ABSTRACT Erythraline is the major alkaloid produced by Erythrina verna Vell., Fabaceae, a plant used in folk medicine and phytotherapeutic products to treat anxiety and sleep disorders. This study aimed to investigate the pharmacokinetic parameters of erythraline after intravenous administration in rats. For the analysis of erythraline in rat plasma, a method was developed and validated using UHPLC-MS/MS. Pharmacokinetic parameters were estimated by non-compartmental analysis. The metabolite 8-oxo-erythraline observed in previous biomimetic model studies was monitored during in vivo experiments. The quantification limit was 5 ng/ml within a linear range of 5-2000 ng/ml. After an intravenous dose of 1 mg/kg, the following pharmacokinetic parameters were observed: elimination half-life of 44.2 min; total clearance of 42.1 ml/min/kg and volume of distribution of 2085 ml/kg. In summary, a precise, accurate and selective UHPLC-MS/MS method was developed and successfully applied to investigate the pharmacokinetics of erythraline in rats. The metabolite 8-oxo-erythraline was observed in rat plasma after 20 min of erythraline administration.

Abstract Condensed tannins have been used for many years in folk medicine to treat gastric problems. The mechanism of action that explains why tannins improve gastritis symptoms is based on their ability to chelate metals, antioxidant activity, and their complexation power with other molecules. Even though these uses are well-known, the requirements to become an herbal medicine are much more complex. Herein, we analyzed Stryphnodendron rotundifolium Mart., Fabaceae, extract using MALDI for tannin characterization and carried out a fluorescence-imaging study to prove the gastroprotective effects of tannins as coating agents. Through these methods we show that condensed tannins form a gastroprotective layer. Moreover, we revise and discuss other possible mechanisms of action for phenolic-rich plant extracts and their potential in the development of herbal medicines to treat ulcers and gastritis.

Abstract Piper angustifolium Lam., Piperaceae, popularly known as "matito", "pimenta-de-macaco", "pimenta-longa" or "jagurandi" in Brazil, has been commonly used in the treatment of cutaneous leishmaniasis-associated lesions, but there are few studies on the activity against visceral leishmaniasis-associated species. This study demonstrates the first in vitro antileishmanial activity of the P. angustifolium essential oil, of which the phytochemical profile showed the presence of sesquiterpenes and monoterpenes. The main compounds were spathulenol (23.8%) and caryophyllene oxide (13.1%). P. angustifolium essential oil was highly active [the half maximum inhibitory concentration = 1.43 μg/ml] against intracellular amastigotes of Leishmania infantum, the etiological agent of visceral leishmaniasis in the New and Old World. Activity was obtained 24 h after addition of the oil (6.25–50 μg/ml), with a reduction of 100% in the infection index at concentrations of 25 and 50 μg/ml. P. angustifolium essential oil showed low cytotoxicity for mammalian fibroblasts and macrophages (the half maximum inhibitory concentration values of 31.67 and 48.22 μg/ml, respectively), and it was 33 and 22 times more toxic to amastigotes than to mammalian cells, as indicated by selectivity indexes. The results demonstrated that P. angustifolium essential oil is a promising alternative for the study of potential drugs for visceral leishmaniasis.