| abstract |
A process for preparing a refined extract from Indigo naturalis, comprising the steps of: a) extracting Indigo naturalis with ethanol at reflux for 2 to 8 hours, b) filtering the mixture at a temperature not lower than 65 ° C to obtain water of filtrate, c) concentrate the filtrate waters, to obtain a crude extract, said crude extract is optionally filtered (with the addition of water) to completely remove the solvent and the last components still present in the solvent, and dry, d) (i) wash the crude extract with hexane at a temperature not less than 50 ° C between 15 and 60 min, (ii) filter at room temperature the mixture obtained in step d) (i) to obtain a product, optionally rinse it with ethanol and water (iii) wash the product obtained in step d) (ii) with ethanol at reflux, and e) filter at room temperature the wash mixture obtained in step d), and dry the resulting product at a lower temperature at 80ºC for to obtain an extract that is optionally micronized. |