王三煒 謝言青 周志宏 劉 錄
云南云中營養(yǎng)與健康研究院/云南中醫(yī)藥大學(xué),云南 昆明 650500
沉香葉是瑞香科植物白木香Aquilariasinensis(Lour.)Gilg含有樹脂木材沉香的葉子,也稱為白木香葉[1]。沉香葉一年采收兩季,來源廣,資源較為豐富。沉香葉作為非藥用部位,往往被丟棄,一方面造成沉香資源的浪費(fèi),另一方面葉對環(huán)境產(chǎn)生了一定的破壞,如何能夠有效利用沉香葉成為了一個(gè)新的研究熱點(diǎn)。
沉香葉中含有黃酮、三萜、揮發(fā)油、苷類、醌類等多種化學(xué)成分[2];現(xiàn)代藥理研究表明,沉香葉具有抗炎[3]、鎮(zhèn)痛[4]、抗菌[5]、降糖[6]等生物活性。然而,目前有關(guān)沉香葉的化學(xué)成分研究較少,為了進(jìn)一步挖掘沉香葉中的化學(xué)成分,本文利用現(xiàn)代分離技術(shù)對沉香葉醇提物進(jìn)行了提取分離,并對分離得到的化合物進(jìn)行了結(jié)構(gòu)鑒定,從中得到18個(gè)化合物,在一定程度上為沉香葉的進(jìn)一步研究奠定了基礎(chǔ),也為沉香的資源開發(fā)利用提供了理論依據(jù)。
ESI-MS和HRESI-MS由API QSTAR Pular-1型質(zhì)譜儀上測定;核磁共振譜[1H-NMR、13C-NMR]用Brucker AM-400、DRX-500或BRUKER AV Ⅲ 600型超導(dǎo)核磁共振儀測定;所用試劑為氘代試劑;高效液相HPLC為Agilent 1600 液相色譜;半制備柱為Ultimate XB-C18(10 mm×250 mm,5 μm)、柱材料為RP-18和硅膠(80目、200目);旋轉(zhuǎn)蒸發(fā)儀;暗箱三用紫外分析儀;電子天平;電熱鼓風(fēng)干燥箱;青島譜科化工有限公司薄層色譜硅膠板;Sephadex LH-20為Mistsubishi Co,Ltd生產(chǎn)(25~100 μm);顯色劑10%硫酸-乙醇溶液。
沉香葉藥材購買于昆明市螺螄灣藥材市場,由云南中醫(yī)藥大學(xué)劉錄教授鑒定為瑞香科植物、沉香屬白木香[Aquilariasinensis(Lour.)Gilg ]的葉。
取沉香葉粉末3.5 kg,用11倍量的70%乙醇回流提取3次,每次3 h,收集兩次濾液、減壓蒸餾得到沉香葉浸膏480 g。
480 g沉香葉浸膏分別用乙酸乙酯、石油醚各萃取7~9次,收集萃取液,對各部分進(jìn)行減壓濃縮,得到石油醚相150.0 g、乙酸乙酯相 120.0 g。
取乙酸乙酯相 120.0 g,經(jīng)硅膠柱層析,用氯仿-甲醇(60∶1~10∶1)作為流動(dòng)相進(jìn)行反復(fù)洗脫,,得到4個(gè)餾分,A(18.6 g)、B(19.1 g)、C(17.4 g)、D(45.8 g)。組分A用硅膠柱(160~200目)進(jìn)行分離,以石油醚-丙酮(15∶1~2∶1)為洗脫劑反復(fù)洗脫分離純化,得到化合物1(1.40 g)、2(1.48 g)、3(537 mg)和A-1(7.9 g);組分A-1先以石油醚-丙酮(20∶1~5∶1)為洗脫劑進(jìn)行洗脫,再經(jīng)過HPLC純化,流動(dòng)相為甲醇-水(85∶15),得到化合物4(122 mg)、5(103 mg)、6(57 mg)、7(73 mg)。組分B用硅膠柱進(jìn)行分離,以石油醚-乙酸乙酯(25∶1~15∶1)為洗脫劑進(jìn)行梯度洗脫,得到8(63 mg)、9(56 mg)、10(47 mg)和組分B-1(6.7 g),組分B-1先經(jīng)過100%甲醇Sephadex LH-20柱色譜后、再經(jīng)過HPLC(90%甲醇)分離純化,得到11(34 mg)、12(28 mg)、13(36 mg)、14(30 mg)。組分C以石油醚:乙酸乙酯(15∶1~1∶1)為流動(dòng)相進(jìn)行硅膠柱層析,再用HPLC(75%甲醇)純化得到15(12 mg)、16(22 mg)、17(17 mg)、18(15 mg)。
