Phytotherapeutic activity of curcumol: Isolation, GC–MS identification, and assessing potentials against acute and subchronic hyperglycemia, tactile allodynia, and hyperalgesia

Figures & data

Figure 1. Chemical structure of curcumol.

Figure 2. GC–MS total ion chromatograms. (A) Standard curcumol. (B) CRF.

Table 1. Acute effect of C. longa extract (turmeric), CRF, and curcumol on blood glucose level in diabetic mice.

		Mean blood glucose concentration ± SEM (mg/dL)
Group	Dose (mg/kg)	0 h	1 h	2 h	6 h
Control	–	104.40 ± 2.90	105.70 ± 2.60	106.63 ± 2.10	104.36 ± 2.70
Diabetic control	–	206.29 ± 5.60	215.43 ± 4.50	218.71 ± 9.70	214.05 ± 7.30
GB	5	220.20 ± 3.70	223.14 ± 1.80	159.24 ± 2.10	130.10 ± 2.40^*
Turmeric	25	200.54 ± 2.60	284.91 ± 2.10	134.81 ± 1.40	139.35 ± 1.90^*
Turmeric	50	201.90 ± 2.60	163.83 ± 1.90	98.81 ± 1.80	135.65 ± 1.70^*
Turmeric	100	202.54 ± 2.60	205.91 ± 2.10	147.81 ± 1.40	125.35 ± 1.90^*
CRF	7	210.54 ± 1.50	222.51 ± 1.80	141.16 ± 1.90	113.50 ± 1.40^*
Curcumol	20	204.54 ± 1.60	145.26 ± 1.90	144.84 ± 1.80	141.54 ± 1.10
Curcumol	30	209.90 ± 1.90	139.56 ± 1.80	140.26 ± 1.50	130.26 ± 1.60
Curcumol	40	216.34 ± 2.20	136.65 ± 1.40	131.58 ± 1.90	129.87 ± 1.80

SEM, standard error of the mean.

* p < 0.05 significant from the control animals.

** p < 0.01 significant from the control animals.

Table 2. Subchronic effect of C. longa extract (turmeric), CRF and curcumol on blood glucose level.

		Mean blood glucose concentration ± SEM (mg/dL)
Group	Dose (mg/kg)	1st day	3rd day	5th day	8th day
Control	–	106.50 ± 2.50	108.70 ± 3.60	107.36 ± 3.20	116.00 ± 4.70
Diabetic control^a	_	201.29 ± 5.60***	210.43 ± 4.50***	213.71 ± 9.70***	209.00 ± 7.30***
GB^b	5	185.20 ± 3.70	178.03 ± 2.90	160.04 ± 2.40**	170.80 ± 3.10
Turmeric^a	25	154.18 ± 1.30	147.89 ± 3.10	139.32 ± 2.50	138.13 ± 1.30**
Turmeric^a	50	131.17 ± 1.70	98.52 ± 2.70	122.44 ± 2.70	129.33 ± 1.50**
Turmeric^a	100	134.12 ± 1.50	132.76 ± 2.10	133.89 ± 2.60	124.13 ± 1.60**
CRF^b	7	110.54 ± 1.50	108.91 ± 2.90	108.36 ± 1.90	106.54 ± 1.40**
Curcumol^a	20	141.54 ± 1.10	139.59 ± 1.70	134.66 ± 2.20	126.23 ± 2.40
Curcumol^a	30	130.26 ± 1.60	127.51 ± 1.90	126.35 ± 1.90	119.56 ± 1.10
Curcumol^a	40	129.87 ± 1.80	125.46 ± 1.70	116.54 ± 1.80	104.46 ± 2.30

SEM, standard error of the mean.

* p < 0.05 significant from the control animals.

** p < 0.01 significant from the control animals.

*** p < 0.001 significant from the control animals.

^aCompared with vehicle control.

^bCompared with diabetic control.

Table 3. Subchronic effect of C. longa extract (turmeric), CRF, and curcumol on body weights in alloxan-induced diabetic mice.

		Mean body weight ± SEM (g)
Group	Dose (mg/kg)	1st day		3rd day	5th day	8th day
Control	__	25.40 ± 0.50		25.50 ± 0.60	25.66 ± 0.97	26.12 ± 0.70
Diabetic control^a	__	26.18 ± 0.70		26.60 ± 0.20	27.65 ± 0.80	26.99 ± 0.50
GB^a	5	21.90 ± 0.70		27.67 ± 1.70	27.94 ± 0.40	29.27 ± 1.10
Turmeric^a	25	22.18 ± 1.30		23.9 ± 3.10	24.32 ± 2.10	27.91 ± 1.20**
Turmeric^a	50	21.20 ± 1.70		24.73 ± 2.70	25.90 ± 1.70	28.80 ± 1.50**
Turmeric^a	100	22.00 ± 1.50		26.90 ± 2.10	27.80 ± 1.60	31.13 ± 1.40**
CRF^a	7	25.10 ± 0.70		25.95 ± 0.90	28.30 ± 0.40	29.55 ± 0.80
Curcumol^a	20	27.00 ± 0.50		27.10 ± 0.50	27.50 ± 0.40	27.90 ± 0.60*
Curcumol^a	30	26.10 ± 0.30		27.01 ± 0.40	27.50 ± 0.60	28.80 ± 0.50*
Curcumol^a	40	25.00 ± 0.40		30.10 ± 0.40	34.20 ± 0.70	35.10 ± 0.40*

SEM, standard error of the mean.

* p < 0.05 significant from the control animals.

