Olive (Olea europaea L.) leaf extract attenuates early diabetic neuropathic pain through prevention of high glucose-induced apoptosis: In vitro and in vivo studies
- Source: Journal of Ethnopharmacology, Jun 14, 2011
By Ayat Kaeidi, et al.
Aim of Study: Since the leaves of olive have been recommended in the literature as a remedy for the treatment of diabetes and they also contain antioxidant agents,* we decided to investigate the possible effects of olive leaf extract (OLE) on in vitro and in vivo models of diabetic pain neuropathy.
Materials and Methods: The high glucose-induced cell damage in naive and NGF-treated Pheochromocytoma (PC12) cells and streptozotocin-induced diabetic rats were used. Tail-flick test was used to access nociceptive threshold. [Nociceptors are nerves that transmit pain from damage or irritation.] Cell viability was determined by MTT assay. Biochemical markers of neural apoptosis [nerve cell death] were evaluated using immunoblotting.
Results: We found that:
• Elevation of glucose (4 times of normal) sequentially increases functional cell damage and caspase-3 activation in NGF-treated PC12 cells.
• Incubation of cells with olive leaf extract (200, 400 and 600 micrograms/ml) decreased cell damage.
• Furthermore, the diabetic rats developed neuropathic pain which was evident from decreased tail-flick latency (thermal hyperalgesia).
• Activated caspase 3 and Bax/Bcl2 ratio were significantly increased in spinal cord of diabetic animals.
• Olive leaf extract treatment (300 and 500 mg/kg per day) ameliorated hyperalgesia, inhibited caspase 3 activation and decreased Bax/Bcl2 ratio.
• Furthermore, olive leaf extract exhibited potent DPPH free radical scavenging capacity.
The results suggest that olive leaf extract inhibits high glucose-induced neural damage and suppresses diabetes-induced thermal hyperalgesia.
The mechanisms of these effects may be due, at least in part, to reduced neuronal apoptosis and suggest therapeutic potential of olive leaf extract in attenuation of diabetic neuropathic pain.
Source: Journal of Ethnopharmacology, Jun 14, 2011;136(1):188-96. PMID: 21540099, by Kaeidi A, Esmaeili-Mahani S, Sheibani V, Abbasnejad M, Rasoulian B, Laboratory of Molecular Neuroscience, Kerman Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Iran.
* Note: To learn more about olive leaf extract's long, diverse role in human health, see “The Olive Leaf – Antimicrobial Ally for 6,000 years,” and “Olive Leaf Extract – A New/Old Healing Bonanza for Mankind.”