Neuroinflammation, oxido-nitrosative stress and altered levels of neurotrophin are responsible for pathogenesis of anxiety and depressive illness. Polyherbal formulation (PHF) contains extracts of garmarogor, devdaru, shankhavali, pitapapapdo, brahmi, jatamansi, nagarmoth, kadu, tagar, himaj, draksha, ashwagandha. These plants are a rich source of alkaloids, flavonoids, tannins, terpenoids, phenolics and known for antioxidant, anti-inflammatory, anti-stress, anxiolytic and neuroprotective activities. The study was performed to investigate the effect of PHF on lipopolysaccharide (LPS) – induced anxiety and depressive-like behaviour in mice. Drug treatments viz. PHF (600 mg/kg; p.o.) and fluoxetine (20 mg/kg, p.o.) were daily administered for 14 days and challenged with saline and/or LPS (0.83 mg/kg, i.p.) on 14th day. Pretreatment with PHF significantly ameliorated the anxiety-like behaviour that is evident from the results of an elevated plus-maze and locomotor activity and depressive effect produced by forced swim test and learning – memory deficiency in Morris water maze test were also prevented. PHF treatment also reduced LPS – induced neuroinflammation by attenuating TNF– α, IL- 6, IL - 1β levels along with a decrease in oxidative stress in terms of increase in reduced glutathione concentration with reduction in lipid peroxidation and nitrite levels. Besides, the significant rise in BDNF (brain-derived neurotrophic factor, a neuroprotective factor) and decrease (p<0.05) in quinolinic acid (neurotoxin) has been observed indicating neuroprotection in formulation treated animals. These results highlight the neuroprotective potential of formulation in LPS – induced anxiety and depressive illness model showing usefulness of formulation in the treatment of psychiatric disorders associated with inflammation and oxidative stress.
Keywords: Neuroinflammation, LPS, oxidative stress, anxiety, depression