Resumen La presente investigación se realizó con el propósito de determinar la composición química de los aceites esenciales de cuatro especies amazónicas del centro shuar Antuash en el cantón Morona, provincia de Morona Santiago; las cuales pertenecen a las principales familias aromáticas del Ecuador. Los aceites esenciales de Critoniopsis pycnantha (Benth.) H. Rob., Myrcia aliena McVaugh, Piper macrotrichum C. DC. y Siparuna schimpffii Diels, fueron obtenidos de las hojas secas mediante destilación analítica por arrastre de vapor, determinándose un rendimiento por peso con respecto a las hojas secas de 0,24%, 0,80%, 0,44% y 0,32%, respectivamente. Estos fueron analizados cualitativamente mediante cromatografía de gases acoplada a espectrometría de masas (GC-MS) y cuantitativamente mediante cromatografía de gases acoplada a detector de ionización de llama (GC-FID), con columna apolar DB-5ms. Se realizó la identificación de los compuestos en base a los espectros de masas y los índices de retención de Van Den Dool Kratz, y se cuantificó calculando los factores de respuesta relativos con base a las entalpías de combustión. Así se determinó riqueza en monoterpenos para el aceite de M. aliena y P. macrotrichum y riqueza en sesquiterpenos para el aceite de C. pycnantha y S. schimpffii. Los compuestos mayoritarios en el aceite esencial de C. pycnantha fueron γ- muuroleno, biciclogermacreno, (E)-cariofileno α-ylangeno y α-humuleno; para M. aliena α-pineno y β-pineno; para P. macrotrichum δ-3-careno, eugenol y acetato de chavibetol; y, para S. schimpffii espatulenol, 2-undecanona, biciclogermacreno y (E)-Isocroweacina.

Abstract This research was carried out with the aim of determining the chemical composition of the essential oils of four Amazonian species from the Antuash community, Morona canton, province of Morona Santiago. These species belong to the main aromatic families of Ecuador. The essential oils (EO) of Critoniopsis pycnantha (Benth.) H. Rob., Myrcia aliena McVaugh, Piper macrotrichum C. DC. and Siparuna schimpffii Diels were obtained from the dry leaves by analytical steam distillation; a percentage yield of 0.24%, 0.80%, 0.44%, and 0.32% was achieved respectively. EO were qualitatively analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and quantitatively analyzed by gas chromatography coupled to flame ionization detector (GC-FID) with a DB-5ms apolar column. The compounds were identified based on mass spectra and the Van Den Dool and Kratz retention indices. They were quantified by calculating the relative response factors based on the combustion enthalpies. M. aliena and P. macrotrichum resulted rich in monoterpenes, and C. pycnantha and S. schimpffii in sesquiterpenes. The major compounds for the essential oils of C. pycnantha were γ-muurolene, bicyclogermacrene, (E)-caryophyllene α-ylangene and α-humulene; M. aliena: α-pinene and β-pinene; P. macrotrichum δ-3-carene, eugenol and chavibetol acetate; and S. schimpffii: spathulenol, 2-undecanone, bicyclogermacrene and (E)-Isocroweacin.

Abstract Lepechinia mutica (Benth.) Epling, Lamiaceae, and Vallea stipularis L.f., Elaeocarpaceae, are the object of the present study. These plants are endemic to the Andean region and have attracted our attention on the basis of interesting results obtained in a preliminary anticholinesterase screening. Actually, carnosol and tiliroside, isolated from L. mutica and V. stipularis, respectively, have shown a promising selective inhibitory activity against butyrylcholinesterase. Specifically, the anti-butyrylcholinesterase activity of carnosol was 5.15 µM and that of tiliroside was 52.9 µM, compared to 8.568 ± 0.570 µM of the positive control Donepezil. Carnosol and tiliroside were purified chromatographically from the ethyl acetate extract of L. mutica and V. stipularis, respectively. Spectrophotometric methods were used for enzymatic studies.

ABSTRACT The species Croton elegans Kunth, belonging to the family Euphorbiaceae and known with the common name “mosquera”, is a native medicinal plant of Ecuador. Due to its medical applications, we are interested in secondary metabolite composition. After extraction with hexane and preparation of the alkaloid extract, preparative chromatographic fractionation in both normal and direct phase was performed. 1H NMR, 13C NMR, HSQC and HMBC experiments, together with polarimetric measurements, were conducted in order to characterize the purified compunds. Two triterpene metabolites (friedelin and cycloeucalenol) and two morphinan alkaloids ((+)-pallidine and (+)-O-methylpallidine) were obtained in a pure form. This work represents the first report on the phytochemistry of C. elegans and probably the second publication on the natural (+)-pallidine alkaloid.

The aim of the present investigation was to appraise variation in the chemical composition and antimicrobial activity against phytopatogenic bacterial of essential oils from Azorella spinosa. Three samples of A. spinosa were collected in different date in the same area. The essential oils were obtained for hydro-destillation using a Clevenger-type apparatus. The chemical composition of essential oils were analysed using Gas chromatography-mass spectrometry showed variation in the yield and composition, the main detected compounds were monoterpenes such as limonene (10.66-12.30%), tricyclene (10.81-16.99%) and sabinene (9.10-11.49%), the most abundant sesquiterpene was γ-gurjenene (5.48-8.47%). The biological activity of essential oils from A. spinosa against wild phytopatogenic microorganisms showed selectivity over Pseudomonas syringae. This is the first report of the essential oil composition of A. spinosa, and confirms that natural products obtained from aromatic plants represent an important source of bioactive molecules that could be used as new alternatives for the treatment of phytopatogenic bacteria infections.

The essential oil of the species Clinopodium nubigenum (Kunth) Kuntze, Lamiaceae, was analyzed by GC-MS and GC-FID, taking into account the more recent literature. Among the seventy compounds identified, the majority are oxygenated monoterpenoids. The essential oil, tested for antimicrobial activity, resulted effective in vitro against Candida albicans. From the aqueous MeOH extract of the aerial parts of the plant two nonvolatile compounds, named schizonepetoside A and schizonepedoside C, have been isolated. They are rare glycosyl terpenoids, which were previously isolated from only one plant, but never found before in the genus Clinopodium.