In vitro antioxidant potential of spray-dried Psidium guajava L. leaves extracts

Psidium guajava (Myrtaceae), popularly known as guava, is widely used in traditional medicine due to its anti-inflammatory, antimicrobial and antioxidant properties. The aim of this research was to study Psidium guajava extract spray-drying in order to obtain powders with good antioxidant properties and stability attributes. The experiments were carried out in a SD 05 LabPlant spray dryer using maltodextrin, Arabic gum, colloidal silicon dioxide and β-cyclodextrin at concentration of 80% relative to solids content. The ABTS, DPPH, FRAP and ORAC assays were used for estimating antioxidant activity (AA) from guava extracts spray dried preparations (SDP). The chemical markers were evaluated through determination of the total phenolic (TP) and flavonoid (TF) content. Averaged AA [µM Trolox equivalent (TE)/g] were 3,296, and 1,913 as determined by the ABTS and ORAC respectively. The IC50 of the SDP ranged from 7.96 to 8.11 µg/mL using the DPPH· method. The FRAP values ranged from 4,210 to 4,540. Pearson's correlation coefficients were calculated in order to determine the association between antioxidant activity assays, total phenolics and flavonoids content. AA determined by DPPH assay had strong negative correlation with TF (r =-0.976), TP (r =-0.980). The FRAP assay showed a strong positive relationship comparing to ORAC (r = 0.965). FT was strongly positive correlated with PT (r = 0.947). In conclusion, the combination of methods was useful to confirm the antioxidant potential of guava SDP which displayed significant antioxidant activities.