薏苡殼萃取物在體外及體內試驗對於雄烯二酮分泌的影響

Abstract

雄烯二酮(androstenedione, AD)主要在腎上腺和卵巢生成，是女性合成睪固酮與雌激素的原料，若分泌不平衡便會產生失調。多囊性卵巢症候群(polycystic ovary syndrome, PCOS)是育齡婦女中常見的內分泌疾病，診斷標準為以下三項中至少有兩項：(1)寡排卵或不排卵、(2)臨床或生化指標有高雄性激素的表現與(3)卵巢呈現多囊性狀；同時因為持續的高雄性激素表現使得發生胰島素阻抗、第二型糖尿病、子宮內膜癌的機率增加。文獻指出薏苡(Coix lachryma-jobi L. var. ma-yuen Stapf)殼(adlay hull, AH)甲醇萃取物(AH methanolic extract, AHM)可抑制雌性大鼠雌二醇的分泌，且降低雄性大鼠的睪固酮生成。本研究以人類絨毛膜促性腺激素(human chorionic gonadotropin, hCG)誘發卵巢初代包膜細胞(theca cell, TC)過量分泌雄烯二酮模式評估薏苡籽實萃取物之抑制活性，進而以動物模式驗證，並篩選有效次區分物與有效化合物。結果顯示，薏苡殼乙醇萃取物(AH ethanolic extract, AHE)具顯著抑制效果，其中以乙酸乙酯區分層(ethyl acetate fraction of AHE, AHE-EA)活性最佳，且可降低PCOS模式動物血清中雄烯二酮含量、禁食血糖與血清胰島素，同時改善卵巢中的氧化壓力；而其次區分物中以AHE-EA-H抑制活性最佳。利用液相層析串聯質譜(liquid chromatography-mass spectrum-mass spectrum, LC-MS-MS)比對此層所得物質進行確效，證實化合物3號、4號、5號、6號和9號在hCG的刺激下具有抑制雄烯二酮的效果；這五個化合物皆可視為有效成分，其中化合物4號在100 μM處理下可抑制82.7%的雄烯二酮分泌，可做為薏苡籽實中調節雄烯二酮分泌的指標物質。

Androstenedione (AD) is mainly synthesized in adrenal glands and ovaries, which is precursors of testosterone and estrogen in women, while imbalance secretion of AD leads to dysfunction of endocrine system. Polycystic ovary syndrome (PCOS) commonly occurs in childbearing women, and the diagnostic criteria include at least 2 subjects with following 3 events: (1) oligo-ovulation or anovulation; (2) hyperandrogenism clinically or in biomarkers; and (3) polycystic ovaries. Preceding high expression of androgens increase the risks of insulin resistance, type 2 diabetes, and endometrial cancer. Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) hull (AH) methanolic extract (AHM) was reported to suppress estradiol release from female rats and decrease level of testosterone in male ones. In the present investigation, the inhibitory effects of extracts from adlay seeds on AD secreted from human chorionic gonadotropin (hCG)-stimulated primary rat theca cell (TC). Further, the effective extracts in vitro were verified in vivo, and the active sub-fractions and effective components were elucidated. Results demonstrated that AH ethanolic extract (AHE) possessed significantly inhibitory capacity, and ethyl acetate fraction from AHE (AHE-EA) showed superior activity, which lowered the levels of serum AD, fasting blood glucose, and serum insulin; meanwhile the oxidative stress in ovaries was improved in PCOS animal model. H-sub-fraction from AHE-EA showed most favorable inhibitory potential in vitro, and was analyzed by liquid chromatography (LC)-mass spectrum (MS)-MS. Compounds 3, 4, 5, 6, and 9 significantly suppressed AD release in vitro among them, 4 inhibited 82.7% of AD at 100 μM, and may be regarded as indicator in adlay seeds on modulation of AD secretion.