Table 4. Effects of crude and fractional extracts from periwinkle leaves and roots on IL-6 secretion by PBMCs

Extract concentrations		IL-6 concentrations (pg/mL) (Mean±SE)
		0.1 ppm	1 ppm	10 ppm	50 ppm	100 ppm	200 ppm
Periwinkle leaves	EtOH	249.60±0.07	242.26±0.11	244.48±0.15	242.24±0.13	126.67±0.16***	21.83±0.94***
	H	244.8±0.09	237.42±0.05*	243.93±0.08	253.41±0.07	255.79±0.12	207.34±0.18**
	CF (IC50=41.37 ppm)	249.09±0.15	243.89±0.08	246.31±0.01	49.13±0.42****	4.17±0.05****	3.25±0.21****
	EA	248.41±0.09	243.85±0.34	246.03±0.08	247.70±0.02	257.66±0.03	224.17±0.33*
	H20	238.21±0.01	241.71±0.23	244.96±0.07	243.65±0.18	249.64±0.21	255.20±0.007
Periwinkle roots	EtOH	259.80±0.005	241.19±0.09	249.33±0.07	265.63±0.16	249.92±0.02	254.76±0.19
	H	251.47±0.03	239.05±0.01*	246.11±0.42	236.31±0.24	251.43±0.34	185.44±0.01*
	CF	244.44±0.17	242.10±0.28	244.92±0.14	240.36±0.21	205.87±0.004*	128.73±0.03**
	EA	243.77±0.04	238.72±0.25	244.09±0.15	249.01±0.06	253.97±0.19	253.53±0.08
	H20	252.30±0.12	238.65±0.15	244.09±0.15	248.81±0.12	250.04±0.16	261.83±0.13
Control		248.57±0.10

Significant difference compared to the control sample (* p<0.01; ** p<0.005; *** p<0.0001).
PBMC, peripheral blood mononuclear cells; IL-6, interleukin-6.