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Cisplatin is used as a first line therapy in treating cancers. However, its use is often accompanied with the development of peripheral neuropathy. 6-Methoxyflavanone (6-MeOF) is a positive allosteric modulator at GABAA receptors and is known for attenuating diabetes-induced neuropathic pain. Neuropathy was induced in male Sprague-Dawley rats (150-250 g), via intraperitoneal injection of cisplatin (3 mg/kg) once a week for four consecutive weeks. 6-MeOF (25, 50 and 75 mg/kg, i.p) and gabapentin (75 mg/kg, i.p) were administered 30 min before each cisplatin injection. Static and dynamic allodynia were assessed using von Frey filaments and cotton buds. The anti-inflammatory activity was analyzed with plethysmometer. Body weights were also measured each week. The binding affinity of 6-MeOF with chloride channel, Cyclooxygenase-1 (COX-1) and Cyclooxygenase-2 (COX-2) was studied using docking approach. The in vitro COX-1 and COX-2 inhibitory effect of 6-MeOF was conducted with COX colorimetric assay. Administration of cisplatin for four consecutive weeks induced static (decreased paw withdrawal threshold; PWT) and dynamic allodynia (decreased paw withdrawal latency; PWL). Co-administration of 6-MeOF for four weeks significantly attenuated the cisplatin-induced expression of nocifensive behaviors observed as significant increase in PWT and PWL. Moreover, it also prevented the body weight loss induced by cisplatin administration. In silico studies depicted a good interaction of 6-MeOF with chloride ion channels and COX-1 and COX-2 enzymes. The in vitro study confirmed the inhibitory activity of 6-MeOF for COX-1 and COX-2. 6-MeOF may be effective in attenuating cisplatin-induced allodynia, probably through interaction with GABAergic receptors and reducing inflammation., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Benzodiazepines are regularly prescribed for treatment of anxiety though there are side effects. Flavonoids have selective affinity for GABA A receptors implicated in anxiolytic-like activity in rodents, but are devoid of the unwanted side effects of benzodiazepines. In this study, 6-methoxyflavanone (6-MeOF), a positive allosteric modulator of γ-amino butyric acid (GABA) responses at human recombinant GABA A receptors, was evaluated for its behavioral profile in the elevated plus-maze as well as the staircase- plus and open-field tests in mice. In addition, the distribution of 6-MeOF in selected brain areas involved in anxiety (amygdala and cerebral cortex) was also examined using a validated high performance liquid chromatography ultraviolet detection (HPLC/UV) method. 6-MeOF (10, 30 and 50mg/kg) exerted an anxiolytic-like effect, increasing entries and time spent in the open arm and the central platform, as well as head-dipping frequency in the mouse elevated plus-maze assay. It also decreased rearing incidence without suppressing the number of steps ascended in the staircase test. Whereas, in the open-field anxiety test, 6-MeOF had no effect on locomotor activity at lower doses, a decrease was observed at the highest dose (100mg/kg). 6-MeOF additionally produced an anxiolytic-like increase in the time spent at the center of the open-field apparatus. These effects were preferentially antagonized by pentylenetetrazole (15mg/kg). Furthermore, pharmacokinetic studies disclosed a rapid appearance of 6-MeOF in the plasma and discrete brain areas. Taken together, our findings suggest that 6-MeOF readily crosses the blood brain barrier (BBB) generating anxiolytic activity, mediated through the GABAergic system., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Diabetic neuropathy is the most prevalent, persistent and debilitating complication of diabetes mellitus often coupled with vulvodynia that may present as an isolated symptom or as a part of constellation of other neuropathic abnormalities., Objective: Flavonoids have selective affinity for GABA receptors and 6-methoxyflavanone (6-MeOF) is a positive allosteric modulator of GABA responses at human recombinant GABA A receptors. GABAergic and opioidergic system inhibition have been shown to facilitate neuropathic pain., Methods: 6-MeOF was evaluated for analgesic effect in the hot plate test and streptozotocin-induced diabetic neuropathic pain in female rats using von Frey hairs. The possible involvement of opioidergic and GABAergic mechanisms was investigated using naloxone and pentylenetetrazole (PTZ) antagonists, respectively. The biodistribution of 6-MeOF in plasma and CNS was examined using a validated HPLC/UV analytical method. The binding affinity of 6-MeOF with opioid and GABA receptors was studied using molecular docking simulation approach., Results: 6-MeOF (10 and 30mg/kg) attenuated the acute phasic thermal nociception in the hot plate test while in the case of streptozotocin-induced diabetic neuropathy model, 6-MeOF (10 and 30mg/kg) produced static/dynamic anti-allodynic (increased paw withdrawal threshold and latency) as well as static/dynamic anti-vulvodynic effects (increased flinching response threshold and latency), when compared to the vehicle and standard gabapentin (75mg/kg). In silico studies depicted the preference of 6-MeOF for the delta- and kappa-opioid and GABA A receptors. Moreover, the pharmacokinetic profile revealed a quick appearance of 6-MeOF in the systemic circulation and brain areas with maximum concentration observed after 30min in the amygdala, brain stem and cerebral cortex., Conclusion: 6-MeOF readily crosses the blood brain barrier and may be effective in attenuating the diabetes-induced allodynia as well as vulvodynia, probably through interactions with the GABAergic and opioidergic systems., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)