Table 3. Effects of crude and fractional extracts from periwinkle leaves and roots on IL-1β secretion by PBMCs

Extract concentrations		IL-1β concentrations (pg/mL) (Mean±SE)
Extract concentrations		0.1 ppm	1 ppm	10 ppm	50 ppm	100 ppm	200 ppm
Periwinkle leaves	EtOH	3.13±0.01^**	3.86±0.01^*	4.27±0.02^*	3.97±0.05^*	3.41±0.02^**	3.95±0.16^*
	H	55.94±0.14	60.78±0.02	10.17±0.003	56.70±0.05	52.67±0.02	4.52±0.03^*
	CF	3.21±0.10^**	-	-	-	-	-
	EA	4.04±0.15^*	2.31±0.16^***	-	7.38±0.03^*	3.57±0.23^*	-
	H₂0	2.85±0.16^***	-	2.89±0.37^***	2.87±0.19^***	3.99±0.08^*	3.79±0.15^*
Periwinkle roots	EtOH	3.64±0.43^*	2.28±0.05^***	3.29±0.28^**	4.23±0.10^*	-	3.34±0.22^**
	H	11.02±0.38	3.34±0.09^**	3.36±0.20^**	2.35±0.02^***	3.16±0.94^**	2.27±0.04^***
	CF	5.70±0.27^*	2.82±0.08^***	5.54±0.01^*	4.15±0.13^*	6.12±0.02^*	2.68±0.04^***
	EA	9.38±0.09	8.08±0.13	2.95±0.27^***	5.54±0.04^*	-	-
	H₂0 (IC₅₀=38.46 ppm)	28.82±0.10	15.29±1.14	7.87±0.71^*	4.38±0.09^*	3.60±0.40^**	2.54±0.21^***
Control		10.62±0.19

Significant difference compared to the control sample (* p<0.01; ** p<0.005; *** p<0.0001).
PBMC, peripheral blood mononuclear cells; IL-1β, interleukin-1β; -, under detection limit.