** p < 0.01 significant from the control animals.

*** p < 0.001 significant from the control animals.

^a Compared with vehicle control.

Table 4. In vivo assessment of the antioxidant activity of C. longa extract (turmeric), CRF, and curcumol using CAT levels in serum of alloxan-induced diabetic mice.

		Catalase activity ± SEM (kU/I)
Group	Dose (mg/kg)	1st day	3rd day	5th day	8th day
Control	–	34.50 ± 1.50	35.10 ± 1.60	34.36 ± 1.20	35.12 ± 1.70
Diabetic control^a	–	22.17 ± 1.60***	23.43 ± 1.30***	23.51 ± 1.90***	22.05 ± 1.40***
GB^b	5	23.10 ± 1.70	25.50 ± 1.70	32.04 ± 1.40	32.87 ± 1.00**
Turmeric^a	25	23.21 ± 1.40	24.89 ± 2.70	26.45 ± 3.90	31.89 ± 3.40*
Turmeric^a	50	24.88 ± 1.20	28.88 ± 1.90	28.77 ± 2.30	35.33 ± 2.80**
Turmeric^a	100	24.55 ± 1.20	30.85 ± 1.30	31.01 ± 1.80	37.65 ± 1.30**
CRF^a	7	20.10 ± 1.70	27.95 ± 1.70	30.50 ± 1.70	32.65 ± 1.80**
Curcumol^a	20	22.50 ± 1.50	24.18 ± 1.30	27.45 ± 1.10	30.74 ± 1.70*
Curcumol^a	30	24.33 ± 1.40	26.51 ± 1.80	31.91 ± 1.50	35.53 ± 1.30**
Curcumol^a	40	25.10 ± 1.70	29.45 ± 1.90	34.55 ± 1.70	39.65 ± 1.10**

SEM, standard error of the mean.

* p < 0.05 significant from the control animals.

** p < 0.01 significant from the control animals.

*** p < 0.001 significant from the control animals.

^aCompared with vehicle control.

^bCompared with diabetic control.

Figure 3. Effect of C. longa ethanolic extract (Turmeric) on the hot plate and tail withdrawal latencies in alloxan-treated mice. (A) Hot plate latency: (crossed-triangles, straight line) NORM, normal control mice. (Closed-squares, straight-line) DIA + VEH, diabetic animals treated with vehicle as control. (Open-circles, straight-line) DIA + turmeric 25 mg/kg, diabetic animals treated with turmeric 25 mg/kg. (Up-triangles, dashed-line) DIA + turmeric 50 mg/kg, diabetic animals treated with turmeric 50 mg/kg. (Right-triangles, dashed-dotted-line) DIA + turmeric 100 mg/kg, diabetic animals treated with turmeric 100 mg/kg. (B) Tail withdrawal latency: (Crossed-triangles, straight line) NORM, normal control mice. (Closed-squares, straight-line) DIA + VEH, diabetic animals treated with vehicle as control. (Open-circles, straight-line) DIA + turmeric 25 mg/kg, diabetic animals treated with turmeric 25 mg/kg. (Up-triangles, dashed-line) DIA + turmeric 50 mg/kg, diabetic animals treated with turmeric 50 mg/kg. (Right-triangles, dashed-dotted-line) DIA + turmeric 100 mg/kg, diabetic animals treated with turmeric 100 mg/kg. Data (n=7) are expressed as mean ± SEM. “*” p < 0.05 compared with control.

Figure 4. Effect of curcumol on the hot plate and tail withdrawal latencies in alloxan-treated mice. (A) Hot plate latency: (Crossed-triangles, straight line) NORM: normal control mice. (Closed-squares, straight-line) DIA + VEH, diabetic animals treated with vehicle as control. (Open-circles, straight-line) DIA + curcumol 20 mg/kg: diabetic animals treated with curcumol 20 mg/kg. (Up-triangles, dashed-line) DIA + curcumol 30 mg/kg: diabetic animals treated with curcumol 30 mg/kg. (Right-triangles, dashed-dotted-line) DIA + curcumol 40 mg/kg, diabetic animals treated with curcumol 40 mg/kg. (B) Tail withdrawal latency: (Crossed-triangles, straight line) NORM, normal control mice. (Closed-squares, straight-line) DIA + VEH, diabetic animals treated with vehicle as control. (Open-circles, straight-line) DIA + curcumol 20 mg/kg, diabetic animals treated with curcumol 20 mg/kg. (Up-triangles, dashed-line) DIA + curcumol 30 mg/kg, diabetic animals treated with curcumol 30 mg/kg. (Right-triangles, dashed-dotted-line) DIA + curcumol 400 mg/kg, diabetic animals treated with curcumol 40 mg/kg. Data (n=7) are expressed in mean ± SEM. “*”p < 0.05 compared with control.

Figure 5. The effect of C. Longa EtOH extract (turmeric), curcumol, and tramadol (TRA) 10 mg/kg on tactile allodynia in the neuropathic model in alloxan-induced diabetic mice. (A) Turmeric group: paw withdrawal thresholds to von Frey filaments were determined on hind paw prior to (Predose) and up to 8 weeks following i.p. injection of 25, 50, and 100 mg/kg turmeric. (B) Curcumol group: paw withdrawal thresholds to von Frey filaments were determined on hind paw prior to (predose) and up to 8 weeks following i.p. injection of (20, 30, and 40 mg/kg) curcumol. (NORM) normal non-diabetic untreated mice. *p ≤0.05 and **p ≤0.01 compared with vehicle (VEH) (n=7 animals/group).