Impact of different solvents on extraction yield, phenolic composition, in vitro antioxidant and antibacterial activities of deseeded Opuntia stricta fruit

Abstract

AbstractOpuntia stricta the shrubby plant is naturally occurring in all parts of the world used as popular ornamental and is known to have medicinal properties due to its phytochemical compositions. In this study, the effect of solvents (80% ethanol, 80% methanol and 80% acetone (v/v) in water) on the extraction yield, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity and antibacterial activity of Opuntia stricta fruit were investigated. For the antioxidant activity assay, three different in-vitro methods DPPH, ABTS and FRAP were followed. The One-way ANOVA calculations showed that the extraction solvents influenced greatly and significantly the TPC, TFC and antioxidant capacity. Overall, 80% ethanol showed highest percentage of extraction yield while 80% acetone extract showed the lowest extraction yield but the highest TPC, TFC and antioxidant activity of Opuntia stricta fruit. In addition, Pearson’s correlation analysis proved a strong correlation between TPC, TFC and all antioxidant methods used. The antibacterial tests demonstrated that 80% methanol and 80% acetone extracts exhibited the highest zones of inhibition (11.66 and 11.33 mm respectively, p > 0.05) against Salmonella thyphimurium. Likewise, the 80% acetone extract revealed the best inhibitory effect contra Escherichia coli (p > 0.05) with an inhibition zone of 11 cm. Unfortunately, it was observed that gram-positive bacteria were less sensitive to all Opuntia stricta extracts compared to the gram-negative bacteria.