Immunomodulation mediated by a herbal syrup containing astandardized Echinacea root extract: A pilot study in healthy humansubjects on cytokine gene expression

In this study, the immunomodulatory effect of a triply standardized Echinacea angustifolia root extract(Polinacea®) was evaluated in 10 healthy subjects. Ten ml of syrup containing one hundred mg of extract(corresponding to 4.7 mg of Echinacoside and 8.0 mg of a high molecular weight-20,000 Da- polysaccha-ride) were administered as a herbal syrup once a day for one month. The immunomodulatory effect wasevaluated before and after herbal syrup administration evaluating the expression levels of the cytokinesIL-2, IL-8, IL-6 and TNF- . Cytokine expression was studied in lympho-monocytes and in plasma sam-ples measuring the mRNA and protein levels, respectively. The results were analysed by ANOVA andnon-parametric Friedman rank sum tests; when possible it was adopted a pair-wise comparisons at dif-ferent post-treatment times, using the paired t-tests with Holm correction. The correlation between thevariations of cytokine plasma levels and the respective mRNA was carried out using a linear regressionmodel.In lympho-monocytes our data indicate the up-regulation of the mRNA levels of IL-2 and IL-8 and thedown regulation of the mRNA levels of the pro-inflammatory cytokines TNF- and IL6. The differentialregulation was maximal after 14 days of treatment. IL-2 up-regulation and IL-6 down-regulation werealso confirmed at the protein level in plasma. Finally, the up-regulation of the mRNA of IL-2/IL-8 and thedown-regulation of IL-6 positively correlated with the protein levels detected in the plasma.In conclusion, this pilot study suggests a relevant role for the standardized Echinacea angustifolia rootextract in the control of cytokine expression. This first demonstration of the immuno-modulating activityof Echinacea angustifolia root extract in the healthy subject, supports at least in part the common use ofsuch products as health promoting supplement.