Diuretic activity and toxicity of some Verbascum nigrum extracts and fractions

Figures & data

Figure 1. Scheme of V. nigrum extract fractionation.

Table 1. Extracts of Verbascum nigrum L., their yields and content of principal components.

		Principal components
Extract	Yield (%)^a	Flavonoids (%)^b	Iridoids (%)^c
VnH	27.2	8.2 ± 0.4	1.2 ± 0.01
VnL	24.5	6.5 ± 0.2	1.1 ± 0.02
VnS	30.1	10.2 ± 0.7	2.3 ± 0.01
VnF	20.1	5.5 ± 0.4	2.1 ± 0.01
VnR	22.8	3.8 ± 0.5	0.5 ± 0.01

Values expressed as mean ± S.E.M. (n = 3).

^aYield of dried extracts on dry plant basis.

^bFlavonoid content in the extracts expressed as hesperidin equivalents.

^cIridoid content in the extracts expressed as aucubin equivalents.

Table 2. Fractions of the Verbascum nigrum L. extract.

Fraction	Yields (g)	Yields (%)^a
Flavonoids (EtOH 40%)^b (Fl1)	5.5 ± 0.27	1.8 ± 0.07
Flavonoids (EtOH 80%)^b (Fl2)	4.0 ± 0.2	1.3 ± 0.07
Flavonoids (EtOH 96%)^b (Fl3)	1.5 ± 0.08	0.5 ± 0.03
Flavonoids total	11.0 ± 0.55	3.6 ± 0.18
Iridoids (Ir)	8.0 ± 0.4	2.7 ± 0.14
Phenolic acids (PhAc)	0.1 ± 0.01	0.03 ± 0.003

Values expressed as mean ± S.E.M. (n = 3).

^aYields of dried fractions on basis of dry plant material used for the extraction.

^bEluent used for the fraction preparation.

Table 3. Effect of oral administration (50 mg/kg) of extracts of Verbascum nigrum L. and reference extracts of Vaccinium vitis-idaea L. and Equisetum arvense L. and furosemide on urinary excretion volume.

	Urine volume (ml)
Treatment	3 h	6 h	Total	Urine excretion (ml/kg BW)^a	Diuretic index^b
Control	0.8 ± 0.08	0.5 ± 0.04	1.3 ± 0.2	5.2 ± 1.4	–
VnH	3.1 ± 0.2***	0.4 ± 0.1	3.5 ± 0.7**	12.9 ± 2.4*	2.5
VnL	2.6 ± 0.3***	0.2 ± 0.1*	2.8 ± 0.1***	9.3 ± 0.5*	1.8
VnS	3.5 ± 0.2***	0.6 ± 0.3	4.1 ± 0.2***	14.6 ± 0.8***	2.8
VnF	2.0 ± 0.5*	0.6 ± 0.2	2.6 ± 0.5*	8.7 ± 2.2	1.7
VnR	0.5 ± 0.1*	0.2 ± 0.05***	0.7 ± 0.2	2.3 ± 0.5	0.4
EaH	2.2 ± 0.1***	0.5 ± 0.2	2.6 ± 0.1***	9.3 ± 0.7*	1.8
VvL	3.8 ± 0.2***	1.0 ± 0.5	4.8 ± 0.3***	17.8 ± 1.1***	3.4
Furosemide	7.3 ± 0.5***	2.1 ± 0.4*	9.4 ± 0.3***	37.6 ± 1.9***	7.2

Values expressed as mean ± S.E.M. (n = 6).

*p < 0.05; **p < 0.01; ***p < 0.001 compared to control group using Student’s t-test.

^aUrine excretion on basis of average body weight in the groups.

^bDiuretics index = (urinary excretion of treated group)/(urinary excretion of control group).

Table 4. Effect of oral administration (50 mg/kg) of extract fractions of Verbascum nigrum L., and reference extracts of Vaccinium vitis-idaea L. and Equisetum arvense L. and furosemide on urinary excretion volume.

	Urine volume (ml)
Treatment	3 h	6 h	Total	Urine excretion (ml/kg BW)^a	Diuretic index^b
Control	0.8 ± 0.08	0.5 ± 0.04	1.3 ± 0.2	5.2 ± 1.4	–
Fl 1	4.5 ± 1.2*	2.1 ± 0.7*	6.6 ± 1.5***	26.5 ± 3.1***	5.1
Fl 2	4.8 ± 1.7*	2.4 ± 0.9	7.2 ± 1.9*	35.9 ± 2.1***	6.9
Fl 3	5.3 ± 1.4**	1.8 ± 0.7	7.1 ± 1.2**	35.4 ± 3.9***	6.8
Ir	0.7 ± 0.1	0.5 ± 0.1	1.3 ± 0.4	5.2 ± 1.8	1
PhAc	1.0 ± 0.2	0.8 ± 0.2	1.8 ± 0.5	7.3 ± 1.9	1.4
EaH	2.2 ± 0.1***	0.5 ± 0.2	2.6 ± 0.1***	9.3 ± 0.7*	1.8
VvL	3.8 ± 0.2***	1.0 ± 0.5	4.8 ± 0.3***	17.8 ± 1.1***	3.4
Furosemide	7.3 ± 0.5***	2.1 ± 0.4*	9.4 ± 0.3***	37.6 ± 1.9***	7.2

Values expressed as mean ± S.E.M. (n = 6).

*p < 0.05; **p < 0.01; ***p < 0.001 compared to control group using Student’s t-test.

^aUrine excretion on basis of average body weight in the groups.

