In vitro antioxidant activities and blood protective effects of aqueous extracts of Xylopia aethiopica L. whole seed and pod

Abstract

Xylopia aethiopica L. (Annonaceae) is medicinally important in the treatment of a wide range of diseases. In Nigeria, X. aethiopica whole seed are locally used in the treatment of constipation. They are used as a tonic tea and beverages, and after pregnancy delivery to facilitate the removal of clotting blood in the system. The study evaluated in vitro antioxidant activities and blood protective effects of X. aethiopica aqueous extracts. The 2,2-diphenyl-1-picrylhydrazyl scavenging activities of the seed (IC₅₀ = 0.19±0.03 mg/mL) and pod (IC₅₀ = 0.24±0.02 mg/mL) extract were not significantly (p>0.05) different with butylated hydroxytoluene BHT (IC₅₀ = 0.17±0.04 mg/mL) and ascorbic acid (IC₅₀ = 0.13±0.05 mg/mL). Furthermore, total antioxidant capacity and nitric oxide reducing power of the seed, pod and whole seed were similar with no significant difference (p>0.05) when compared with BHT. However, the seed (IC₅₀ = 0.89±0.09 mg/mL), pod (IC₅₀ = 0.35±0.03 mg/mL) and whole seed (IC₅₀ = 0.32±0.03 mg/mL) expressed significantly (p<0.05) lower hydrogen peroxide decomposing activity when compared with BHT (IC₅₀ = 0.15±0.00 mg/mL) and ascorbic acid (IC₅₀ = 0.15±0.01 mg/mL). The extract expresses no erythrocyte lysis activities at a concentration range of 6.25 – 100 µg/mL and protect against accumulation of CuSO₄-induced conjugated dienes in plasma. The present study demonstrated the protective nature of X. aethiopica L. seed, pod and whole seed extracts against the accumulation of conjugate dienes, thrombolytic activities and membrane stability effects.  X. aethiopica L. is recommended for consideration as a significant natural antioxidant source.