Table 2.

Antioxidant properties of different parts or their extracts/fractions of isolated compounds.

Extract/isolated compounds	Test system	Results	References
Crude oil from seeds	DPPH ABTS TPC	DPPH: EC50 = 0.1 mg/mL ABTS: EC50 = 0.1 mg/mL Significant antioxidant effect Standards: methyl ether, fatty acids	[56]
Seeds extract	DPPH, ABTS, total phenolic content	EC50 = 10 − 100 μg/mL Significant antioxidant effect Standards: methyl ether, fatty acids
Methanolic and aqueous peel extracts	DPPH	EC50 = 10 − 100 μg/mL Concentration-dependent radical scavenging activity The methanolic extract exhibited a better antioxidant effect Standard: DPPH	[29]
Aqueous seeds extract	TPC, TFC DPPH, ABTS, H2O2, linoleic acid oxidation nitrite scavenging assay	TPC: EC50 = 81.3 ± 1.4 μg gallic acid/g TFC: EC50 = 486.8 ± 4.1 μg catechin/g dry mass DPPH: EC50 = 0.6 − 3 mg/mL Concentration-dependent antioxidant activity Standards: catechin 0.05-0.5 mg/mL, BHT, ascorbic acid 10 mg/mL	[61]
Seed oil	DPPH ABTS radical scavenging assay	DPPH: EC50 = 0.1 mg/mL The antioxidant activity of the seed oil was lower than the catechin and BHT at the same concentration. Standard: FAME	[44]
Hispidalin	DPPH Lipid peroxidation assay	DPPH: EC50 = 2 − 40 μg/mL EC50 = 40 μg/mL Significant DPPH radical scavenging and inhibition of lipid peroxidation capacity Standard: methyl ether	[59]
Methanol, ethanol, aqueous peel extracts	DPPH Reducing power assay	Significant antioxidant effect Standard: acarbose 20, 40, 60, 80, 100 μg.mL−1	[17]
Seed extract	DPPH ABTS	Significant antioxidant effect Standard: FAME	[28]
Polysaccharides of fruit extract	DPPH	EC50 = 0.98 mg/mL Significant antioxidant effect Standard: glucose	[50]

Abbreviations: TPC: total phenolic contents; TFC: total flavonoid contents (TFC); ABTS: 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid); DPPH: 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability; BHT: antioxidant butylated hydroxytoluene; FAME: fatty acid methyl ester; EC₅₀: the half-maximal effective concentration.