•Advances in bioaccessibility and bioavailability of carotenoids in the past 5 years.•Focus on cooking and traditional and novel processing techniques.•Consideration of storage in the plant and lipid ...co-consumption.•Competitive or synergistic effects of other compounds discussed.
This article aims to highlight discoveries during the past 5 years regarding aspects of the bioaccessibility of carotenoids and apo-carotenoids, their uptake by intestinal cells, and their absorption that have received less attention in other recent reviews. New discoveries on the impact of various types of lipid on carotenoid bioavailability, their liberation from plant chromoplasts, and the effects of components such as pectin in the food matrix are discussed. Comparison of thermal and non-thermal processing techniques, as well as various styles of food preparation, also are considered. Finally, present knowledge of the impact of dietary lipids, including omega-3 fatty acids, fat soluble vitamins, phytosterols, and minerals, as well as novel excipient foods on carotenoid bioaccessibility and bioavailability, are considered.
In an elaborate form of inter-species exploitation, many insects hijack plant development to induce novel plant organs called galls that provide the insect with a source of nutrition and a temporary ...home. Galls result from dramatic reprogramming of plant cell biology driven by insect molecules, but the roles of specific insect molecules in gall development have not yet been determined. Here, we study the aphid Hormaphis cornu, which makes distinctive “cone” galls on leaves of witch hazel Hamamelis virginiana. We found that derived genetic variants in the aphid gene determinant of gall color (dgc) are associated with strong downregulation of dgc transcription in aphid salivary glands, upregulation in galls of seven genes involved in anthocyanin synthesis, and deposition of two red anthocyanins in galls. We hypothesize that aphids inject DGC protein into galls and that this results in differential expression of a small number of plant genes. dgc is a member of a large, diverse family of novel predicted secreted proteins characterized by a pair of widely spaced cysteine-tyrosine-cysteine (CYC) residues, which we named BICYCLE proteins. bicycle genes are most strongly expressed in the salivary glands specifically of galling aphid generations, suggesting that they may regulate many aspects of gall development. bicycle genes have experienced unusually frequent diversifying selection, consistent with their potential role controlling gall development in a molecular arms race between aphids and their host plants.
•Novel aphid bicycle genes contribute to plant gall development•Variation in a bicycle gene alters plant gene expression and a gall phenotype•bicycle genes encode a large family of diverse, secreted, cysteine-rich proteins•Many bicycle genes have experienced repeated diversifying selection
Korgaonkar et al. report on novel secreted aphid proteins encoded by bicycle genes. Variation in the bicycle gene determinant of gall color alters expression of targeted plant genes, suggesting that BICYCLE proteins modulate gall development.
Chlorophyll is the vivid chromophore which imparts the green color to plant leaves, and is consumed by humans through green vegetables. The basic porphyrin structure of chlorophyll binds magnesium in ...plants, but can bind different divalent metals (e.g., copper, zinc, iron) facilitated by food processing techniques and/or chemical synthesis. This review covers the known elements of chlorophyll and metallo‐chlorophyll absorption, distribution, metabolism, excretion in vitro and in vivo. The review discusses what is understood about the ability of these novel metallo‐chlorophyll derivatives to deliver essential metals. This review also detail chlorophyll and metallo‐chlorophyll toxin binding properties which largely occur during digestion, focusing on toxins including dioxins, heterocyclic aromatic amines, polyaromatic hydrocarbons, and aflatoxin. Finally, the article highlights the gaps in the understanding of the metabolism and metal and toxin‐binding bioactivity of this family of molecules.
Chlorophylls and metallo (i.e., copper, iron, zinc) chlorophyll derivatives are studied for their ability to survive digestion, be absorbed, and metabolized in the human body. Evidence also suggests they have bioactivity. Iron chlorophyllin in particular is as good as heme in delivering iron to enterocyte‐like Caco‐2 cells, and delivers more iron than FeSO4. Moreover, metallo‐chlorophyllins can bind toxins (i.e., dioxins, heterocyclic aromatic amines, polyaromatic hydrocarbons, and aflatoxin) to prevent absorption.
•Iron chlorophyllin-bound iron was less bioaccessible than iron from FeSO4•Caco-2 cells synthesized 2.5x more ferritin following incubation with IC vs. FeSO4•Cell ferritin was increased 8x following ...incubation with IC+ascorbic acid+albumin
Iron deficiency remains a top nutrient deficiency worldwide. Iron chlorophyllin (IC), a compound structurally analogous to heme, utilizes the protoporphyrin ring of chlorophyll to bind iron. IC has previously been shown to deliver more iron to Caco-2 cells than FeSO4, the most common form prescribed for supplementation. However, previous test conditions used digestive conditions outside of those observed in humans. This study sought to assess IC bioaccessibility and Caco-2 cell uptake using physiologically relevant digestive solutions, pH, and incubation time, as compared to other iron sources (i.e. FeSO4, and hemoglobin (Hb)). Co-digestion with ascorbic acid (AA) and albumin was also investigated.
