Análise da legislação sobre o uso de plantas medicinais no Brasil. Potencial químico-farmacológico de Palicourea rigida Kunth

Abstract

Palicourea rigida Kunth, belonging to the family Rubiaceae, have been used in folk medicine for the treatment of inflammation and infection of the urinary tract and the female reproductive tract. This study aimed to evaluate the potential chemical-pharmacological P. rigida and verify its appropriateness to normative standards of the Unified Health System (SUS). Dried and sprayed leaves were extracted in ethanol. After removing the solvent, ethanol extract was submmited to the fractionation by partition to obtain the hexanic, dichlorometanic, in ethyl acetate and butanolic fractions. Phytochemical screening, quantification of total phenols and flavonoids by spectrophotometry and analysis by high performance liquid chromatography were performed. The antioxidant activity was evaluated by DPPH, bioautography, power reduction and -carotene/linoleic acid methods. Acute toxicity was determined and the antinociceptive (writhing, formalin and hot plate tests) and anti-inflammatory activities (paw edema and pleurisy methods) were evaluated. Analysis of the feasibility of inclusion of P. rigida in list of plants of interest to the SUS has been verified. Data were expressed by mean ± standard error. Analysis of variance followed by Turkey or Student-Newman-Keuls tests was used to measure the degree of significance to p < 0.05. Flavonoids, tannins, coumarins, terpenoids and steroids, alkaloids and anthraquinones were detected in P. rigida. The total phenols ranged between 3.72 and 28.05 g/100 g, while flavonoids were 1.95 and 14.15 g/100g. Rutin and quercetin were identified in ethyl acetate and butanolic fractions, respectively. Using DPPH, the values of EC50 showed between 24.51 ± 0.52 to 125.79 ± 0.10 mg/mL, while reducing power produced EC50 of 183.09 ± 1.84 to 703.14 ± 1.15 mg/mL. The percentages of inhibition of -carotene oxidation were 24.30 ± 3.38 to 84.76 ± 1.40. The ethanol extract inhibited the writhing at 32.88 (100 mg/kg), 34.25 (200 mg/kg) and 61.64% (400 mg/kg). Doses of 200 and 400 mg/kg inhibited the first phase in 13.80 (200 mg/kg) and 24.74% (400 mg/kg), while the second phase was reduced by 10.52 (100 mg / kg) , 22.92 (200 mg/kg) and 35.73% (400 mg/kg). After 90 min of treatment, doses of 200 mg/kg (36.61%) and 400 mg/kg (71.21%) prolonged the latency time. Doses of 200 and 400 mg/kg reduced the paw edema after 3 and 4 hours of treatment. The volume of exudate was reduced by 27.18 (200 mg/kg) and 36.89% (400 mg/kg) and total white cell count suffered inhibition of 11.94 and 24.91% at the doses of 200 and 400 mg/kg, respectively. The results indicated that P. rigida is a promising source of bioactive compounds with antioxidant, antinociceptive and anti-inflammatory activities that justifies the popular usage and gathers important characteristics of interest to the SUS.