Department of Pharmaceutical and Applied Chemistry, University of Siena, 53100 Siena, Italy.
J Photochem Photobiol B. 2010 Dec 2;101(3):355-61. doi: 10.1016/j.jphotobiol.2010.08.008. Epub 2010 Aug 25.
Carotenoids are a group of phytochemicals that are recognized as playing an important role in the prevention of several degenerative diseases due to their antioxidant activity. The low water-solubility and poor photostability of β-carotene, a potentially important dietary antioxidant, prompted us to investigate β-carotene complexes able to increase its water solubility as well as its photostability in aqueous solution. In this work we have used humic acid in order to synthesize β-carotene-humic acid complexes in different ratios. Complexes were characterized by FT-IR and DSC. β-Carotene determination were performed by HPLC and antioxidant activity of β-carotene, humic acid and the complexes were determined by the TEAC method. The formulation β-carotene-humic acid 2:1 showed the highest photostability and water solubility. The antioxidant activity of the complexes was about 20 times lower than "free" β-carotene, suggesting a decreased chemical reactivity of the carotenoid in the complex. We showed that complexation of β-carotene with humic acids was able to increase its water solubility and photostability, and to affect the antioxidant activity of β-carotene after inclusion in HAs. This work provides a useful tool to avoid antioxidants photodegradation and oxidation by radicals, thus maintaining their biological activity.
类胡萝卜素是一类植物化学物质，由于其抗氧化活性，被认为在预防几种退行性疾病方面发挥着重要作用。β-胡萝卜素是一种潜在的重要膳食抗氧化剂，但它的水溶性低，光稳定性差，这促使我们研究能够提高其水溶性和光稳定性的β-胡萝卜素复合物。在这项工作中，我们使用腐殖酸来合成不同比例的β-胡萝卜素-腐殖酸复合物。通过傅里叶变换红外光谱（FT-IR）和差示扫描量热法（DSC）对复合物进行了表征。通过高效液相色谱（HPLC）测定了β-胡萝卜素的含量，并用 TEAC 法测定了β-胡萝卜素、腐殖酸和复合物的抗氧化活性。β-胡萝卜素-腐殖酸 2:1 的配方表现出最高的光稳定性和水溶性。复合物的抗氧化活性比“游离”β-胡萝卜素低约 20 倍，这表明在复合物中，类胡萝卜素的化学反应性降低。我们表明，β-胡萝卜素与腐殖酸的络合能够提高其水溶性和光稳定性，并影响 HAs 中包含的β-胡萝卜素的抗氧化活性。这项工作为避免抗氧化剂的光降解和自由基氧化提供了有用的工具，从而保持其生物活性。
