ISSN 2278- 4136 ZDB-Number: 2668735-5 IC Journal No: 8192 Volume 2 Issue 1 Online Available at www.phytojournal.com Journal of Pharmacognosy and Phytochemistry Vol. 2 No. 1 2013 www.phytojournal.com Page | 225 Carotenoids Omayma A. Eldahshan 1 and Abdel Nasser B. Singab 1* 1. Pharmacognosy Department, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt. [E-mail: dean@pharma.asu.edu.eg] Carotenoids form one of the most important classes of plant pigments and play a crucial role in defining the quality parameters of fruit and vegetables. Carotenoids are of great interest due to their essential biological functions in both plants and animals. Herein, the review article discuss how carotenoids synthesised in plants leading to different types, their role in plants and biological activities to human and all details concerning the most important carotenoids in our life Keyword: Carotenoids, Classification, Biosynthesis, Function, β-Carotene 1. Introduction Without pigments we’re nothing. Life presents us with a kaleidoscope of colors. From the green grass of home to a forest's ruddy autumn hues, we are surrounded by living color. Living things obtain their colors, with few exceptions, from natural pigments. In addition to their role in coloration, natural pigments carry out a variety of important biological functions [1] . Plants play an important aesthetic function by providing flowers with a broad spectrum of colors [2] . Plant pigments are important in signalling, as in attracting pollinating and dispersal agents, and repelling herbivores. They are also important for humans, attracting our attention and providing us with nutrients. Plant pigments are important clues to humans and other herbivorous animals in helping identify plants find plant parts such as fruit, leaves, stems, roots, or tubers and determine stages of plant development such as ripeness or overall senescence. It was realized early in this century that many of these pigments play a positive role in human health. Plant pigments are obviously physiologically important, and recent research suggests novel protective mechanisms, both photo-protective and anti-oxidative. Plant pigments are economically important, in determining the colours and patterns of attractive flowers and valuable fruits. They are also important nutritionally, with an understanding of emerging new roles in nutrition and in aiding health [3] . All of these reasons were a motivation for production a review about one of the most important plant pigments; carotenoids. 1.1Carotenoids Carotenoids form one of the most important classes of plant pigments and play a crucial role in defining the quality parameters of fruit and vegetables [4] . They are found principally in plants, algae, and photosynthetic bacteria, where they play a critical role in the photosynthetic process. They also occur in some non-photosynthetic bacteria, yeasts, and molds, where they may carry out a