化合物1白色粉末(CHCl3),分子式:C30H52O。1H-NMR (600 MHz,CDCl3)δ:5.36 (1H,brd,J=4.8 Hz,H-6),3.53(1H,tq,J=9.6,4.8 Hz,H-3),1.02 (3H,d,J= 7.9 Hz,H-21),0.93 (3H,d,J= 6.4 Hz,H-29),0.86 (3H,d,J= 6.9 Hz,H-27),0.84 (3H,s,H-19),0.82 (3H,d,J= 6.9 Hz,H-26),0.69 (3H,s,H-18);13C-NMR (150 MHz,CDCl3)δ:140.7 (C-5),121.6 (C-6),71.7 (C-3),56.7 (C-14),56.0 (C-17),50.0 (C-9),45.7 (C-24),42.2 (C-13),42.2 (C-4),39.7 (C-12),37.2 (C-1),36.4 (C-10),36.1 (C-20),33.8 (C-22),31.8 (C-2),31.8 (C-8),31.6 (C-7),29.6 (C-23),29.0 (C-25),28.2 (C-16),26.0 (C-23a),24.2 (C-15),23.0 (C-28),21.0 (C-11),19.7 (C-27),19.3 (C-19),19.1 (C-26),18.7 (C-21),12.1 (C-29),11.8 (C-18)。以上數(shù)據(jù)與文獻(xiàn)[7]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物1為Homostigmast-5-en-3β-ol。
化合物2白色粉末(CHCl3),分子式:C30H52O。1H-NMR (600 MHz,CDCl3)δ:3.74 (1H,brd,J= 2.8 Hz,H-3),1.91 (1H,dt,J= 9.6,2.7 Hz,H-2a),1.74 (1H,dt,J= 13.1,3.3 Hz,H-6a),1.16,1.01,0.99,0.99,0.97,0.95 and 0.87 (each 3H,s,H-24~30),0.95 (3H,d,J= 7.6 Hz,H-23);13C-NMR (150 MHz,CDCl3)δ:72.6 (C-3),61.2 (C-10),53.1 (C-8),49.1 (C-4),42.7 (C-18),41.6 (C-6),39.6 (C-14),39.2 (C-22),38.3 (C-9),37.7 (C-13),37.2 (C-5),36.2 (C-16),35.7 (C-19),35.5 (C-11),35.4 (C-2),35.2 (C-29),32.8 (C-21),32.3 (C-15),32.4 (C-30),31.7 (C-28),30.8 (C-12),30.2 (C-17),28.4 (C-20),20.3 (C-27),18.6 (C-26),18.4 (C-25),17.5 (C-7),16.5 (C-24),15.7 (C-1),11.6 (C-23)。以上數(shù)據(jù)與文獻(xiàn)[8]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物2為表木栓醇。
化合物3白色粉末(CHCl3),分子式:C30H52O。1H-NMR (600 MHz,CDCl3)δ:2.38 (1H,m,H-2a),2.32~2.24 (2H,m,H-2b,H-4),1.96 (1H,m,H-1a),1.76 (1H,m,H-6a),1.66 (1H,m,H-1b),1.19,1.06,1.02,1.01,0.96,0.88 and 0.73 (each 3H,s,H-22~30),0.87 (3H,d,J= 6.9 Hz,H-23);13C-NMR (150 MHz,CDCl3)δ:213.4 (C-3),59.6 (C-10),58.3 (C-4),53.2 (C-8),42.7 (C-18),42.3 (C-5),41.6 (C-2),41.4 (C-6),39.8 (C-13),39.4 (C-22),38.4 (C-14),37.5 (C-9),36.2 (C-16),35.7 (C-11),35.4 (C-19),35.2 (C-29),32.7 (C-21),32.3 (C-15),32.2 (C-28),31.7 (C-30),30.6 (C-12),30.2 (C-17),28.4 (C-20),22.4 (C-1),20.4 (C-26),18.8 (C-27),18.3 (C-7),18.1 (C-25),14.9 (C-24),6.7 (C-23)。以上數(shù)據(jù)與文獻(xiàn)[9]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物3為木栓酮。
