Desenvolvimento tecnológico de extratos padronizados em cumarinas das partes aéreas de Justicia pectoralis Jacq. (Acanthaceae)

Abstract

Justicia pectoralis (Acanthaceae) is an herb of medicinal interest employed in folk medicine in several Latin American countries, as an analgesic, anti-inflammatory and sedative. It is globally known for the properties of its coumarins, especially 1,2-benzopyrone and umbelliferone, which are used as chemical markers in quality control of the medicinal plant. The aim of this work was to develop spray-dried extracts from aerial parts of the J. pectoralis and assessment its acute oral toxicity, with a view to obtaining an intermediate to produce herbal medicines and to acquisition the quality control parameters. The species used in the preparation of the liquid extracts was cultivated, collected, dried, pulverized and characterized. The HPLC-UV/VIS analytical method for measurement of 1,2 benzopyrone and umbelliferone was validated. Box- Behnken design and response surface methodology (RSM) were used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE). The ethanol concentration (%, w/w), extraction time (min) and material-to-solvent ratio (g/mL) were the variables studied. The liquid extract was achieved on a larger scale by percolation of powdered material using ethanol concentration of 20% (w/w). The optimization of spray drying conditions evaluated the independent variables: inlet air temperature (°C), extract flow (mL/min.), and adjuvant concentration (% w/w), in function of the dependent variables: yield drying (%), moisture (%), water activity, and coumarins content (%, w/w) in a Box Behnken factorial design (33). The acute oral toxicity of the dry extract obtained under the optimized conditions was evaluated in Wistar rats. The results demonstrated that the optimal UAE condition was obtained with ethanol concentration of 15% (w/w), time of 34 min and material-to-solvent ratio of 0.1 g mL-1. The optimal conditions for spray drying process were: inlet temperature of 140 ° C, feed flow of 0.60 L/h and adjuvant concentration maltodextrin of 48%. The plant material characterization shows that the plant cultivated in Goiás's state is the J. pectoralis and that may present the same medicinal potentials of J. pectoralis cultivated in other parts of the world. The extractions were efficient to obtain a high coumarin content and the dry extract resulting from the optimized drying process demonstrated technological potential to made solid medicines. The dry extract obtained under the optimized conditions demonstrated low toxicity with LD50 estimated between 2000 and 5000 mg/kg.