Table 1.
The effects of N. sativa and its active component, thymoquinone (TQ) on neurological and mental disorders.
| Neurological or mental Disorders | Model used and intervention (s) | Finding (mechanism) | References |
|---|---|---|---|
| Alzheimer's disease (AD) | Lipopolysaccharide-induced AD in mice, received TQ (2.5 & 5mg/kg) for 7 days. | (i) ↓ TBARS & 5-LOX levels (ii) ↑ GSH extent and SOD action (iii) Causes disaggregation of Aβ peptide (iv) prevents declining of neurons (v) Slows degeneration of cognitive ability |
[64, 65] |
| Aβ-induced neurotoxicity (analyzed by culturing hippocampus and cortical neurons). TQ is administered along with Aβ1−42 for 72 hours |
(i) Reducing Aβ-induced neurotoxicity. (Improved cell viability) by: (ii) Inhibiting mitochondrial membrane potential depolarization (iii) Hindering reactive oxygen species generation |
[66] |
|
|
| |||
| Parkinson's disease (PD) | 1-methyl-4-phenylpyridinium (MPP+) and rotenone-induced neurotoxicity in PD model, cultures were treated with TQ (0.01, 0.1, 1 and, 10 μM) on day 8th for 4 days. | (i) Rescued dopaminergic neurons through: (ii) Its antioxidant and anti-inflammatory effects |
[67] |
| Experimental model of early PD induced by 6-hydroxydopamine neurotoxicity, pretreatment of daily TQ (5 & 10 mg/kg) and one additional dose after surgery were used. | (i) ↓ MDA level (ii) Prevents loss of neurons in substantia nigra (iii) Protects hippocampal & human induced pluripotent stem cell against α-synuclein induced synaptic toxicity |
[68, 69] |
|
|
| |||
| Depression and anxiety | (i) Open field and elevated plus maze models; forced swim test (ii) Locomotor behavior in familiar and new environment in rats, N. sativa oil (0.1 mL/day) aqueous seed extract (2 mL/day) orally for 4-6 weeks |
(i) ↑ in open field activity & struggling time (ii) ↑ 5-HT (iii) ↓ 5HIAA level in the brain (iv) ↑ tryptophan level in plasma & brain (v) ↑ locomotors activity in novel environment (vi) ↑ brain DA level |
[59, 70, 71] |
| Stressed and unstressed mice, 10 and 20 mg/kg of TQ for 4 weeks | Unstressed mice: at 10 & 20 mg/Kg showed anti-anxiety (i) without altering nitrite levels (ii) ↑ GABA content (only 20mg/Kg). Stressed mice: 20 mg/kg showed anxiolytic effects with (i) ↓ plasma nitrite level (ii) Reversal of reduced GABA |
[72] | |
| Randomized control trial on healthy human subjects, N. sativa capsule (500 mg) daily for 4 weeks. | (i) Stabilize disturbed mood (ii) ↓ anxiety (iii) Modulate memory positively |
[73] | |
|
| |||
| Epilepsy | Pentylenetetrazole-induced seizure, N. sativa oil; TQ | (i) Prevented seizure occurrence (ii) ↓ Reactive oxygen species generation (iii) Reduced seizure score (iv) Showed additive effects with phenobarbitone |
[74–76] |
| Double-blinded placebo randomized control trial (refractory epilepsy), TQ as adjunctive therapy for 4 weeks | (i) Significant reduction of seizure frequency (those who received combination therapy) | [77] | |
|
| |||
| Opioid dependence and Tolerance | Morphine brought tolerance and dependency in mice, 4mL/kg of N. sativa oil along with morphine (5mg/kg) | (i) Attenuated the development of tolerance (ii) Inhibited nitric oxide overproduction (iii) ↓ in brain MDA level |
[78] |
| Randomized trial (on 35 known addicts of opiates), 500 mg N. Sativa three times daily |
(i) ↓ the withdrawal effects significantly (ii) ↑ appetite (no significant weight gain) (iii) No changes in physiological parameters (blood pressure, pulse and respiratory rate) |
[79] | |
TBARs= Thiobarbituric acid reactive substances, GABA= gamma amino butyric acid, 5-HT= 5 hydroxytryptamine, MDA= malondialdehyde, DA= dopamine, 5HIAA= 5 hydroxyindoleacetic acid, GSH= glutathione peroxidase, SOD= superoxide dismutase, TQ= thymoquinone, Aβ= beta amyloid peptides, ↑=increase, ↓=decrease.