowers).

The use of hydrotalcites for the synthesis of two chiral building blocks in a simple way is described as a new and green methodology. The synthesis of these compounds implies a regioselective Baeyer–Villiger reaction in a very selective way with ulterior opening and lactonisation. This methodology should be considered green for the use of hydrogen peroxide as the only oxidant and hydrotalcites as the catalyst, and because no residues are produced apart from water. The procedure is very adequate for using in gram scale, in order to increase the value of the obtained compounds. The conditions are excellent and can be applied for nonstable compounds, as they are very mild. The synthesised compounds are magnific starting materials for the synthesis of biologically active or natural compounds. The use of a cheap, commercial and chiral compound as carvone disposable in both enantiomeric forms adds an extra value to this methodology.

Foeniculum vulgare Mill. is a biennial or perennial plant belonging to the Apiaceae family and is native to the Mediterranean area, but came to be naturalized elsewhere. F. vulgare is used in folk medicine, being useful in the treatment of various problems, especially those of the digestive system. It is also recommended for diabetes, bronchitis and chronic coughs, treatment of kidney stones and it is considered as having diuretic properties. It is a species with several applications in the food industry and it is also used in cosmetic and pharmaceutical products. F. vulgare has two major subspecies: piperitum and capillaceum with bitter and sweet essential oils. The vulgare subspecies is characterized by having as main compounds two phenylpropanoids: estragole and anethole and one oxygen-containing monoterpene: fenchone. The relative concentration of these compounds may vary according to the collection point, extraction method of and part of the plant under study. The aim of this study was to analyze the chemical composition of the essential oils of fennel seeds harvested from twenty cultivated wild populations, collected in Portugal. The essential oils were obtained by hydrodistillation using a Clevenger-type apparatus, with a yield between 0.49 and 2.94% (w/v). The essential oils were then analyzed by GC-MS. The major components of the oils were identified as being anethole (7.9 – 78.5%), estragole (1.8 – 66.0%) and fenchone (12.0 – 37.0%). This analysis allowed the comparison with existing chemotypes proposed in a previous study, being possible to conclude the existence of eight populations from chemotype anethole, five populations from chemotype fenchone and four populations from chemotype estragole. It was also obtained three more populations that it was not possible to include in these chemotypes. Keywords: Chemical composition, phenylpropenes, monoterpene, oil yield References: [1] Bernáth, J. et al. (1996)J. Essent. Oil Res 8: 247 – 253.