^bDiuretics index = (urinary excretion of treated group)/(urinary excretion of control group).

Table 5. Effect of oral administration (50 mg/kg) of extracts of Verbascum nigrum L. and reference extracts of Vaccinium vitis-idaea L. and Equisetum arvense L. and furosemide on urinary electrolyte excretion.

	Na ^+				K^+
Treatment	3 h (mEq/100 g)	6 h (mEq/100 g)	Total (mEq/100 g)	S.i. Na^+	3 h (mEq/100 g)	6 h (mEq/100 g)	Total (mEq/100 g)	S.i. K^+	Na^+/K^+
Control	0.51 ± 0.04	0.42 ± 0.04	0.93 ± 0.02	–	0.14 ± 0.01	0.10 ± 0.03	0.24 ± 0.01	–	3.88
VnH	2.01 ± 0.2***	1.51 ± 0.02***	3.52 ± 0.04***	3.8	0.57 ± 0.05***	0.28 ± 0.02***	0.85 ± 0.01***	3.5	4.14
VnL	1.30 ± 0.02***	0.84 ± 0.03***	2.14 ± 0.01***	2.3	0.49 ± 0.04***	0.17 ± 0.05	0.66 ± 0.01***	2.8	3.24
VnS	2.23 ± 0.11***	1.64 ± 0.07***	3.87 ± 0.02***	4.1	0.59 ± 0.03***	0.32 ± 0.05**	0.91 ± 0.01***	3.8	4.25
VnF	0.91 ± 0.03***	0.60 ± 0.02**	1.51 ± 0.01***	1.6	0.23 ± 0.05	0.15 ± 0.07	0.38 ± 0.02***	1.6	3.97
VnR	0.40 ± 0.02	0.42 ± 0.08	0.82 ± 0.02***	0.9	0.09 ± 0.01**	0.08 ± 0.01	0.17 ± 0.01**	0.7	4.82
EaH	0.80 ± 0.02***	0.08 ± 0.01***	0.88 ± 0.01**	0.9	0.21 ± 0.01**	0.10 ± 0.01	0.31 ± 0.01**	1.3	2.84
VvL	2.63 ± 0.04***	0.52 ± 0.02*	3.15 ± 0.02***	3.4	0.79 ± 0.09***	0.09 ± 0.01	0.88 ± 0.02***	3.7	3.58
Furosemide	0.74 ± 0.04**	0.77 ± 0.01**	1.51 ± 0.02***	1.6	0.21 ± 0.03*	0.24 ± 0.05*	0.45 ± 0.02***	1.9	3.35

Values are expressed as mean ± S.E.M. (n = 6). S.i. = Saluretic index = (Ion excretion in treated group)/(Ion excretion in control group).

*p < 0.05; **p < 0.01; ***p < 0.001 compared to control group using Student’s t-test.

Table 6. Effect of oral administration (50 mg/kg) of extract fractions of Verbascum nigrum L., and reference extracts of Vaccinium vitis-idaea L. and Equisetum arvense L. and furosemide on urinary electrolyte excretion.

	Na^+				K^+
Treatment	3 h (mEq/100 g)	6 h (mEq/100 g)	Total (mEq/100 g)	S.i. Na^+	3 h (mEq/100 g)	6 h (mEq/100 g)	Total (mEq/100 g)	S.i. K^+	Na^+/K^+
Control	0.51 ± 0.04	0.42 ± 0.04	0.93 ± 0.02	–	0.14 ± 0.01	0.10 ± 0.03	0.24 ± 0.01	–	3.88
Fl 1	2.39 ± 0.2***	1.51 ± 0.06**	3.90 ± 0.04***	4.2	0.72 ± 0.06***	0.43 ± 0.06***	1.15 ± 0.02***	4.8	3.39
Fl 2	2.92 ± 0.1***	1.30 ± 0.07***	4.22 ± 0.02***	4.5	0.81 ± 0.06***	0.49 ± 0.04***	1.30 ± 0.01***	5.4	3.25
Fl 3	3.03 ± 0.2***	1.22 ± 0.05***	4.25 ± 0.04***	4.5	0.73 ± 0.08***	0.45 ± 0.04***	1.18 ± 0.02***	4.9	3.60
Ir	0.5 ± 0.03	0.3 ± 0.02*	0.80 ± 0.01**	0.9	0.09 ± 0.01***	0.09 ± 0.01	0.18 ± 0.01**	0.8	4.44
PhAc	0.49 ± 0.01	0.42 ± 0.04	0.91 ± 0.01	1.0	0.12 ± 0.05	0.11 ± 0.01	0.23 ± 0.01	1.0	3.95
EaH	0.80 ± 0.02***	0.08 ± 0.01***	0.88 ± 0.01**	0.9	0.21 ± 0.01**	0.10 ± 0.01	0.31 ± 0.01**	1.3	2.84
VvL	2.63 ± 0.04***	0.52 ± 0.02*	3.15 ± 0.02***	3.4	0.79 ± 0.09***	0.09 ± 0.01	0.88 ± 0.02***	3.7	3.58
Furosemide	0.74 ± 0.04**	0.77 ± 0.01**	1.51 ± 0.02***	1.6	0.21 ± 0.03*	0.24 ± 0.05*	0.45 ± 0.02***	1.9	3.35

Values are expressed as mean ± S.E.M. (n = 6). S.i. = Saluretic index = (Ion excretion in treated group)/(Ion excretion in control group).

*p < 0.05; **p < 0.01; ***p < 0.001 compared to control group using Student’s t-test.