A Systematic Review of the Uterine Relaxant Effect of Herbal Sources.

BACKGROUND: Preterm birth is a worldwide tragedy with a high incidence. Several medications are used to inhibit acute preterm labor, but tocolysis by these medicines do not extend pregnancy beyond 1-2 days. OBJECTIVES: The purpose of this study was to discover new medications from plant extracts or their active compounds which inhibit the uterine contractions in order to treat preterm labor. DATA SOURCES: PubMed, Google Scholar, Scopus and IranMedex databases were searched up to 1st February 2012 with the most relevant keywords. STUDY SELECTION: All studies in which plant extracts or their active compounds inhibited the uterine contractions both in vivo and in vitro were included. THE RESULTS: Of initial search, 259 records were reviewed and finally 72 were included among which only 31 studies isolated an active compound from the plants extract belonging mostly to classes of flavonoids and terpenes classes. Flavonoids have been known as a phosphodiesterase (PDE) and a protein kinase C (PKC) inhibitor. It seems that the uterolytic activity of reviewed flavonoids such as naringenin, kaempferol and quercetin, especially in a calcium free solution, was via these inhibitory pathways. CONCLUSION: Laboring uterus response to dissimilar tocolytics differs from that of non-laboring uterus. In order to find a treatment for preterm labor, future studies should focus on the laboring uterus and also determine the structure activity relationship of the different tocolytics. This systematic review was registered to the PROSPERO with code number CRD42015027551.

A systematic review of the uterine relaxant effect of herbal sources.

BACKGROUND: Preterm birth is a worldwide tragedy with a high incidence. Several medications are used to inhibit acute preterm labor, but tocolysis by these medicines do not extend pregnancy beyond 1-2 days. OBJECTIVES: The purpose of this study was to discover new medications from plant extracts or their active compounds which inhibit the uterine contractions in order to treat preterm labor. DATA SOURCES: PubMed, Google Scholar, Scopus and IranMedex databases were searched up to 1st February 2012 with the most relevant keywords. STUDY SELECTION: All studies in which plant extracts or their active compounds inhibited the uterine contractions both in vivo and in vitro were included. THE RESULTS: Of initial search, 259 records were reviewed and finally 72 were included among which only 31 studies isolated an active compound from the plants extract belonging mostly to classes of flavonoids and terpenes classes. Flavonoids have been known as a phosphodiesterase (PDE) and a protein kinase C (PKC) inhibitor. It seems that the uterolytic activity of reviewed flavonoids such as naringenin, kaempferol and quercetin, especially in a calcium free solution, was via these inhibitory pathways. CONCLUSION: Laboring uterus response to dissimilar tocolytics differs from that of non-laboring uterus. In order to find a treatment for preterm labor, future studies should focus on the laboring uterus and also determine the structure activity relationship of the different tocolytics. This systematic review was registered to the PROSPERO with code number CRD42015027551.

A systematic review of the uterine relaxant effect of potassium channel openers.

Despite significant advances in the understanding of uterine physiology, preterm labor is still a predicament with a high incidence. The mechanism that triggers uterine contraction is currently unclear. ATP-sensitive potassium (KATP) channel stimulation has an inhibitory effect on uterine contractile pursuit through hyperpolarization of myometrial cells where KATP channels openers (KCOs) act as a tocolytic. In this review, studies that report the effects of KCOs on the contractile activity of the myometrium have been collected and evaluated. All electronic databases were searched up to 1(st)December 2012 with the most relevant keywords. Studies related to the effect of KCOs on the human or animal myometrium both in vivo and in vitro were included. Of initial search, 45 records were reviewed and finally, 23 were included. All of these studies found that KCOs have an inhibitory effect on the myometrium contractions, but different sample size and inconsistencies in reporting the effects make the absolute judgment about efficacy of these compounds too difficult. Of course, we can state that the inhibitory effects of KCOs were greater in myometrium of non-labor group. Conclusion is that although some positive effects are expected, yet further placebo-controlled studies are needed to reach a consensus.

A review of the herbal phosphodiesterase inhibitors; future perspective of new drugs.

Phosphodiesterase inhibitors (PDEIs) are a class of drugs that are widely used because of their various pharmacological properties including cardiotonic, vasodilator, smooth muscle relaxant, antidepressant, antithrombotic, bronchodilator, antiinflammatory and enhancer of cognitive function. In the recent years, interest in drugs of plant origin has been progressively increased. Some pharmacologically active substances that come from plants demonstrate PDEI activity. They mainly belong to alkaloids, flavonoids, and saponins. In this review, studies on herbal PDEI were reviewed and their possible therapeutic applications were discussed. Screening plants for PDE inhibitory activity may help to develop standardized phytotherapeutic products or find new sources for new lead structures with PDEI pharmacological activity. The studies discussed in this paper are mainly in vitro and for more reasonable and conclusive results, it is required to conduct in vivo and finally human and clinical tests.