化合物4白色粉末(CHCl3),分子式:C30H52O。1H-NMR (600 MHz,CDCl3)δ:5.32 (1H,s,H-7),4.85,4.68 (1H,s,H-29a,29b),2.76 (1H,td,J= 14.5,5.6 Hz,H-2a),1.11,1.05,1.03,1.01 and 0.83 (each 3H,s,H-18,19,30~32),1.06 (9H,s,H-26~28),0.92 (3H,d,J= 6.5 Hz,H-21);13C-NMR (150 MHz,CDCl3)δ:217.1 (C-3),159.1 (C-24),146.1 (C-8),117.7 (C-7),105.7 (C-29),53.1 (C-17),52.5 (C-5),51.3 (C-14),48.6 (C-9),47.8 (C-4),43.6 (C-13),38.5 (C-1),36.6 (C-20),36.4 (C-25),36.3 (C-2),35.1 (C-22),35.1 (C-10),34.2 (C-15),33.8 (C-12),29.5 (C-26~28),28.4 (C-11),28.4 (C-16),27.6 (C-32),24.7 (C-31),24.5 (C-6),22.1 (C-18),21.5 (C-30),18.56 (C-21),18.4 (C-23),12.7 (C-19)。以上數(shù)據(jù)與文獻(xiàn)[10]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物4為wallenone。
化合物5白色粉末(CHCl3),分子式:C30H52O。1H-NMR (600 MHz,CDCl3)δ:0.56 (1H,d,J= 4.0 Hz,H-19),0.76 (1H,d,J= 4.0 Hz,H-19),0.85 (3H,d,J= 8.0 Hz,21-CH3),0.87 (3H,s,30-CH3),0.96 (3H,s,18-CH3),0.98 (3H,s,31-CH3),1.02 (3H,s,32-CH3),1.04 (3H,s,28-CH3),1.08 (3H,s,29- CH3),1.65 (3H,s,27-CH3),2.26 (1H,m,H-2b),2.67 (1H,m,H-2a),4.64 (1H,brs,H-26),4.68 (1H,brs,H-26);13C-NMR (150 MHz,CDCl3)δ:217.1 (C-3),152.5 (C-25),109.4 (C-26),52.2 (C-17),50.4 (C-4),48.6 (C-14),48.6 (C-5),47.8 (C-8),38.6 (C-24),37.6 (C-23),37.5 (C-2),36.7 (C-20),35.7 (C-12),33.6 (C-1),32.7 (C-15),30.6 (C-22),29.7 (C-19),28.2 (C-7),27.7 (C-32),27.4 (C-3),26.6 (C-16),26.1 (C-10),25.8 (C-11),22.3 (C-28),21.2 (C-9),21.6 (C-6),20.7 (C-29)。以上數(shù)據(jù)與文獻(xiàn)[11]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物5為cyclobalanone。
化合物6白色粉末(CHCl3),分子式C30H50O2。1H-NMR (600 MHz,CDCl3)δ:0.78 (s,3H),0.97 (s,3H),1.01 (s,3H),1.03 (s,3H),1.08 (s,3H),1.17 (s,3H).13C-NMR (150 MHz,CDCl3)δ:39.5 (C-1),34.1 (C-2),218.1 (C-3),47.3 (C-4),54.8 (C-5),19.7 (C-6),32.6 (C-7),41.9 (C-8),50.0 (C-9),36.8 (C-10),21.5 (C-11),24.1 (C-12),49.6 (C-13),41.6 (C-14),34.4 (C-15),21.9 (C-16),53.9 (C-17),44.0 (C-18),41.2 (C-19),26.5 (C-20),51.0 (C-21),73.9 (C-22),26.5 (C-23),21.1 (C-24),15.7 (C-25),16.4 (C-26),16.8 (C-27),16.2 (C-28),28.7 (C-29),30.8 (C-30)。以上與文獻(xiàn)[12]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物6為羥基何帕酮。
