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Natural Carotenoids
Published in Hafiz Ansar Rasul Suleria, Megh R. Goyal, Masood Sadiq Butt, Phytochemicals from Medicinal Plants, 2019
Umair Shabbir, Sana Khalid, Munawar Abbas, Hafiz Ansar Rasul Suleria
Carotenoid availability and their types can be determined by their color, for example, (1) β-carotene and α-carotene are abundantly present in yellow-orange fruits and vegetables; (2) zeinoxanthin and α-cryptoxanthin present in orange fruits, for example, papaya, mandarin, and orange; and (3) lycopene is the main component of tomatoes, grapefruit, and watermelon with bright red color. Lutein (about 45%), β-carotene (about 25-30%), neoxanthin (10-15%), and violaxanthin (10-15%) are present in green leafy vegetables.53 α-Carotene, lutein, antheraxanthin, zeaxanthin, and β-cryptoxanthin are also found in green vegetables in small amounts. Usually, β-carotene is abundantly found in many vegetables and fruits than to α-carotene.
The Xanthophyll Cycle
Published in Ruth G. Alscher, John L. Hess, Antioxidants in Higher Plants, 2017
Barbara Demmig-Adains, William W. Adams
Among the xanthophylls typically found in the leaves of higher plants, only lutein is a derivative of α-carotene (β, ε-carotene). All other major xanthophylls are derived from β-carotene (β,β-carotene); zeaxanthin, antheraxanthin, violaxanthin, and neoxanthin. A portion of the presumed biosynthetic pathway17 of the formation of the xanthophyll cycle components is depicted in Figures 4 and 5. Neoxanthin is not included in this diagram, but it has been suggested that neoxanthin can be formed from violaxanthin (see below). Excess light specifically stimulates the β,β-carotenoid pathway, and leads to the accumulation of large amounts of β-carotene, and, particularly, the components of the xanthophyll cycle, zeaxanthin, antheraxanthin, and violaxanthin.15,16 The xanthophyll cycle appears to be present throughout all families of higher plants.15,16 From indirect evidence, it seems that, among the three xanthophyll cycle components, zeaxanthin is formed first through hydroxylation of β-carotene. Antheraxanthin and violaxanthin are formed subsequently through epoxidation of zeaxanthin. The epoxidation state of the xanthophyll cycle is thereafter regulated by light. It has recently been reported that a mutant of Arabidopsis, unable to form more than trace amounts of violaxanthin, accumulated larger amounts of both β-carotene and zeaxanthin than did the wild type.18,19 This mutant also possessed reduced levels of lutein as a derivative of α-carotene,19 and was therefore enhanced in the β,β-carotenoid pathway, apparently at the expense of the ß,ε-carotenoid pathway. This mutant contained only trace amounts of neo-xanthin as well, a result consistent with a formation of neoxanthin from violaxanthin.18,19
Anticancer Activity of Leonurus sibiricus L.: Possible Involvement of Intrinsic Apoptotic Pathway
Published in Nutrition and Cancer, 2022
Vasanth Krishnan, Selvakumar Subramaniam, Chang Chia–Chuan, Balamurugan Venkatachalam, Amal Thomas Cheeran, Huang Chi-Ying F.
HPLC chromatogram reveals the presence of carotenoids and xanthophyll with the corresponding peak area: β-carotene (2.89 < LOQ), chlorophyll a (6.16 < LOQ), chlorophyll b (7.83 < LOQ), zeaxanthin (7.83 < LOQ), trans-lutein (9.5 < LOQ), trans-antheraxanthin, cis-neoxanthin (11.31 < LOQ), trans-neoxanthin (11.84 < LOQ) and trans-vioxanthin (12.12 < LOQ). The values represented refers to the quantities in 10 μl of injected volume for chromatogram peaks and < LOQ is under the quantification limit. Chlorophyll a and b peaks were determined according to the reference with standards. The chromatographic resolution ranged from 1.15 to 15.13 for all peaks and indicated that a proper solvent strength was used (Figure 5).
Separating toxicity and shading in algal growth inhibition tests of nanomaterials and colored substances
Published in Nanotoxicology, 2022
Lars Michael Skjolding, Sara Nørgaard Sørensen, Karen Scharling Dyhr, Rune Hjorth, Louise Schlüter, Camilla Hedberg, Nanna B. Hartmann, Philipp Mayer, Anders Baun
The freshwater green alga Raphidocelis subcapitata belongs to the class Chlorophyceae, which has pigments similar to those found in higher plants, including chlorophylls, α- and β-carotene, lutein, neoxanthin, violaxanthin, antheraxanthin and zeaxanthin (Young 1993). Changes in the cellular composition of the pigments as a function of light intensity were clearly demonstrated in experiments using neutral-density filters (Figure 2(A)). Decreasing light intensity resulted in a decrease in photo-protective pigments such as astaxanthin, antheraxanthin, and zeaxanthin. The decrease in cellular content of astaxanthin, antheraxanthin and zeaxanthin with decreasing light intensity corresponds with their photo-protective function, as described in literature (Dubinsky and Stambler 2009; Niyogi et al. 1997) (Figure 2(A)). Oppositely, the content of the light harvesting pigments chlorophyll a and b, lutein, neoxanthin, and α- and β-carotene generally increased with decreasing light intensity, although for some of these pigments the content level off at the highest shading level, implying a physical limit for the up-regulation mechanism (Figure 2(A)). It should be noted that pigments such as zeaxanthin, violaxanthin and antheraxanthin are structural components of both light harvesting complexes and photo-protective complexes (units for absorption of excess light energy). Thus, direct interpretation of increases or decreases as function of light availability should be done in connection with the regulation of other pigments to avoid misinterpretation. Similar trends of increasing light harvesting pigments as a function of decreasing light has also been found in other species of chlorophytes e.g. Chlorella sp. and Brachiomonas submarina (Schlüter et al. 2000) as well as Sphaerocystis schroeteri, Stichococcus sp., Mougeotia sp. and Botryococcus braunii (Lauridsen et al. 2011).