Studies on In-vitro Anti-inflammatory and Antioxidant Potentials of Annona muricata Leaf Extracts

Article history: Received: May 3, 2019 Accepted: May 28, 2020 Inflammation has stimulated significant worldwide scientific interest because of its implication in many human diseases. Most inflammations are caused by reactive oxygen species or free radicals. Annona muricata leaf extracts were investigated for their in-vitro antioxidant and anti-inflammatory potentials. Annona muricata leaves were dried at room temperature, blended using a mill. and extracted with solvents of varying degree of polarities. The solvents used were hexane, ethyl acetate, and ethanol. After sequential extraction, the crude extracts were examined for their in-vitro anti-inflammatory activities on lipoxygenase inhibition, proteinase inhibition, albumin denaturation inhibition, and red blood cell membrane stabilization assays, while the antioxidant activities were examined using DPPH, ABTS and hydrogen peroxide assays. The results showed that the ethanol extract had significantly higher albumin denaturation inhibition activity at 500 μg/mL (p < 0.01). The activity of all the extracts on proteinase inhibition decreased with the increase in concentration of the extracts. Indomethacin (standard), ethanol extract, and ethyl acetate extract exhibited a dose dependent increase in lipoxygenase activity. The ethanol extract showed high red blood cell membrane stabilization activity at 500 μg/mL and the activity was comparable with that of the standard (diclofenac). Hydrogen peroxide scavenging activity of the extracts and standard (Vitamin C) were comparable at 20 – 100 μg/mL. The ethanol extract showed significantly higher (p < 0.01) DPPH radical scavenging activity compared with other extracts. A similar trend was also observed for ABTS radical scavenging activity. Generally, the ethanol extract exhibited higher antiinflammatory and antioxidant activities in most of the assays, this could be attributed to the polar compounds present in the extract.