Xanthine oxidase inhibitory activities of extracts and flavonoids of the leaves of Blumea balsamifera

Figures & data

Figure 1.  Structure of flavonoids isolated from the leaves of Blumea balsamifera studied for their xanthine oxidase inhibitory activities and scavenging capacity on enzymatically (xanthine/xanthine oxidase system) generated superoxide radicals.

Table 1.  The IC₅₀ values of extracts of the leaves of Blumea balsamifera for inhibition of xanthine oxidase and reduction of superoxide level.

Extracts of Blumea balsamifera leaves	Inhibition of xanthine oxidase (XO)			Scavenging of superoxide radicals (SOD)
	*IC50 (mg/mL ± SD)	b	r	*IC50 (mg/mL ± SD)	b	r
Methanol extract (MEB)	0.111 ± 0.002	21.94	0.95	0.063 ± 0.001	23.95	0.97
Chloroform extract (CEB)	0.138 ± 0.004	21.41	0.96	0.092 ± 0.001	24.02	0.97
Pet-ether extract (PEB)	0.516 ± 0.003	13.56	0.96	0.321 ± 0.001	15.17	0.97
Statistical significance Tukey HSD p < 0.05	Significant			Significant

*Results are mean ± SD (n = 3). IC₅₀ values were calculated from regression lines where x was log of tested compound concentration and y was percentage inhibition of enzyme activity; b, slope of the regression line; r, correlation coefficient.

Figure 2.  The concentration of different solvent extracts of Blumea balsamifera leaves versus the inhibition of xanthine oxidase and scavenging of enzymatically generated superoxide radicals. Results are mean ± SD (n = 3).

Table 2.  The IC₅₀ values of flavonoids of the leaves of Blumea balsamifera for inhibition of xanthine oxidase.

Compounds	Inhibition of xanthine oxidase *IC50 (μM)	b	r
Allopurinol (AP)	0.97 ± 0.05	12.42	0.98
l-Ascorbic acid	Inactive at 1-100 μM
Dihydroquercetin-7,4′-dimethyl ether (1)	Inactive at 1-100 μM
Blumeatin (2)	53.21 ± 1.14	12.61	0.94
Tamarixetin (3)	3.16 ± 0.13	9.90	0.97
Rhamnetin (4)	36.09 ± 0.27	13.67	0.94
Luteolin-7-methyl ether (5)	42.19 ± 0.93	14.26	0.96
Luteolin (6)	2.38 ± 0.01	12.01	0.97
Quercetin (7)	2.92 ± 0.03	10.20	0.95
5,7,3′,5′-Tetrahydroxyflavanone(8)	32.14 ± 0.91	12.43	0.95
Dihydroquercetin-4′-methyl ether (9)	58.86 ± 0.14	11.73	0.98
Statistical significance	6 & AP
Tukey HSD	2 & 5
p<0.05	6 & 7
(Not significant)	7 & 3

*IC₅₀ values were calculated from regression lines where x was log of tested compound concentration and y was percentage inhibition of enzyme activity; b, slope of the regression line; r, correlation coefficient. Results are mean ± SD (n = 3).

Figure 3.  The concentration of flavonoids (2–9) and reference compounds (allopurinol and ascorbic acid) versus inhibition of xanthine oxidase, the enzyme that produces uric acid and superoxide radicals. Results are mean ± SD (n = 3).

Table 3.  The IC₅₀ values of flavonoids of the leaves of Blumea balsamifera for reduction of enzymatically (xanthine/xanthine oxidase) generated superoxide radicals.

Compounds	Scavenging of superoxide radicals*IC50 (μM)	b	r
**SOD	606.71 mU/mL ± 2.24	10.46	0.95
Allopurinol (AP)	0.99 ± 0.01	17.45	0.96
l-Ascorbic acid	32.01 ± 0.11	10.16	14.75
Dihydroquercetin-7,4′-dimethyl ether (1)	Inactive at 1-100 μM
Blumeatin (2)	29.35 ± 0.35	7.39	0.97
Tamarixetin (3)	2.83 ± 0.01	13.22	0.96
Rhamnetin (4)	12.44 ± 0.09	13.91	0.97
Luteolin-7-methyl ether (5)	30.15 ± 0.6	14.69	0.98
Luteolin (6)	2.38 ± 0.01	8.87	0.98
Quercetin (7)	2.77 ± 0.05	15.76	0.93
5,7,3′,5′-Tetra-hydroxyflavanone(8)	10.31 ± 0.18	12.44	20.94
Dihydroquercetin-4′-methyl ether (9)	57.98 ± 0.46	11.49	0.97
Statistical significance	3 & 6
Tukey HSD	2 & 5
p < 0.05	6 & 7
Not significant	7 & 3

*Results are mean ± SD (n = 3).

**Statistical analysis was not performed for superoxide dismutase (SOD).

Figure 4.  The concentration of flavonoids (2–9) and reference compounds (allopurinol and ascorbic acid) versus scavenging of enzymatically (xanthine/xanthine oxidase system) generated superoxide anions. Results are mean ± SD (n = 3).