Edible plants are commonly used as natural food, tea and herbal medicine [1]. Most of these plants have not been screened for their anti-mutagenic activities. Thus, the information regarding the anti-mutagenic activity of these plants will be useful to validate their traditional uses and to establishing anti-mutagenic data bases [2]. Antimutagens isolated from edible and medicinal plants are useful because they may prevent human cancer, and have no toxic effects on living organisms [3]. Herbal drugs, containing active principles are currently developed to protect against attack of free radicals on DNA and its outcome such as aging and cancer [4]. Several useful drugs have been developed from components discovered from medicinal plants, and this forms an important source of new pharmaceuticals [5]. Developing countries are utilising medicinal plants in healthcare systems for primary health care needs. The use of medicinal plants is highly widespread because of their easy access, claimed therapeutic efficacy based on local knowledge and expertise amongst the local communities as well as the affordability [6]. Plants contain many metabolites with various bioactivities including antioxidant, anti-inflammatory and anticancer activities [7]. Bioactive compounds of plant origin are found to be antioxidants and are shown to have possible health effects, mainly due to their anti- oxidative properties [8]. Many mutagens and carcinogens act by producing reactive oxygen species (ROS), which are harmful to living systems.

Reactive oxygen species induce oxidative damage to cell structures and biomolecules such as lipids, nucleic acids and proteins [8]. DNA mutation is an important step in carcinogenesis. Elevated levels of oxidative DNA changes have been noted in many tumours, strongly implicating such damage in the aetiology of cancer [9]. The prevention of oxidative damage to DNA is important to limit mutagenesis, cytostasis, and cytotoxicity. It may contribute to prevention of mutation-related diseases [10-11]. A common factor in the pathogenesis of chronic degenerative diseases is the involvement of oxidative stress. Plant compounds may reduce oxidative stress, thereby reducing the risk of diseases [12].

Carotenoids form a part of natural pigments which have been found to lessen the risk of many chronic diseases such as cancer, heart disease, and certain eye diseases [13]. The bioavailability of carotenoids is affected by a number of factors such as food matrix, processing conditions, and fat content [14]. The bioavailability of lutein and zeaxanthin is greater in heat-processed than from unprocessed/raw vegetables [15]. Lutein and zeaxanthin are also more (from 50% to 100%) bioaccessible from fruits than from dark green vegetables [16].

Upon intestinal absorption as micelles, lutein and zeaxanthin are incorporated in chylomicrons, together with other dietary lipids [17]. Chylomicrons are rapidly remodeled by lipoprotein lipase in peripheral tissues and then enter as chylomicron remnants into the bloodstream [18]. The resulting chylomicron remnants containing carotenoids are then transferred to the liver, where they can be either stored or re-secreted into the circulation in association with lipoproteins [18]. In the fasting blood, lutein (> 50%) and zeaxanthin (> 40%) are predominantly transported by HDL [19]. The serum concentration of lutein ranges from 0.1–1.44 μmol/L, and from 0.07–0.17 μmol/L for zeaxanthin, the large variability being due to the wide difference in carotenoids intake among individuals [20].

The specific affinity of lutein and zeaxanthin to HDL regulate their post-hepatic tissue distribution via HDL receptor mediated uptake. In humans, the highest levels of these pigments are reached in the macula of the eye where their concentrations range between 0.1 and 1 mM [21]. Shyam et al (2017) have found that all three human SR-B proteins and CD36 are capable of binding the macular xanthophyll carotenoids, zeaxanthin, lutein, and its metabolite meso-zeaxanthin [22]. A cross-sectional study by Renzi et al. (2012) observed that serum lutein and zeaxanthin and lipoprotein concentrations are significantly related and changing lipoprotein levels may impact levels of these retinal xanthophylls. Johnson et al (2016) reported that lutein concentrations are related to levels of steroidogenic acute regulatory domain-3 (StARD3) protein in human brain [23]. A role of StARD3 as a lutein-binding protein was first identified in the macula lutea of primates [24] together with glutathione S-transferase-1 (GSTP1) as a zeaxanthin-binding protein [25]. StARD3 along GSTP1 provide numerous binding sites for lutein and zeaxanthin respectively, that account for the unique distribution and stability of carotenoids found in the primate macula lutea. It is possible that CD36 interacts with StARD3 as a surfaces receptor to mediate carotenoid uptake into the macula [24]. These data prove the involvement of HDL transport and StARD3 in the uptake of lutein by the brain, and may partially explain the preferential accumulation of the xanthophylls in the central nervous system.

