Kim Moo-Sung, Cho Hong-Bum
R&D Center, Macrocare Tech Ltd, Ochang, Republic of Korea.
J Microbiol. 2007 Dec;45(6):578-82.
The primary objective of this study was to assess the in vitro melanogenesis inhibitory effects of methanolic extracts of the edible and medicinal lichens, Umbilicaria (Gyrophora) esculenta and Usnea longissima. The quantities of the total phenolic compounds of methanolic extract of the two lichen extracts were determined to be 1.46% and 2.62%, respectively. In order to evaluate the antioxidative effects of the extracts, we also measured electron donating abilities (EDA) and lipid peroxidation rates. The EDA values measured by the reduction of 1.1''-diphenyl-2-picrylhydrazyl (DPPH) were 72.8% and 80.7% for the extracts, with SC50 (median scavenging concentration) values of 1.29+/-0.05 mg/ml and 1.03+/-0.06 mg/ml, respectively. The rates of inhibition of lipid peroxidation using linoleic acid were 92.1% and 97.3% for the extracts, with IC50 (median inhibitory concentration) values of 0.57+/-0.05 mg/ml and 0.53+/-0.06 mg/ml, respectively. The inhibitory rates of the extracts against tyrosinase were 67.4% and 84.8%, respectively. The extracts were shown to reduce melanin formation in human melanoma cells. Melanin contents in the samples treated with 0.01% and 0.1% U. esculenta were 47.1% and 31.2%, respectively, and those treated with 0.01% and 0.1% Usnea longissima were 51.1% and 34.9%, respectively, whereas a value of 54.0% was registered when ascorbic acid was utilized as a positive control. In addition to direct tyrosinase inhibition, it was determined that the lichen extracts affected the activity of tyrosinase via the inhibition of tyrosinase glycosylation. As a result, the methanolic extracts of U. esculenta and Usnea longissima evidenced melanogenesis inhibitory effects, which occurred via multiple routes.
本研究的主要目的是评估食用和药用地衣脐衣（石耳属）和长松萝甲醇提取物的体外黑色素生成抑制作用。两种地衣提取物甲醇提取物中总酚类化合物的含量分别测定为1.46%和2.62%。为了评估提取物的抗氧化作用，我们还测量了供电子能力（EDA）和脂质过氧化率。通过1,1'-二苯基-2-苦基肼（DPPH）还原测定的提取物的EDA值分别为72.8%和80.7%，SC50（半数清除浓度）值分别为1.29±0.05mg/ml和1.03±0.06mg/ml。使用亚油酸的脂质过氧化抑制率分别为92.1%和97.3%，IC50（半数抑制浓度）值分别为0.57±0.05mg/ml和0.53±0.06mg/ml。提取物对酪氨酸酶的抑制率分别为67.4%和84.8%。提取物显示可减少人黑色素瘤细胞中的黑色素形成。用0.01%和0.1%石耳处理的样品中的黑色素含量分别为47.1%和31.2%，用0.01%和0.1%长松萝处理的样品中的黑色素含量分别为51.1%和34.9%，而当使用抗坏血酸作为阳性对照时，该值为54.0%。除了直接抑制酪氨酸酶外，还确定地衣提取物通过抑制酪氨酸酶糖基化影响酪氨酸酶的活性。结果，石耳和长松萝的甲醇提取物通过多种途径证明了黑色素生成抑制作用。
