Title: Gabriele Trauner, et al. Modulation of GABAA receptors by valerian extracts is related to the content of valerenic acid. Planta Med. 2008 Jan;74(1):19-24.
Title: Tania Lefebvre, et al. In vitro activity of commercial valerian root extracts against human cytochrome P450 3A4. J Pharm Pharm Sci. 2004 Aug 12;7(2):265-73.