Bioactive compounds are natural chemical compounds found in both plant and animal products and have role in promoting good health. These compounds are now being studied in the prevention of cancer, heart disease and other diseases. Vegetables constitute a major part of any balanced diet and good source of various bioactive compounds such as lycopene, resveratrol, tannins, and indoles, phenols, etc. As bioactive compounds are natural compounds and always regulated by several biochemical pathways and controlled by genetical and environmental factors. The biochemical pathway and synthesis of the compound are controlled by one or many genes which are scattered in the available or unknown germplasms of a particular vegetable crop. Conventional breeding in conjunction with molecular biology has bright prospects of developing vegetable varieties high in various bioactive compounds suitable for fresh market as well as fusion/functional food industry. Vegetables rich in various bioactive compounds and their role in human health are given in Table 1.



Role in human health


Tomato, Watermelon and Carrot

Protect against cancer, fight infection


Beet root

High anti-oxidative, free radical scavenging activities


Carrot, Cantaloupe, Pumpkin, Sweet Potato and cauliflower



Brinjal, carrot, amaranth, dolichos bean, cabbage and broccoli

Cardiovascular dysfunction, protective effect on pancreatic cells


Yellow corn, carrot and sweet pepper

Good for eyes


Broccoli, Kale, Spinach, Cabbage and Asparagus

Act as a chemopreventive compound

Chlorogenic acid, nasunin


Anti-carcinogenic, anti-obesity, and anti-diabetic properties



Heart disease, diabetes, peptic ulcer, inflammation, asthma, gout, viral infections

Indole-3-carvinol, gluconapin, Sulfaforaphane

Cauliflower, broccoli

Protect against cancer, heart disease and stroke

Allyl propyl disulfide, d-allyl disulfide

Onion, garlic

Protect against certain cancers and heart disease, boost the immune system

Flavonoids (isoflavones)


Protect against cancer, lower cholesterol

Momordicin and Charantin


Diabetes, Blood purifier, Hypertension, Dysentery, Anathematic

Biotechnological approach for improving bioactive compounds

Marker assisted breeding using genetic map and QTL analysis

Tomato: QTL associated with carotenoids using introgression populations of Solanum pennellii, S. peruvianum and S. hirsutum have been described by Bernacchi et al. (1998). The dominant gene Anthocyanin fruit (Aft), which induces limited pigmentation upon stimulation by high light intensity, was introgressed into domesticated tomato plants by an interspecific cross with S. chilense (Jones, 2003; Mes, 2008). Similarly, the gene Aubergine (Abg), which was introgressed from Solanum lycopersicoides, can induce a strong and variegated pigmentation in the peel of tomatoes.

Brassica vegetables: The 'or' mutation in Chinese cabbage is a recessive, single-locus mutation give carotenoid pigments in head leaves of the plant (Zhang et al., 2008). Fenglan (2008) found SCAR markers linked to “or” gene inducing beta-carotene accumulation in Chinese cabbage. Ripley and Roslinsky (2005) identified an ISSR Marker for 2-propenyl glucosinolate content in Brassica.

Sweet potato: Cervantes-Flores et al. (2010) have also recently reported QTLs in sweet potato for high dry matter, starch content and Beta-carotene which leads to opening up the possibility of genetic manipulation and further enhancement of this root crop.

Carrot: Seven monogenic traits have been mapped for carrot: yel, cola, Rs, Mj-1, Y, Y2, and P1. QTL have been mapped for carrot total carotenoids and five component carotenoids; phytoene, Alpha-carotene, Beta-carotene, zeta-carotene, and lycopene (Santos and Simon, 2002) and the majority of the structural genes of the carotenoid pathway is now placed into this map (Just et al., 2007)

Genetic engineering approach

For beta-carotene

Tomato: To enhance the carotenoid content and profile of tomato fruit, Romer et al. (2000) produced transgenic lines containing a bacterial carotenoid gene (crtI) encoding the enzyme phytoene desaturase, which converts phytoene into lycopene. Diretto et al. (2006) have silenced the first step in the beta-epsilon branch of carotenoid biosynthesis, lycopene epsilon cyclase (LCY-e) in potato, a tuber crop that contains low levels of carotenoids. This antisense tuber-specific silencing of the gene results in significant increases in carotenoid levels, with up to 14-fold more Beta-carotene.

Potato: Direttoet al. (2007) introduced three genes, encoding phytoene synthase (CrtB), phytoenedesaturase (CrtI) and lycopene beta-cyclase (CrtY) from Erwinia in potato to produce beta carotene. Gerjets and Sandmann (2006) developed genetically engineered potato for the production of commercially important keto carotenoids including astaxanthin (3, 3'-dihydroxy 4, 4'-diketo-Beta-carotene).

Sweet potato: Kim et al. (2012) developed transgenic sweet potato through the inhibition of hydroxylation of b-carotene, the effects of silencing CHY-b in the carotenoid biosynthetic pathway. In transgenic line #7, the total carotenoid content reached a maximum of 117 lg/g dry weight, of which b-carotene measured 34.43 lg/g dry weights.

Cauliflower: Lu et al. (2006) developed transgenic cauliflower with high levels of Beta-carotene accumulation. Transformation of the 'or' gene into wild type cauliflower converts the white colour of curd tissue into distinct orange colour with increased level of Beta-carotene.

For anthocyanin

Tomato: In tomato, overexpression of Anthocyanin 1 (Ant1), a transcription factor regulating anthocyanin production has led to the accumulation of anthocyanins in fruit skin and a layer immediately below it (Mathews et al., 2003). Maligeppagol et al. (2013) developed transgenic tomato accumulating high amounts (70"100 fold) of anthocyanin in the fruits by fruit specific expression of two transcription factors, Delila and Rosea1 isolated from Antirrhinum majus. The transgenic tomato plants were identical to the control plants, except for the accumulation of high levels of anthocyanin pigments throughout the fruit during maturity, thus giving the fruit a purplish colour. Stushnoff et al. (2010) in potato identified 27 genes that are differentially expressed in purple and white tuber tissues.

For folates

Tomato: Garza et al. (2004, 2007) developed transgenic tomatoes by engineering fruit- specific overexpression of GTP cyclohydrolase I that catalyzes the first step of pteridine synthesis, and amino-deoxy-chorismate synthase that catalyzes the first step of PABA synthesis. Vine-ripened fruits contained on average 25-fold more folate than controls by combining PABA and pteridine overproduction traits through crossbreeding of transgenic tomato plants.

For glucosinolate

Cole crops: Chromosome segments from a wild ancestor, Brassica villosa, have been introgressed to enhance glucosinolate levels such as indole-3-carbinol or sulphoraphane. Hence, high glucosinolate broccoli might be suitable for increasing the amount of sulphoraphane in the diet (Sarikamis et al., 2006). Three high-glucoraphanin F1 broccoli hybrids were developed through genome introgression from the wild species Brassica villosa and contained a B. villosa Myb28 allele. Two high-glucoraphanin hybrids have been commercialized as Beneforte broccoli (Traka et al., 2013).

For allicin

Onion: Three sets of transgenic onion plants containing antisense alliinase gene constructs (a CaMV 35S-driven antisense root alliinase gene, a CaMV 35S-driven antisense bulb alliinase, and a bulb alliinase promoter-driven antisense bulb alliinase) have been produced (Eady et al., 2003).


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I am working on improvement of vegetable through conventional and biotechnological approach