化合物7經(jīng)石油醚-醋酸乙酯(4∶1)、石油醚-丙酮(12∶1)、二氯甲烷-醋酸乙酯(50∶1)與對照品β-谷甾醇3個(gè)體系對比Rf值和顯色之后,故鑒定化合物7為β-谷甾醇。
化合物8淡黃色粉末(CHCl3),分子式C17H14O6。1H-NMR (600 MHz,CDCl3)δ:12.77 (1H,s,5-OH),7.48 (1H,dd,J= 8.3,2.0 Hz,H-6’),7.34 (1H,d,J= 2.0 Hz,H-2’),7.04 (1H,d,J= 8.4 Hz,H-5’),6.58 (1H,s,H-3),6.48 (1H,d,J= 2.3 Hz,H-8),6.38 (1H,d,J= 2.3 Hz,H-6),4.01 (3H,s,3’-OCH3),3.87 (3H,s,7-OCH3);13C-NMR (150 MHz,CDCl3)δ:182.7 (C-4),165.7 (C-7),164.3 (C-2),162.4 (C-5),157.7 (C-8a),149.5 (C-4’),147.1 (C-3’),123.2 (C-1’),120.8 (C-6’),115.3 (C-5’),108.6 (C-2’),105.6 (C-4a),104.5 (C-3),98.3 (C-6),92.7 (C-8),56.5 (3’-OCH3),56.1 (7-OCH3)。以上與文獻(xiàn)[13]報(bào)道數(shù)據(jù)一致,故鑒定化合物8為5,3’-二羥基-7,4’-二甲氧基黃酮。
化合物9淡黃色粉末(CHCl3),分子式:C18H16O6。1H-NMR (600 MHz,CDCl3)δ:12.81 (1H,s,OH),7.54 (1H,dd,J= 8.5,2.1 Hz,H-6’),7.36 (1H,d,J= 2.1 Hz,H-2’),6.97 (1H,d,J= 8.5 Hz,H-5’),6.58 (1H,s,H-3),6.51 (1H,d,J= 2.2 Hz,H-8),6.37 (1H,d,J= 2.2 Hz,H-6),3.99 (3H,s,7-OCH3),3.98 (3H,s,4’-OCH3),3.87 (3H,s,3’-OCH3);13C-NMR (250 MHz,CDCl3)δ:182.5 (C-4),165.4 (C-2),164.1 (C-7),162.3 (C-8a),152.4 (C-3’),149.4 (C-4’),123.7 (C-1’),120.2 (C-6’),111.3 (C-5’),108.7 (C-2’),105.7 (C-4a),104.6 (C-3),98.2 (C-6),92.8 (C-8),56.2 (3’-OCH3,4’-OCH3),55.9 (7-OCH3)。以上與文獻(xiàn)[14]報(bào)道數(shù)據(jù)一致,故鑒定化合物9為木犀草素-7,3’,4’-三甲醚。
化合物10淡黃色粉末(CHCl3),分子式:C17H14O6。1H-NMR (600 MHz,CDCl3)δ:12.97 (1H,s,-OH),10.04 (1H,brs,-OH),7.58 (2H,overlapped,H-2,6),6.94 (2H,overlapped,H-3,5),6.77 (1H,d,J= 0.8 Hz,H-8),6.35(1H,d,J=1.2 Hz,H-6),3.88 (3H,s,-OCH3),3.87 (3H,s,-OCH3);13C-NMR (75 MHz,CDCl3)δ:181.8 (C=O),165.1 (C-7),163.8 (C-2),161.2 (C-5),157.2 (C-9),150.7 (C-4),148.1 (C-3),121.3 (C-1),120.5 (C-6),115.6(C-5),110.2 (C-2),104.7 (C-10),103.3 (C-3),97.8 (C-6),92.7 (C-8),56.1 (-OCH3),55.8 (-OCH3)。以上與文獻(xiàn)[15]報(bào)道數(shù)據(jù)一致,故鑒定化合物10為 5,4’-二羥基-7,3’-二甲氧基黃酮。