Two enzymes - β-carotene-15,15′-oxygenase (BCO1) and β-carotene-9′,10′-oxygenase (BCO2) - mediate the cleavage of carotenoids at specific sites of the polyene chain [26]. These two enzymes have different substrate specificity for various carotenoids, different cellular localization and perform different functions within the cell [27]. Specifically BCO2 localized in the mitochondria has been proposed to prevent toxic accumulation of these pigments in the tissues [28]. Xanthophylls can serve as substrate for BCO2 giving rise to a number of 3-hydroxy metabolites depending on the site and number of cleavages [29]. These hydroxyl-metabolites may be excreted through urine after conjugation.

Ravikrishnan et al.,(2011) observed that administration (gavage) of lutein/zeaxanthin concentrate at dose levels of 0, 4, 40 and 400 mg/kg bw/day for 90-days in Wistar rats did not result in any toxicity- related changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, and organ weights. No toxicity findings were noted in urinalysis, hematology or clinical biochemistry parameters at the end of the treatment or recovery period and terminal necropsy also did not reveal any treatment- related gross or histopathology findings. The results of mutagenicity testing in Salmonella typhimurium did not reveal any genotoxicity. The no-observed-adverse-effect level (NOAEL) for lutein/zeaxanthin concentrate was determined as 400mg/kg bw/day, the highest dose tested.

The Salmonella typhimurium assay (Ames test) is a widely accepted as a short term assay for identifying substances that can produce genetic damage that leads to gene mutations [31-32].

In the present study, an effort has been made to analysing the antimutagenic activity of oxycarotenoid (lutein and zeaxanthin) rich extracts isolated from Coriandrum sativum (coriander leaves) and Murraya koenigii (curry leaves).

Green leafy vegetables are shown to increase the antioxidant capacity of the plasma and reduce the risk of diseases such as cancer, heart diseases, and stroke [35]. The reason of this beneficial effect of antioxidants from plants could be their protective effects by counter acting reactive oxygen species [36]. The natural pigments, carotenoids, have been found to lessen the risk of many chronic diseases such as cancer, heart disease, and certain eye diseases [13]. Carotenoid-rich diets from fruits and vegetables have been associated with a decreased risk of lung, stomach and prostate cancers [37]. Lutein and zeaxanthin are antioxidant carotenoids found in many fruits, vegetables and flowers as well as in dark leafy vegetables [33].

Oxycarotenoid (lutein and zeaxanthin) rich extracts form Coriandrum sativum and Murraya koenigii showed significant antimutagenicity against direct acting mutagens TA 98 and TA1535 and this antimutagenic activity may be due to the antioxidant property.

In conclusion, this study showed that the oxycarotenoid- rich extracts of Coriandrum sativum and Murraya koenigii possessed significant antimutagenic properties and hence the inclusion of these plants in the diet may have beneficial effects on human health. A plant extract indicating antimutagenicity may not necessarily be an anticarcinogen; however, it can be an indication of a possible candidate for such purpose.

The authors acknowledge the support of Little Flower Medical Research Centre, Kerala and Care Kerala Ltd, Kerala.

