571
is also manufactured by chemical processes. There is enough scientific evidence to
support that diets high in fiber reduce the risk for obesity and diabetes, which are
primary risk factors for cardiovascular disease (CVD) (US Department of
Agriculture 2010).
25.2.3.2 Phytochemicals
Phytochemicals are the secondary metabolites of plants that function to protect the
plant from environmental stresses including pollutants, ultraviolet light, and infestation by insect pests, fungi, and bacteria. Besides this, they provide various health
benefits against oxidative stress, neurodegenerative disorders, cancer, diabetes,
immune disease, and inflammation. These are found in small amounts in fruits and
vegetables, grains, seeds, nuts, and legumes (Gibney et al. 2009; Lee and Min 2018;
Titchenal et al. 2018). Plant–derived dietary phytochemicals from fruits and vegetables prevent or delay the onset of chronic diseases and perform other functions like
mimicking hormones, altering absorption of cholesterol, and blocking the actions of
certain enzymes. There has been a growing interest among consumers in plant–
derived nutraceuticals and functional foods having scientifically proven health benefits (Howes 2018). Several clinical and epidemiological studies (in vitro and in
vivo) have reported their relevance in maintaining health and preventing diseases
(Howes and Simmonds 2014). Some important phytochemical nutrients like terpenoids, carotenoids, alkaloids, phenolics, phenolic acids, and flavonoids, organosulfur compounds and others exhibit significant health benefitting effects.
Terpenoids Plant–derived volatile essential oils are complex mixtures of phytochemicals like monoterpenes, sesquiterpenes, and diterpenes that are used for both
culinary and medicinal purposes. Among the various volatile monoterpenes 1,8–cineole was found effective against respiratory disorders (Howes 2018). Similarly α–
humulene has been found to be potent phytopharmaceutical in modulation of
inflammatory pathways (Howes 2018; Guimarães et al. 2014). Diterpenoids are also
reputed for their medicinal and phytopharmaceuticals properties. The steviol glycosides (diterpenes) found in Stevia rebaudiana leaves are good source of natural
sweetener in the food industry and have potential health benefits. Triterpenoids are
widely distributed in nature and occur as the C–30 aglycones or as esters or glycosides. Triterpenes from liquorice (Glycyrrhiza species) root include glycyrrhizin (a
triterpene glycoside) and glycyrrhetinic acid, which have been investigated for their
therapeutic potential to manage inflammatory lung diseases such as asthma. One of
the major challenges with the use of natural product glycosides to manage inflammatory conditions, is that they may be hydrolyzed in the gut and the original biologically
active constituent may not be adequately absorbed in this form (Howes 2018).
Carotenoids Carotenoids are lipid–soluble plant pigments found in photosynthetic
plants, microbes, and in animal tissues. About 600 different carotenoids have been
isolated and characterized in nature, and about 10% of these can be metabolized to
vitamin A in a variety of animal species, including humans. Provitamin A carot25 Bioavailability of Nutrients and Safety Measurements
is also manufactured by chemical processes. There is enough scientific evidence to
support that diets high in fiber reduce the risk for obesity and diabetes, which are
primary risk factors for cardiovascular disease (CVD) (US Department of
Agriculture 2010).
25.2.3.2 Phytochemicals
Phytochemicals are the secondary metabolites of plants that function to protect the
plant from environmental stresses including pollutants, ultraviolet light, and infestation by insect pests, fungi, and bacteria. Besides this, they provide various health
benefits against oxidative stress, neurodegenerative disorders, cancer, diabetes,
immune disease, and inflammation. These are found in small amounts in fruits and
vegetables, grains, seeds, nuts, and legumes (Gibney et al. 2009; Lee and Min 2018;
Titchenal et al. 2018). Plant–derived dietary phytochemicals from fruits and vegetables prevent or delay the onset of chronic diseases and perform other functions like
mimicking hormones, altering absorption of cholesterol, and blocking the actions of
certain enzymes. There has been a growing interest among consumers in plant–
derived nutraceuticals and functional foods having scientifically proven health benefits (Howes 2018). Several clinical and epidemiological studies (in vitro and in
vivo) have reported their relevance in maintaining health and preventing diseases
(Howes and Simmonds 2014). Some important phytochemical nutrients like terpenoids, carotenoids, alkaloids, phenolics, phenolic acids, and flavonoids, organosulfur compounds and others exhibit significant health benefitting effects.
Terpenoids Plant–derived volatile essential oils are complex mixtures of phytochemicals like monoterpenes, sesquiterpenes, and diterpenes that are used for both
culinary and medicinal purposes. Among the various volatile monoterpenes 1,8–cineole was found effective against respiratory disorders (Howes 2018). Similarly α–
humulene has been found to be potent phytopharmaceutical in modulation of
inflammatory pathways (Howes 2018; Guimarães et al. 2014). Diterpenoids are also
reputed for their medicinal and phytopharmaceuticals properties. The steviol glycosides (diterpenes) found in Stevia rebaudiana leaves are good source of natural
sweetener in the food industry and have potential health benefits. Triterpenoids are
widely distributed in nature and occur as the C–30 aglycones or as esters or glycosides. Triterpenes from liquorice (Glycyrrhiza species) root include glycyrrhizin (a
triterpene glycoside) and glycyrrhetinic acid, which have been investigated for their
therapeutic potential to manage inflammatory lung diseases such as asthma. One of
the major challenges with the use of natural product glycosides to manage inflammatory conditions, is that they may be hydrolyzed in the gut and the original biologically
active constituent may not be adequately absorbed in this form (Howes 2018).
Carotenoids Carotenoids are lipid–soluble plant pigments found in photosynthetic
plants, microbes, and in animal tissues. About 600 different carotenoids have been
isolated and characterized in nature, and about 10% of these can be metabolized to
vitamin A in a variety of animal species, including humans. Provitamin A carot25 Bioavailability of Nutrients and Safety Measurements