Differential inhibition of Scutellaria barbata D. Don (Lamiaceae) on HCG-promoted proliferation of cultured uterine leiomyomal and myometrial smooth muscle cells.

Scutellaria barbata D. Don (Lamiaceae)(SB) is a perennial herb which is natively distributed throughout Korea and southern China. This herb is known in traditional Chinese Medicine as Ban-Zhi-Lian and traditional Korean medicine as Banjiryun, respectively. SB has been used as an anti-inflammatory and antitumor agent. We aimed to determine the expressin of cell cycle-related signal molecules for growth inhibition after HCG treatment by the herb SB in two different human myometrial smooth muscle cells (SMCs) and leiomyomal SMCs. Water-soluble ingredients of SB, myometrial SMCs and the leiomyomal cell lines were used in vitro. Uterine myomas often enlarge rapidly during pregnancy, implying that human chorionic gonadotrophin (HCG) may influences cell proliferation in uterine leiomyomata. We investigated the effects of SB on the cell proliferation and the expression of cell cycle-related proteins in these cells. Although HCG/LH receptor was present in both cultured myometrial and leiomyomal cells, as assayed by reverse transcription polymerase chain reaction analysis, treatment with HCG significantly increased cell proliferation in both myometrial and leiomyomal cells. However, SB reduced the proliferative effect of HCG in leiomyoma and myometrial cells, respectively. In HCG-treated leiomyomal cells, the expression of proliferating cell nuclear antigen, cyclin E and cdc2 was significantly reduced by SB treatment. These results suggest that SB reduced the HCG-promoted proliferation of myometrial and leiomyomal cells.