An 8-week randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of red Platycodon grandiflorus root extract on enhancement of immune function

Abstract

Background: The immune-enhancing effects of red Platycodon grandiflorus root extract (RPGE) has been reported in vitro and in vivo, but there are few studies on humans. Therefore, this study aimed to investigate the efficacy and safety of RPGE in enhancing immune function in healthy subjects. Subjects and methods: An 8-week randomized, double-blind, parallel, placebo-controlled clinical trial was conducted at the Gachon University Gil Medical Center, Incheon, South Korea. A total of 100 adults aged 20–75 years with white blood cell counts of 3000–10,000 cell/µL were randomly divided into two groups (RPGE group, 50 and placebo group, 50) using a computer-generated random list with a 1:1 allocation ratio. The subjects consumed RPGE (2 times/day, 2 tablets/time, 375 mg RPGE powder/tablet) or placebo for 8 weeks. All test foods for the human study were coded and administered under double-blind conditions. The primary outcome was a change in the NK cell activity after 8 weeks of treatment compared to the baseline. Results: Among 100 subjects enrolled for the study, 87 completed the study. NK cell activity (p = 0.005) and IFN-γ level (p = 0.003) of the RPGE group (n = 41) were higher than those of the placebo group (n = 46). The findings of the safety assessment revealed absence of clinically significant changes in any test and serious adverse events throughout the study. Conclusion: In conclusion, these results demonstrate the efficacy and safety of RPGE, suggesting it to be a beneficial agent for enhancing immune function in humans. Trial registration: CRIS Registration Number KCT0005945, https://cris.nih.go.kr. © 2021 Elsevier GmbH