Dual activity of anthocyanidin reductase supports the dominant plant proanthocyanidin extension unit pathway

Proanthocyanidins (PAs) are plant natural products important for agriculture and human health. They are polymers of flavan-3-ol subunits, commonly (−)-epicatechin and/or (+)-catechin, but the source of the in planta extension unit that comprises the bulk of the polymer remains unclear, as does how PA composition is determined in different plant species. Anthocyanidin reductase (ANR) can generate 2,3-cis-epicatechin as a PA starter unit from cyanidin, which itself arises from 2,3-trans-leucocyanidin, but ANR proteins from different species produce mixtures of flavan-3-ols with different stereochemistries in vitro. Genetic and biochemical analyses here show that ANR has dual activity and is involved not only in the production of (−)-epicatechin starter units but also in the formation of 2,3-cis-leucocyanidin to serve as (−)-epicatechin extension units. Differences in the product specificities of ANRs account for the presence/absence of PA polymerization and the compositions of PAs across plant species.

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Plant Natural Products for Human Health

International Journal of Molecular Sciences ◽

10.3390/ijms20040830 ◽

2019 ◽

Vol 20 (4) ◽

pp. 830 ◽

Cited By ~ 12

Author(s):

Chun-Tao Che ◽

Hongjie Zhang

Keyword(s):

Natural Products ◽

Human Health ◽

Clinical Effects ◽

Special Issue ◽

Plant Natural Products ◽

Global Trend ◽

Pharmacokinetic Properties ◽

Health Related

The aim of this Special Issue on “Plant Natural Products for Human Health” is to compile a series of scientific reports to demonstrate the medicinal potential of plant natural products, such as in vitro and in vivo activities, clinical effects, mechanisms of action, structure-activity relationships, and pharmacokinetic properties. With the global trend growing in popularity for botanical dietary supplements and phytopharmaceuticals, it is hoped that this Special Issue would serve as a timely reference for researchers and scholars who are interested in the discovery of potentially useful molecules from plant sources for health-related applications.

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Chemical Diversity of Plant Cyanogenic Glycosides: An Overview of Reported Natural Products

Molecules ◽

10.3390/molecules26030719 ◽

2021 ◽

Vol 26 (3) ◽

pp. 719

Author(s):

Meri Yulvianti ◽

Christian Zidorn

Keyword(s):

Natural Products ◽

Plant Species ◽

Chemical Diversity ◽

Cyanogenic Glycosides ◽

Sugar Moiety ◽

Plant Natural Products ◽

Naturally Occurring

Cyanogenic glycosides are an important and widespread class of plant natural products, which are however structurally less diverse than many other classes of natural products. So far, 112 naturally occurring cyanogenic glycosides have been described in the phytochemical literature. Currently, these unique compounds have been reported from more than 2500 plant species. Natural cyanogenic glycosides show variations regarding both the aglycone and the sugar part of the molecules. The predominant sugar moiety is glucose but many substitution patterns of this glucose moiety exist in nature. Regarding the aglycone moiety, four different basic classes can be distinguished, aliphatic, cyclic, aromatic, and heterocyclic aglycones. Our overview covers all cyanogenic glycosides isolated from plants and includes 33 compounds with a non-cyclic aglycone, 20 cyclopentane derivatives, 55 natural products with an aromatic aglycone, and four dihydropyridone derivatives. In the following sections, we will provide an overview about the chemical diversity known so far and mention the first source from which the respective compounds had been isolated. This review will serve as a first reference for researchers trying to find new cyanogenic glycosides and highlights some gaps in the knowledge about the exact structures of already described compounds.

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Plant natural products: a primerThe present review is one in the special series of reviews on animal–plant interactions.

Canadian Journal of Zoology ◽

10.1139/z10-035 ◽

2010 ◽

Vol 88 (7) ◽

pp. 601-614 ◽

Cited By ~ 12

Author(s):

M. A. Bernards

Keyword(s):

Natural Products ◽

Structural Diversity ◽

Structural Type ◽

Biological Functions ◽

Plant Interactions ◽

In Planta ◽

Functional Roles ◽

Chemical Mechanisms ◽

Know How ◽

Plant Natural Products

Over the course of evolution, plants have adapted various structural and chemical mechanisms to protect themselves and interact with their environment. The chemical mechanisms are largely based on the secondary metabolites or natural products. Although plant natural products are generally divided into three main categories (terpenoids, alkaloids, and phenylpropanoids) that are based on structural type and biosynthetic origin, there are many other smaller categories of unique compounds. Many important in planta biological functions can be attributed to plant natural products, in large part, owing to their tremendous structural diversity. To understand the functional roles of plant natural products, both as protective compounds and interorganismal signals, it is important to know how they are formed in plants. This minireview provides a general background about the three main categories of plant natural products, their biosynthetic origins, and their structural diversity.

