Antioxidant and antimicrobial activities of Psidium guajava L. spray dried extracts

Abstract Psidium guajava L. (guava) is widely used in traditional medicine for the treatment of diarrhea, gastroenteritis and as anti-inflammatory, among other uses. This research evaluated the antimicrobial and antioxidant activities of spray dried extracts from leaves of Psidium guajava L. (SDGEs). Different technological adjuvants, namely: maltodextrin (MD), colloidal silicon dioxide (A), arabic gum (E) and β-cyclodextrin (βCD) at concentration of 8% (wet base) were added to drying composition. SDGEs were characterized through determination of the total phenolic and flavonoid content. The extracts were tested against fungi ( Candida albicans , Candida krusei and Candida glabrata ), Gram-positive bacteria ( Staphylococcus aureus ) and Gram-negative bacteria ( Escherichia coli and Pseudomonas aeruginosa ) by the microdilution assay. The antioxidant activity of the SDGEs was assessed by the DPPH protocol. The results showed that the MDEA and βCD SDGEs were more effective against C. glabrata (MIC = 80 μg/mL), followed by MA SDGE which exhibited activity against C. krusei and C. glabrata also (MIC = 100 μg/mL). The better inhibitory effect on S. aureus was observed to the MA SDGE with a value of 100 μg/mL. The IC 50 of the SDGEs ranged from 7.96 to 8.11 μg/mL by DPPH• method. The results indicates significant antimicrobial and antioxidant activities of Psidium guajava SDGEs presenting high potential as an active phytopharmaceutical ingredient for development of herbal medicines.