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Herein, we describe the synthesis and characterization of fused pyrroles in cholestane and norcholestane side chains derived from kryptogenin and diosgenin, respectively. Both conventional and microwave heating techniques were used to synthesize the steroidal pyrroles from primary amines, with the microwave method producing the highest yields. In particular, the norcholestane pyrroles were tested as acaricides against the two-spotted spider mite (Tetranychus urticae Koch) under laboratory conditions and as plant growth promoters on habanero pepper (Capsicum chinense Jacq) under greenhouse conditions.

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INTRODUCTION: Lauraceae alkaloids are a structurally diverse class of plant specialised secondary metabolites that play an important role in modern pharmacotherapy, being useful as well as model compounds for the development of synthetic analogues. However, alkaloids characterisation is challenging due to low concentrations, the complexity of plant extracts, and long processes for accurate structural determinations. OBJECTIVE: The use of high-performance thin layer chromatography coupled with desorption electrospray ionisation multistage mass spectrometry (HPTLC DESI-MSn ) as a fast tool to identify alkaloids present in Ocotea spixiana extract and evaluate the extract's acaricide activity. METHODS: Ocotea spixiana twigs were extracted by conventional liquid-liquid partitioning. HPTLC analysis of the ethyl acetate extract was performed to separate isobaric alkaloids prior to DESI-MSn analysis, performed from MS3 up to MS7 . The extract's acaricide activity against Rhipicephalus microplus was evaluated by in vitro (larval immersion test) and in silico tests. RESULTS: HPTLC-DESI-MSn analysis was performed to identify a total of 13 aporphine and four benzylisoquinoline-type alkaloids reported for the first time in O. spixiana. In vitro evaluation of the extract and the alkaloid boldine showed significant activity against R. microplus larvae. It was established in silico that boldine had important intermolecular interactions with R. microplus acetylcholinesterase enzyme. CONCLUSION: The present study demonstrated that HPTLC-DESI-MSn is a useful analytical tool to identify isoquinoline alkaloids in plant extracts. The acaricide activity of the O. spixiana ethyl acetate extract can be correlated to the presence of alkaloids.

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Introducción: especies de la familia Lauraceae son fuentes importantes de sustancias bioactivas, como las que actúan de insecticidas. En los estudios de bioprospección de lauraceas colombianas, a siete especies medicinales pertenecientes a esta familia se les evaluó su actividad acaricida frente a Dermatophagoides farinae y Blomia tropicalis, considerados como un problema en salud pública a nivel intradomiciliario. Objetivo: determinar la actividad acaricida de los extractos etanólicos de las especies de Lauraceae sobre los ácaros intradomiciliarios Dermatophagoides farinae y Blomia tropicalis, así como caracterizar los extractos obtenidos mediante ensayo fitoquímico preliminar. Métodos: la actividad acaricida in vitro de los extractos de las siete especies, colectadas en diferentes regiones de Colombia, se evaluó sobre individuos adultos a través de las pruebas de contacto directo y acción fumigante. Cada uno de los extractos se caracterizó químicamente mediante ensayos de coloración o precipitación. Resultados: en la prueba de contacto, el extracto de hojas de Persea caerulea eliminó al 100 % de Dermatophagoides farinae. En la prueba de acción fumigante, el extracto de hojas de Persea caerulea, eliminó 100 % de Dermatophagoides farinae y 83,4 % de Blomia tropicalis (después de 120 min de exposición; a 0,1 mg/mL). El ensayo fitoquímico preliminar permitió identificar la posible presencia de metabolitos acorde con la quimiotaxonomía de las Lauraceae. Conclusiones: los resultados permiten sugerir que especies de la familia Lauraceae serían catalogados como fuente potencial de biocontroladores contra los ácaros domiciliarios Dermatophagoides farinae y Blomia tropicalis.

Introduction: Lauraceae plants are considered as important sources of bioactive substances, as those acting as insecticides. As part of our program for bioprospecting studies on Colombian Lauraceae plants, seven medicinal species belonging to this family were studied for their acaricide activity against Dermatophagoides farinae and Blomia tropicalis, considered public health problems at domiciliary level. Objective: to evaluate acaricide activity of ethanol extracts from Lauraceae plants on domiciliary mites Dermatophagoides farinae and Blomia tropicalis as well as to characterize ethanol-soluble extracts by preliminary phytochemical assay. Methods: in vitro acaricide activity of extracts from seven plants belonging to the Lauraceae family, harvested in different regions of Colombia, was assessed on individual adults through direct contact test and fumigant action. Each plant extract was tested for chemical characterization by means of coloration and precipitation tests. Results: in direct contact bioassay, the leaf extract from Persea caerulea eliminated 100 % of Dermatophagoides farinae. In fumigant action bioassay, the leaf extract of Persea caerulea eliminated 100 % Dermatophagoides farinae and 83.37 % of Blomia tropicalis (after 120 minutes exposure at 0.1 mg/mL). The preliminary phytochemical testing identified the possible presence of metabolites according to the Lauraceae chemotaxonomy. Conclusions: obtained results indicated that Lauraceae plants could be catalogued as a source of potential biocontrol agents against specific domiciliary mites Dermatophagoides farinae and Blomia tropicalis.