植物工廠內不同非生物逆境對黃花蜜菜生成三種二次代謝物之影響

Abstract

黃花蜜菜 (Wedelia chinensis) 含有三種酚類二次代謝物可以發揮協同作用，抑制前列腺癌細胞的生長，分別為蟛蜞菊內酯 (wedelolactone)、木犀草素 (luteolin) 與芹菜素 (apigenin)。目前黃花蜜菜皆栽種於田間或溫室，其二次代謝物的含量會受戶外環境影響而無法穩定生產，且栽培過程容易受到農藥污染。 本研究旨在探討於植物工廠中運用不同非生物逆境處對黃花蜜菜生成二次代謝物的影響，以建立黃花蜜菜二次代謝物在植物工廠中的量產模式。本研究之試驗皆在全環境控制的植物工廠進行，採完全隨機設計，於黃花蜜菜扦插栽培28天後進行不同的非生物逆境處理，包含不同光質 (FL、FL+UVA、FL+UVB、FL+FR、8R1B、4R5B與1R8B)、缺水逆境與缺肥逆境，並在逆境處理7天後與35天後採收，分析植株的鮮重、乾重與蟛蜞菊內酯、木犀草素、芹菜素的含量，計算各處理組的二次代謝物產能，並建立具備抑制前列腺癌細胞的黃花蜜菜萃取物之綜效指標，以量化評估生產出的黃花蜜菜實際應用於治療的效果。 結果顯示，UV光、藍光、缺水逆境處理皆可以提升黃花蜜菜的木犀草素與芹菜素含量，其中以UVB光的效果最為顯著(木犀草素含量為51.85 µg mL-1與芹菜素含量為28.33 µg mL-1)，但是對於蟛蜞菊內酯的含量 (低於檢量極限) 則無顯著影響；缺肥逆境35天可以提高黃花蜜菜的蟛蜞菊內酯含量 (9.85 µg mL-1)，但木犀草素含量 (15.84 µg mL-1) 與芹菜素含量 (0.85 µg mL-1) 會下降。以二次代謝物產能的表現上來看，相較於溫室的栽培方式，植物工廠中以白光搭配UVB光逆境處理35天可以提升木犀草素產能6倍與芹菜素產能21倍，缺肥逆境35天可以提升蟛蜞菊內酯產能3.2倍。比較具備抑制前列腺癌細胞的黃花蜜菜萃取物之綜效指標，植物工廠中以白光搭配UVB光逆境處理35天的綜效指標為溫室栽培的8-12倍。本研究證明了植物工廠穩態量產黃花蜜菜的二次代謝物之可行性，也制訂出相關的栽培程序，以供栽種業者作為參考。

Wedelia chinensis contains three secondary metabolites called wedelolactone, luteolin and apigenin, which have synergistic effect on inhibiting the growth of prostate cancer cells. Nowadays, Wedelia chinensis is all cultivated in field or in greenhouses. Hence, the outdoor environment will affect the content of the secondary metabolites of Wedelia chinensis and make the production unstable. Besides, it is readily contaminated by pesticide. To construct the model of mass production of the three secondary metabolites of Wedelia chinensis in plant factory, the study focused on the effect of different abiotic stresses on the production of secondary metabolites of Wedelia chinensis in plant factory. The study was conducted in the fully-environmental- controlled plant factory and under completely randomized design. At 28 days after cutting, the plants were treated with different abiotic stresses, including different light qualities (FL, FL+UVA, FL+UVB, FL+FR, 8R1B, 4R5B, 1R8B), water stress and nutrient-deficiency stress, harvested after 7 and 35 days of stress treatment respectively. The fresh weight, dry weight, and the content of wedelolactone, luteolin, apigenin of the samples were analyzed. Each treatment of production capacity of the secondary metabolites was calculated. To quantify and evaluate the effect of the plant in practical application on medical treatment, this study established a comprehensive index of the extract that can inhibit prostate cancer cells. The results showed that UV light, blue light, and water stress could increase the content of luteolin and apigenin, and the effect of UVB light was the most significant (luteolin 51.85 µg mL-1, apigenin 28.33 µg mL-1), but theses stresses had no significant effect on the content of wedelolactone (not detectable). Nutrient-deficiency stress for 35 days could increase the content of wedelolactone (9.85 µg mL-1), but the content of luteolin (15.84 µg mL-1) and apigenin (0.85 µg mL-1) decreased. From the view of the production capacity of the secondary metabolites, compared to the cultivation in greenhouse, white light with UVB light treatment for 35 days in plant factory could increase the production of luteolin and apigenin by 6 times and 21 times respectively, and nutrient-deficiency stress for 35 days could increase the production capacity of wedelolactone by 3.2 times. Besides, the comprehensive index of 35 days of white light with UVB light stress treatment for 35 days in plant factory was 8-12 times higher than the index of cultivation in greenhouse. Demonstrating the feasibility of mass production of the secondary metabolites of Wedelia chinensis in plant factory, this study also established the cultivation procedures for industrial reference.