Antinociceptive Potential of the Sri Lankan Endemic Plant Vernonia zeylanica.

Figures & data

Table 1.. Effect of oral administration of different doses of aqueous stem extract (ASE) of Vernonia zeylanica. on the hot-plate reaction time of rats.

	Hot plate reaction time (sec) (mean ± SEM)
		Treatment
Treatment (mg/kg)	Pretreatment	1 h	2 h	3 h	4 h	5 h	6 h
Control (n = 8)	8.2 ± 0.5	7.2 ± 0.4	7.7 ± 0.8	7.6 ± 0.6	8.8 ± 1.1	7.6 ± 0.9	8.0 ± 1.1
750 (n = 8)	7.9 ± 0.4	9.9 ± 0.4	8.8 ± 0.9	7.8 ± 1.0	7.6 ± 0.9	7.6 ± 0.9	8.2 ± 0.6
1500 (n = 8)	7.5 ± 0.4	9.6 ± 1.1	9.4 ± 0.6	10.3 ± 1.2	8.8 ± 1.0	8.6 ± 1.5	7.5 ± 0.6
2500 (n = 8)	8.4 ± 0.6	10.9 ± 0.8	9.7 ± 1.3	9.8 ± 1.3	8.6 ± 0.7	7.7 ± 0.6	9.0 ± 0.8
Morphine (n = 5)	8.2 ± 0.8	13.6 ± 0.7	16.0 ± 1.0	13.0 ± 1.2	11.5 ± 1.5	9.0 ± 1.5	9.4 ± 1.3

*Values are significant at p ≤ 0.05 vs. control.

Table 2.. The effect of naloxone intraperitoneal injection on the hot-plate reaction time of aqueous stem extract (ASE) (1500 mg/kg) of Vernonia zeylanica..

	Hot-plate reaction time (s) (mean ± SEM)
Treatment	Pretreatment	First hour
Saline + extract (n = 6)	7.4 ± 0.5	8.8 ± 0.5
Naloxone + extract (n = 6)	8.2 ± 0.5	6.9 ± 1.0

*Values are significant at p. ≤ 0.05.

Table 3.. In vitro. antioxidant activity of the aqueous stem extract (ASE) of Vernonia zeylanica..

Sample	Concentration (µg/mL)	Antioxidant index
BHT (n = 9)	100	69.37 ± 2.21
Vitamin E (n = 9)	100	57.95 ± 1.05
Ascorbic acid (n = 9)	100	73.34 ± 2.66
ASE (n = 6)	15	39.85 ± 4.52
	30	30.54 ± 2.67
	60	36.95 ± 7.59
	125	38.40 ± 3.41

Antioxidant index = (1 − T./C.) × 100, where T. is absorbance of extract and C. is absorbance of control.

Table 4.. Effect of orally administered aqueous stem extract (ASE) (1500 mg/kg) of Vernonia zeylanica. on sedative parameters of the rat hole-board test (mean ± SEM) at 1 h posttreatment.

Treatment	Number of rears	Locomotor activity	Number of head dips	Total time spent on head dips (sec)	Time/head dip (sec)
Control (n = 9)	18.9 ± 2.3	19.6 ± 2.8	8.4 ± 1.3	14.06 ± 1.53	1.83 ± 0.20
1500 mg/kg (n = 9 )	10.3 ± 3.2	12.1 ± 1.4	4.6 ± 0.9	9.61 ± 1.99	1.99 ± 0.23

*Values are significant at p ≤ 0.05.