Abstract

Pepperfruit (Dennettia tripetala G. Baker (Annonaceae) is a well-known Nigerian spicy medicinal plant normally used in folk medicine to cure fever, cough, toothache, as well as a stimulant and in the preparation of some special dishes for pregnant and postpartum women. The present study sought to assess the antioxidant properties of the aqueous extract of ripe (RPF) and unripe pepperfruit (UPF) extract. The aqueous extract of the pepperfruits were prepared, and their antioxidant phytoconstituents (total phenol, total flavonoid and ascorbic acid) and activities (Fe²⁺ chelation ability, OH* scavenging ability, reducing power, DPPH and ABTS radical scavenging abilities) were subsequently determined. The total phenol (1.4 mg/g) content of RPF was significantly higher (P < 0.05) than that of UPF (1.0 mg/g), while there was no significant difference in the vitamin C and total flavonoid content. Conversely, UPF had higher antioxidant activities, as typified by higher reducing power, DPPH*, ABTS* and OH* scavenging abilities, and Fe chelating ability. Therefore, the physiological changes that accompanies ripening of pepperfruit that brings about changes in pigment would increase the total phenol content, but decreases the antioxidant properties of pepperfruit. 

Key words: Pepperfruit, phenol, flavonoid, vitamin C, antioxidant.