Mitigation of acrylamide-induced behavioral deficits, oxidative impairments and neurotoxicity by oral supplements of geraniol (a monoterpene) in a rat model

• Geraniol (GE) and curcumin (CU) protect against acrylamide (ACR) induced neuropathy.
• GE/CU improve the performance in a battery of behavioral tests for sensory and motor function.
• Alleviate ACR-induced oxidative stress in cytosol/mitochondria with concomitant elevation in enzyme activities.
• GE/CU enhance the levels of GSH and antioxidant enzymes, improve cholinergic function and dopamine levels.
• Efficacy of GE was highly comparable to CU.

In the recent past, several phytoconstituents are being explored for their potential neuromodulatory effects in neurological diseases. Repeated exposure of acrylamide (ACR) leads to varying degree of neuronal damage in experimental animals and humans. In view of this, the present study investigated the efficacy of geraniol (GE, a natural monoterpene) to mitigate acrylamide (ACR)-induced oxidative stress, mitochondrial dysfunction and neurotoxicity in a rat model and compared its efficacy to that of curcumin (CU, a spice active principle with multiple biological activities). ACR administration (50 mg/kg bw, i.p. 3 times/week) for 4 weeks to growing rats caused typical symptoms of neuropathy. ACR rats provided with daily oral supplements of phytoconstituents (GE: 100 mg/kg bw/d; CU: 50 mg/kg bw/d, 4 weeks) exhibited marked improvement in behavioral tests. Both phytoconstituents markedly attenuated ACR-induced oxidative stress as evidenced by the diminished levels of reactive oxygen species, malondialdehyde and nitric oxide and restored the reduced glutathione levels in sciatic nerve (SN) and brain regions (cortex – Ct, cerebellum – Cb). Further, both phytoconstituents effectively diminished ACR-induced elevation in cytosolic calcium levels in SN and Cb. Furthermore, diminution in the levels of oxidative markers in the mitochondria was associated with elevation in the activities of antioxidant enzymes. While ACR mediated elevation in the acetylcholinesterase activity was reduced by both actives, the depletion in dopamine levels was restored only by CU in brain regions. Taken together our findings for the first time demonstrate that the neuromodulatory propensity of GE is indeed comparable to that of CU and may be exploited as a therapeutic adjuvant in the management of varied human neuropathy conditions.