The present study was designed to investigate the ameliorative role of ethanolic extract from leaves of Butea monosperma in chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain in rats. Hot plate, acetone drop, paw pressure, Von Frey hair and tail immersion tests were performed to assess the degree of thermal hyperalgesia, cold chemical allodynia, mechanical hyperalgesia & allodynia in the left hind paw and tail thermal hyperalgesia. Further on, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and total calcium levels were estimated to assess the biochemical changes in the sciatic nerve tissue. Histopathological changes were also observed in the sciatic nerve tissue. Ethanolic extract of Butea monosperma leaves and pregabalin (serving as positive control) were administered for 14 consecutive days starting from the day of surgery. CCI resulted in significant changes in behavioural and biochemical parameters. Pretreatment of Butea monosperma attenuated CCI induced development of behavioural, biochemical and histopathological alterations in a dose dependent manner, which is comparable to that of pregabalin pretreated group. These findings may be attributed to its potential anti-oxidative, neuroprotective and calcium channel modulatory actions of Butea monosperma.

The present study was designed to investigate the antinociceptive potential of Vernonia cinerea (VC) on vincristine-induced painful neuropathy in rats. A chemotherapeutic agent, vincristine (50 μg/kg intraperitoneally for 10 consecutive days), was administered for the induction of neuropathic pain in rats. The painful behavioral changes were assessed using hot plate, acetone drop, paw pressure, Von Frey hair and tail immersion tests to assess the degree of hyperalgesic and allodynic pain sensation in paw and tail. Tissue biomarker changes including thiobarbituric acid reactive substances (TBARSs), reduced glutathione (GSH) and total calcium levels were estimated in sciatic nerve tissue samples to assess the degree of oxidative stress. Histopathological changes were also observed in transverse sections of rat sciatic nerve tissue. Ethanolic extract of VC leaves and pregabalin were administered for 14 consecutive days from day 0 (day of surgery). Pregabalin served as a positive control in the present study. Vincristine administration resulted in a significant reduction in painful behavioral changes along with a rise in the levels of TBARS, total calcium and decrease in GSH levels when compared with the normal control group. Furthermore, significant histopathological changes were also observed. Pretreatment with VC significantly attenuated vincristine-induced development of painful behavioral, biochemical and histological changes in a dose-dependent manner, which is similar to that of pregabalin-pretreated group. The attenuating effect of VC in vincristine-induced nociceptive painful sensation may be due to its potential of antioxidative, neuroprotective and calcium channel inhibitory action.

The present study was designed to investigate the antinociceptive effects of methanolic leaf extract of Swietenia mahagoni (MESM) on acrylamide-induced painful neuropathy in rats. The intraperitoneal administration of acrylamide (30 mg/kg; for 24 consecutive days) has been employed for the induction of painful neuropathy. Acrylamide induced nociceptive pain sensitive changes, which have been assessed by hot plate, Von Frey Hair, and tail immersion tests at different time intervals, that is, 0, 6, 12, 18, and 24th day. Furthermore, the biochemical changes, that is, thiobarbituric acid-reactive substances, reduced glutathione, and total calcium levels have been estimated in sciatic nerve tissue on 24th day and histopathological changes have been observed in sciatic nerve tissue sample. MESM and pregabalin have been administered for 14 consecutive days before 1 h of the each acrylamide injection. Administration of acrylamide resulted in significant changes in behavioral and biochemical parameters. Pretreatment of MESM ameliorated acrylamide-induced behavioral, biochemical, and histopathological changes in a dose-dependent manner, which is similar to that of pregabalin-pretreated group. These findings suggested that the neuroprotective effect of S. mahagoni may be due to its potential of antioxidative, calcium channel modulatory, and neuroprotective action.

Neuropathic pain is a chronic neurodegenerative disease. It is well characterized by spontaneous pain, hyperalgesia, hypothesia, dysesthesia and allodynia. The present study was designed to investigate the antinociceptive potential of Butea monosperma on vincristine-induced painful neuropathy in rats. Vincristine was administered for induction of neuropathic pain in experimental animals. Hot plate, acetone drop, paw pressure, Von Frey hair and tail immersion tests were performed to assess the degree of thermal hyperalgesia, cold chemical allodynia, mechanical hyperalgesia and allodynia in the hind paw and tail thermal hyperalgesia, respectively, as an index of peripheral and central pain sensation. Tissue thiobarbituric acid reactive substances (TBARSs), reduced glutathione (GSH) and total calcium levels were estimated to assess the biochemical changes in the sciatic nerve tissue. Microscopically, histopathological changes were also observed in the sciatic nerve tissue. Ethanolic extract of B. monosperma leaves and pregabalin were administered for 14 consecutive days. Vincristine administration resulted in significant reduction in behavioural (i.e. hyperalgesia and allodynic pain sensation) changes along with a rise in the levels of TBARS, total calcium and decrease in GSH levels when compared with the normal control group. Moreover, significant histological changes were also observed. Pretreatment with B. monosperma significantly attenuated vincristine-induced development of painful behavioural, biochemical and histological changes in a dose-dependent manner, which is similar to that of pregabalin-pretreated group. B. monosperma ameliorated vincristine-induced painful neuropathy. It may be due to its potential of antioxidative, neuroprotective and calcium channel inactivation.