Antidiabetic Activities of 80% Methanol Extract and Solvent Fractions of Verbascum Sinaiticum Benth (Scrophulariaceae) Leaves in Mice

Figures & data

Table 1 Preliminary Phytochemical Screening of V. Sinaiticum Leaf Extracts

Phytochemicals	Tests	V. sinaiticum Extracts
		CME	NHF	EAF	ARF
Alkaloids	Wagner’s test	+	+	+	+
Flavonoids	Alkaline reagent test	+	˗	+	˗
Glycosides	Keller-Kiliani test	+	˗	+	˗
Phenols	Ferric chloride test	+	˗	+	+
Saponins	Foam test	+	˗	˗	+
Steroids	Salkowski’s test	+	+	˗	˗
Tannins	Braymer’s test	+	˗	+	˗
Terpenoids	Salkowski’s test	˗	+	+	˗

Notes: (+): present, (-): absent.

Abbreviations: ARF, aqueous residue fraction; CME, crude methanol extract; EAF, ethyl acetate fraction; NHF: n-hexane fraction.

Table 2 Hypoglycemic Effect of the Crude 80% Methanol Extracts of V. Sinaiticum Leaves in Normoglycemic Mice

Groups	Blood Glucose Level
	0 hr.	1 hr.	2 hr.	3 hr.	4 hr.
Tween 2%	95.17 ± 8.06	93.50 ± 7.99	90.17 ± 9.27	92.00 ± 8.31	91.50 ± 8.70
GLC 5 mg	98.50 ± 10.23	87.83 ± 9.70^Ea	80.67 ± 8.24^Ab,Db	75.33 ± 6.52^Ab	51.67 ± 7.54^Cc,Dc,Ec
CME 100 mg	92.83 ± 6.92	91.67 ± 7.31	87.67 ± 6.61	83.50 ± 9.00	75.17 ± 6.03
CME 200 mg	96.50 ± 10.37	88.67 ± 9.94	81.83 ± 7.64	76.83 ± 7.02^Aa	64.33 ± 8.29^Aa,Ca
CME 400 mg	97.67 ± 8.90	92.50 ± 8.38	88.00 ± 7.70^Ab,Db	74.83 ± 9.07^Ca	58.83 ± 7.08^Ab

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; negative control treated with Tween 2% of 10 mg/kg; positive control with GLC 5 mg/kg; A, compared to the Tween 2%; B, compared to GLC; C,D,E, compared to CME all doses; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: GLC, Glibenclamide; CME, Crude methanol extracts.

Table 3 Hypoglycemic Effect of the Solvent Fractions of V. Sinaiticum Leaves in Normoglycemic Mice

Groups	Blood Glucose Level
	0 hr.	1 hr.	2 hr.	3 hr.	4 hr.
Tween 2%	95.17 ± 8.06	93.50 ± 7.99	90.17 ± 9.27	92.00 ± 8.31	91.50 ± 8.70
GLC 5 mg	98.50 ± 10.23	87.83 ± 9.70^Ea	80.67 ± 8.24^Ea	75.33 ± 6.52^Ab	51.67 ± 7.54*
ARF 100 mg	99.83 ± 7.73	98.33 ± 7.54	96.83 ± 6.15	94.17 ± 4.29	93.33 ± 3.77
ARF 200 mg	101.67 ± 7.31	97.33 ± 7.41	94.17 ± 7.20	89.33 ± 3.15	81.83 ± 2.39
ARF 400 mg	99.50 ± 7.04	95.33 ± 6.69^Bb	90.33 ± 6.82	84.17 ± 4.87^Fa	68.83 ± 4.61^Aa
EAF 100 mg	100.33 ± 6.11	97.17 ± 5.88	95.00 ± 6.09	93.83 ± 4.39	91.17 ± 4.82
EAF 200 mg	97.50 ± 5.85	88.33 ± 3.71^Ba	81.50 ± 2.29^Ea	75.50 ± 3.62^Fc,Jb	66.83 ± 4.50^Aa,Cc
EAF 400 mg	94.67 ± 3.02	89.50 ± 4.45^Bc	84.17 ± 4.38	73.67 ± 4.81^Eb,Jb	57.50 ± 2.35^Ka,Db
NHF 100 mg	91.67 ± 4.91	91.00 ± 4.73	88.67 ± 4.59	95.67 ± 3.75	88.83 ± 4.15
NHF 200 mg	103.50 ± 4.67	100.67 ± 4.05	98.17 ± 3.38	97.50 ± 3.05	97.17 ± 1.60
NHF 400 mg	97.00 ± 3.35	96.83 ± 3.11	95.17 ± 4.17	93.17 ± 3.43^Ca	88.33 ± 2.39

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; negative control treated with Tween 2%; positive control treated with GLC; A, compared to Tween 2%; B, compared to GLC; C-K, compared to the solvent fractions; *Compared to multiple extracts; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: ARF, aqueous residue fraction; EAF, ethyl acetate fraction; GLC, Glibenclamide; NHF, n-hexane fraction.

