Phytochemicals in Vegetables: A Valuable Source of Bioactive Compounds

Natural products and primary and secondary metabolites of plants have many biological functions, many of which are considered as health-beneficial for mankind. This chapter will focus on biologically active ingredients in widely consumed root vegetables, such as potato, celeriac, turnips, radish, beets, Hamburg parsley, taro, yam, parsnip and salsify. A recent update of studies is presented regarding underground parts of the mentioned vegetables – plant underground parts. Chemical constituents responsible for such biological activities, with focus on recent findings for each root vegetable separately are presented.

The genus Allium is one of the richest sources of phenols among vegetable foods and is highly ranked for its contribution of phenolic compounds to human diet. We thoroughly studied the chemical composition and quality of phenolic compounds in various Allium species with special emphasis on their bioactive properties. Pre-harvest (genotype and cultivation practices) and post-harvest conditions (storage and processing) had strong effects on the chemical composition and bioactive potency of the phenol fraction in Allium vegetables. In conclusion, genetic variability among Allium populations and ecotypes should further be examined to facilitate the selection of elite germplasms with increased contents in bioactive compounds in order to improve the preharvest quality of Allium and Allium-based foodstuffs. Proper cultivation practices and postharvest treatments have to be implemented in order to retain the preferred quality features and phenolic compounds in particular.

Beans are a staple food in many Latin American and African countries, as well as an important foodstuff in vegetarian diets. This chapter provides an update on the most recent scientific literature pertaining to the phenolics of different types of edible beans, their free radical-scavenging and antioxidant capacities, and how processing and germination affect the endogenous phenolics of beans. Indicated as well are the findings reported from a myriad of in vitro antioxidant assays one can perform to characterize the antioxidant potential of an extract prepared from the different bean types. It is noteworthy that variability in antioxidant determinations of the phenolics from bean crude extracts can exist, as the results are greatly impacted by the extraction methodologies employed and the details of the colorimetric or HPLC assays performed.

Cucurbitaceae represents a large plant family with more than 120 genera and 800 species, among which many significant cultivated vegetable species are included, such as watermelon, melon, cucumber and cucurbits (squash, pumpkin and zucchini). These species are usually consumed for their edible fruits, however several other uses have been reported for the various plant parts, including medicinal and therapeutic ones among others. The present chapter will demonstrate the most common vegetable species in terms of their chemical composition and health effects, as well as their edible, medicinal and industrial uses, based on the phytochemical content of the various plant parts. Special focus will be given on cucurbitacins which are an important group of phytochemicals present in the Cucurbitaceae family, since several studies have confirmed its bioactive properties and multiple health effects. Finally, selected less known species of this family (gourds) will be presented, considering their important health effects and their use in vegetable grafting. In conclusion, future perspectives for further valorization of these species will be highlighted, especially for the ones that are less commonly used.

Knowledge about quantitative and qualitative characterization of phytochemical contents in Asteraceae leafy vegetables is continuously increasing due to the strong interest from scientists and consumers. This chapter deals with leafy vegetables of Lactuca sativa, Cichorium intybus and C. endivia species, given their relevance within the botanical family. It gives an overview of the wide differences occurring in genotype panels, in bioactive compound types and levels, focusing on phenolics, carotenoids and sesquiterpenes lactones. It also provides information on their biosynthesis pathways in plants together with health effects, bioaccessibility and bioavailability of diverse phytonutrient classes. Finally, it outlines the effects of the main pre-harvest and post-harvest factors affecting the amount and status of final products intended for dietary intake, and reports on some genetic aspects and biotechnologies aimed to biofortification of these species.

Parsley (Petroselinum crispum L.), celery (Apium graveolens L.), celeriac (Apium graveolens var. rapaceum), carrot (Daucus carota L.), parsnip (Pastinaca sativa L.), lovage (Levisticum officinale Koch.) and angelica (Angelica archangelica L.) are vegetable plants belonging to the Apiaceae family. They are often used as spices due to their characteristic aroma, originating from the volatile compounds present in the plant tissues. Mainly, all parts of the plant i.e. roots, leaves and fruit are used in nutrition. However, the focus of this chapter is plant fruit (i.e. seed), which is mostly used as spice. The contemporary method used for the analysis of volatiles compounds is called headspace and it is widely applied in flavor chemistry. The dominant compounds in P. crispum are α-pinene (46.2-49.0%) and β-pinene (33.5- 35.4%), while in A. graveolens, it is limonene (84.1-94.4%). In D. carota, the main components are sabinene (28.3%) and α-pinene (25.0%), while in P. sativa fruit, it is octyl ester of butanoic acid (53.8%) and 1-octanol (27.6%). In L. officinale and A. archangelica, the dominant component in fruit is β-phellandrene (77.1% and 84.7%, respectively).

The aim of this book chapter was to highlight the great importance of plants from Apiaceae family as functional food products, focusing on its anticancer properties. The plants that will be discussed for their anticancer properties include: caraway (Carum carvi L.), dill (Anethum graveolens L.), anise (Pimpinella anisum L.), fennel (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.), celery and celeriac (Apium graveolens L.), lovage (Levisticum officinale Koch.), carrot (Daucus carota L.), parsley (Petroselinum crispum L.), parsnip (Pastinaca sativa L.), angelica (Angelica archangelica L.), cumin (Cuminum cyminum L.), chervil (Anthriscus sp.) and eryngo (Eryngium campestre L.). Leaves, roots and seeds of these plants are widely used as spices, flavoring agents and dietary supplements in the folk medicine and pharmaceutical industry. Furthermore, roots and leaves of these plants are valuable sources of phytochemicals used on a daily basis as food with nutraceutical potential. Their essential oils have characteristic aroma and have potent antioxidant and antimicrobial properties, which contribute to their ability to serve as natural food conservatives. Additionally, due to their anticancer, hypoglycemic, hypolipidemic, hepatoprotective and other activities these plants are widely used as alternative and healthy food for the prevention and treatment of many disorders.

