Influence of extractive parameters on the preparation of a solution from <i>Psidium guajava</i> L.

The aim of this work is evaluate the influence of extractives parameters on tannin content of solutions obtained from leaves of P. guajava and the antimicrobial activity of the best extract solution. The type of extraction, drug proportion and alcohol concentration were studied following a factorial design and the responses evaluated were tannin content and dry residue. The tannins content was assayed by spectrophotometric method at 271nm using casein as precipitant agent and the dry residue was determined by gravimetric method. The statistical analysis demonstrated that only the alcohol concentrations have significant influence on tannins content, but on the dry residue both factors (drug and alcohol proportion) were important. In accordance of the results, the best extractive method was decoction on reflux during 15 min using alcohol concentration 50 % (v/v) as solvent and this extract solution shows a promising antimicrobial activity. Colegio de Farmacéuticos de la Provincia de Buenos Aires