Passionflower Extract Improves Diurnal Quality of Life in Japanese Subjects with Anxiety: A Randomized, Placebo-controlled, Double-blind Trial

Abstract

Background and objective: Passiflora incarnata (passionflower) has traditionally been used to treat insomnia and anxiety. We recently reported that an aqueous ethanol extract of passionflower (PFE) and its flavonoid glycosides enhanced the expression of Period (Per) 2, a clock gene, in mouse liver and fibroblasts. However, the influence of PFE on daily activities or emotions has not been examined in humans. Therefore, we conducted a clinical trial of PFE supplementation in healthy Japanese subjects.Methods: This randomized, double-blind, placebo-controlled study examined the effects of PFE (200 mg daily) containing 3% flavonoid glycosides (6 mg daily). We enrolled 44 Japanese men and women who were reluctant to work or doing house chore or engaging in irregular flame works. All subjects were randomly allocated into either the PFE group (n=22) or the placebo group (n=22) using a computerized random-number generator. Capsules containing either PFE or placebo were administered for 12 weeks between August 2017 and January 2018. Emotional status and sleep quality were evaluated by using the Japanese version of Medical Outcomes Study Short-Form 36-Item Health (SF-36) questionnaire and the Oguri-Shirakawa-Azumi (OSA) sleep inventory score at 6- and 12-week of ingestion.Results: The per protocol set comprised 20 subjects in the PFE group and 18 subjects (20 subjects for OSA and safety evaluation) in the placebo group. After intake of PFE (200 mg/day) for 6 weeks, some of the SF-36 domain scores were significantly improved compared with those of the placebo group, including the scores for role/social component summary, social functioning, and role-emotional. After 12 weeks, the scores for mental component summary and vitality showed significant improvement in the subjects taking PFE (200 mg/day) compared to those taking placebo. In contrast, none of the OSA sleep score parameters were significantly improved by PFE compared with placebo. Laboratory tests did not reveal any abnormalities suggesting adverse effects of PFE.Conclusions: Intake of PFE (200 mg/day for 12 weeks) improved several emotional parameters related to daytime social and mental activities. PFE was suggested to be useful for improving anxiety.