Since contractility of the uterus appears to be the major source of
pain during dysmenorrhoea, alleviation of the contractions is believed to be a possible treatment strategy.
Bak Foong Pills, a traditional Chinese formulation for use in gynaecological disorders, has long been thought as effective in the treatment of dysmenorrhoeal symptoms. The present study thus aims to investigate whether
ethanol extract of
Bak Foong Pills (
BFP-Ex) or its constituent herbs may have direct effects on alleviating dysmenorrhoeal symptoms by altering uterine tone. This was investigated using isolated uterine preparations and intracellular messenger analysis of
adenylate cyclase, via [(3)H]-
adenine assay, and
calcium, with fluorometry imaging, in myometrial cultures.
BFP-Ex can stimulate uterine relaxation following
oxytocin-induced contractions ex-vivo. Attempted inhibition of
BFP-Ex's relaxatory response with a
nitric oxide inhibitor and
adenylate cyclase inhibitor, however, had no significant effect, suggesting that most of
BFP-Ex's relaxatory response was not due to increases in NO or cAMP. Further studies on
tetramethylpyrazine (
TMP), a major active ingredient of
BFP-Ex, indicated that
TMP could modulate intracellular
calcium levels in favour of uteri relaxation. The ability of
Bak Foong Pills to alleviate
menstrual pain may be due to direct regulation of uterine tone.