Safety and immunomodulatory activity of Houttuynia cordata fermentation product in healthy volunteers and its effect on antiretroviral-drug level in rats

Houttuynia cordata Thunb. fermentation product (HCFP) is widely used in Thailand as a dietary supplement for immune support with no experimental verification. The aims of this study were to investigate the safety and immunomodulation of HCFP in healthy volunteers and to study its effect on antiretroviral drugs in Sprague Dawley rats. The basic characteristics and blood chemistry of 10 healthy volunteers did not show any significant differences between before and after 4 weeks of intervention with a daily intake of HCFP, and no major adverse event was observed. The immunomodulation study revealed that the percentage of neutrophils was significantly increased after 8 weeks of intervention in 30 healthy volunteers. The CD4+:CD8+ T cell was increased from 1.24 ± 0.49 to 1.29 ± 0.56 with no significant difference. The plasma concentrations of EFV and TDF in Sprague Dawley rats showed no significant difference between the single drug group and combination with HCFP group.