Zea mays, Stigma maydis prevents and extenuates acetaminophen-perturbed oxidative onslaughts in rat hepatocytes

Figures & data

Table 1. Effect of Zea mays, Stigma maydis aqueous extract on serum activities of liver function enzymes of APAP-treated rats (n = 6, Mean ± SEM).

Treatments	ALP (U/I)	ALT (U/I)	AST (U/I)	GGT (U/I)
Sterile placebo (control)	173.13 ± 1.20^a	21.95 ± 0.07^a	30.51 ± 0.06^a	3.91 ± 1.40^a
APAP treated	326.18 ± 1.90^b	73.51 ± 0.06^b	100.81 ± 0.04^b	10.12 ± 1.92^b
400 mg/kg b.w. CSE	170.12 ± 1.11^a	21.99 ± 0.03^a	30.50 ± 0.08^a	3.96 ± 1.26^a
200 mg/kg b.w. CSE, then APAP	215.14 ± 1.44^c	42.56 ± 0.04^c	50.62 ± 0.07^c	5.00 ± 1.80^c
400 mg/kg b.w. CSE, then APAP	172.90 ± 1.12^a	21.86 ± 0.05^a	35.53 ± 0.03^a	5.14 ± 1.20^c
200 mg/kg b.w. vitamin C, then APAP	172.84 ± 1.36^a	31.06 ± 0.07^d	33.51 ± 0.01^a	4.07 ± 1.22^a
APAP, then 200 mg/kg b.w. CSE	225.22 ± 1.13^c	42.67 ± 0.08^c	53.62 ± 0.01^c	7.00 ± 1.10^d
APAP, then 400 mg/kg b.w. CSE	173.03 ± 1.10^a	21.79 ± 0.03^a	49.60 ± 0.05^c	5.33 ± 1.11^c
APAP, then 200 mg/kg b.w. vitamin C	171.32 ± 1.04^a	31.06 ± 0.08^d	50.61 ± 0.09^c	5.07 ± 1.09^c

APAP: acetaminophen; CSE: corn silk extract; ALT: alanine aminotransferase; AST: aspartate aminotransferase; ALP: alkaline phosphatase; GGT: gamma glutamyl transferase.

^abcdValues with different superscripts for each parameter are significantly different (p < 0.05).

Table 2. Effect of Zea mays, Stigma maydis aqueous extract on serum concentrations of albumin, bilirubin and total protein of APAP-treated rats (n = 6, mean ± SEM).

Treatments	Albumin	Total bilirubin	Direct bilirubin	Total protein
	(g/L)	(μmol/L)	(μmol/L)	(g/L)
Sterile placebo (control)	5.10 ± 1.12^a	12.48 ± 1.01^a	5.95 ± 1.83^a	35.72 ± 1.14^a
APAP treated	0.61 ± 1.73^b	53.76 ± 2.32^b	15.32 ± 1.82^b	13.78 ± 1.91^b
400 mg/kg b.w. CSE	5.00 ± 1.09^a	16.19 ± 1.09^a	4.99 ± 1.75^a	34.80 ± 1.25^a
200 mg/kg b.w. CSE, then APAP	2.01 ± 1.32^c	33.64 ± 2.97^c	7.18 ± 1.89^c	25.28 ± 1.90^c
400 mg/kg b.w. CSE, then APAP	5.94 ± 1.26^a	10.10 ± 1.86^a	6.00 ± 1.99^a	33.66 ± 1.80^a
200 mg/kg b.w. vitamin C, then APAP	5.02 ± 1.70^a	11.55 ± 1.65^a	6.09 ± 1.51^a	31.39 ± 1.91^a
APAP, then 200 mg/kg b.w. CSE	3.15 ± 1.08^d	12.64 ± 2.97^d	12.34 ± 1.09^d	23.19 ± 1.23^c
APAP, then 400 mg/kg b.w. CSE	2.09 ± 1.12^c	36.10 ± 1.86^c	6.23 ± 1.56^a	33.65 ± 1.45^a
APAP, then 200 mg/kg b.w. vitamin C	6.05 ± 1.45^a	11.55 ± 1.65^a	6.12 ± 1.45^a	32.45 ± 1.22^a

APAP: acetaminophen; CSE: corn silk extract.

^abcdValues with different superscripts for each parameter are significantly different (p < 0.05).

Table 3. Mean percentage protection offered by Zea mays, Stigma maydis and vitamin C against APAP-induced hepatic injury on some liver function parameters.

Treatments	Mean % protection
	ALP	ALT	AST	GGT	ALB	D-BIL	T-BIL	TP
CSE-treated (200 mg/kg)	69.26*	59.92*	90.50	66.35*	61.68*	60.91*	39.52*	47.65*
CSE-treated (400 mg/kg)	100.11	100.24	100.11	78.66	89.66	99.06	68.48	90.59
Vitamin C-treated	100.69	82.33	100.69	89.37	108.92	97.06	88.84	82.68

Value with (*) along the same column for each parameter is significantly different from vitamin C-treated group (p < 0.05). CSE: corn silk extract; ALT: alanine aminotransferase; AST: aspartate aminotransferase; ALP: alkaline phosphatase; GGT: gamma glutamyl transferase; ALB: albumin; T-BIL: total bilirubin; D-BIL: direct bilirubin; TP: total protein.