化合物11淡黃色粉末(CHCl3),分子式:C17H14O6。1H-NMR (600 MHz,CDCl3)δ:12.96 (1H,s,-OH),7.95 (2H,d,J= 8.8 Hz,H-2’,6’),6.96(2H,d,J= 8.8 Hz,H-3’,5),6.83 (1H,s,H-3),6.74 (1H,d,J= 2.1 Hz,H-8),6.36 (1H,d,J= 2.1 Hz,H-6),3.86 (3H,s,-OCH3);以上與文獻(xiàn)[16]報(bào)道數(shù)據(jù)一致,故鑒定化合物11為芫花素。
化合物12淡黃色粉末(CHCl3),分子式:C17H16O5。1H-NMR (600 MHz,CDCl3)δ:12.83 (1H,s,4’-OH),7.86 (2H,d,J= 8.8 Hz,H-2’,6’),7.07 (2H,d,J= 8.6 Hz,H-3’,5’),6.57 (1H,s,H-3),6.48 (1H,d,J= 2.2 Hz,H-8),6.38 (1H,d,J= 2.2 Hz,H-6),3.91 (3H,s,7-OCH3),3.88(3H,s,5-OCH3);13C-NMR (151 MHz,CDCl3)δ:196.2 (C-4),168.0 (C-7),164.2 (C-2),162.8(C-4’),156.4(C-8a),127.8 (C-2’,C-6’),115.8(C-3’,C-5’),103.2 (C-3),95.2 (C-6),94.3 (C-8),55.8 (7-OCH3),50.8 (5-OCH3),43.3 (C-3)。以上與文獻(xiàn)[17]報(bào)道數(shù)據(jù)一致,故鑒定化合物12為5,7-二甲氧基-4’-羥基二氫黃酮。
化合物13淡黃色粉末(CHCl3),分子式:C17H14O5。1H-NMR (600 MHz,CDCl3)δ:7.86 (2H,d,J= 8.9 Hz,H-2’,6’),7.03 (2H,d,J= 8.9 Hz,H-3’,5’),6.59 (1H,s,H-3),6.49 (1H,d,J= 2.2 Hz,H-8),6.38 (1H,d,J= 2.2 Hz,H-6),3.91 (3H,s,7-OCH3),3.89(3H,s,4’-OCH3);13C-NMR (250 MHz,CDCl3)δ:182.6 (C-4),165.5 (C-7),164.1 (C-2),162.7 (C-5),162.3 (C-4’ ),157.8 (C-8a),128.2 (C-2’,C-6’),123.7 (C-1’),114.6 (C-3’,C-5’),106.7 (C-4a),104.5 (C-3),98.1 (C-6),92.7 (C-8),55.9 (7-OCH3),55.7 (4’-OCH3)。以上與文獻(xiàn)[18]報(bào)道數(shù)據(jù)一致,故鑒定化合物13為洋芹素-7,4’-二甲醚。
化合物14淡黃色粉末(CHCl3),分子式:C17H14O5。1H-NMR (600 MHz,CDCl3)δ:12.83 (1H,s,4’-OH),7.86 (2H,d,J= 8.8 Hz,H-2’,6’),7.08 (2H,d,J= 8.6 Hz,H-3’,5’),6.57(1H,s,H-3),6.48(1H,d,J= 2.2 Hz,H-8),6.38 (1H,d,J= 2.2 Hz,H-6),3.91 (3H,s,7-OCH3),3.88 (3H,s,5-OCH3);13C-NMR (250 MHz,CDCl3)δ:182.6 (C-4),165.5 (C-7),164.1 (C-2),162.7 (C-4’),162.3 (C-5),157.8 (C-8a),128.2 (C-2’,C-6’),123.7 (C-1’),114.6 (C-3’,C-5’),105.7 (C-4a),104.5 (C-3),98.1 (C-6),92.7 (C-8),55.6 (5-OCH3),55.7 (7-OCH3)。以上與文獻(xiàn)[19]報(bào)道數(shù)據(jù)一致,故鑒定化合物14為4’-羥基-5,7-二甲氧基黃酮。
