Interactions of herbal constituents influences the effects of STW 5 on inflammatory processes and disturbed motility

The herbal drug STW 5 (Iberogast®) contains nine individual plant extracts which affect inflammatory processes and disturbed motility in the gut.

The aim of this study was to investigate the effect of individual constituents as well as selected combinations on different parameters related to inflammatory processes.

STW 5, STW 5-II (a combination containing only 6 of the 9 extracts) and lemon balm reduced LPS (10 ng/ml)-induced lactate dehydrogenase (LDH) release from CaCo-2 cells by 74 – 75%. Iberis amara, peppermint, chamomile, angelica and milk thistle inhibited this parameter by 25 – 37%. Liquorice, caraway and celandine had no effect. The combinations of Iberis amara and peppermint as well as peppermint and milk thistle revealed synergistic or additive effects, whereas the combination of chamomile and angelica evoked additive or antagonistic effects depending on their compositions (i.e. relative ratios of individual extracts).

STW 5, STW 5-II, Iberis amara, peppermint, liquorice, caraway, milk thistle and lemon balm inhibited LPS (100 ng/ml)-induced TNFa release from THP-1 cells to 51 – 67%. Chamomile and angelica revealed a more potent effect. The combinations of Iberis amara and peppermint as well as chamomile and liquorice had additive or antagonistic effects depending on their compositions.

STW 5 and STW 5-II reduced the acetylcholine (ACh)-induced contractions in rat ileum preparations to 81 – 83%. The individual components inhibited the contractions to 83 – 91% excepting lemon balm which had no effect. The combinations of Iberis amara and peppermint as well as liquorice and caraway had additive or antagonistic effects depending on their compositions.

Taken together our results allow greater insight into the interactions between individual herbal constituents of STW 5 and confirm the concept of multi-target actions.