本論文的目的，在探討桑最具美白活性成份的藥材部位及最理想的萃取條件，並探討桑的萃出物對黑色素生成的抑制活性及相關的細胞生理機轉。本論文中，是利用桑葉、桑枝粉、桑枝片、嫩桑枝、半熟桑椹等五種為材料，以95%酒精、80%酒精、50%酒精、20%酒精、水等五種不同濃度的溶劑進行微波萃取，並將製備出來的萃出物，進行對黑色素生成抑制作用的評估，評估的項目有：(一)桑萃出物對蘑菇酪胺酸酶的抑制率及IC50；(二) 對B-16 黑色素瘤細胞上清液中黑色素的抑制率；(三) 對B-16 黑色素瘤細胞溶解物中黑色素的抑制率;(四) 對細胞溶解物中酵素活性的影響；(五)以細胞電子顯微鏡觀察萃出物對B-16 黑色素瘤細胞作用後的抑制情形。實驗結果顯示，桑葉、桑枝粉、桑枝片、嫩桑枝、半熟桑椹的各種萃出物，皆可對蘑菇酪胺酸酶的活性產生不同程度的抑制，其中又以桑枝粉及桑枝片的萃出物抑制效果最好，且抑制作用會隨著萃出物投與濃度的增加而增加，而所求出的IC50，以桑枝粉的80%酒精萃出物的IC50 為2.3μg∕mL最佳。桑枝粉及桑枝片80%酒精的萃出物，亦對B-16 黑色素瘤細胞上清液中的黑色素有較佳的抑制率，其抑制率也會隨著萃出物所投與濃度的增加而增加。B-16黑色素瘤細胞內黑色素生合成的量，也同樣會受到桑枝粉及桑枝片80%酒精的萃出物的抑制。
研究結果顯示，桑最具美白活性成份的藥材部位是桑的粗枝，桑的粗枝經過乾燥、磨粉後，以80%酒精浸泡一小時後，微波萃取六分鐘，可萃得有效抑制黑色素生成的萃出物，以該萃出物進行B-16 黑色素瘤細胞的抑制實驗時，並沒有細胞毒性的產生。
由於桑是一種在亞洲及臺灣已普遍種植、栽培容易且成本低廉的一種植物，期野憎荅銃i一步，以此模式開發出具有安全性、有效性、低成本、無污染的美白原料。 The objective of this research is to investigate the different parts of the mulberry which contains the best potential skin-whitening components and the best extractive conditions. It is also to investigate the inhibitory effects of mulberry extracts on melanogenesis and relative mechanism on cell biology. This research used mulberry's leaves, branch powders, branch sections, young twigs and half ripe fruits as materials. Materials used microwaved with 95% alcohol ; 80% alcohol ; 50% alcohol ; 20% alcohol and water as solvents to extract. These extracts were evaluated based on inhibitory effects on melanogenesis. The evaluated items are : (1) The percentage inhibition of mushroom tyrosinase activity and IC50 , (2) The percentage inhibition of melanin in B-16 melanoma cell supernatant, (3) The percentage inhibition of melanin in B-16 melanoma cell lysate, (4) The cell lysate of enzyme activity (5)The extracts inhibitory effects on B-16 melanoma cells examined under electronic microscope. The results showed all of the various mulberry's leaves‚ branch powders‚ branch sections‚ young twigs‚ half ripe fruits extracts could exert distinctive potency on inhibition of mushroom tyrosinase activity. Among these extracts, both mulberry's branch powders extracts and branch sections extracts showed the best potent inhibition activity and a dose-dependent inhibitory effect on mushroom tyrosinase activity. We determined the effect of these extracts on mushroom tyrosinase inhibition by IC50 . The 80% alcohol extracts of the mulberry's branch powders showed the best IC50 was 2.3μg∕mL. Both the 80% alcohol extracts of the mulberry's branch powders and the 80% alcohol extracts of the mulberry's branch sections showed the best potent inhibition activity and a dose-dependent inhibition percentage of melanin in B-16 melanoma cell supernatant, too. The synthesis of melanin in B-16 melanoma cells was also inhibited by the 80% alcohol extracts of the mulberry's branch powders and the 80% alcohol extracts of the mulberry's branch sections.
The results showed the mulberry's branch content has the best potential skin-whitening components. The mulberry's branch to be treated with the dry and abrasive procedure. To immerse the mulberry's branch powders in the 80% alcohol for one hour. After that use microwave to extract for 6 minutes to get the potent inhibitory effects activity of mulberry extracts on melanogenesis. The extracts showed no cytotoxicity when treated for B-16 melanoma cells . The mulberry is common and easy to plant in Asia and Taiwan and is inexpensive. The results are encouraging and deserve further advanced application to develop and discover the skin-whitening ingredients which have proven to be secure, effective, inexpensive with no contamination.
