In Vitro Antioxidant Activities of Polyphenols Purified from Four Plant Species Used in Rice Beer Preparation in Assam India

Figures & data

TABLE 1 Phenolic compounds detected by HPLC in the PPE of the four plant species

Phenolic compound	RT (min)	Concentration in the plant leaves (ppm)
		A. heterophyllus	C. extensa	O. corymbosa	A. malaccensis
Gallic acid	7.16	ND	ND	ND	ND
Hydroquinone	8.91	ND	ND	ND	ND
Resorcinol	15.68	ND	30.91	ND	ND
Catechol	18.85	ND	74.91	ND	36.90
Chlorogenic acid	22.79	24.69	ND	259.15	ND
Catechin	23.16	ND	ND	8.94	3.14
Vanillic acid	25.15	ND	ND	ND	ND
Caffeic acid	26.17	ND	47.63	110.68	ND
Syringic acid	26.43	ND	ND	ND	ND
p-coumaric acid	32.75	90.05	5.87	ND	ND
Ferulic acid	35.71	400.48	912.75	48.73	15.06
Naringin	38.08	ND	16020.16	ND	4842.14
Quinic acid	38.20	ND	ND	2277.69	1703.75
Salicylic acid	38.42	24164.93	4412.78	12534.11	95.26
Quercetin	39.63	282.19	150.26	2088.74	202.33
Apigenin	40.07	5394.60	4340.50	1080.67	17785.22

Note: RT: retention time; ND: not detected.

FIGURE 1 HPLC chromatograms of the PPE for detection of phenolic compounds (AH: A. heterophyllus; CE: C. extensa; OC: O. corymbosa; AM: A. malaccensis).

TABLE 2 The IC₅₀ values of the PPE under various assay conditions

	IC50 values (µg/mL) of PPE
Assay conditions	A. heterophyllus	C. extensa	O. corymbosa	A. malaccensis	BHT/ α-tocopherol
DPPH scavenging	+	+	+	+	+
ABTS decolorization	28.64	39.95	64.86	103.76	+
•OH scavenging	—	—	—	—	+
H2O2 scavenging	171.48	165.76	201.04	146.50	+
NBT scavenging	120.92	298.75	—	293.84	—
NO• scavenging	256.93	—	130.40	52.51	286.25
Fe^2+ chelating	—	230.38	—	—	+
FTC inhibition (0 h)	—	—	—	—	—
FTC inhibition (24 h)	+	+	+	+	+
FTC inhibition (48 h)	+	+	+	+	+
FTC inhibition (72 h)	146.72	50.00	103.01	190.04	112.77
TBA inhibition (0 h)	—	—	—	—	—
TBA inhibition (24 h)	—	—	280.06	—	275.00
TBA inhibition (48 h)	+	+	+	+	+
TBA inhibition (72 h)	+	+	+	+	+
TBA inhibition (96 h)	+	+	+	+	+

Note: “+” denotes above 50% activity of all assay concentrations; “—” denotes below 50% activity of all assay concentrations.

FIGURE 2 A: DPPH free radical scavenging activity assay of the PPE; B: ABTS radical cation decolorization assay of the PPE; C: Hydroxyl radical scavenging assay of the PPE; D: Hydrogen peroxide scavenging activity assay of the PPE. The results are means ± SD (n = 3); (AH: A. heterophyllus; CE: C. extensa; OC: O. corymbosa; AM: A. malaccensis).

FIGURE 3 A: Superoxide anion scavenging activity assay of the PPE; B: Nitric oxide scavenging activity assay of the PPE; C: Ferrous-ion chelating assay of the PPE; D: Ferric reducing antioxidant power assay of the PPE. The results are means ± SD (n = 3); (AH: A. heterophyllus; CE: C. extensa; OC: O. corymbosa; AM: A. malaccensis).

TABLE 3 Ferric thiocyanate assay showing the inhibition of lipid peroxidation by PPE

Time	Concentration (µg/mL)	A. heterophyllus	C. extensa	O. corymbosa	A. malaccensis	α tocopherol
0 h	50	10.36	4.99	11.45	9.11	0.88
	100	13.11	11.49	27.36	13.23	5.98
	150	13.73	16.23	30.46	24.72	11.83
	200	25.72	18.23	31.34	25.47	13.03
	250	26.72	23.72	37.40	27.47	14.56
	300	29.34	26.72	40.79	28.21	16.28
24 h	50	68.16	80.52	72.12	72.07	72.26
	100	72.85	80.76	77.40	77.86	72.66
	150	79.63	85.11	85.83	80.02	75.92
	200	87.46	85.28	86.91	82.59	78.94
	250	87.93	85.59	87.23	85.95	79.20
	300	92.31	88.32	87.97	86.29	79.58
48 h	50	65.06	72.18	61.92	56.98	70.83
	100	70.37	75.31	69.90	61.75	71.55
	150	76.17	79.93	79.59	71.70	73.06
	200	76.97	81.13	79.90	72.98	74.53
	250	84.04	81.45	82.10	74.38	74.96
	300	84.50	82.57	83.83	82.23	77.36
72 h	50	14.83	50.66	44.51	19.96	43.45
	100	32.17	61.77	49.40	27.64	45.81
	150	51.44	66.77	65.17	32.41	63.61
	200	56.44	69.46	69.36	54.82	64.41
	250	72.19	70.84	70.39	56.00	66.19
	300	77.38	80.83	73.82	75.79	67.64

TABLE 4 Thiobarbituric acid assay showing the inhibition of lipid peroxidation by the PPE

Time	Concentration (µg/mL)	A. heterophyllus	C. extensa	O. corymbosa	A. malaccensis	α tocopherol
0 h	50	0.11	3.24	20.02	18.09	21.03
	100	1.34	9.51	21.81	21.59	26.96
	150	4.92	11.74	22.48	22.60	28.75
	200	13.98	19.57	24.83	24.38	37.25
	250	20.69	20.25	25.72	25.84	41.16
	300	28.19	21.25	28.64	28.41	41.16
24 h	50	21.92	33.53	43.35	27.78	16.17
	100	30.85	35.81	43.55	32.34	27.08
	150	33.93	37.30	43.95	37.01	33.13
	200	40.58	38.79	44.94	39.78	38.69
	250	42.56	42.56	45.83	41.67	39.89
	300	45.93	47.32	52.88	44.25	60.32
48 h	50	79.87	68.64	87.65	66.99	85.35
	100	84.55	69.42	90.23	69.17	85.56
	150	84.65	75.25	90.35	72.47	85.68
	200	82.65	76.72	90.56	73.62	85.78
	250	86.04	76.99	90.90	76.06	86.26
	300	91.49	81.39	91.77	77.15	86.89
72 h	50	79.91	74.39	81.93	70.30	76.84
	100	82.41	76.20	83.65	73.91	79.94
	150	84.46	79.41	83.83	77.47	80.19
	200	85.42	80.72	84.18	81.86	83.95
	250	85.74	82.51	82.61	84.96	85.59
	300	87.13	85.01	85.87	84.66	86.47
96 h	50	71.54	74.51	77.49	64.13	75.84
	100	74.57	72.60	79.59	68.56	80.94
	150	76.77	77.03	80.42	70.66	84.33
	200	81.07	78.11	81.92	72.91	85.83
	250	81.09	79.36	82.72	74.83	86.32
	300	83.24	80.63	83.73	76.43	86.30