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Plant Natural Products: Promising Resources for Cancer Chemoprevention

Molecules ◽

10.3390/molecules26040933 ◽

2021 ◽

Vol 26 (4) ◽

pp. 933

Author(s):

Li Ma ◽

Mengmeng Zhang ◽

Rong Zhao ◽

Dan Wang ◽

Yuerong Ma ◽

...

Keyword(s):

Natural Products ◽

Human Health ◽

Cancer Chemoprevention ◽

Sulfur Compounds ◽

Life Safety ◽

Plant Natural Products ◽

Therapeutic Drugs ◽

Induction Of Apoptosis ◽

Promising Source

Cancer is a major factor threatening human health and life safety, and there is a lack of safe and effective therapeutic drugs. Intervention and prevention in premalignant process are effective ways to reverse carcinogenesis and prevent cancer from occurring. Plant natural products are rich in sources and are a promising source for cancer chemoprevention. This article reviews the chemopreventive effects of natural products, especially focused on polyphenols, flavonoids, monoterpene and triterpenoids, sulfur compounds, and cellulose. Meanwhile, the main mechanisms include induction of apoptosis, antiproliferation and inhibition of metastasis are briefly summarized. In conclusion, this article provides evidence for natural products remaining a prominent source of cancer chemoprevention.

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Phytosterols: Potential Metabolic Modulators in Neurodegenerative Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms222212255 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12255

Author(s):

Niti Sharma ◽

Mario A. Tan ◽

Seong Soo A. An

Keyword(s):

Natural Products ◽

Neurodegenerative Diseases ◽

Plant Species ◽

Biological Activities ◽

Herbal Medicines ◽

Pharmacological Activities ◽

Isolated Structures ◽

Biological And Pharmacological Activities

Phytosterols constitute a class of natural products that are an important component of diet and have vast applications in foods, cosmetics, and herbal medicines. With many and diverse isolated structures in nature, they exhibit a broad range of biological and pharmacological activities. Among over 200 types of phytosterols, stigmasterol and β-sitosterol were ubiquitous in many plant species, exhibiting important aspects of activities related to neurodegenerative diseases. Hence, this mini-review presented an overview of the reported studies on selected phytosterols related to neurodegenerative diseases. It covered the major phytosterols based on biosynthetic considerations, including other phytosterols with significant in vitro and in vivo biological activities.

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Exploring the Functional Relationship between y-Type Thioredoxins and 2-Cys Peroxiredoxins in Arabidopsis Chloroplasts

Antioxidants ◽

10.3390/antiox9111072 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1072

Author(s):

Ana Jurado-Flores ◽

Víctor Delgado-Requerey ◽

Alicia Gálvez-Ramírez ◽

Leonor Puerto-Galán ◽

Juan Manuel Pérez-Ruiz ◽

...

Keyword(s):

Functional Relationship ◽

Redox Balance ◽

Photosynthetic Performance ◽

Fine Tuning ◽

Minor Effect ◽

Large Set ◽

In Planta ◽

Arabidopsis Mutants ◽

Biochemical Analyses

Thioredoxins (Trxs) are small, ubiquitous enzymes that catalyze disulphide–dithiol interchange in target enzymes. The large set of chloroplast Trxs, including f, m, x and y subtypes, use reducing equivalents fueled by photoreduced ferredoxin (Fdx) for fine-tuning photosynthetic performance and metabolism through the control of the activity of redox-sensitive proteins. Although biochemical analyses suggested functional diversity of chloroplast Trxs, genetic studies have established that deficiency in a particular Trx subtype has subtle phenotypic effects, leading to the proposal that the Trx isoforms are functionally redundant. In addition, chloroplasts contain an NADPH-dependent Trx reductase with a joint Trx domain, termed NTRC. Interestingly, Arabidopsis mutants combining the deficiencies of x- or f-type Trxs and NTRC display very severe growth inhibition phenotypes, which are partially rescued by decreased levels of 2-Cys peroxiredoxins (Prxs). These findings indicate that the reducing capacity of Trxs f and x is modulated by the redox balance of 2-Cys Prxs, which is controlled by NTRC. In this study, we explored whether NTRC acts as a master regulator of the pool of chloroplast Trxs by analyzing its functional relationship with Trxs y. While Trx y interacts with 2-Cys Prxs in vitro and in planta, the analysis of Arabidopsis mutants devoid of NTRC and Trxs y suggests that Trxs y have only a minor effect, if any, on the redox state of 2-Cys Prxs.

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