Table 4 The Glucose-Lowering Effect of the Crude 80% Methanol Extracts of V. Sinaiticum Leaves in Glucose-Loaded Mice

Groups	Blood Glucose Level
	0 hr.	0.5 hr.	1 hr.	2 hr.
Tween 2%	97.83 ± 11.42	172.67 ± 19.16	164.83 ± 15.17	101.5 ± 12.58
GLC 5 mg	101.33 ± 9.54	181.17 ± 12.72	86.50 ± 9.80^Ab,Ea	50.17 ± 4.01^Ac,Ba
CME 100 mg	93.83 ± 3.30	207.83 ± 12.32	130.67 ± 8.50	80.17 ± 5.31
CME 200 mg	99.67 ± 5.02	208.67 ± 13.39	128.50 ± 9.66^Ac,Ca	65.50 ± 4.10
CME 400 mg	104.50 ± 4.14	245.50 ± 15.23	152.33 ± 11.12^Aa,Cb	59.83 ± 3.52^Bb

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; negative control treated with Tween 2%; positive control with GLC; A, compared to Tween 2%; B, compared to GLC; C,D,E, compared to the crude extracts; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: GLC, Glibenclamide; CME, Crude methanol extracts.

Table 5 The Glucose-Lowering Effects of the Solvent Fractions of V. Sinaiticum Leaves in Glucose-Loaded Mice

Groups	Blood Glucose Level
	0 hr.	0.5 hr.	1 hr.	2 hr.
Tween 2%	97.83 ± 11.42	172.67 ± 19.16	164.83 ± 15.17	101.50 ± 12.58
GLC 5 mg	101.33 ± 9.54	181.17 ± 12.72	86.50 ± 9.80^Ab,Ea	50.17 ± 4.01*
ARF 100 mg	98.00 ± 4.78	200.33 ± 10.97	152.50 ± 10.63	91.50 ± 5.01
ARF 200 mg	92.50 ± 2.81	206.50 ± 9.83^Ac	131.17 ± 10.21^Eb	73.83 ± 3.06^Fa
ARF 400 mg	96.33 ± 5.63	209.83 ± 18.63	138.50 ± 13.30^Ib,Jb,Ka	65.67 ± 3.66^Ka
EAF 100 mg	103.17 ± 3.32	196.17 ± 10.25	142.17 ± 12.66	90.83 ± 4.48
EAF 200 mg	99.33 ± 4.60	173.67 ± 8.11^Ea	128.67 ± 9.62^Aa	62.67 ± 3.84^Da,Kb
EAF 400 mg	97.67 ± 2.85	201.33 ± 14.31^Ac,Ab	132.33 ± 11.69^Aa,Db,Ea	56.83 ± 4.78^Ab,Kb
NHF 100 mg	90.50 ± 3.49	192.83 ± 11.42	151.17 ± 9.33	98.17 ± 3.96
NHF 200 mg	98.33 ± 3.50	212.33 ± 20.72	158.50 ± 7.61	94.67 ± 4.83
NHF 400 mg	102.67 ± 6.52	202.67 ± 19.56	142.83 ± 15.61	92.33 ± 4.94^Aa,Fb

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; negative control treated with Tween 2%; positive control treated with GLC; A, compared to Tween 2%; B, compared to GLC; C-K, compared to the solvent fractions; *Compared to multiple extracts; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: ARF: aqueous residue fraction; EAF: ethyl acetate fraction; GLC, Glibenclamide; NHF: n-hexane fraction.

