薏苡種皮乙醇萃取物對子宮平滑肌收縮的影響

Abstract

原發型經痛為女性婦科疾病中相當常見的一種症狀，盛行率極高，對女性生活品質帶來相當大的影響。而經痛發生的原因主要被認為與經期時子宮內膜分泌過多的前列腺素 F2α（prostaglandin F2α, PGF2α）而刺激子宮平滑肌過度收縮有關。薏苡（Coix lachryma-jobi L. var. ma-yuen Stapf.）為禾本科一年生草本植物，自古即被認為是藥食兼用的材料，具消炎、止痛、抗痙攣等功效，然而許多傳統中醫藥典籍卻明確的記載著孕婦不宜食用的敘述。本研究室於先前研究中發現糙薏仁水萃物（dehulled adlay water extract, DAW）具促進懷孕母鼠子宮收縮的作用，薏苡殼甲醇萃取物（adlay hull methanolic extract, AHM）則可抑制大鼠子宮平滑肌收縮。因此，本研究以 PGF2α 刺激誘發子宮平滑肌過度收縮的模式來探討薏苡籽實乙醇萃取物是否具有改善子宮平滑肌過度收縮的效果，並尋找可能的活性物質。結果發現薏苡種皮乙醇萃取物（adlay testa ethanolic extract, ATE）最具抑制由 PGF2α 所誘發子宮平滑肌過度收縮之效果，麩皮及精白薏仁乙醇萃取物則未見有任何促進或抑制的效果。以 ATE 的區分層、次區分層篩選的結果為正丁醇層中的 C 層（ATE-Bu-C）及乙酸乙酯層的 D 層（ATE-EA-D）抑制由 PGF2α 所誘發子宮過度收縮的效果最佳，在 100 μg/mL 濃度下可藉由抑制細胞外鈣離子的流入而抑制平滑肌收縮。在人類子宮平滑肌細胞膜式（HUtSMCs）中，皆可見 ATE-Bu-C 和 ATE-EA-D（50 μg/mL）較控制組（PGF2α 刺激組）減少細胞內鈣離子濃度達 40% 以上。進一步利用高效能液相層析串聯質譜儀（HPLC-MS）定性樣品後所得的結果做活性分析，發現成分中的類黃酮（flavonoiods）具抑制子宮收縮的效果，其中又以槲皮素（quercetin）和異甘草素（isoliquiritigenin）的抑制效果最佳。本研究的結果顯示薏苡種皮乙醇萃取物具有改善由 PGF2α 所誘發子宮過度收縮的效果，似可發展為改善經痛的保健食品。

Primary dysmenorrhea is one of the common symptoms in gynecological diseases, and its high prevalence is related to the disruption in quality of female’s life. The cause of pain at the time of menses is believed to be due to the production of prostaglandin in the endometrium during ovulatory cycle. Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf.), a plant of the grass crop, has long been used in traditional Chinese medicine (TCM) and also used as a nourishing food. It has also been reported to exert antiphlogistic and anodynic effects. Nevertheless, some medical reports have also suggested that adlay seeds should not be used during pregnancy. Published results have indicated that the dehulled adlay water extract (DAW) are capable of enhancing uterine contraction. In contrast, adlay hull methanolic extract (AHM) showed inhibitory effect of uterine smooth muscle contraction. Thus, the purpose of this study is to understand the effects and the action mechanisms of adlay ethanolic extracts and to confirm which compounds could regulate PGF2α-induced uterine contractions. The results demonstrate that adlay testa ethanolic extract (ATE) have an inhibitory effect on PGF2α-induced uterine contractions in rats but adlay bran ethanolic extract (ABE) and polished adlay ethanolic extract (PAE) did not. ATE-Bu-C and ATE-EA-D (100 μg/mL), subfractions of ATE-Bu and ATE-EA, decreased contractions more significantly by blocking external calcium influx. In HUtSMCs model, ATE-Bu-C and ATE-EA-D (50 μg/mL) significantly reduce the intracellular calcium concentration over 40% than control group. Furthermore, on HPLC-MS based analysis was applied. The flavonoids were quantified and posses the great inhibitory effects on uterine contractions, especially quercetin and iosliquritigenin. These present findings show the ability of ATE to inhibit PGF2α-induced uterine contractions, and have the potential to be developed as a functional food targeting primary dysmenorrhea.