| 摘要: | 茉莉花，學名: Jasminum sambac (L.) Ait.，是茉莉花茶的重要成分，於民間療法及中醫傳統藥典上記載著有養顏美容，清熱，解毒等功效。茉莉花茶是世界各地常見的飲品。然而，只有少數研究工作報導茉莉花的營養保健作用。先前的研究顯示茉莉花富含抗氧化物質，酚類化合物及類黃酮化合物等，具有抗氧化，抑制尿酸等功效。隨著健康意識的提升，人們對於身體健康日常保健的方法逐漸提高了關注，因此方便且有保健功效的飲食、泡茶（茉莉花茶），漸漸地步入大眾的眼裡。在本研究中，借鑒民間與傳統所使用的方法，製備了茉莉花水萃取物（WEJF）和茉莉花乙醇萃取物（EEJF），然後進行生化特性和酶抑制活性的測定（黃嘌呤氧化酶抑制試驗）來探索其營養作用。結果顯示WEJF和EEJF的總酚含量分別為545.0 ± 32.7 mg GAE/g和601.3 ± 68.9 mg GAE/g，WEJF和EEJF的總黃酮含量分別為8.8 ± 0.4 μg QE/g和18.3 ± 1.1 μg QE/g。在抗氧化能力方面，WEJF和EEJF對DPPH自由基清除能力的EC50分別為5.2 ± 0.8 mg/ml和3.1 ± 0.2 mg/ml。結果顯示WEJF和EEJF的總酚類和總黃酮含量較高，但沒有表現出較高的自由基清除能力，這意味著這些抗氧化成分應該發揮另一種抗氧化作用。在總還原力測定中，發現 WEJF 和 EEJF 具有還原力，K值分別為 0.25 ± 0.02 A·ml/mg和0.38 ± 0.06 A·ml/mg。在α-葡萄糖苷酶抑制試驗中，EEJF的IC50為36.07 ± 29.28 mg/ml, 而WEJF的IC50為272.59 ± 25.54 mg/ml。在黃嘌呤氧化酶抑制試驗中，WEJF顯示IC50為36.07 ± 29.28 mg/ml，這結果顯示在飲用茉莉花茶後對降低體內血糖和尿酸的作用很小。在酪胺酸酶抑制試驗中，發現WEJF和EEJF對酪胺酸酶具有抑制活性，IC50分別為176.35 ± 25.54 mg/ml 和11.63 ± 29.28 mg/ml，顯示EEJF具有比WEJF更好的美白效果（酪胺酸酶抑制性測定）和更高的黃酮含量，這與之前的報導一致，即很多黃酮具有對酪胺酸酶的抑制活性；但粗萃取的EEJF用量對於實際應用來說仍然過高，需要對活性成分進行純化和濃縮。將樣品進行微波消化後進行ICP-MS分析試驗，結果顯示茉莉花粉末樣品、WEJF和EEJF的汞、砷、鉛、鎘皆低於國家安全標準的規範，因此本實驗的茉莉花樣品是符合中藥材安全規範的。
Jasmine flower is an important component in the Jasmine tea, which is a common drink around the world. However, only few research works have addressed its nutraceutical effects. In this study, water extracts of jasmine flower (WEJF) and ethanol extracts of jasmine flower (EEJF) were prepared, and then biochemical characterization and enzyme inhibitory assays were used to explore its nutraceutical effects. Results showed that the content of total phenolics for WEJF and EEJF were 545.0 ± 32.7 mg GAE/g and 601.3 ± 68.9 mg GAE/g, respectively, and the content of total flavonoids for WEJF and EEJF were 8.8 ± 0.4 μg QE/g and 18.3 ± 1.1 μg QE/g, respectively. In terms of antioxidant capacity, DPPH free radical scavenging ability of EC50 was showed to be 5.22 ± 0.81 mg/ml and 3.09 ± 0.16 mg/ml for WEJF and EEJF, respectively. Results showed that WEJF and EEJF have high content of total phenolic and total flavonoid but did not show a high free radical scavenging ability, which implied these antioxidant components should play another kind of antioxidant effects. In the total reducing power assay, WEJF and EEJF were found to possess reducing power with K value of 0.25 ± 0.02 A·ml/mg and 0.38 ± 0.06 A·ml/mg, respectively. In the α-glucosidase inhibitory assay, EEJF showed IC50 of 36.07 ± 29.28 mg/mL and WEJF showed IC50 of 272.59 ± 25.54 mg/ml. In the xanthine oxidase inhibitory assay, WEJF showed IC50 of 36.07 ± 29.28 mg/ml, while EEJF showed no inhibitory effect. It suggested that only has light effects in reducing blood sugar and uric acid in the body after drinking Jasmine tea. In the tyrosinase inhibitory assay, WEJF and EEJF were found to possess inhibitory activity against tyrosinase with IC50 of 176.35 ± 25.54 mg/ml and 11.63 ± 29.28 mg/ml, respectively. EEJF was found to have better whitening effects (inhibitory assay of tyrosinase) and higher content of flavonoids than water extracts, which agreed with previous reports that a lot of flavonoids possessed inhibitory activity against tyrosinase; however, the crude EEJF amount is relatively high for practical applications, thus its active ingredients need to be refined and concentrated. ICP-MS analysis of WEJF and EEJF after treating them by microwave digestion showed that the contents of Hg, Cd, Pb and As in jasmine flower powder, WEJF and EEJF were lower than the national standard of safety and quality, so the jasmine samples in this experiment were in line with the safety standards of traditional Chinese medicines. |
