Antioxidant properties of garlic as affected by selenium and humic acid treatments

Figures & data

Table 1 Some nutritional values of garlic under selenium and humic acid treatments.

Treatment	Antioxidant activity (% of DPPH radicals inhibited)	Total phenol content (mg gallic acid equivalent/g extract)	Flavonoids content (mg quercetin equivalent/g extract)	Allicin (mg/mL)	Total sulphur (% in dry matter)
Se0H0	14.058^ef	38.730^a	21.861^a	2.759^b	0.367^bc
Se0H10	29.186^a	31.534^a	19.174^a	2.700^b	0.347^bc
Se0H20	15.713^cdef	42.696^a	21.761^a	3.323^a	0.506^a
Se10H0	11.451^f	33.810^a	11.264^a	2.734^b	0.415^b
Se10H10	24.012^ab	24.233^a	18.998^a	2.634^b	0.421^b
Se10H20	20.556^cde	38.647^a	14.348^a	2.754^b	0.405^b
Se20H0	23.313^ab	36.878^a	17.483^a	2.693^b	0.364^bc
Se20H10	21.193^bcd	25.450^a	14.520^a	2.723^b	0.390^bc
Se20H20	22.446^abc	30.476^a	16.488^a	2.461^b	0.390^bc
Se30H0	23.165^ab	27.249^a	14.100^a	2.591^b	0.390^bc
Se30H10	14.898^def	29.312^a	25.587^a	2.653^b	0.309^c
Se30H20	22.067^bc	37.249^a	15.095^a	2.505^b	0.384^bc

Se₀, Se₁₀, Se₂₀, Se₃₀: 0, 10, 20 and 30 μg selenium/mL, respectively. H₀, H₁₀, H₂₀: 0, 10 and 20 kg humic acid/ha, respectively.

Figures followed by different letter within a column are significantly different (P < 0.05).

Table 2 Total phenol content of garlic under humic acid treatment.

Humic acid	Total phenol content (mg gallic acid equivalent/g extract)
H0	34.167^ab
H10	27.632^b
H20	37.267^a

H₀, H₁₀, H₂₀: 0, 10 and 20 kg humic acid/ha, respectively.

Figures followed by different letter within a column are significantly different (P < 0.05).

Table 3 Flavonoids content of garlic under selenium treatment.

Selenium treatment	Flavonoids content (mg quercetin equivalent/g extract)
Se0	20.932^a
Se10	14.870^b
Se20	16.163^b
Se30	15.260^b

Se₀, Se₁₀, Se₂₀, Se₃₀: 0, 10, 20 and 30 μg selenium/mL, respectively.

Figures followed by different letter within a column are significantly different (P < 0.05).

Figure 1 Chromatograms of garlic extracts. Peaks are: A, allicin; B, ethylparaben (IS).

Figure 2 Simplified mechanism of allicin formation.

Figure 3 Correlation between selenium concentration and allicin content in Mazand garlic.

Table 4 Selenium concentration of garlic cloves in different Se treatments.

Treatments	Se0	Se10	Se20	Se30
Se concentration (ppb)	675.96	950.13	1086.86	1324.07

Se₀, Se₁₀, Se₂₀, Se₃₀: 0, 10, 20 and 30 μg selenium/mL, respectively.