Age-Dependent Analysis of the Effects of Pueraria Decoction on Autonomic Nerve Activities using Head-Up Tilt Test

Background: Pueraria Decoction (PD) is a Japanese herbal medicine of Kampo tradition, which is used for acute febrile diseases, inflammatory disease and allergic rhinitis. Moreover, PD is reported to have beneficial effects on autonomic disturbance in patients. Objective: The objective of the study is to investigate the effects of PD on autonomic nervous system of healthy adult subjects using spectral analysis of heart rate and blood pressure variability during Head-Up Tilt Test (HUTT). Here, we investigated the effects of PD on autonomic nervous system of healthy adults using spectral analysis of heart rate and blood pressure variability during Head-Up Tilt Test (HUTT). Methods: Twenty healthy subjects were divided into young and middle-aged groups, and examined twice with HUTT, before and 5 minutes after taking 5 g of PD. Spectral analysis of RR interval and Systolic Blood Pressure (SBP) variability was then used to measure the changes in autonomic functions. Results: As for all study participants, low frequency power of the SBP (SBP-LF) was increased, and high frequency power of RR interval (RR-HF) was decreased by tilt. However, PD did not show any effect on SBP-LF or RR-HF both at supine and tilt positions. Tilting did not change the ratio of low and high frequency power of RR interval (RRLF/ HF) before taking PD, which was increased after taking it. When analyzed separately by age, RR-HF was decreased in middle-aged group compared to the young counterpart in all conditions. Interestingly, PD increased RR-HF in middle-aged group at supine position, and a significant reduction of the value appeared at tilt similar like young group. After taking PD, tilt increased RR-LF/HF in both young and middle-aged groups. Conclusion: Our study finds that PD has a function to stimulate sympathetic nerve, and simultaneously restores the decreased parasympathetic functions in both young and elderly groups. Such findings suggest that PD might have a combined effect to protect the whole autonomic nervous system.