EFFECTIVENESS OF PROCESSES OF DRYING OF LEAVES OF PSIDIUM GUAJAVA L. IN FUNCTION OF LEVELS OF FLAVANOLS, PHENOLIC COMPOUNDS AND ANTIOXIDANT ACTIVITY

Leaves of Psidium guajava L. (guava) in brazilian communities are used in cases of diarrhea, dysentery, flatulence and abdominal pain. There is no standardization of organ used, how to use or dosage of plant. In the communities, the traditional population reports the use "in natura" of leaves and bark in teas (infusion and decoction) and beverages. With the expansion of phytotherapy in Brazil, the vegetable drug (dried leaves of guava) is available in the herbalists, without having standardized quality and/or determination of minimum levels of biomarkers. Seeking to establish a standard that meet the brazilian market of medicinal plants, this study aimed to validate methodologies for natural and artificial drying of the leaves of guava at different stages of maturity – young, in primary development and adult, fully expanded – relating them to of the quantification secondary compounds and antioxidant properties. In the botanical standardization was made macroscopic description of the leaves. In the processes of drying, 5 g of fresh leaves (young and adult) were exposed to artificial drying - DMW (microwave), DCAO (circulating air oven), DCO (conventional oven) and natural (DTL - drying thin layer) to constant weight, constituting treatments (TDMW1, TDMW2, TDCAO1, TDCAO2, TDCO1, TDCO2, TDTL1 and TDTL2). After the drying process, in all treatments, methanol extracts were made by maceration. In dried extracts of treatments, the flavonoids identified qualitatively by TLC (finger print) e was quantified the contents of phenolic compound, flavanols and antioxidant activity for validation of drying processes. All analyzes were performed with four replicates and the data from the experiments were subjected to ANOVA and mean comparison test (Tukey) at 5 % significance level. The stage of leaf development did not influence the drying processes, for residual humidity. The organoleptic characteristics (color, odor, flavor) don’t changes in any treatment. The highest yield of extracts of dried leaves (both stages) was obtained in artificially dried process (microwave - DMW). In the TLC, flavanols and tannins were detected in all treatments. The levels of phenolics, in the development stages, did not differed in function of artificial and natural drying, thus being both effective processes. The extracts obtained after drying in circulating air oven (DCAO) had higher yield of flavanols for young and mature leaves. The content of flavanols of extracts of young leaves was greater than that of mature leaves, when compared against the same methodology drying and the antioxidant activity of extracts from young leaves of guava obtained after drying in a conventional oven were superior to all other extracts, confirming that the phytomedication obtained with young leaves should have better pharmacological effect. In function on the results obtained, the best drying process was in a ventilated oven for young leaves and mature leaves, in terms of biocompounds's preservation.