Effect of maturity on macromineral content of selected leafy vegetables. (1/12)

Macro mineral contents were estimated in commonly consumed green leafy vegetables in India, namely; Koyyathotakura and Peddathotakura (varieties of Amaranthus species); Erragogu and Tellagogu (variety of Hibiscus species); Gangabayalakura (Portulaca olereceo) and Palak (Spineces olerecea) at three different stages of maturity. Varietal differences were also observed. The results of the study showed that as the plant matured from stage I (15 days) to stage II (30 days) calcium and magnesium content increased. In contrast, phosphorus content decreased as the plant matured. Varietal differences were also observed at different stages of maturity. The results also indicated that the consumption of green leafy vegetables at stage I (15 days) and stage II (30 days) potentially provide the greatest amount of minerals.  (+info)

Characterization and functional identification of a novel plant 4,5-extradiol dioxygenase involved in betalain pigment biosynthesis in Portulaca grandiflora. (2/12)

Betalains are pigments that replace anthocyanins in the majority of families of the plant order Caryophyllales. Betalamic acid is the common chromophore of betalains. The key enzyme of the betalain biosynthetic pathway is an extradiol dioxygenase that opens the cyclic ring of dihydroxy-phenylalanine (DOPA) between carbons 4 and 5, thus producing an unstable seco-DOPA that rearranges nonenzymatically to betalamic acid. A gene for a 4,5-DOPA-dioxygenase has already been isolated from the fungus Amanita muscaria, but no homolog was ever found in plants. To identify the plant gene, we constructed subtractive libraries between different colored phenotypes of isogenic lines of Portulaca grandiflora (Portulacaceae) and between different stages of flower bud formation. Using in silico analysis of differentially expressed cDNAs, we identified a candidate showing strong homology at the level of translated protein with the LigB domain present in several bacterial extradiol 4,5-dioxygenases. The gene was expressed only in colored flower petals. The function of this gene in the betalain biosynthetic pathway was confirmed by biolistic genetic complementation in white petals of P. grandiflora genotypes lacking the gene for color formation. This gene named DODA is the first characterized member of a novel family of plant dioxygenases phylogenetically distinct from Amanita sp. DOPA-dioxygenase. Homologs of DODA are present not only in betalain-producing plants but also, albeit with some changes near the catalytic site, in other angiosperms and in the bryophyte Physcomitrella patens. These homologs are part of a novel conserved plant gene family probably involved in aromatic compound metabolism.  (+info)

Protective effect of Portulaca oleracea extracts on hypoxic nerve tissue and its mechanism. (3/12)

The aim of this study was to investigate whether Portulaca oleracea (PO) extracts have hypoxic neuroprotective effects and if so, by what mechanism. After being orally administrated with the PO extracts or distilled water for seven days, adult male BALB/c mice were adapted to a normobaric low oxygen environment (10% oxygen and 90% nitrogen) for different time and then were sacrificed. The mouse cortices were used for histological analysis by hematoxylin and eosin (H-E staining). The activities of pyruvate kinase (PK), phosphofructokinase (PFK), lactic acid (LD) and the level of lactate dehydroenase (LDH) and ATP were detected, and the mRNA and protein levels of EPO in the cortices were analyzed. PC-12 cells and primarily cultured nerve cells were used for 3-(4,5-Dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. The degree of LDH in the cell culture medium was tested. The results showed that the PO extracts enhanced the EPO mRNA and protein expression in the mouse cortices. Compared to the control group, the mouse in the group treated with the PO extracts by 1 g/d had significantly higher activities of PF, PFK, LDH and higher levels of ATP in the cortices, especially under the hypoxic environment for 24 hours. Histological analysis indicated that the extracts lessened the inflammation damage of the mouse brain. MTT assay results showed the PO extracts or the herb-containing serum raised the viability of the cells under the tested hypoxic conditions and decreased the degree of LDH in the culture medium in a dose-dependent manner. We thus demonstrated that the PO extracts had protective effects on hypoxic nerve tissue.  (+info)

Hypoglycemic effects of crude polysaccharide from Purslane. (4/12)

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Characterization of structures and antiviral effects of polysaccharides from Portulaca oleracea L. (5/12)

Three polysaccharides including a neutral polysaccharide (RN), an acidic polysaccharide (RA) and a pectic polysaccharide (RP) were isolated from aerial part of Portulaca oleracea L. and evaluated for their anti-herpes simplex virus type 2 (HSV-2) and anti-influenza A virus (IFV-A). RN was found to consist of glucose (Glc), mannose (Man) and arabinose (Ara) with small amounts of galactose (Gal), and identified to be an arabinoglucomannan. RA was mainly composed of Gal and Ara with a small proportion of glucuronic acid (GlcA). It was characterized as a type II arabinogalactan (AGII), which consisted of a 1,3-, 1,6- and 1,3,6-linked galactopyranosyl (Galp) and non-reducing terminal and 1,5-linked arabinofuranosyl (Araf) residues. RP was deduced to be a pectin, which consisted of a predominant amount of galacturonic acid (GalA) with small amounts of Gal, rhamnose (Rha) and Ara. The GalA residues were found to be highly methyl-esterified and partially acetylated. Results of antiviral tests showed that only RP had anti-HSV-2 activity. Furthermore, its anti-HSV-2 target was elucidated to be the step of virus penetration into host cells. No marked virucidal activity of RP was observed.  (+info)

Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3-C4 intermediate in genus Portulaca L. (Portulacaceae). (6/12)

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Molecular cloning and partial characterization of a peroxidase gene expressed in the roots of Portulaca oleracea cv., one potentially useful in the remediation of phenolic pollutants. (7/12)

Portulaca (Portulaca oleracea cv.) efficiently removes phenolic pollutants from hydroponic solution. In plant roots, peroxidase (PRX) is thought to be involved in the removal of phenolic pollutants by the cross-linking them to cell wall polysaccharides or proteins at the expense of reduction of hydrogen peroxide (H(2)O(2)). In this study, we found that portulaca roots secreted an acidic PRX isozyme that had relatively high H(2)O(2) affinity. We isolated five PRX genes, and the recombinant PRX proteins produced in cultured tobacco cells were partially characterized. Among these genes, PoPRX2 probably encoded the acidic PRX isozyme. PoPRX2 had an extra N-terminal region which has not been reported for other PRX proteins. We found that PoPRX2 oxidized phenolic pollutants, including bisphenol A, octylphenol, nonylphenol, and 17beta-estradiol. In addition, we found that the Cys261 residue of PoPRX2 played an important role in the determination of affinity for H(2)O(2) and stability toward H(2)O(2).  (+info)

Characterization of bisphenol A metabolites produced by Portulaca oleracea cv. by liquid chromatography coupled with tandem mass spectrometry. (8/12)

The garden plant portulaca (Portulaca oleracea cv.) efficiently removes bisphenol A (BPA), an endocrine-disrupting chemical, from a hydroponic solution, but the molecular mechanisms underlying BPA metabolism by portulaca remain unclear. In this study, BPA metabolites converted by portulaca were analyzed by liquid chromatography coupled with tandem mass spectrometry. We observed the hydroxylation of BPA and the oxidization of it to quinone. Polyphenol oxidases are likely to contribute to BPA degradation by portulaca.  (+info)

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