Secondary metabolites in plants: transport and self-tolerance mechanisms

Shitan, Nobukazu

doi:10.1080/09168451.2016.1151344

Cited by 182 publications

(115 citation statements)

References 151 publications

(167 reference statements)

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“…In fact, the phytochemistry of the EAF of M. hirsuta revealed that, besides these triterpenes, other metabolites are also present in this fraction (steroids, phenols, tannins, anthocyanins, anthocyanidins and flavonoids). Therefore, the cytotoxic activity previously observed in the EAF might be related to the presence or interaction of these additional constituents (Maciel et al 2002, Shitan 2016, thus revealing the importance of bioassays and toxicity tests of isolated active compounds prior to their clinical utilization and prevention of potential side effects (Rates 2001).…”

Section: Phytochemistry and Toxicity Of Mansoa Hirsuta 323mentioning

confidence: 99%

Evaluation of cytogenotoxicity, antioxidant and hypoglycemiant activities of isolate compounds from Mansoa hirsuta D.C. (Bignoniaceae)

Pereira

Queiroz

Siqueira

et al. 2017

An. Acad. Bras. Ciênc.

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Mansoa hirsuta (Bignoniaceae) is a native plant from caatinga in Brazilian semiarid. This plant has been locally used as antimicrobial and hypoglycemiant agents, but their action mechanisms and toxicity remain largely unknown. Therefore, we evaluated the composition and antioxidant, cytoprotective and hypoglycemiant effects of raw extract, fractions and compounds from leaves of M. hirsuta. The cytogenotoxic effects of ursolic and oleanolic acids, the main phytotherapic components of this plant, were assessed. The raw extract and fractions presented steroids, saponins, flavonols, flavanonols, flavanones, xanthones, phenols, tannins, anthocyanins, anthocyanidins and flavonoids. The ethyl acetate fraction inhibited efficiently the cascade of lipid peroxidation while the hydroalcoholic fraction was richer in total phenols and more efficient in capturing 2,2-diphenyl-1-picrylhydrazyl ( · DPPH) and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS ·+ ) radicals. The isolated fraction of M. hirsuta also inhibited the α-amylase activity. Cytotoxic effects were absent in both raw extract and fractions while ursolic+oleanolic acids were efficient in protecting cells after exposure to hydrogen peroxide. Moreover, this mixture of acid shad no significant interference on the mitotic index and frequency of nuclear and/ or chromosomal abnormalities in Allium cepa test. Therefore, M. hirsuta represents a potential source of phytochemicals against inflammatory and oxidative pathologies, including diabetes.

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Section: Phytochemistry and Toxicity Of Mansoa Hirsuta 323mentioning

confidence: 99%

Evaluation of cytogenotoxicity, antioxidant and hypoglycemiant activities of isolate compounds from Mansoa hirsuta D.C. (Bignoniaceae)

Pereira

Queiroz

Siqueira

et al. 2017

An. Acad. Bras. Ciênc.

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“…Many hydrophobic specialized metabolites, such as terpenoids and meroterpenoids, are secreted to specific extracellular compartments or the rhizosphere, although only a few studies have reported the transport mechanism of these natural products (Shitan, 2016). For example, a recent study demonstrated that shikonin, a naphthoquinone meroterpenoid, is secreted from L. erythrorhizon hairy roots through pathways common to the ADP-ribosylation factor/guanine nucleotide-exchange factor system and actin filament polymerization (Tatsumi et al, 2016).…”

Section: Glandular Scales Are the Meroterpenoid-producing Factories Imentioning

confidence: 99%

An Aromatic Farnesyltransferase Functions in Biosynthesis of the Anti-HIV Meroterpenoid Daurichromenic Acid

