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Validação da metodologia de quantificação espectrofotométrica das saponinas de Pfaffia glomerata (Spreng.) Pedersen - Amaranthaceae

Was made standardization for the spectrophotometric quantification method of Pfaffia glomerata roots saponins. The initial tests made use of Merck saponin, prepared in five different concentrations (0.08-0.28 mg/ml) for obtaining the calibration curve and linearity; the tests with the roots were carried out with hydroalcoholic extracts purified with n-butanol. The chromogenic reagent was Cobalt chloride in the concentration of 0.2% and the scanning of 200 through 400 nm of wavelength leaded to a maximum absorption peak in 284 nm. The method showed linearity for the concentrations range used (R²= 0.9963). The precision (variance coefficients) was between 7 and 12% and the quantification limit was 0.08 mg/ml, and the detection limit 0.02 mg/ml. The accuracy of the proposed procedure presented relative error of 6.3; 3.4; 3.5; 1.8 and 0.3% for the concentrations used. The data from the standard curve were applied in some roots samples, leading to the values of total saponins average 13,5±2,0%. The data obtained allow the spectrophotometric quantification of Merck saponin and the saponins from the P. glomerata roots.


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