恆春楊梅根部化學成分及生物活性之研究

恆春楊梅(Myrica adenophora Hance)為楊梅科(Myricaceae)植物，為一常綠灌木，分布於中國大陸與台灣南部和東部地區灌叢地區。對近1,500種台灣產之植物進行活性篩選，發現恆春楊梅根部具有抗結核、抗氧化及抗發炎活性，且恆春楊梅的根部未曾有天然物分離研究及其相關活性之研究。因此，本研究之目的為針對恆春楊梅根部進行化學成分及生物活性之探討。利用活性導向試驗，恆春楊梅根部乙酸乙酯層萃取物分離得到七個新化合物包含：三個新的A-type proanthocyanidins: adenodimerins A‒C (1‒3)；兩個新的esters of sucrose: myricadenins A‒B (4, 5)；一個新的phenolic glycoside: adenomyrin (6)及一個新的flavonoid: myrichromanone (7)，伴隨24個已知化合物: myricanone (8)、5-deoxymyricanone (9)、myricannin C (10)、porson (11)、12-hydroxymyricanone (12)、myricannin D (13)、myricanone 5-O-β-D-glucopyranoside (14)、(R)-(‒)-myricanol (15)、11-O-β-D-xylopyranosylmyricanol (16)、(‒)-myricanol 5-O-β-D-glucopyranoside (17)、(R)-4-(5-hydroxy-7-(4-hydroxyphenyl)heptyl)-2-methoxyphenol (18)、(+)-galeon (19)、actinidione (20)、myricanene A 5-O-α-L-arabinofuranosyl(1→6)-β-D-glucopyranoside (21)， myricitrin (22) 、quercitrin (23)、myricetin (24)、myricalactone (25)、3β-trans-p-coumaroyloxy-2α,23-dihydroxyolean-12-en-28-oic acid (26)、chebuloside I (27)、arjunolic acid (28)、taraxerol (29) 、gallic acid (30)、β-sitosterol (31)。以上化合物之構造皆以光譜分析決定。活性實驗中，化合物9、15、19具有抗結核活性，MIC值分別為25.8、30.0、15.0 μg/mL。化合物2、8、10、15、17、22、23、24具有抗氧化活性，ABTS radicals scavenging之SC50值分別為7.5、19.6、12.0、22.3、19.6、9.9、13.9、15.6 μg/mL。化合物8、10、15具有抗發炎活性(iNOS assay)其EC50值分別為0.98、13.01、7.50 μM。

關鍵字

恆春楊梅；楊梅屬；抗結核；抗氧化；抗發炎

並列摘要

Myrica adenophora Hance (Myricaceae) is a small tree, distributed in China and Taiwan. In Taiwan, it grows in thickets at low altitudes in the southern and eastern parts of the island. Approximately over 1,500 species of Formosan plants have been screened for anti-tubercular, anti-oxidant, and anti-inflammatory activity. The methanolic extract of the root of this plant showed potent anti-tubercular, antioxidant, and anti-inflammatory activities. The aims of this study are the isolation of chemical constituents and their biological activities from the root of this species. Bioassay-guided fractionation of active ethyl acetate-soluble layer from the root of this species led to the isolation of 31 compounds, including three new A-type proanthocyanidins: adenodimerin A‒C　(1‒3), two new esters of sucrose: myricadenin A‒B (4, 5), a new phenolic glycoside: adenomyrin (6), a new flavonoid: myrichromanone (7), along with 24 known compounds including myricanone (8), 5-deoxymyricanone (9), myricannin C (10), porson (11), 12-hydroxymyricanone (12), myricannin D (13), myricanone 5-O-β-D-glucopyranoside (14), (R)-(‒)-myricanol (15), 11-O-β-D-xylopyranosyl-myricanol (16), (‒)-myricanol 5-O-β-D-glucopyranoside (17), (R)-4-(5-hydroxy-7-(4-hydroxyphenyl)heptyl)-2-methoxyphenol (18), (+)-galeon (19), actinidione (20), myricanene A 5-O-α-L-arabinofuranosyl(1→6)-β-D-glucopyranoside (21), myricitrin (22), quercitrin (23), myricetin (24), myricalactone (25), 3β-trans-p-coumaroyloxy-2α,23-dihydroxyolean-12-en-28-oic acid (26), chebuloside I (27), arjunolic acid (28), taraxerol (29) , gallic acid (30), β-sitosterol (31). The structures of these isolates were elucidated by spectral analysis. Among the isolates, compounds 9, 15, and 19 exhibited anti-tubercular activity with the MICs values of 25.8, 30.0, and 15.0 μg/mL against Mycobacterium tuberculosis H37Rv in vitro, respectively. Compounds 2, 8, 10, 15, 17, 22, 23, and 24 exhibited anti-oxidant activity with the SC50 values of ABTS radicals scavenging 7.5, 19.6, 12.0, 22.3, 19.6, 9.9, 13.9, and 15.6 μg/mL, respectively. Compounds 8, 10, and 15 exhibited anti-inflammatory activity in the iNOS assay with the EC50 values of 0.98, 13.01, and 7.50 μM, respectively.