The increase in per capita consumption of vegetables rich in phytochemicals can improve the human nutrition status. Among the different kinds of vegetables, the cole group provides beneficial health effects attributed to the presence of diverse antioxidant compounds such as beta carotene, anthocyanins, ascorbic acid, phenolics, folic acid and organosulphur compounds like glucosinolates and so forth. In all the Brassica oleracea vegetables group, there are two different kinds of sulfur-containing phytochemicals vis. glucosinolates and S-methyl cysteine sulfoxide. In the 21st century, efforts are undergoing to improve the quality not only of grains but also of vegetable crops. The different spontaneous mutations representing regulatory genes conferring carotenoid and anthocyanin accumulation in cauliflower have been reported and offer a genetic resource for the development of new varieties with enhanced health-promoting properties and visual appeal. The enhancement of nutritional quality and improvement of glucosinolates for imparting human health benefits or processing fitness require not only the pursuit of breeding efficiency by marker-assisted selection or new analytical methods and modern biotechnological tools but also careful consideration of the organoleptic features of cole vegetables. This review presents a summary of recent advances related with phytochemical value in cole vegetables and future perspectives.

The family Solanaceae features many popular vegetable crops, mainly belonging to its three major genera Solanum, Capsicum, and Physalis. They have played an important role in human nutrition and health since ancient times, most of them being native to South and Central America, but nowadays domesticated worldwide. Edible fruit, leaves, tubers as well as non-edible plant parts are a valuable source of often unique compounds with multiple biological activities. Despite numerous studies and intensive research, there are still novel compounds being discovered from both cultivated and wild species, that could bring more benefits into treatment of civilisation diseases not only as part of pharmaceutical products, but also as functional foods important in everyday prevention of health problems, especially those related to oxidative stress. Apart from the edible parts, the organic waste from production of these vegetables is a useful source of bioactive substances and extracts that can be used both in the food and pharmaceutical industry. In this chapter, the most important species from three genera are described in detail with emphasis being given on the research studies published within the last two decades. Major bioactive constituents representing each genus and biological activity of extracts and individual compounds, with special attention to the most interesting findings regarding antioxidant, anti-inflammatory and anticancer activity, are also discussed in the corresponding subsections.

Artichoke, cultivated cardoon, and their common relative, the wild cardoon are botanical varieties of the species Cynara cardunculus L., a perennial plant native to the Mediterranean Basin and belonging to the Asteraceae family. While commonly used as food, leaf extracts of this plants have been traditionally used as a natural remedy in folk medicine. These plants are in fact a rich source of bioactive compounds such as polyphenols, inulin, and sesquiterpene lactones. Many studies demonstrated that these compounds and their metabolites are responsible for several beneficial properties attributed to the extracts of artichoke and cardoon. As we gain knowledge on the effects and mode of action of these compounds, artichoke and cardoon are considered ‘functional food’ and are increasingly used to extract bioactive compounds and for numerous pharmaceutical applications. In this chapter, after a brief introduction on the origin and the importance of these crops, each class of bioactive compounds is presented summarizing the specific chemical properties, the biosynthesis, and the concentration range in plant tissues. The third section discusses the main factors (plant portion, physiological stage, plant genotype, environment, pre-harvest agronomic practices, post-harvest handling and processing) influencing the concentration of bioactive compounds in artichoke and cardoon. The following section is focused on the physiological fate of the bioactive compounds, reviewing the results of the most recent in vitro and in vivo studies conducted to assess their bioaccessibility, bioavailability, and pharmacokinetics. Finally, in the last section the main health-promoting effects attributed to artichoke and cardoon polyphenols are reviewed.

Okra (Abelmoschus esculentus L. Moench.) or lady finger, is a tropical vegetable of the Malvaceae family, which is usually consumed for its immature fresh or dried pods, while other parts of the plant such as leaves and seeds are also edible or have alternative uses. In addition, it is a versatile species and considered as a multipurpose crop, since plant tissues contain many chemical compounds that find applications in the food and pharmaceutical industry, as well as in other not widely known industrial uses (e.g. making of ropes, sacks, fishing lines, paper, biofuel, blood plasma replacement, stabilize foams). This chapter will describe chemical composition and uses of okra plant tissues, including pharmaceutical and industrial uses of the species. Moreover, special focus will be given on the health effects of the various plant parts and products (fruit, seeds, leaves, roots, flours, mucilage) and the mechanisms involved, while the most recent research results from both in vivo and in vitro models will be presented in order to establish the health effects of okra products and byproducts. In conclusion, considering that okra is an underutilized plant for most parts of the world, the potential of further exploiting the species and the future perspectives will be highlighted.

Diversity of the Brazilian flora is very prominent. The land possesses over 50,000 different flowering plants species among native and non-native. Approximately 5,000 of them are edible. This richness, however, is far from being optimally utilized. The term unconventional vegetables is applied to those that are consumed by a small part of the population, mostly by communities restricted to highly specific areas. These vegetables are frequently of high nutritional value and have good taste. Globalization and the consequently increased use of processed foods, however, is having a negative influence on the consumption and cultivation of these vegetables in all regions. This trend is manifesting in both rural and urban areas. The final consequence is a diminution of the consumption of foods from local and regional sources and, consequently, a modification of eating habits of the Brazilians of all social classes. In this chapter, attention was given to six unconventional native vegetables from Brazil that are regionally consumed as food (baru, cubiu, jambu, ora-pro-nobis, pinhão, and pequi), emphasizing on their nutritional characteristics and the health benefits resulting from their consumption.