Influence of process conditions on physicochemical properties and antinociceptive activity in vivo of spray-dried Rapanea ferruginea Mez. stem bark extract

Abstract Rapanea ferruginea (Capororoca) stem bark tea is commonly employed in traditional medicine to treat inflammatory and painful diseases. Myrsinoic acid B was isolated from the ethanolic extract, and presented antinociceptive effects. The present work aimed to study the influence of process conditions on physicochemical properties and antinociceptive activity in vivo of spray-dried R. ferruginea Mez. stem bark extract in order to obtain a more stable intermediate herbal product. R. ferruginea stem bark extract powder was assessed using a spray-dryer technique, and the influence of the formulation components and drying process was verified through two 3 2 factorial designs. Physical properties including morphology, size, hygroscopicity, moisture content, process yield, powder flow and thermal analysis were evaluated. Myrsinoic acid B concentration was assessed using a HPLC method and the antinociceptive activity was evaluated by formalin assay. Analysis of variance showed that some of the studied factors significantly influenced the concentration of myrsinoic acid B and the physical characteristics. In general, spray drying can satisfactorily be employed as a drying technique for R. ferruginea stem bark extracts. Regarding the antinociceptive activity, both concentrated and extract powders were effective against the two phases of nociception. The formulation with the best physical properties did not have the higher concentration of myrsinoic acid B, but presented a better result in the formalin assay, suggesting a synergic action among the extract's chemical components.