Following gastric, duodenal, and jejunal digestion, IC-bound iron was less bioaccessible than iron delivered as FeSO4, and IC-bound iron was less bioaccessible than Hb-bound iron. IC-bound iron bioaccessibility was not affected by AA and was enhanced 2x with co-digested with a low dose of albumin. However, Caco-2 cell incubation with IC-containing digesta increased cell ferritin 2.5x more than FeSO4 alone, and less than Hb. IC with AA or with 400 mg albumin also increased cell ferritin more than IC alone, with the greatest increases observed following incubation of digesta containing IC + AA + 400 mg albumin.
These results suggest IC can serve as an improved source of iron for supplementation as compared to FeSO4. These results also support further in vivo investigations of IC-based iron delivery in populations at risk of iron deficiency.
Consumption of diets rich in fruits and vegetables, which provide some fat-soluble vitamins and many phytochemicals, is associated with a lower risk of developing certain degenerative diseases. It is ...well accepted that not only the parent compounds, but also their derivatives formed upon enzymatic or nonenzymatic transformations, can produce protective biological effects. These derivatives can be formed during food storage, processing, or cooking. They can also be formed in the lumen of the upper digestive tract during digestion, or via metabolism by microbiota in the colon. This review compiles the known metabolites of fat-soluble vitamins and fat-soluble phytochemicals (FSV and FSP) that have been identified in food and in the human digestive tract, or could potentially be present based on the known reactivity of the parent compounds in normal or pathological conditions, or following surgical interventions of the digestive tract or consumption of xenobiotics known to impair lipid absorption. It also covers the very limited data available on the bioavailability (absorption, intestinal mucosa metabolism) and summarizes their effects on health. Notably, despite great interest in identifying bioactive derivatives of FSV and FSP, studying their absorption, and probing their putative health effects, much research remains to be conducted to understand and capitalize on the potential of these molecules to preserve health.
•Some derivatives of fat-soluble vitamins and phytochemicals have biological effects.•They can be formed upon enzymatic modifications or physicochemical degradations.•They can be formed in food, the upper digestive tract lumen or via the microbiota.•Some diseases of the gastrointestinal tract affect the production of derivatives.•Some lipid absorption inhibitors affect the production of some of the derivatives.
Enzymology of vertebrate carotenoid oxygenases Harrison, Earl H.; Kopec, Rachel E.
Biochimica et biophysica acta. Molecular and cell biology of lipids,
11/2020, Letnik:
1865, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Mammals and higher vertebrates including humans have only three members of the carotenoid cleavage dioxygenase family of enzymes. This review focuses on the two that function as carotenoid ...oxygenases. β-Carotene 15,15′-dioxygenase (BCO1) catalyzes the oxidative cleavage of the central 15,15′ carbon-carbon double of β-carotene bond by addition of molecular oxygen. The product of the reaction is retinaldehyde (retinal or β-apo-15-carotenal). Thus, BCO1 is the enzyme responsible for the conversion of provitamin A carotenoids to vitamin A. It also cleaves the 15,15′ bond of β-apocarotenals to yield retinal and of lycopene to yield apo-15-lycopenal. β-Carotene 9′,10′-dioxygenase (BCO2) catalyzes the cleavage of the 9,10 and 9′,10′ double bonds of a wider variety of carotenoids, including both provitamin A and non-provitamin A carotenoids, as well as the xanthophylls, lutein and zeaxanthin. Indeed, the enzyme shows a marked preference for utilization of these xanthophylls and other substrates with hydroxylated terminal rings. Studies of the phenotypes of BCO1 null, BCO2 null, and BCO1/2 double knockout mice and of humans with polymorphisms in the enzymes, has clarified the role of these enzymes in whole body carotenoid and vitamin A homeostasis. These studies also demonstrate the relationship between enzyme expression and whole body lipid and energy metabolism and oxidative stress.
In addition, relationships between BCO1 and BCO2 and the development or risk of metabolic diseases, eye diseases and cancer have been observed. While the precise roles of the enzymes in the pathophysiology of most of these diseases is not presently clear, these gaps in knowledge provide fertile ground for rigorous future investigations.
This article is part of a Special Issue entitled Carotenoids: Recent Advances in Cell and Molecular Biology edited by Johannes von Lintig and Loredana Quadro.
•Vertebrates have two carotenoid cleavage enzymes, a family widespread in other taxa.•BCO1 catalyzes central cleavage of dietary provitamin A carotenoids to retinaldehyde.•BCO2 catalyzes eccentric cleavage of a wider variety of carotenes and xanthophylls.•BCO1/2 function in vitamin A, carotenoid, lipid, energy, and oxidative homeostasis•BCO1/2 SNPs in humans are associated with metabolic, eye, and neoplastic diseases.
Asymmetric β-apo-carotenoids (nonvitamin A–active metabolites) of provitamin A carotenoids have been observed in humans, but no study has investigated their formation during digestion.
