Inhibitory effect of aqueous extract of different parts of unripe pawpaw (Carica papaya) fruit on Fe²⁺-induced oxidative stress in rat pancreas in vitro.

CONTEXT: Carica papaya L. (Caricaceae) is widespread throughout tropical Africa; it is cultivated for its fruits and it is eaten in various ways.

OBJECTIVE: This study sought to investigate the inhibitory effect of the aqueous extract of different parts of unripe pawpaw fruit on Fe²⁺-induced lipid peroxidation in rat's pancreas in vitro.

MATERIALS AND METHODS: The aqueous extract of the unripe pawpaw fruit parts; peel (PG), seed (SG), flesh (FG), flesh with peel (FPG) and a combination of equal amount of all parts (CG) were prepared, the total phenolic content and the antioxidant activities of the extracts were then evaluated using various spectrophotometric methods.

RESULT: PG had the highest total phenol content (1.24 mg GAE/g), flavonoid content (0.63 mg QUE/g), reducing power (7.07 mg AAE/g) and Fe²⁺ chelating ability while the SG had the highest 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability. Furthermore, all the extracts caused a significant decrease (p < 0.05) in the malondialdehyde contents in the pancreas with SG (IC₅₀ = 4.25 mg/mL) having the highest inhibitory effect on Fe²⁺-induced lipid peroxidation.

DISCUSSION AND CONCLUSION: This protective effect of the extracts on Fe²⁺-induced lipid peroxidation in rat pancreas could be attributed to their phenolic compounds and, the possible mechanism may be through their antioxidant activities. However, the effect of combination of different parts of unripe pawpaw fruit in equal amount (w/w) on the inhibition of Fe²⁺-induced lipid peroxidation in rat pancreas exhibited additive properties.