et al. 2018

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Rhododendron dauricum produces daurichromenic acid, an anti-HIV meroterpenoid, via oxidative cyclization of the farnesyl group of grifolic acid. The prenyltransferase (PT) that synthesizes grifolic acid is a farnesyltransferase in plant specialized metabolism. In this study, we demonstrated that the isoprenoid moiety of grifolic acid is derived from the 2-C-methyl-d-erythritol-4-phosphate pathway that takes place in plastids. We explored candidate sequences of plastid-localized PT homologs and identified a cDNA for this PT, RdPT1, which shares moderate sequence similarity with known aromatic PTs. RdPT1 is expressed exclusively in the glandular scales, where daurichromenic acid accumulates. In addition, the gene product was targeted to plastids in plant cells. The recombinant RdPT1 regiospecifically synthesized grifolic acid from orsellinic acid and farnesyl diphosphate, demonstrating that RdPT1 is the farnesyltransferase involved in daurichromenic acid biosynthesis. This enzyme strictly preferred orsellinic acid as a prenyl acceptor, whereas it had a relaxed specificity for prenyl donor structures, also accepting geranyl and geranylgeranyl diphosphates with modest efficiency to synthesize prenyl chain analogs of grifolic acid. Such a broad specificity is a unique catalytic feature of RdPT1 that is not shared among secondary metabolic aromatic PTs in plants. We discuss the unusual substrate preference of RdPT1 using a molecular modeling approach. The biochemical properties as well as the localization of RdPT1 suggest that this enzyme produces meroterpenoids in glandular scales cooperatively with previously identified daurichromenic acid synthase, probably for chemical defense on the surface of R. dauricum plants.

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“…Therefore, grifolic acid has to be effectively secreted once it is biosynthesized by an aromatic prenyltransferase. Many hydrophobic specialized metabolites are secreted, probably to serve in plant defense and/or to avoid self-poisoning, although only a few studies have been reported with respect to the mechanisms for transportation of these components (Shitan, 2016). For example, a diterpenoid sclareol in Nicotiana plumbaginifolia and monolignols in Arabidopsis (Arabidopsis thaliana) are transported to the apoplast by ATP-binding cassette transporters (Stukkens et al, 2005;Alejandro et al, 2012).…”

Section: Localization and Possible Physiological Function Of Dca In Rmentioning

confidence: 99%

Identification and Characterization of Daurichromenic Acid Synthase Active in Anti-HIV Biosynthesis

et al. 2017

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Daurichromenic acid (DCA) synthase catalyzes the oxidative cyclization of grifolic acid to produce DCA, an anti-HIV meroterpenoid isolated from We identified a novel cDNA encoding DCA synthase by transcriptome-based screening from young leaves of The gene coded for a 533-amino acid polypeptide with moderate homologies to flavin adenine dinucleotide oxidases from other plants. The primary structure contained an amino-terminal signal peptide and conserved amino acid residues to form bicovalent linkage to the flavin adenine dinucleotide isoalloxazine ring at histidine-112 and cysteine-175. In addition, the recombinant DCA synthase, purified from the culture supernatant of transgenic , exhibited structural and functional properties as a flavoprotein. The reaction mechanism of DCA synthase characterized herein partly shares a similarity with those of cannabinoid synthases from, whereas DCA synthase catalyzes a novel cyclization reaction of the farnesyl moiety of a meroterpenoid natural product of plant origin. Moreover, in this study, we present evidence that DCA is biosynthesized and accumulated specifically in the glandular scales, on the surface of plants, based on various analytical studies at the chemical, biochemical, and molecular levels. The extracellular localization of DCA also was confirmed by a confocal microscopic analysis of its autofluorescence. These data highlight the unique feature of DCA: the final step of biosynthesis is completed in apoplastic space, and it is highly accumulated outside the scale cells.

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Secondary metabolites in plants: transport and self-tolerance mechanisms

Cited by 182 publications

References 151 publications

Evaluation of cytogenotoxicity, antioxidant and hypoglycemiant activities of isolate compounds from Mansoa hirsuta D.C. (Bignoniaceae)

Evaluation of cytogenotoxicity, antioxidant and hypoglycemiant activities of isolate compounds from Mansoa hirsuta D.C. (Bignoniaceae)

An Aromatic Farnesyltransferase Functions in Biosynthesis of the Anti-HIV Meroterpenoid Daurichromenic Acid

Identification and Characterization of Daurichromenic Acid Synthase Active in Anti-HIV Biosynthesis

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