International Journal of Research and Review Vol.7; Issue: 12; December 2020 Website: www.ijrrjournal.com Review Article E-ISSN: 2349-9788; P-ISSN: 2454-2237 Apocarotenoids: A Brief Review Seba M C, Anatt Treesa Mathew, Sheeja Rekha, Prasobh G R Department of Pharmaceutical Chemistry, Sree Krishna College of Pharmacy and Research Centre, Parassala, Kerala Corresponding Author: Seba M C ABSTRACT The development of apocarotenoids is started by oxidative cleavage reactions Carotenoids are broad group of natural that can be catalyzed by enzymes, generally pigments, extending from red to orange, to CCDs, or take place via exposure of yellow colours. Produced by plants and certain carotenoids to ROS. β-Cyclocitral is an microorganisms (e.g.: fungi, bacteria and example for a carotenoid cleavage product microalgae), carotenoids have significant physiological function (e.g.: light harvesting). that can be produced following both Apocarotenoids are organic compounds, which scenarios. The formation of this β-carotene– is cleavage products of C40 isoprenoid derived volatile in photosynthetic tissues is 1 pigments, named carotenoids, catalyzed by initiated by a singlet oxygen O2 attack, enzyme carotenoid oxygenase, produced which takes place in the photosystem II, absolutely by plants and microorganisms. particularly in the presence of high light Apocarotenoids show vital roles in several stress, while in citrus fruits, it is catalyzed biological activities (e.g., plant hormones). by a CCD (CCD4b) that cleaves β-carotene, Various carotenoids and apocarotenoids have β-cryptoxanthin, and zeaxanthin. Although great economic significance in feed, cosmetics, some CCDs display a quite relaxed substrate food supplements, pharmaceutical industries and and site (double bond) specificity , cleavage also possess high commercial values Key Words: Carotenoids, Apocarotenoids, reactions catalyzed by these enzymes Carotenoid oxygenase generally take place at definite double bond(s) in defined carotenoid/apocarotenoid INTRODUCTION substrate(s). It should be also stated here Carotenoids are broad group of that some bacterial and fungal members of isoprenoid pigments, which comprises more the CCD family split biphenylic, stilbene .(2) than 600 different compounds. Carotenoids substrates instead of carotenoids are existing in all clades of life; but, their The electron-rich polyene system of production is limited to photosynthetic carotenoids makes them liable to oxidation organisms and certain nonphotosynthetic cleavage that cleave the carotenoid fungi and bacteria. In plants, carotenoids are backbone. This cleavage reaction is crucial constituents of the photosynthetic catalyzed by carotenoid cleavage apparatus where they deed as dioxygenases (CCDs), which construct a photoprotective pigments and involve in the ubiquitous family of non-heme iron light harvesting process. And also, plant enzymes, and give the products called carotenoids deliberate their bright orange, apocarotenoids. Apocarotenoids can reddish, or yellow colors to several fruits similarly obtain through non-enzymatic and flowers. Animals are unable to produce cleavage by reactive oxygen species (ROS). carotenoids de novo and be dependent on In these two processes, apocarotenoids nutritional sources to get their needs of fulfill, with or without further enzymatic these pigments that play as vitamin A modifications, various important biological precursor and antioxidants. (1) functions. The group of plant International Journal of Research and Review (ijrrjournal.com) 252 Vol.7; Issue: 12; December 2020 Seba M C et.al. Apocarotenoids: a brief review apocarotenoids includes important usage as a food additive in the US, EU, and phytohormones, such as abscisic acid and Australia and New Zealand. strigolactones, and signaling molecules, Epidemiological data have revealed such as β-cyclocitral, 3',4'-Didehydro-2'- that people with high β-carotene ingestion apo-b-caroten-2'-al, Apo-2-lycopenal, Apo- and high plasma levels of β-carotene have a 6'-lycopenal( 6'-Apo-y-caroten-6'-al), considerably reduced danger of lung cancer. Azafrinaldehyde (5,6-Dihydroxy-5,6- Though, studies of supplementation with dihydro-10'-apo-β-caroten-10'-al), Bixin (6'- bulky doses of β-carotene in smokers have Methyl hydrogen 9'-cis-6,6'-diapocarotene- revealed an surge in cancer risk, possibly as 6,6'-dioate), Citranaxanthin (5',6'-Dihydro- excessive β-carotene results in breakdown 5'-apo-β-caroten-6'-one or 5',6'-dihydro-5'- products that reduce plasma vitamin A and apo-18'-nor-β-caroten-6'-one or 6'-methyl- aggravate the lung cell 6'-apo-β-caroten-6'-one), Crocetin (8,8'- proliferation prompted by smoke. The chief Diapo-8,8'-carotenedioic acid), β-carotene breakdown product assumed of Crocetinsemialdehyde (8'-Oxo-8,8'-diapo-8- this behavior is trans-beta-apo-8'-carotenal carotenoic acid), Crocin (Digentiobiosyl (common apocarotenal), which has been 8,8'-diapo-8,8'-carotenedioate), found in one study to be mutagenic and Hopkinsiaxanthin( 3-Hydroxy-7,8- genotoxic in cell cultures which do not react didehydro-7',8'-dihydro-7'-apo-b-carotene- to β-carotene itself. (4) 4,8'-dione or 3-hydroxy-8'-methyl-7,8- didehydro-8'-apo-b-carotene-4,8'-dione), Methyl apo-6'-lycopenoate (Methyl 6'-apo- y-caroten-6'-oate), Paracentrone ( 3,5- Dihydroxy-6,7-didehydro-5,6,7', 8'- tetrahydro-7'-apo-b-caroten-8'-one or 3,5- dihydroxy-8'-methyl-6,7-didehydro-5,6- dihydro-8'-apo-b-caroten-8'-one), Sintaxanthin (7',8'-Dihydro-7'-apo-b- BIXIN caroten-8'-one or 8'-methyl-8'-apo-b- Bixin is an apocarotenoid seen caroten-8'-one). (3) in annatto, a natural food coloring obtained from the seeds of the achiote tree (Bixa orellana). Annatto seeds contain about 5% APOCAROTENAL OR TRAN-β-APO- pigments, which consist of 70-80% bixin. 8'-CAROTENAL Apocarotenal, or trans-β-apo-8'- Bixin is chemically unstable when carotenal is a carotenoid seen isolated and converts in spinach and citrus fruits. Aapocarotenal via isomerization into trans-bixin (β-bixin), plays a part as a precursor of vitamin A,but the double-bond isomer. it has 50% less pro-vitamin A activity when Bixin is soluble in fats compare with β-carotene. The empirical and alcohols but insoluble in water. Upon chemical formula for apocarotenal is exposure to alkali, the methyl ester is hydrolyzed to produce C30H40O. Apocarotenal posses an orange to the dicarboxylic acid norbixin, a water- soluble derivative.(5) orange-red colour and is used in foods, pharmaceuticals and cosmetic products. Depending on the product forms, apocarotenal is used in fat based food (margarine, sauces, salad dressing), beverages, dairy products and sweets. Its E number is E160e and it is approved for International Journal of Research and Review (ijrrjournal.com) 253 Vol.7; Issue: 12; December 2020 Seba M C et.al. Apocarotenoids: a brief review AZAFRINALDEHYDE(6) complaint. It concluded that crocetin may (p=0.025) give to improving the quality of sleep (9) In high concentrations, it has protective effects against retinal damage in (8) vitro and in vivo. The sodium salt of crocetin, transcrocetinate sodium (INN, also known CITRANAXANTHIN as trans sodium crocetinate or TSC) is an Citranaxanthin is a carotenoid experimental drug that increases the pigment used as a food additive under the E movement of oxygen from red blood cells number E161i as a food coloring agent. into hypoxic (oxygen-starved) tissues. There are natural sources of citranaxanthin, (9) Transcrocetinate sodium belongs to a but it is generally prepared synthetically. It group of substances known as bipolar trans is used as an animal feed additive to impart carotenoid salts, which constitute a subclass a yellow color to chicken fat and egg of oxygen diffusion-enhancing compounds. yolks.(4) Citraxanthin is deep violet crystals; Transcrocetinate sodium was one of the first sensitive to oxygen and light and should such compounds discovered. (10) therefore be kept in a light-resistant container under inert gas . Chemical names of Citranaxanthin is 6'-methyl-6'-apo- ß- carotene-6'-one, 5',6'-dehydro-5'-apo-18'- nor- ß-caroten-6'one , and the chemical formula is C33H440. (7) CROCIN DIGENTIOBIOSYL Crocetin and crocin (digentiobiosyl ester of crocetin) are the chief bioactive ingredients of saffron which is used as a costly spice, food colorant and traditional CROCETIN herbal medicine. These specific carotenoids Crocetin is a natural apocarotenoid have extended much research attention for dicarboxylic acid that is seen in the crocus their widespread pharmacological activities. (11) flower and Gardenia jasminoides (fruits). It Following oral administration, crocetin gives brick red crystals having melting point is quickly absorbed into the blood of 285 °C. (6) circulation and broadly distributed into the The chemical structure of crocetin extra-vascular tissues of the body, whereas forms the central core of crocin, the the water-soluble compound crocin is compound responsible for the color scarcely absorbed through the (12) of saffron. Crocin and crocetin may gastrointestinal tract. Crocetin and crocin provide neuroprotection in rats by reducing have been shown to be effective in the the production of various neurotoxic inhibition and/or treatment of several molecules, based on an in-vitro cell study. diseases such as, myocardial ischemia, (7) A 2009 study including 14 individuals atherosclerosis, hemorrhagic shock, cerebral (13) showed that oral administration of crocetin injury and cancer. The compounds may reduces the effects of physical fatigue employ their biological