Herbal anxiolytics with sedative actions

Anxiety disorders such as generalized anxiety disorder (GAD), panic disorder, social phobia, and post-traumatic stress disorder (PTSD) present with a marked element of psychological anxiety and distress. Further, as sleep disorders are highly comorbid, it is often useful to consider the sedative actions of herbal anxiolytics. Herbal medicines that possess anxiolytic properties generally have effects on gamma- aminobutyric acid (GABA), either via direct receptor binding, ionic channel or cell membrane modulation, GABA transaminase or glutamic acid decarboxylase inhibition. The subsequent increased GABA neurotransmission has a damping effect on stimulatory pathways, which ultimately provides a psychologically calming effect. Mechanisms of action of these phytomedicines have been elucidated via in vitro and in vivo studies. For example, Awad and colleagues sought to determine whether several common herbal medicines directly affected the primary brain enzymes responsible for GABA metabolism. In vitro rat brain homogenate assays revealed aqueous extract of lemon balm (Melissa offi cinalis) to exhibit the greatest inhibition of GABA transaminase activity, while chamomile ( Matricaria recutita) and hops ( Humulus lupulus) inhibited glutamic acid decarboxylase activity. In addition to treating anxiety disorders, many anxiolytic plant medicines have additional applications, as discussed below in the "clinical considerations" section. The herbs outlined in this section have demonstrated clinical efficacy in treating various types of anxiety disorders, as well as being sedatives.