香櫞與佛手柑精油揮發性成分與其抗氧化能力之研究

Determination of Volatile Components and Antioxidative Capacity of Essential Oils Extracted from the Medicinal Citron and Fingered Citron

葉湘裕(Hsiang-Yu Yeh) ； 楊楷民(Kai-Ming Yang) ； 鄭明清(Ming-Ching Cheng) ； 程國恩(Guo-En Cheng) ； 林麗雲(Li-Yun Lin)

《臺灣農業化學與食品科學》 49卷2期 (2011/04) Pp. 74-81

https://doi.org/10.6578/TJACFS.2011.010

摘要

柑橘水果自古即與人類的生活有著密切的關係，香櫞(Medicinal citron; MC)與佛手柑(Fingered citron; FC)同為Citrus medica L之水果，由於原生種(MC)及突變種(FC)之間特性差異微小常令人無法辨識。本研究以水蒸汽蒸餾法抽取香櫞與佛手柑之精油，分析兩者精油揮發性成分組成及其抗氧化能力，以了解彼此差異。以GC及GC/MS分析鑑定精油組成，於佛手柑精油中共鑑定出25種揮發性化合物，包含11種單萜烯、七種倍半萜烯、五種萜烯醇與二種萜烯醛；於香櫞精油中則鑑定出42種揮發性化合物，包含12種單萜烯、14種倍半萜烯、八種萜烯醇、三種萜烯醛、三種萜烯酯、一種萜烯酮與一種其他化合物，兩者精油主要化合物皆為limonene及γ-terpinene。兩種精油在抗氧化能力的表現上，顯示品種之差異並不影響其清除DPPH自由基能力或總抗氧化能力，但發現佛手柑精油於清除DPPH自由基能力上，會因成熟度的增加而減少其清除能力（由1.90下降至0.84 mg Trolox/mL），而香櫞則未有此現象。經管柱層析後之正戊烷及乙醚的區分物，其抗氧化能力皆能明顯增加，其中又以乙醚區分物的提升幅度最大（二－四倍），顯示精油經管柱層析後可能會增加有效物質的濃度而明顯提升其抗氧化能力。

關鍵字

香櫞 ； 佛手柑 ； 精油 ； 揮發性成分 ； 抗氧化能力

並列摘要

Medicinal citron (MC) and Fingered citron (FC) belong to Citrus medica L. Thus, the relation seems quite close. In this study, we extracted the essential oils from MC and FC using a steam distillation method and analyzed the volatile components and antioxidative capacity to understand their difference. By means of GC and GC/MS analyses, we found that the essential oil extracted from FC contains 25 compounds which include 11 kinds of monoterpenoids, 7 kinds of sesquiterpenoids, 5 kinds of alcohols and 2 kinds of aldehydes. Forty-two compounds were identified in the essential oil from MC which include 12 kinds of monoterpenoids, 14 kinds of sesquiterpenoids, 8 kinds of alcohols and 3 kinds of aldehydes. The research has shown that the main compounds of essential oils extracted from both MC and FC are limonene and γ-terpinene. The evaluation of the DPPH (1,1-diphenyl-2-picrylhydrazyl radical) free radical scavenging capability, TEAC (Trolox-equivalent antioxidant capacity), and anti-oxidative capability showed no difference between FC and MC. We also found that the higher degree of maturity of FC, the lower antioixdative capacity of its essential oil. No such phenomenon was observed for the essential oil of MC. The essential oils are separated with ether and pentane by silica gel column chromatography. The ether fractionate of essential oils revealed increasing antioxidative capability compared to crude essential oils. The results of this study approved that silica gel chromatography may increase the anti-oxidative capacity of the essential oils extracted from MC and FC.

並列關鍵字

Medicinal citron ； Fingered citron ； Essential oils ； Volatile components ； Antioxidative capability