09 1 12 86-94 61 2009 10.3989/gya.075509 Özen Tevfik Grasas y Aceites Antioxidant activity of wild edible plants in the Black Sea Region of Turkey 4 414 47 2015 10.4103/0253-7613.161267 Sarac Nurdan Indian Journal of Pharmacology Antioxidant, mutagenic, and antimutagenic activities of Tragopogon longirostis var. longirostis, an edible wild plant in Turkey 3 03 393-397 80 2003 10.1016/s0308-8146(02)00279-0 Negi P.S. Jayaprakasha G.K. Jena B.S. Food Chemistry Antioxidant and antimutagenic activities of pomegranate peel extracts 1345 1348 5 2011 Ghazali R Abdullah R Ramli N Rajab NF Ahmad-Kamal MS Yahya NA J Med Plant Res Mutagenic and antimutagenic activities of Mitragynaspeciosa Korth extract using Ames test 7 07 1022-1037 66 2003 10.1021/np030096l Newman David J. Cragg Gordon M. Snader Kenneth M. Journal of Natural Products Natural Products as Sources of New Drugs over the Period 1981−2002 82 2002 WHO Lyon: IARC Press International Agency for Research on Cancer. IARC monographs on the evaluation of carcinogenic risks to humans. Volume 82.Some traditional herbal medicines, some mycotoxins, naphthalene and styrene 211 219 14 1998 Kim JH Park MK Lee JY Okuda H Kim S Hwang WI Biochem Arch Antioxidant and antitumor effects of Manda 6726 04 381-381 398 1999 10.1038/18793 Cao Yihai Cao Renhai Nature Angiogenesis inhibited by drinking tea 2 02 161-165 17 2001 10.1016/s0899-9007(00)00570-0 Castro Laura Freeman Bruce A Nutrition Reactive oxygen species in human health and disease 10 07 1195-1214 17 2003 10.1096/fj.02-0752rev Cooke Marcus S. Evans Mark D. Dizdaroglu Miral Lunec Joseph The FASEB Journal Oxidative DNA damage: mechanisms, mutation, and disease 1 02 47-54 16 2005 10.1097/00041433-200502000-00009 Blomhoff Rune Current Opinion in Lipidology Dietary antioxidants and cardiovascular disease 1 02 77-83 17 2003 10.1016/s0887-2333(02)00120-0 González-Avila M Arriaga-Alba M de la Garza M del Carmen HernándezPretelı́n M Domı́nguez-Ortı́z M.A Fattel-Fazenda S Villa-Treviño S Toxicology in Vitro Antigenotoxic, antimutagenic and ROS scavenging activities of a Rhoeo discolor ethanolic crude extract 2 04 56-65 5 2002 10.1046/j.1523-5408.2002.00004.x Johnson Elizabeth J. Nutrition in Clinical Care The Role of Carotenoids in Human Health 10 6 06 1024-1037 9 2011 10.3390/md9061024 Kotake-Nara Eiichi Nagao Akihiko Marine Drugs Absorption and Metabolism of Xanthophylls 9 15 22 2009 Perry A Rasmussen H Johnson EJ J Food Comp Anal Xanthophyll (lutein, zeaxanthin) content in fruits, vegetables and corn and egg products 5 05 258-264 27 2007 10.1016/j.nutres.2007.04.002 O'Connell Orla F. Ryan Lisa O'Brien Nora M. Nutrition Research Xanthophyll carotenoids are more bioaccessible from fruits than dark green vegetables 06 33-40 647 2018 10.1016/j.abb.2018.04.008 Giordano Elena Quadro Loredana Archives of Biochemistry and Biophysics Lutein, zeaxanthin and mammalian development: Metabolism, functions and implications for health 27 12 11 4849-4868 5 2013 10.3390/nu5124849 Shete Varsha Quadro Loredana Nutrients Mammalian Metabolism of β-Carotene: Gaps in Knowledge 01 3 03 762-769 85 2007 10.1093/ajcn/85.3.762 Wang Wei Connor Sonja L Johnson Elizabeth J Klein Michael L Hughes Shannon Connor William E The American Journal of Clinical Nutrition Effect of dietary lutein and zeaxanthin on plasma carotenoids and their transport in lipoproteins in age-related macular degeneration 29 1 02 11 2012 10.1186/1476-511x-11-33 Renzi Lisa M Hammond Billy R Dengler Melissa Roberts Richard Lipids in Health and Disease The relation between serum lipids and lutein and zeaxanthin in the serum and retina: results from cross-sectional, case-control and case study designs 01 34-66 50 2016 10.1016/j.preteyeres.2015.10.003 Bernstein Paul S. Li Binxing Vachali Preejith P. Gorusupudi Aruna Shyam Rajalekshmy Henriksen Bradley S. Nolan John M. Progress in Retinal and Eye Research