Pharmacokinetic evaluation of the crude extract and secondary metabolites from the leaves of Copaifera langsdorffii Desf

Copaifera langsdorffii Desf., popularly known as \"copaíba\" is abundantly distributed in the Brazilian cerrado, with several biological activities that have been described in the literature for its oleoresin. However, since few years ago, our research group has been studying the aerial parts of this species, and it was found that the hydroalcoholic extract of its leaves display antilithiatic activity. Aiming to identify the compounds related to this activity, the phytochemical study of the leaves hydroalcoholic extract was undertaken. By using chromatography techniques, it was possible to choose the most promising fractions to isolate compounds. From the ethyl acetate fraction, it was isolated by countercurrent chromatography (HSCCC) followed by preparative HPLC purification, the flavonoids quercetin-3-O-?-L-rhamnopyranoside (quercitrin) and kaempferol-3-O-?-L-rhamnopyranoside (afzelin). From the aqueous fraction, it was isolated the galloylquinic acid derivatives 5\'\'-O-methyl-3,4-di-O-galloylquinic and 5\',5\'\'-di-O-methyl-3,4-O-di-galloylquinic by using gel filtration chromatography (Sephadex) followed by preparative HPLC purification. For the pharmacokinetic assays, the hydroalcoholic extract, quercitrin and 5\', 5\'\'-di-O-methyl-3,4-di-O-galloylquinic acid were chosen to be studied. For both compounds, it was validated analytical methods in plasma and saline, to perform pharmacokinetic studies. It was also held the microdialysis probe calibration in vitro by retrodialysis, to determine the conditions to be employed in vivo. In general, quercitrin fitted to a two-compartmental pharmacokinetic model and after intravenous administration of 1 mg/kg, it presented a short half-life (t1/ 2 = 0.40 ± 0.07 h) a fast (? = 11.32 ± 1.90 h-1) and good (Vdss = 2.10 ± 0.52 L/kg) tissue distribution and high clearance (CL = 6.85 ± 0.62 L/h/kg). In the kidney microdialisates analyses, the free renal fraction of quercitrin was 13 times greater than the free plasma concentration. The galloylquinic compound, which is a new isolated one, was studied intravenously in three concentrations (1 mg/kg, 1.5 mg/kg and 2 mg/kg) and fitted to a two-compartmental model with Michaelis-Menten elimination, presenting the non-linear behavior (ASC0-? 103.85 ± 23.90, 273.7 ± 81.6 and 363.6 ± 142.32 ?g h/mL, respectively). It was not possible to quantify the free concentration of galloylquinic in the kidney by microdialysis, because it bound to the probe. Thus, the study of tissue distribution was performed, in which it was demonstrated that both quercitrin and galloylquinic showed high penetration in the kidneys, with a tissue/plasma ratio of 23.7 and 12.4, respectively. With regard to the pharmacokinetic profile of the hydroalcoholic extract of C. langsdorffii and n-butanol fraction after oral administration, it was found that it was not possible to detect any of the isolated compounds in plasma, suggesting that these compounds were metabolized and probably become even more water soluble for disposal renally. Based on the results, it is concluded that quercitrin and galloylquinic are rapidly eliminated and may be related to antilithiatic activity of the leaves of C. langsdorffii. (AU)