Xylopia aethiopica HPLC-DAD polyphenol profiling and antioxidant status from South-South region of Nigeria

Abstract To fill nutrient gaps, supplements are employed in the field of nutrition. The spice Xylopia aethiopica grows wild in many African countries and has been used as flavouring for soups. This study evaluates the polyphenols and antioxidant profile of different fractions of X. aethiopica methanol extract. Powdered sample of X. aethiopica (250 g) was suspended in methanol (1.5 litre) for 48 hours and the extract was concentrated at 45 °C using water bath to obtain methanol crude extract which was fractionated into n-hexane (n-Hex), chloroform (Chl), diethyl ether (DEE), n-butanol (n-Bu) and aqueous fractions using liquid- liquid partition separation technique. Antioxidant properties were investigated using standard methods and the polyphenols were estimated using high performance liquid chromatography with diodearray detector (HPLC-DAD). Results revealed that the DEE fraction had significantly (p < 0.05) high total phenol content (TPC), proanthocyanidins, anthocyanins, 1,1-diphenyl-2-picrylhidrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) as compared with other fractions. The highest luteolin and taxifolin content was detected in n-Hex fraction. Polyphenols found in DEE fraction in the established HPLC-DAD assay were p-anisic acid (0.07 ng/g), caffeic acid (0.56 ng/g), vanillic acid (0.91 ng/g), salicylic acid (1.64 ng/g), gallic acid (3.09 ng/mL), ferulic acid (3.64 ng/g), p-coumaric acid (5.15 ng/g), sinapinic acid (6.63 ng/g) and protocatechuic acid (24.89 ng/g). The different fractions of X. aethiopica displayed various polyphenols potential with probable antioxidant activity, which may be useful in neutralizing free radicals and the treatment of chronic inflammatory associated metabolic ailments, such as obesity and diabetes.