Figure 1. Effect of Zea mays, Stigma maydis aqueous extract on tissue concentrations of conjugated dienes, lipid hydroperoxides and malondialdehyde of APAP-treated rats. Values are mean ± standard deviation (SEM) of six determinations. ^abcdeBars with different superscripts for each parameter are significantly different (p < 0.05). APAP: acetaminophen; CSE: corn silk extract.

Table 4. Effect of Zea mays, Stigma maydis aqueous extract on specific activities of enzymic antioxidant system of APAP-treated rats (n = 6, mean ± SEM).

	Antioxidant enzymes (nmol min^−1 mg protein^−1)
Treatments	SOD	CAT	GRx	GPx
Sterile placebo (control)	55.20 ± 0.10^a	45.38 ± 0.22^a	63.93 ± 1.80^a	252.19 ± 2.10^a
APAP treated	22.19 ± 0.11^b	13.29 ± 0.19^b	25.29 ± 1.82^b	96.35 ± 1.00^b
400 mg/kg b.w. CSE	69.39 ± 0.09^c	60.19 ± 0.25^c	70.35 ± 1.16^a	272.16 ± 2.15^c
200 mg/kg b.w. CSE, then APAP	45.35 ± 0.20^d	32.93 ± 0.19^d	42.86 ± 1.19^c	219.31 ± 2.11^d
400 mg/kg b.w. CSE, then APAP	53.98 ± 0.16^a	43.62 ± 0.12^a	69.72 ± 1.10^a	245.03 ± 2.21^a
200 mg/kg b.w. vitamin C, then APAP	51.99 ± 0.17^a	42.96 ± 0.10^a	66.93 ± 1.22^a	226.63 ± 2.89^d
APAP, then 200 mg/kg b.w. CSE	35.23 ± 0.10^e	22.18 ± 0.15^e	42.11 ± 1.20^c	159.22 ± 1.21^e
APAP, then 400 mg/kg b.w. CSE	46.12 ± 0.11^d	32.62 ± 0.14^d	66.09 ± 1.12^a	248.11 ± 2.04^a
APAP, then 200 mg/kg b.w. vitamin C	47.17 ± 0.17^d	33.96 ± 0.11^d	46.91 ± 1.03^c	229.12 ± 2.11^d

^abcdeValues with different superscripts for each parameter are significantly different (p < 0.05). APAP: acetaminophen; CSE: corn silk extract: SOD: superoxide dismutase; GRX: glutathione reductase; GPX: glutathione peroxidase.

Table 5. Effect of Zea mays, Stigma maydis aqueous extract on the levels of non-enzymic antioxidant system, protein carbonyl and fragmented DNA of APAP-treated rats (n = 6, Mean ± SEM).

Treatments	Reduced glutathione (nmol mg protein^−1)	Peroxidized glutathione (X)	GSH:GSSG ratio	Protein carbonyl (nmol mg protein^−1)	Fragmented DNA (%)
Sterile placebo (control)	46.25 ± 1.10^a	0.17 ± 0.05^a	272.06 ± 0.20^a	15.72 ± 0.13^a	12.12 ± 0.30^a
APAP-treated	10.18 ± 1.13^b	2.93 ± 0.07^b	5.27 ± 0.08^b	58.55 ± 0.12^b	79.15 ± 0.30^b
400 mg/kg b.w. CSE	33.36 ± 1.88^c	0.12 ± 0.10^c	278.00 ± 0.32^a	15.16 ± 0.12^a	12.75 ± 0.20^a
200 mg/kg b.w. CSE, then APAP	41.70 ± 1.26^a	0.17 ± 0.02^a	245.29 ± 0.19^c	25.73 ± 0.13^c	42.16 ± 0.30^c
400 mg/kg b.w. CSE, then APAP	42.80 ± 1.15^a	0.15 ± 0.07^a	285.33 ± 0.15^a	19.10 ± 0.12^a	13.19 ± 0.20^a
200 mg/kg b.w. vitamin C, then APAP	46.34 ± 1.18^a	0.17 ± 0.03^a	272.59 ± 0.17^a	19.01 ± 0.14^a	13.11 ± 0.20^a
APAP, then 200 mg/kg b.w. CSE	20.89 ± 1.09^d	0.25 ± 0.02^d	83.56 ± 0.15^d	35.16 ± 0.11^d	31.16 ± 0.30^d
APAP, then 400 mg/kg b.w CSE	22.88 ± 1.90^d	0.19 ± 0.07^e	120.42 ± 0.09^e	23.09 ± 0.13^c	23.19 ± 0.20^e
APAP, then 200 mg/kg b.w. vitamin C	21.93 ± 1.65^d	0.19 ± 0.03^e	115.42 ± 0.10^e	25.21 ± 0.11^c	22.11 ± 0.20^e

APAP: acetaminophen; CSE: corn silk extract; X: nmol mg protein⁻¹.

