The chemical diversity and distribution of glucosinolates and isothiocyanates among plants
TL;DR: This review addresses the complex array of glucosinolates, the precursors of isothiocyanates, present in sixteen families of dicotyledonous angiosperms including a large number of edible species including Brassica vegetables.
About: This article is published in Phytochemistry.The article was published on 2001-01-01. It has received 2679 citations till now. The article focuses on the topics: Myrosinase & Gluconasturtiin.
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TL;DR: Nearly six decades after the structural elucidation of IAA, many aspects of auxin metabolism, transport and signalling are well established; however, more than a few fundamental questions and innumerable details remain unresolved.
2,044 citations
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...IAA] is of particular interest in plants like arabidopsis that make indolic glucosinolate secondary metabolites (Fahey et al., 2001), because IAOx is the branch-point between indole-3-methylglucosinolate and IAA biosynthesis (Fig....
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TL;DR: Glucosinolates are sulfur-rich, anionic natural products that upon hydrolysis by endogenous thioglucosidases called myrosinases produce several different products that function as cancer-preventing agents, biopesticides, and flavor compounds.
Abstract: Glucosinolates are sulfur-rich, anionic natural products that upon hydrolysis by endogenous thioglucosidases called myrosinases produce several different products (e.g., isothiocyanates, thiocyanates, and nitriles). The hydrolysis products have many different biological activities, e.g., as defense compounds and attractants. For humans these compounds function as cancer-preventing agents, biopesticides, and flavor compounds. Since the completion of the Arabidopsis genome, glucosinolate research has made significant progress, resulting in near-complete elucidation of the core biosynthetic pathway, identification of the first regulators of the pathway, metabolic engineering of specific glucosinolate profiles to study function, as well as identification of evolutionary links to related pathways. Although much has been learned in recent years, much more awaits discovery before we fully understand how and why plants synthesize glucosinolates. This may enable us to more fully exploit the potential of these compounds in agriculture and medicine.
1,955 citations
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...The R groups of most glucosinolates are extensively modified from these precursor amino acids, with methionine undergoing an especially wide range of transformations (49)....
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...The approximately 120 described glucosinolates share a chemical structure consisting of a β-D-glucopyranose residue linked via a sulfur atom to a (Z )-N-hydroximinosulfate ester, plus a variable R group (Figure 1) derived from one of eight amino acids (49)....
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...For each category of glucosinolate, a different range of chain lengths is known to occur naturally (49)....
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...Up to nine cycles are known to occur in plants (49)....
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TL;DR: Moringa oleifera Lam (Moringaceae) is a highly valued plant, distributed in many countries of the tropics and subtropics. as mentioned in this paper provides a rich and rare combination of zeatin, quercetin, beta-sitosterol, caffeoylquinic acid and kaempferol.
Abstract: Moringa oleifera Lam (Moringaceae) is a highly valued plant, distributed in many countries of the tropics and subtropics. It has an impressive range of medicinal uses with high nutritional value. Different parts of this plant contain a profile of important minerals, and are a good source of protein, vitamins, beta-carotene, amino acids and various phenolics. The Moringa plant provides a rich and rare combination of zeatin, quercetin, beta-sitosterol, caffeoylquinic acid and kaempferol. In addition to its compelling water purifying powers and high nutritional value, M. oleifera is very important for its medicinal value. Various parts of this plant such as the leaves, roots, seed, bark, fruit, flowers and immature pods act as cardiac and circulatory stimulants, possess antitumor, antipyretic, antiepileptic, antiinflammatory, antiulcer, antispasmodic, diuretic, antihypertensive, cholesterol lowering, antioxidant, antidiabetic, hepatoprotective, antibacterial and antifungal activities, and are being employed for the treatment of different ailments in the indigenous system of medicine, particularly in South Asia. This review focuses on the detailed phytochemical composition, medicinal uses, along with pharmacological properties of different parts of this multipurpose tree.
1,568 citations
TL;DR: The Keap1–Nrf2 regulatory pathway plays a central role in the protection of cells against oxidative and xenobiotic damage and discovery and development of selective Nrf2 inhibitors should make a critical contribution to improved cancer therapy.
Abstract: The Keap1–Nrf2 regulatory pathway plays a central role in the protection of cells against oxidative and xenobiotic damage. Under unstressed conditions, Nrf2 is constantly ubiquitinated by the Cul3–Keap1 ubiquitin E3 ligase complex and rapidly degraded in proteasomes. Upon exposure to electrophilic and oxidative stresses, reactive cysteine residues of Keap1 become modified, leading to a decline in the E3 ligase activity, stabilization of Nrf2 and robust induction of a battery of cytoprotective genes. Biochemical and structural analyses have revealed that the intact Keap1 homodimer forms a cherry-bob structure in which one molecule of Nrf2 associates with two molecules of Keap1 by using two binding sites within the Neh2 domain of Nrf2. This two-site binding appears critical for Nrf2 ubiquitination. In many human cancers, missense mutations in KEAP1 and NRF2 genes have been identified. These mutations disrupt the Keap1–Nrf2 complex activity involved in ubiquitination and degradation of Nrf2 and result in constitutive activation of Nrf2. Elevated expression of Nrf2 target genes confers advantages in terms of stress resistance and cell proliferation in normal and cancer cells. Discovery and development of selective Nrf2 inhibitors should make a critical contribution to improved cancer therapy.
