Effects of Tannin Extract from Gongronema latifolium Leaves on Lipoxygenase Cucumeropsis manii Seeds

Table 2

Results of lipoxygenase effects of crude Gongronema latifolium and two other known antioxidants.

	Final concentration (g/L)	Activity of lipoxygenase (𝐾cat)	%Inhibition	IC50 (g/L)
	2.3×10^−3	0.312±0.41	68.80±0.35
Crude extract	6.8×10^−3	0.289±0.11	71.10±0.20	4.2×10^−3±0.09×10^−3
	9.1×10^−3	0.250±0.23	75.00±0.19
Control	—	1.000±0.22	—
	7.4×10^−3	0.952±0.12	95.2±0.20
Ascorbic acid	1.1×10^−2	0.800±0.16	80.0±0.23	4.3×10^−2±0.11×10^−2
	2.17×10^−2	0.571±0.20	57.1±0.22
Control	—	1.000±0.29	—
	8.93×10^−2	0.769±0.09	76.9±0.11
Propyl gallate	1.33×10^−2	0.667±0.11	66.7±0.19	8.0×10^−2±0.09×10^−2
	2.61×10^−2	0.476±0.85	47.6±0.09
Control	—	1.000±0.89	—

Lipoxygenase activity was assayed as change in absorbance at 234 nm after 5 min of incubation in the presence and absence of the extract, propyl gallate, and ascorbic acid,  respectively. The equation 𝐶=𝐴⋅𝑉⋅/𝜖⋅𝑙⋅𝑣. was applied in the calculation of lipoxygenase activity where 𝐴 is the value of absorbance increase, 𝑉 is the vol of incubation mixture, 𝜖 is the extinction coefficient for linoleic acid (25×10⁻³mol⋅L⋅cm⁻¹), 𝑙 is the length of the cuvette (1 cm), and 𝑣 is the volume of enzyme (0.1 mL). Experiments were conducted in triplicates and 𝑃<0.05.