Lutein, zeaxanthin, and meso-zeaxanthin: The basic and clinical science underlying carotenoid-based nutritional interventions against ocular disease 11 21-28 634 2017 10.1016/j.abb.2017.09.013 Shyam Rajalekshmy Vachali Preejith Gorusupudi Aruna Nelson Kelly Bernstein Paul S. Archives of Biochemistry and Biophysics All three human scavenger receptor class B proteins can bind and transport all three macular xanthophyll carotenoids 913-917 30 2016 Tanprasertsuk Jirayu Li Binxing Bernstein Paul S. Vishwanathan Rohini Johnson Mary Ann Poon Leonard Johnson Elizabeth J Pendyala Gurudutt FASEB J Relationship between Concentrations of Lutein and StARD3 among Pediatric and Geriatric Human Brain Tissue 05 13 04 2541-2549 50 2011 10.1021/bi101906y Li Binxing Vachali Preejith Frederick Jeanne M. Bernstein Paul S. Biochemistry Identification of StARD3 as a Lutein-Binding Protein in the Macula of the Primate Retina 09 22 06 4798-4807 48 2009 10.1021/bi9004478 Bhosale Prakash Li Binxing Sharifzadeh Mohsen Gellermann Werner Frederick Jeanne M. Tsuchida Kozo Bernstein Paul S. Biochemistry Purification and Partial Characterization of a Lutein-Binding Protein from Human Retina 10 5 10 1234S-1244S 96 2012 10.3945/ajcn.112.034629 von Lintig Johannes The American Journal of Clinical Nutrition Provitamin A metabolism and functions in mammalian biology 07 10 07 4457-4469 28 2014 10.1096/fj.14-252411 Palczewski Grzegorz Amengual Jaume Hoppel Charles L. Lintig Johannes The FASEB Journal Evidence for compartmentalization of mammalian carotenoid metabolism 03 28 05 14609-14619 291 2016 10.1074/jbc.m116.723684 dela Seña Carlo Sun Jian Narayanasamy Sureshbabu Riedl Kenneth M. Yuan Yan Curley Robert W. Schwartz Steven J. Harrison Earl H. Journal of Biological Chemistry Substrate Specificity of Purified Recombinant Chicken β-Carotene 9′,10′-Oxygenase (BCO2) 04 16 07 2966-2977 139 2012 10.1242/dev.079632 Lobo G. P. Isken A. Hoff S. Babino D. von Lintig J. Development BCDO2 acts as a carotenoid scavenger and gatekeeper for the mitochondrial apoptotic pathway 11 11 2841-2848 49 2011 10.1016/j.fct.2011.08.011 Ravikrishnan R. Rusia Shraddha Ilamurugan G. Salunkhe Ulhas Deshpande Jayant Shankaranarayanan J. Shankaranarayana M.L. Soni Madhu G. Food and Chemical Toxicology Safety assessment of lutein and zeaxanthin (Lutemax™ 2020): Subchronic toxicity and mutagenicity studies 1-2 11 29-60 455 2000 10.1016/s0027-5107(00)00064-6 Mortelmans Kristien Zeiger Errol Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis The Ames Salmonella/microsome mutagenicity assay 6 12 347-363 31 1975 10.1016/0165-1161(75)90046-1 Ames Bruce N. McCann Joyce Yamasaki Edith Mutation Research/Environmental Mutagenesis and Related Subjects Methods for detecting carcinogens and mutagens with the salmonella/mammalian-microsome mutagenicity test 1 1 10 8 2018 Sherena PA Annamala PT Mukkadan JK Dinesha Ramadas Research and reviews: A journal of Biotechnology Biochemical assays of crude and purified oxycarotenoid extracts isolated from coriander leaves and their effect on oxidative stability of oils by Rancimat assay 3-4 03 173-215 113 1983 10.1016/0165-1161(83)90010-9 Maron Dorothy M. Ames Bruce N. Mutation Research/Environmental Mutagenesis and Related Subjects Revised methods for the Salmonella mutagenicity test 4 07 588-592 35 2000 10.21273/hortsci.35.4.588 Prior Ronald L. Cao Guohua HortScience Antioxidant Phytochemicals in Fruits and Vegetables: Diet and Health Implications 4 08 705-711 97 2006 10.1016/j.foodchem.2005.05.049 Wong Chi-Chun Li Hua-Bin Cheng Ka-Wing Chen Feng Food Chemistry A systematic survey of antioxidant activity of 30 Chinese medicinal plants using the ferric reducing antioxidant power assay 5 10 419-427 14 1995 10.1080/07315724.1995.10718532 Flagg E W Coates R J Greenberg R S Journal of the American College of Nutrition Epidemiologic studies of antioxidants and cancer in humans.