Antioxidant and physiological effects of Si-Wu-Tang on skin and liver: a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND: Si-Wu-Tang (SWT) is used to treat various gynecological disorders in Chinese medicine. This study investigated the antioxidant and physiological effects of SWT on the skin and liver in healthy adults. METHODS: This randomized, crossover, double-blind, placebo-controlled clinical trial was conducted at Chung Shan Medical University Hospital in December 2008. Participants with uncontrolled diabetes, heart disease, liver disease, kidney disease, cancer, and pregnancy were excluded. Sixty healthy volunteers taking no medications were recruited from the community based on the results of their medical history questionnaires and biochemical analyses to confirm their health status. The participants were assigned to two groups: one group drank 125 mL of placebo (n = 30) and the other drank SWT (n = 30) for six continuous days per month for 6 months. The placebo and SWT were then switched between the groups after a 1-month washout period. Anthropometric measurements (body weight, body fat, and body mass index) were performed and fasting blood samples were drawn for various biochemical assays at 1, 3, 6, 10 and 13 months. Abdominal ultrasound and skin examinations were performed at 1, 6 and 13 months. The skin examinations involved assessment of skin roughness, sebum content, hydration, surface water loss, erythema, melanin index, and elasticity on the face (sunlight-exposed sites: middle of ear and nose) and inner arm (sunlight-unexposed sites: center of wrist and elbow joint). RESULTS: Administration of SWT significantly increased the antioxidant index (P = 0.001) and antioxidant enzymes activities (P = 0.001) from baseline to month 6. SWT also suppressed the concentration of serum lipids (triglycerides, P = 0.01; high-density lipoprotein cholesterol, P = 0.23; low-density lipoprotein cholesterol, P = 0.48) and hepatic marker enzymes (glutamic pyruvic transaminase, P = 0.76; glutamic oxaloacetic transaminase, P = 0.65) when compared with the placebo group. Abdominal ultrasound in the SWT group revealed a positive impact of SWT on mild fatty liver, gallstones, and mild splenomegaly. Moreover, SWT intake concomitantly elevated erythema (P = 0.011) and markedly lowered skin surface water loss (P = 0.016), sebum content (P = 0.021), and wrinkles (P = 0.024). CONCLUSIONS: Oral administration of SWT for 6 months improved the antioxidant level and positively regulated the lipid profile, liver function, and skin integrity and texture. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13020-016-0102-0) contains supplementary material, which is available to authorized users.