Joint action of herbal components influence the effects of STW 5 on inflammatory processes and disturbed motility

STW 5 (Iberogast®) contains nine herbal extracts affecting inflammatory processes and disturbed motility in the gut. The aim of the study was to investigate the effect of individual ethanolic extracts (in concentration used in STW 5) and selected combinations on targets related to inflammation. Cytotoxicity was examined in CaCo-2 cells using the lactate dehydrogenase (LDH) assay. THP-1 cells were used to determine TNFα release using an ELISA. ACh-induced contractions of rat ileum preparations were measured in an organ bath setup. STW 5 (500 µg/ml), STW 5-II (5.1 µg/ml, containing only 6 of the 9 extracts) and lemon balm (59.9 µg/ml) reduced LPS (10 ng/ml)-induced LDH leakage from CaCo-2 cells by 74 – 75%. Iberis amara (29.1 µg/ml), peppermint (38.9 µg/ml), chamomile (116.3 µg/ml), angelica (84.7 µg/ml) and milk thistle (15.2 µg/ml) inhibited LDH leakage by 25 – 37%. Liquorice (84.9 µg/ml), caraway (30.9 µg/ml) and celandine (61.9 µg/ml) 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. STW 5, STW 5-II, Iberis amara, peppermint, liquorice, caraway, milk thistle and lemon balm in concentration used in the LDH assay inhibited LPS (100 ng/ml)-induced TNFα release to 51 – 67%. 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 extracts inhibited the contractions to 83 – 91% except lemon balm. The combination of Iberis amara and peppermint as well as liquorice and caraway had additive or antagonistic effects depending on the ratios. Our results highlighted the interactions between the extracts of STW 5 and confirm the concept of multi-target actions.

Keywords: Iberogast, Cytotoxixity, TNF-alpha, CaCo-2 cells, THP-1 cells, synergy, drug interaction