^abcdeValues with different superscripts for each parameter are significantly different (p < 0.05).

Figure 2. Liver micrograghs (×400, haematoxylin and eosin stained) of (a) normal control rat, (b) hepatotoxic rat, (c) CSE (400 mg/kg b.w.) treated rat, (d) hepatotoxic rat pre-treated with CSE (200 mg/kg b.w.), (e) hepatotoxic rat treated with CSE (400 mg/kg b.w), (f) hepatotoxic rat pre-treated with vitamin C (200 mg/kg b.w.), (g) hepatotoxic rat post-treated with CSE (200 mg/kg b.w.), (h) hepatotoxic rat post-treated with CSE (400 mg/kg b.w.) and (i) hepatotoxic rat post-treated with vitamin C (200 mg/kg b.w.). CSE: corn silk aqueous extract; I: inflammation; CN: coagulative necrosis; H: haemorrhage.

Table 6. Histopathological grading of liver tissue sections of Zea mays, Stigma maydis aqueous extract treated animals.

Treatments	Scores
	0	1	2	3	4
Control	(6)	(0)	(0)	(0)	(0)
APAP-treated	(0)	(0)	(2)	(3)	(1)
400 mg/kg of CSE.	(6)	(0)	(0)	(0)	(0)
200 mg/kg b.w. CSE, then APAP	(4)	(2)	(0)	(0)	(0)
400 mg/kg b.w. CSE, then APAP	(6)	(0)	(0)	(0)	(0)
200 mg/kg b.w. vitamin C, then APAP	(4)	(2)	(0)	(0)	(0)
APAP, then 200 mg/kg b.w. CSE	(3)	(2)	(1)	(0)	(0)
APAP, then 400 mg/kg b.w. CSE	(5)	(1)	(0)	(0)	(0)
APAP, then 200 mg/kg b.w. vitamin C	(4)	(2)	(0)	(0)	(0)

n = 6; figure in parenthesis represents number of rats affected in the group. APAP: acetaminophen; CSE: corn silk extract.

Figure 3. GC–MS chromatogram of Zea mays, Stigma maydis aqueous extract.

Table 7. Bioactive constituents of Zea mays, Stigma maydis aqueous extract as revealed by GC-MS chromatogram.

S/N	Active component	Retention time (Min)	Peak area (%)	Molecular formula	Molecular weight (g mol^−1)
1	Trimethylbenzene^#	4.40	1.05	C9H12	120.19
2	Dimethoxybenzene^#	6.43	0.42	C8H10O2	138.17
3	Ascorbic acid**	8.17	1.47	C6H8O6	176.12
4	Biphenyl^#	8.43	0.80	C12H10	154.21
5	O-Diethylphthalate^#	9.37	4.03	C12H14O4	222.24
6	2-Methyl-napthalene*	9.75	4.08	C11H10	142.19
7	Gluten**	10.07	1.35	C29H37N5O9	599.63
8	beta-Carotene**	10.35	1.15	C40H56	536.87
9	Thymol**	10.93	6.01	C10H14O	150.24
10	Maizenic acid*	11.22	8.79	C47H51NO14	853.91
11	3-O-methyl-maysin*	12.12	5.57	C28H31O15	607.50
12	Maysin*	12.60	9.15	C27H28O14	576.50
13	Cyanidin*	13.42	7.06	C15H11O6	287.24
14	Cinnamic acid**	13.90	7.33	C9H8O2	146.15
15	Apigenidin*	14.55	5.28	C15H10O5	270.24
16	Hordenine*	15.15	7.91	C10H15NO	165.24
17	Luteolinidin*	15.78	3.73	C15H11O5	271.24
18	Benzaldehyde^#	16.30	7.38	C7H6O	106.12
19	Phenylacetaldehyde*	17.03	2.25	C8H8O	120.15
20	Pelargonidin*	17.38	4.83	C15H11O5	271.24
21	Orientin*	19.43	2.82	C12H20O11	448.37
22	Betaine**	20.38	0.67	C5H11NO2	117.15
23	Glycolic acid**	21.38	0.40	C2H4O3	76.05

# Flavoring agents.

* Antioxidants.

** Antioxidant and hepatoprotective agents.

Figure 4. Tentative mechanism of antioxidative and hepatoprotective potentials of Zea mays, Stigma maydis aqueous extract. The red dotted arrows represent sites of induction and optimization by CSE that consequently promote scavenging of O₂^- and OH⁻. This ultimately normalized and increased cellular reduced glutathione (GSH) concentration and facilitates its mobilization towards NAPQI detoxification and by extension stalling nitration. CSE: corn silk aqueous extract; GPx: glutathione peroxidase; GRx: glutathione reductase.