dinoprost and benzyl-isothiocyanate

The present study examines the effect of benzyl isothiocyanate (BITC) on uterine contraction in vitro. BITC (10-320 microM) caused irreversible, concentration-dependent inhibition of the spontaneous, prostaglandin F(2alpha) (PGF(2alpha)) and oxytocin-induced force of gravid and non-gravid rat uterine contractions in contrast to equivalent concentrations of DMSO (solvent control). At 160 microM of BITC, spontaneous, PGF(2alpha) and oxytocin-induced force of gravid rat myometrial contractions were reduced to 16 +/- 6%, 15 +/- 7 % and 17 +/- 4% (of the control contractions), respectively. Moreover, at 320 microM of BITC, spontaneous, PGF(2alpha) and oxytocin-induced force of non-gravid rat uterine contractions were reduced to 10+/-5 %, 4+/-1 % and 7+/-2 % (of the control contractions), respectively. Incubation of isolated non-gravid rat uterine strips in Ringer Locke solution containing 100 microM of BITC for 1h prior to recording their activity also caused significant and irreversible depression of KCl (60mM)-induced tension development in the uterus relative to the solvent control (P < 0.01). In 56% of BITC-pretreated uterine tissues, spontaneous contractions were totally abolished. Cryosections of BITC-treated uterus (hematoxyline and eosin stained) examined under light microscope revealed structural disintegrity with marked vacuolar degeneration of the endometrium and myometrium. It thus appears that like the vascular smooth muscle (reported by previous workers), BITC is also capable of causing functional aberration of isolated uterus by provoking degeneration of the myometrium.

Topics: Animals; Dimethyl Sulfoxide; Dinoprost; Dose-Response Relationship, Drug; Female; Isothiocyanates; Male; Muscle, Smooth; Myometrium; Oxytocin; Potassium Chloride; Pregnancy; Pregnancy, Animal; Rats; Rats, Sprague-Dawley; Uterine Contraction

Carica papaya L. seeds extracted with 80% ethanol (EEPS) caused concentration-dependent tocolysis of uterine strips isolated from gravid and non-gravid rats. Prostaglandin F2alpha and oxytocin-induced contractions of the isolated rat uterus were also inhibited in a concentration-dependent fashion by EEPS. Recoveries of the uterine activity after EEPS-induced uterine quiescence were very weak. Higher concentration of EEPS caused prompt uterine quiescence, which was also significantly irreversible. Pre-incubation of the rat uterus in Ringer Locke solution containing 10 mg/ml of EEPS for 1 hour prior to suspension in tissue baths led to significant depression of the spontaneous and KCl (60 mM)-induced uterine contractions relative to the solvent control (P<0.05). Cross sections of EEPS-pretreated non-gravid rat uterus (stained with hematoxyline and eosin) examined under light microscope revealed degeneration of the endometrium and myometrium with obvious cytoplasmic vacuolation indicating that EEPS could have direct toxic effect on the uterine tissues. Previous workers have reported benzyl isothiocyanate (BITC) as the main bioactive and anthelmintic compound in different extracts of papaya seeds. Using electron impact ionization methods, the presence of BITC in EEPS was also shown in this study. Mass spectra of both EEPS and standard BITC showed a base peak of benzyl/tropylium ion at m/z 91 (indicative of an aromatic compound) and the molecular ion peak of BITC (m/z 149). Our earlier studies have demonstrated BITC-induced functional and morphological derangement of isolated uterus. We thus conclude that at high concentration, EEPS is capable of causing irreversible uterine tocolysis probably due to the damaging effect of BITC (its chief phytochemical) on the myometrium.

Topics: Animals; Carica; Dinoprost; Female; In Vitro Techniques; Isothiocyanates; Male; Mass Spectrometry; Plant Extracts; Pregnancy; Rats; Rats, Sprague-Dawley; Seeds; Tocolytic Agents; Uterus