Valerenic acid reduces anxiety-like behavior in young adult, female (C57BL/6J) mice

Extracts from the plant Valeriana officinalis are marketed as an herbal remedy to treat anxiety and insomnia. Valerenic acid (VA) is a major chemical component of Valeriana extracts. To date, there is relatively little information about how VA affects behavior. The purpose of these experiments was to (1) test whether administration of VA induces measurable changes in anxiety-like, depression-like, or locomotor behaviors; (2) determine whether the effects of VA on behavior are dose-dependent; and (3) compare the effects of VA on behavior to those of diazepam, a commonly prescribed treatment for anxiety. Young adult, female mice (C57BL/6J; 3–4 months old; 12 mice/group) were given one of three dosages of VA (3 mg/kg, 6 mg/kg, or 12 mg/kg), diazepam (1 mg/kg), or a vehicle control solution (20% ethanol v/v) by intraperitoneal injection. Thirty minutes after injection, each mouse was tested in the elevated plus maze (EPM), open field test (OFT), and tail suspension test (TST), in that order. All tests were video recorded and analyzed for relevant behavioral parameters. The results demonstrated that VA treatment effectively reduced multiple anxiety-related behaviors measured in the EPM. In fact, at a dose of 12 mg/kg, the anxiolytic effect of VA was just as robust as that of diazepam. Furthermore, the effects of VA on behavior were specifically anxiolytic, as VA did not induce changes in locomotor activity in the OFT, or depression-related behavior as measured in the TST. Our results provide strong support for VA as a putative anxiolytic drug.