Johra Fatima Tuj, Bepari Asim Kumar, Bristy Anika Tabassum, Reza Hasan Mahmud
Department of Pharmaceutical Sciences, School of Health and Life Sciences, North South University, Bashundhara R/A, Dhaka 1229, Bangladesh.
Antioxidants (Basel). 2020 Oct 26;9(11):1046. doi: 10.3390/antiox9111046.
Carotenoids are natural lipid-soluble antioxidants abundantly found as colorful pigments in fruits and vegetables. At least 600 carotenoids occur naturally, although about 20 of them, including β-carotene, α-carotene, lycopene, lutein, zeaxanthin, meso-zeaxanthin, and cryptoxanthin, are detectable in the human blood. They have distinct physiological and pathophysiological functions ranging from fetal development to adult homeostasis. β-carotene is a precursor of vitamin A that essentially functions in many biological processes including vision. The human macula lutea and eye lens are rich in lutein, zeaxanthin, and meso-zeaxanthin, collectively known as macular xanthophylls, which help maintain eye health and prevent ophthalmic diseases. Ocular carotenoids absorb light from the visible region (400-500 nm wavelength), enabling them to protect the retina and lens from potential photochemical damage induced by light exposure. These natural antioxidants also aid in quenching free radicals produced by complex physiological reactions and, consequently, protect the eye from oxidative stress, apoptosis, mitochondrial dysfunction, and inflammation. This review discusses the protective mechanisms of macular xanthophylls in preventing eye diseases such as cataract, age-related macular degeneration, and diabetic retinopathy. Moreover, some preclinical animal studies and some clinical trials are discussed briefly to understand carotenoid safety and efficacy.
类胡萝卜素是天然的脂溶性抗氧化剂，作为有色色素大量存在于水果和蔬菜中。天然存在的类胡萝卜素至少有600种，不过在人体血液中可检测到的约有20种，包括β-胡萝卜素、α-胡萝卜素、番茄红素、叶黄素、玉米黄质、中间玉米黄质和隐黄质。它们具有从胎儿发育到成人内稳态等不同的生理和病理生理功能。β-胡萝卜素是维生素A的前体，在包括视觉在内的许多生物过程中发挥重要作用。人黄斑和晶状体富含叶黄素、玉米黄质和中间玉米黄质，统称为黄斑叶黄素，有助于维持眼部健康并预防眼科疾病。眼部类胡萝卜素吸收可见光区域（波长400 - 500nm）的光，使它们能够保护视网膜和晶状体免受光照引起的潜在光化学损伤。这些天然抗氧化剂还有助于淬灭复杂生理反应产生的自由基，从而保护眼睛免受氧化应激、细胞凋亡、线粒体功能障碍和炎症的影响。本文综述讨论了黄斑叶黄素在预防白内障、年龄相关性黄斑变性和糖尿病视网膜病变等眼部疾病中的保护机制。此外，还简要讨论了一些临床前动物研究和一些临床试验，以了解类胡萝卜素的安全性和有效性。