化合物15無色無定形粉末(CHCl3),分子式:C26H22O8。1H-NMR (400 MHz,CD3COCD3)δ:6.69 (4H,s,H-2’,6’,2’’,6’’),4.68 (2H,d,J=3.8 Hz,H-4,8),4.24 (2H,m,H-2a,6a),3.86 (2H,m,H-2b,6b),3.83 (12H,s,4-OCH3),3.11 (2H,m,H-1,5);13C-NMR (100 MHz,CD3COCD3)δ:147.7 (C-3’,5’,3’’,5’’),135.4 (C-4’,4’’),132.4 (C-1’,1’’),103.7 (C-2’,6’,2’’,6’’),85.8 (C-4,8),71.6 (C-2,6),55.7 (OCH3),54.5 (C-1,5)。以上與文獻(xiàn)[20]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物15為丁香脂素。
化合物16黃色無定形粉末(CHCl3),分子式:C8H8O4。1H-NMR (600 MHz,CDCl3)δ:5.78 (2H,s,Ar-H),3.74 (6H,s,1-OCH3,6-OCH3);13C-NMR (150MHz,CDCl3)δ:186.8 (C-4),176.6 (C-1),157.4 (C-2,6),107.5 (C-3,5),56.6 (2-OCH3,6-OCH3)。以上與文獻(xiàn)[21]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物16為 2,6-二甲氧基對苯醌。
化合物17黃色無定形粉末(CHCl3),分子式:C8H8O4。1H-NMR (400 MHz,CDCl3)δ:5.87 (2H,s,H-3,6),3.83 (6H,s,2×OCH3);13C-NMR (100 MHz,CDCl3)δ:186.8 (C-1,4),157.7 (C-2,5),107.5 (C-3,6),56.8 (OCH3)。以上與文獻(xiàn)[22]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物17為2,5-二甲氧基對苯醌。
化合物18無色無定形粉末(CHCl3),分子式:C9H12O3。1H-NMR (600 MHz,CDCl3)δ:5.87 (3H,s,Ar-H),3.87(9H,s,1-OCH3,3-OCH3,5-OCH3);13C-NMR (CDCl3,125MHz)δ:157.4 (C-1,3,5),107.5 (C-2,4,6),56.6 (1-OCH3,3-OCH3,5-OCH3)。以上與文獻(xiàn)[23]報(bào)道數(shù)據(jù)基本一致,故鑒定化合物18為1,3,5-三甲氧基苯。
本文對沉香葉醇提物的化學(xué)成分進(jìn)行了研究,利用現(xiàn)代分離技術(shù)和波譜解析方法,從沉香葉乙醇提取物中共分離得到18個(gè)化合物并對其進(jìn)行了結(jié)構(gòu)鑒定,分別為7個(gè)三萜類化合物、7個(gè)黃酮類化合物、2個(gè)醌類化合物和1個(gè)倍半萜類化合物,并且首次從瑞香科沉香屬植物中發(fā)現(xiàn)了homostigmast-5-en-3β-ol(1)、wallenone(4)、cyclobalanone(5)、這3個(gè)三萜類化合物和5,7-二甲氧基-4’-羥基二氫黃酮(12)、4-羥基-5,7-二甲氧基黃酮(14)這2個(gè)黃酮類化合物。本實(shí)驗(yàn)對這18個(gè)化合物進(jìn)行了細(xì)胞毒性實(shí)驗(yàn)研究,結(jié)果顯示18個(gè)化合物均未表現(xiàn)出細(xì)胞毒性,此外查閱文獻(xiàn)發(fā)現(xiàn),化合物2[24]、化合物3[25]、化合物4[26]、化合物7[24]、化合物11[27]均表現(xiàn)出了良好的鎮(zhèn)痛抗炎活性,
查閱文獻(xiàn)可知,沉香葉中主要的化學(xué)成分為黃酮類和三萜類化合物[28-29],本實(shí)驗(yàn)結(jié)果也表明沉香葉中含有大量的黃酮和三萜類成分。通過本實(shí)驗(yàn)對沉香葉的化學(xué)成分進(jìn)行的研究,進(jìn)一步挖掘了沉香葉的物質(zhì)基礎(chǔ),為沉香葉關(guān)于抗炎鎮(zhèn)痛的藥用價(jià)值提供依據(jù),也為沉香葉的開發(fā)利用提供了理論依據(jù)。