The aim of ...this study was to follow the formation and absorption of asymmetric β-apo-carotenoids during digestion.
Healthy men were intragastrically and intraduodenally intubated, and randomly assigned to consume a lipid-rich control meal (n = 3) or a lipid-rich test meal containing 20 mg 13C-10-β-carotene (n = 7). Digesta samples were collected over 5 h, and blood collected over 7 h. The triglyceride-rich lipoprotein (TRL) fractions of plasma were also isolated. Lipophilic extracts of digesta, plasma, and TRL were analyzed via a high-performance liquid chromatography-tandem mass spectrometry method developed to identify 13C-labeled β-apo-carotenals/carotenone, 13C-β-apo-carotenols, and 13C-β-apo-carotenoic acids.
Relative to 13C-β-carotene, 13C-β-apo-carotenal levels remained ∼3 orders of magnitude lower throughout digestion (no 13C-β-apo-carotenols, or 13C-β-apo-carotenoic acids were observed). A mixed model determined relative influence of digesta type and time on digesta metabolite level. Increasing time significantly increased the model levels of digesta 13C-β-apo-10′,12′,14′,15-carotenal and 13C-β-apo-13-carotenone (P < 0.05) and trended toward decreased 13C-β-apo-8′-carotenal (P = 0.0876). Gastric digesta were associated with a significantly higher level of 13C-β-apo-8′-carotenal (P = 0.0289), and lower levels of 13C-β-apo-12′,14′,15-carotenal (P < 0.05), relative to duodenal digesta. Anticipated retinoids, but no asymmetric 13C-β-apo-carotenals, 13C-β-apo-carotenols, or 13C-β-apo-carotenoic acids, were observed in the blood or TRL samples.
β-Carotene appears to be robust to digestion, with minor amounts of β-apo-carotenals/carotenone formed. Absence of asymmetric 13C-β-apo-carotenals in plasma and TRL suggests lack of absorption, levels below the limit of detection, lack of stability, or further conversion during the digestive process to as-yet unidentified products. Lack of asymmetric 13C-β-apo-carotenals in plasma also suggests a lack of postprandial intestinal BCO2 activity in healthy humans. This trial was registered at clinicaltrials.gov as NCT03492593.
It has been postulated that chemical or enzymatic catabolism of carotenoids could produce apo‑carotenoids which have biological activity. Our objective was to generate and chemically characterize a ...series of apo‑luteinoids (i.e. products resulting from the catabolism of lutein) which could putatively be found in vivo. Lutein was oxidized using potassium permanganate to produce a series of apo‑luteinals/luteinone of subsequently shorter chain lengths, from apo‑8′‑luteinal to apo‑11‑luteinal. Sodium borohydride reduced this mixture into the corresponding alcohols (i.e. apo‑luteinols). Similarly, Tollens' reagent was employed to oxidize the aldehyde series into carboxylic acids (i.e. apo‑luteinoic acids). Mixtures of products were separated via HPLC and characterized in-line using photodiode array (PDA) and tandem mass spectrometry (MS-MS). A global HPLC-PDA-MS/MS method was developed to separate the products, and application of the methods to the symmetric xanthophyll zeaxanthin further confirmed the ε- and β-ring species. These methods can be employed for the study of lutein oxidation products in plants, foods and biological samples.
The wave of individuals impacted by dementia continues to rise rapidly as worldwide lifespan increases. Dietary strategies to slow cognitive decline and prolong time to clinical dementia remain ...understudied, but with potentially powerful public health consequences. Indeed, previously conducted large, randomized, placebo‐controlled trials of micronutrients remain an under‐leveraged resource to study changes in cognitive performance. As a motivating example, we highlight an ancillary report from the Physicians’ Health Study, where subjects randomized to β‐carotene (a provitamin A carotenoid) had a more attenuated change in longitudinal global cognitive performance and verbal memory, as compared to subjects randomized to placebo. Despite mechanistic evidence from cell and animal studies supporting a vitamin A‐mediated role in the biology associated with cognition, limited follow‐up work has been conducted. We argue that dietary factors (including provitamin A) deserve a second look, leveraging multi‐omic approaches, to elucidate how they may mitigate cognitive decline and dementia risk.
Lycopene is a non-provitamin A carotenoid that is responsible for the red to pink colors seen in tomatoes, pink grapefruit, and other foods. Processed tomato products are the primary dietary lycopene ...source in the United States. Unlike many other natural compounds, lycopene is generally stable to processing when present in the plant tissue matrix. Recently, lycopene has also been studied in relation to its potential health effects. Although promising data from epidemiological, as well as cell culture and animal, studies suggest that lycopene and the consumption of lycopene containing foods may affect cancer or cardiovascular disease risk, more clinical trial data is needed to support this hypothesis. In addition, future studies are required to understand the mechanism(s) whereby lycopene or its metabolites are proven to possess biological activity in humans.
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