Table 6 The Antihyperglycemic Effect of the Crude 80% Methanol Extracts of V. Sinaiticum Leaves in Streptozotocin-Induced Diabetic Mice

Groups	Blood Glucose Level
	0 hr.	1 hr.	2 hr.	3 hr.	4 hr.
Tween 2%	108.67 ± 11.40	107.83 ± 12.91	105.83 ± 11.58	103.67 ± 10.60	101.50 ± 10.35
CBNC	288.50 ± 23.63	279.67 ± 17.39	271.83 ± 26.93	268.33 ± 29.58	261.50 ± 27.68
GLC 5 mg	293.33 ± 17.98	275.50 ± 20.94	192.67 ± 13.96^Bb,Fa	141.17 ± 9.27^Bc,Ec	105.33 ± 11.09^Bc
CME 100 mg	301.50 ± 24.13	301.17 ± 24.12	285.50 ± 24.55	273.83 ± 23.90	228.00 ± 25.08
CME 200 mg	281.17 ± 19.11	227.00 ± 10.23^Aa,Cb	204.17 ± 10.41	187.83 ± 8.11	158.83 ± 8.36^Bc,Da
CME 400 mg	291.50 ± 28.27	264.33 ± 23.66	241.17 ± 21.56^Ba	191.00 ± 11.22^Ba,Da	142.17 ± 7.48

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; Normal control was treated with Tween 2%; negative control with CBNC; positive control with GLC; A, compared to Tween 2%; B, compared to CBNC; C, compared to GLC; D,E,F, compared to the crude extracts; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: CBNC; Citrate buffer negative control; GLC, Glibenclamide; CME, Crude methanol extract.

Table 7 The Antihyperglycemic Effect of the Solvent Fractions of V. Sinaiticum Leaves in Streptozotocin-Induced Diabetic Mice

Groups	Blood Glucose Level
	0 hr.	1 hr.	2 hr.	3 hr.	4 hr.
Tween 2%	108.67 ± 9.56	107.83 ± 11.01	105.83 ± 9.70	103.67 ± 8.85	101.50 ± 8.63
CBNC	288.50 ± 23.63	279.67 ± 17.39	271.83 ± 26.93	268.33 ± 29.58	261.50 ± 27.68
GLC 5 mg	293.33 ± 17.98	275.50 ± 20.94^Ab,Db	192.67 ± 13.96^Ea,Fa	141.17 ± 9.27^Bc,Ib,Lb	105.33 ± 11.09*
ARF 100 mg	317.33 ± 20.23	301.17 ± 21.56	285.67 ± 19.93	251.67 ± 16.53	249.67 ± 15.84
ARF 200 mg	366.17 ± 20.87	337.50 ± 20.77	275.50 ± 18.50	254.00 ± 17.91^Lb	242.83 ± 17.58
ARF 400 mg	341.17 ± 15.70	309.83 ± 26.20^Cb	289.33 ± 25.11	265.33 ± 25.28^Da,Gb	210.50 ± 17.30^Da,Gb
EAF 100 mg	315.67 ± 18.55	293.33 ± 21.05	282.00 ± 21.01	258.67 ± 22.78	238.00 ± 21.56
EAF 200 mg	278.33 ± 10.53	261.00 ± 13.59^Ca,Db	234.33 ± 13.38^Ea,Fa	189.33 ± 14.02^Da,Gb,Lb	152.83 ± 14.79^Da,Ga
EAF 400 mg	286.50 ± 15.68	273.50 ± 22.36^Ca,Db	252.33 ± 26.03^Fa	195.17 ± 19.77^Ab,Da	136.33 ± 9.80*
NHF 100 mg	276.17 ± 8.29	263.33 ± 11.54	251.50 ± 24.26	244.50 ± 15.09	235.17 ± 13.21
NHF 200 mg	283.50 ± 9.36	272.33 ± 10.82	260.50 ± 11.25	250.17 ± 18.57	222.83 ± 13.52
NHF 400 mg	322.00 ± 21.46	309.83 ± 20.24	288.67 ± 20.34	266.83 ± 21.49^Ba	256.67 ± 17.35

Notes: All values are expressed as the mean ± standard error of the mean (SEM) (n = 6). Data were analyzed by one-way ANOVA followed by Tukey’s post hoc test; normal control was treated with Tween 2%; negative control with CBNC; positive control with GLC; A, compared to Tween 2%; B, compared to CBNC; C, compared to GLC; D-L, compared to the all solvent fractions; *, compared to multiple extracts; ^ap<0.05; ^bp<0.01; ^cp<0.001.

Abbreviations: ARF, aqueous residue fraction; CBNC, Citrate buffer negative control, EAF, ethyl acetate fraction; GLC, Glibenclamide, NHF, n-hexane fraction.