1,232 citations
Cites background from "The chemical diversity and distribu..."
...Broccoli sprouts are rich in glucosinolate that is hydrolyzed by gut microflora or by myrosinase in the cruciferous vegetables to sulforaphane [1-isothiocyanato-4-(methylsulfinyl)-butane] (Fahey et al. 2001)....
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01 Jan 2005
TL;DR: Critically evaluate the published scientific evidence on M. oleifera, highlight claims from the traditional and tribal medicinal lore and from non-peer reviewed sources that would benefit from further, rigorous scientific evaluation, and suggest directions for future clinical research that could be carried out by local investigators in developing regions.
Abstract: Moringa oleifera, or the horseradish tree, is a pan-tropical species that is known by such regional names as benzolive, drumstick tree, kelor, marango, mlonge, mulangay, nebeday, saijhan, and sajna. Over the past two decades, many reports have appeared in mainstream scientific journals describing its nutritional and medicinal properties. Its utility as a non-food product has also been extensively described, but will not be discussed herein, (e.g. lumber, charcoal, fencing, water clarification, lubricating oil). As with many reports of the nutritional or medicinal value of a natural product, there are an alarming number of purveyors of “healthful” food who are now promoting M. oleifera as a panacea. While much of this recent enthusiasm indeed appears to be justified, it is critical to separate rigorous scientific evidence from anecdote. Those who charge a premium for products containing Moringa spp. must be held to a high standard. Those who promote the cultivation and use of Moringa spp. in regions where hope is in short supply must be provided with the best available evidence, so as not to raise false hopes and to encourage the most fruitful use of scarce research capital. It is the purpose of this series of brief reviews to: (a) critically evaluate the published scientific evidence on M. oleifera, (b) highlight claims from the traditional and tribal medicinal lore and from non-peer reviewed sources that would benefit from further, rigorous scientific evaluation, and (c) suggest directions for future clinical research that could be carried out by local investigators in developing regions.
1,091 citations
References
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TL;DR: It would appear that major public health benefits could be achieved by substantially increasing consumption of fruit and vegetable consumption, and in particular in cancers of the esophagus, oral cavity, and larynx, for which 28 of 29 studies were significant.
Abstract: Approximately 200 studies that examined the relationship between fruit and vegetable intake and cancers of the lung, colon, breast, cervix, esophagus, oral cavity, stomach, bladder, pancreas, and ovary are reviewed. A statistically significant protective effect of fruit and vegetable consumption was found in 128 of 156 dietary studies in which results were expressed in terms of relative risk. For most cancer sites, persons with low fruit and vegetable intake (at least the lower one-fourth of the population) experience about twice the risk of cancer compared with those with high intake, even after control for potentially confounding factors. For lung cancer, significant protection was found in 24 of 25 studies after control for smoking in most instances. Fruits, in particular, were significantly protective in cancers of the esophagus, oral cavity, and larynx, for which 28 of 29 studies were significant. Strong evidence of a protective effect of fruit and vegetable consumption was seen in cancers of the pancreas and stomach (26 of 30 studies), as well as in colorectal and bladder cancers (23 of 38 studies). For cancers of the cervix, ovary, and endometrium, a significant protective effect was shown in 11 of 13 studies, and for breast cancer a protective effect was found to be strong and consistent in a meta analysis. It would appear that major public health benefits could be achieved by substantially increasing consumption of these foods.
3,250 citations
TL;DR: The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon, and the types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables.
Abstract: In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber. Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented. J Am Diet Assoc. 1996; 96:1027-1039.
2,316 citations
TL;DR: This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption and places particular emphasis on members of the Brassica family.
Abstract: This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption. The paper, which includes references published in 1981, is also intended to compliment existing reviews on the chemistry of these sulfur‐containing natural products. Particular emphasis is placed upon members of the Brassica family because of their importance as vegetables, condiments, oilseeds, and animal feedingstuffs. Since much of the work considered here relates to glucosinolate decomposition products, biochemical information concerning the nature, occurrence, and properties of the glucosinolate‐degrading enzyme, myrosinase, is considered in Section III. The methods available for the chemical analysis of glucosinolates and their various breakdown products are discussed critically. Factors affecting the glucosinolate content of plants and plant products arc outlined in Section VII. Particular emphasis is placed upon the effect of proces...
1,269 citations
TL;DR: The authors showed that 3-day-old sprouts of certain crucifers including broccoli and cauliflower contain 10-100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants.
Abstract: Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection against carcinogenesis, mutagenesis, and other forms of toxicity of electrophiles and reactive forms of oxygen. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism. Thus, edible plants belonging to the family Cruciferae and genus Brassica (e.g., broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.g., sulforaphane or 4-methylsulfinylbutyl isothiocyanate) are very potent inducers of phase 2 enzymes. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10-100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants. Glucosinolates and isothiocyanates can be efficiently extracted from plants, without hydrolysis of glucosinolates by myrosinase, by homogenization in a mixture of equal volumes of dimethyl sulfoxide, dimethylformamide, and acetonitrile at -50 degrees C. Extracts of 3-day-old broccoli sprouts (containing either glucoraphanin or sulforaphane as the principal enzyme inducer) were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz(a)anthracene-treated rats. Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products (e.g., indole-3-carbinol) that can enhance tumorigenesis. Hence, small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety.
1,182 citations