Exploration of Anticancer Activity in Alpinia Intermedia Extracts from Taiwan

1. 山月桃之抗癌活性研究 • 薑科植物以月桃屬種類較多，其中台灣有26種，且14種為台灣原生種。而本研究採集8種台灣原生種之月桃屬植物葉部，分別以50%和95%的乙醇迴流萃取，並評估萃取物對數種癌和正常細胞株之毒性。其中以95%的山月桃萃取物對AGS, HeLa, HL-60和KB細胞株具有最強的抑制癌細胞生長，IC50分別為89.45、 76.82、29.92和 28.31 micro-g/mL。繼而比較山月桃之各部位活性，仍以葉部對各種癌細胞的抑制作用最強，且誘導HL-60凋亡，因此利用HL-60毒性追蹤分離山月桃葉部萃取物之抗癌活性成分。首先以正己烷和水作溶解分離，而正己烷劃分部對HL-60及P-388D1細胞的IC50 均約為17.34 micro-g/mL，比水層作用強，並且連續九天注射100 mg/kg 於P-388D1之CDF1擔癌鼠腹腔後，能夠有意義地延長其生命(ILS%=15 %)。因此，再利用矽膠管柱分離正己烷劃分部，結果得到了intermedins A、B及coronarin E三個labdane型之雙萜類，其產率分別為0.043, 0.009, 0.005 %。Intermedins A及B是屬於新穎型的化合物結構，其中intermedin A抑制HL-60和P-388D1之生長作用，並誘導其進行凋亡。體內抗癌活性試驗顯示intermedin A在2及20 mg/kg劑量下對P-388D1之CDF1擔癌鼠顯示劑量依存性的體內抗癌效力。綜合結論，推測intermedin A新穎型雙萜化合物可能成為開發抗癌藥物的前導物質。

2. The antitumor principle constituents of Alpinia intermedia Gagnep. • Eight kinds of Taiwanese native Zingiberaceae Alpinia plants were collected and extracted with 50% and 95% EtOH. The cytotoxic effect of these extracts was evaluated in several tumor and normal cell lines. Among the extracts, 95% EtOH extract of A. intermedia (A.I.) showed the strongest cytotoxicity on AGS, HeLa, HL-60 and KB cells. The IC50 values were 89.45, 76.82, 29.92, and 28.31 micro-g/mL, respectively. However, the leaves of A.I. showed stronger cytotoxic effect than root, stem, flower, or fruit of A.I., and the leaves extract induced apoptosis in HL-60 cell. Therefore, A.I. extracts were partitioned with n-hexane and H2O. The n-hexane layer (AIH) was more cytotoxic than aqueous layer, and the IC50 values were 17.34 micro-g/mL in both HL-60 and P-388D1 cells. Moreover, AIH could significantly prolong the survival days of P-388D1 bearing CDF1 mice treating with 100 mg/kg of AIH for 9 days. AIH was loaded on silica gel column and three diterpenoids were isolated, purified by a bioassay-guided method. Three structures were determined from MS and NMR spectrum, and two of the three compounds (intermedins A and B) are novel compounds. Among them, intermedin A showed the most significant cytotoxic effect in HL-60 and P-388D1 cell lines and induced apoptosis in these cells. Intermedin A tested (2 and 20mg/kg) also significantly prolonged the survival days of P-388D1 bearing CDF1 mice (ILS%: 26.67 and 40%). According to the above results, intermedin A might be a potential lead compound for anti-tumor drugs development in the future.