There is a common belief in the Southeast Asian Chinese community that a smooth blood circulation is important for good health. There are several “blood cleansing” Traditional Chinese Medicinal (TCM) herbs shown to improve blood circulation by reducing blood viscosity and promoting blood circulation in animal studies [1,2]. Blood viscosity or fluidity is influenced by circulating plasma lipoproteins [3,4], platelet activity and other physiological parameters [5]. Modulating these components, possibly by improving metabolic function might improve fluidity and blood flow. Several studies have demonstrated a link between these parameters, blood viscosity and various forms of liver dysfunction [6,7,8]. In linking traditional health concepts with scientific rationale, we hypothesize that liver protective ‘blood cleansing’ TCM herb materials may help to reduce blood viscosity.

Sesamin, a lignan that occurs exclusively in sesame seeds, has been reported to inhibit cholesterol absorption and synthesis [9], in addition to improving hepatic detoxification in rats [10]. Schisandra chinensis with common names like Schisandra, Magnolia vine and Wu-wei-zi, similarly, has been reported to confer liver protective effect in a rat model of hepatotoxicity [11,12] and is an established Chinese herbal medicine associated with liver protection and function [13]. In the present study, we examined the action of sesamin-schisandra extract combination for its potential to improve blood fluidity in humans.

Exclusion criteria included drug allergy, gastrointestinal disorder or surgery, respiratory or cardiac disorder, excessive intake of tobacco (>50 cigarettes per day), alcohol (>equivalent of 120 ml ethyl alcohol), significant irregular dietary habits, blood donation within two weeks of study initiation and any condition deemed unsuitable for study participation. Subjects would be withdrawn from the study in the event they need to take medication (such as aspirin, anticogulants) that might affect blood viscosity. Of the 20 subjects initially screened for each group, only ten subjects were found to be eligible.

The effect of SCH on blood fluidity was assessed at baseline (week 0), 1-week and 2-week after continuous oral intake. At each time point, fasting blood samples for blood fluidity assessment were taken in the morning before breakfast. Blood chemistry, hematology and urine tests for safety assessments were performed at screening (2 weeks prior to study) and 2 weeks post dosing.

Among the 10 subjects, 1 subject was found to have increased platelet aggregation (blood passing time>70s) after 1 week of SCH. The data from this particular subject was excluded from the study.

Figure 1 Effect of continuous intake of Schisandra for 2 weeks on the fasting blood passage time. There was a sustained decreasing trend in blood passage time during 2 weeks of Schisandra administration. Values represent Mean ± SEM.

In human subjects, the fasting blood passing time shows a sustained decreasing trend over the two-week trial period, suggesting that SCH may have beneficial effect in promoting blood fluidity. The blood passage time following SCH intake were similar at week 1 and week 2 when compared to baseline (week 0), suggesting that a limit of action was reached within that time frame. As shown in figure 1, the blood passage time stabilized at 47 sec and did not fall below the pre-determined ‘normal’ blood passage time (≤ 44 sec), it appears that SCH has a sustained beneficial effect on blood fluidity. This ceiling of activity in reducing blood viscosity and no undesirable change in haematology, liver function indicators, lipid profiles and urine tests also infer safety for the consumption of sesamin-schisandra extract combination.

Various chinese medicinal herbs claim to increase blood circulation and combat “blood stasis” in humans [15] (Shen and Cui, 1998). Scientific research has substantiated the ability of several herbs to reduce blood viscosity, and in the case of the popular Ginko biloba, platelet aggregation [15]. Herbal combinations with demonstrated clinical effects in human subjects include ‘Pushen’ [16] and ‘Dahuang Zhechong Wan’ [17]. Another well-known natural remedy is garlic (Allium sativum), which exhibits blood viscosity reducing quality and is associated with a reduction in cholesterol levels, platelet aggregation and overall reduction in cardiovascular disease risk [18]. Kiesewetter and colleagues [19] discussed that improved blood fluidity attributed to garlic can increase capillary perfusion which can have a cleansing effect, contributing to ‘purification’ of the microcirculation.

In contrast to Gingko biloba and garlic, where a reduction in platelet aggregation and/or plasma lipids is the proposed mechanism for reducing blood viscosity, sesamin in combination with schisandra extract might work by an indirect route of enhancing liver metabolic functions. A recent DNA microarray study indicated that sesamin regulates the metabolism of lipids, xenobiotics, and alcohol at the mRNA level [20]. Moreover, several studies supported the liver protective efficacy of sesamin and schisandra extract [10,12,13]. In support of our hypothesis, Xie and colleagues [2] showed that a combination of 4 herbs including ‘Dang gui’ (Angelica Sinensis) and ‘Dan Shen’ (Salviae Miltiorrhizae) could improve blood circulation whilst reducing oxidative damage in mice with chronic liver damage. Together with the current data, this presents a link between liver protection and blood circulation.

Considering this is the first pilot clinical study on the combined efficacy and safety of sesamin and schisandra extract, and majority of data is derived from animal studies, it warrants further investigations to confirm the role of sesamin and schisandra extract in improving blood fluidity and flow. In conclusion, this study indicates that SCH can enhance blood fluidity without causing undesirable side effect.