本文调查研究了虾青素单酯和二酯及总类胡萝卜素的抗癌作用以及虾青素对紫外7,12-二甲基苯并蒽诱导的小鼠皮肤癌的抵抗作用。当虾青素含量为200微克/千克（小鼠体重）时，虾青素单酯和二酯能够分别降低96% 和88%紫外7,12-二甲基苯并蒽诱导肿瘤的发生率，而虾青素和总类胡萝卜素可以降低66%及85%。已知紫外7,12-二甲基苯并蒽可以产生高浓度自由基及酪氨酸酶，从而导致皮肤色素沉着及肿瘤发生。令人惊奇的是虾青素单酯和二酯可以增加7倍左右的酪氨酸酶，降低10倍抗氧化水平，与之相对的是虾青素和总类胡萝卜素增加1.4倍左右的酪氨酸酶，降低2.2倍抗氧化水平。这些结果以及虾青素单酯和二酯处理可使动物血清中视黄醇达到72 ng/mL，虾青素处理可使动物血清中视黄醇达到58 ng/mL一起表明虾青素单酯和二酯在抗癌方面更有效。
Effective inhibition of skin cancer, tyrosinase, and antioxidative properties by astaxanthin and astaxanthin esters from the green alga Haematococcus pluvialis
Astaxanthin mono-(AXME) and diesters(AXDE) were characterized and examined for anticancer potency with total carotenoids(TC) and astaxanthin(AX) against UV-7,12-dimethylbenz(a)anthracene (DMBA)-induced skin cancer model in rat. At 200 μg/kg bw, AXDE and AXME reduced UV-DMBA-induced tumor incidences up to 96 and 88%, respectively, when compared to AX (66%) and TC (85%). UV-DMBA has been known to generate high levels of free radicals and tyrosinase enzyme, leading to characteristic symptoms of skin pigmentation and tumor initiation. Intriguingly, ~7-fold increase in tyrosinase and 10-fold decrease in antioxidant levels were normalized by AXDE and AXME as opposed to only ~1.4-2.2-fold by AX and TC, respectively. This result together with the appearance of 72 and 58 ng/mL of retinol in the serum of respective AXE-treated (AXDE + AXME) and AX-treated animals suggested that better anticancer potency of AXEs could be due to increased bioavailability.
J Agric Food Chem. 2013, 61(16):3842-3851.
Rao AR, Sindhuja HN, Dharmesh SM, Sankar KU, Sarada R, Ravishankar GA.
|
