ABSTRACT
The cyclic peptide alkaloid, chamaedrine, was isolated from the roots of Melochia chamaedris (Sterculiaceae), along with four known cyclic peptide alkaloids (adouetine X, frangulaline, scutianine B and scutianine C), and waltherione A, parasorbic acid, propacine, and (-)-epicatequine. Their structures were elucidated on the basis of spectroscopic analysis, especially by 2D NMR ((1)H-(1)H-COSY, NOESY, HMQC, HMBC).
Subject(s)
Alkaloids/chemistry , Malvaceae/chemistry , Peptides, Cyclic/chemistry , Plant Extracts/chemistry , Plant Roots/chemistry , Alkaloids/isolation & purification , Amino Acids/analysis , Hydrolysis , Magnetic Resonance Spectroscopy , Molecular Conformation , Peptides, Cyclic/isolation & purification , Plant Extracts/isolation & purificationABSTRACT
The antimicrobial activity of the methanol extract from Solidago microglossa roots, essential oil from its aerial part and some isolated compounds was investigated. The oil exhibited concentration-dependent activity against all the tested bacteria and yeasts.
Subject(s)
Anti-Infective Agents/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Phytotherapy , Plant Oils/pharmacology , Solidago , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/therapeutic use , Anti-Infective Agents/toxicity , Artemia/drug effects , Flowers , Humans , Microbial Sensitivity Tests , Plant Leaves , Plant Oils/administration & dosage , Plant Oils/therapeutic use , Plant Oils/toxicity , Plant RootsABSTRACT
The antimicrobial activity of Hyamatantus sucuba roots methanol extract, fractions prepared from this extract (n-hexane, CHCl(3), EtOAc, and n-butanol) and some isolated compounds were evaluated against some Gram(+) and Gram(-) bacteria and yeasts.
Subject(s)
Anti-Infective Agents/pharmacology , Apocynaceae/chemistry , Plant Extracts/pharmacology , Alkaloids/isolation & purification , Anti-Infective Agents/isolation & purification , Bacillus subtilis/drug effects , Candida/drug effects , Escherichia coli/drug effects , Iridoids , Klebsiella pneumoniae/drug effects , Lactones/isolation & purification , Microbial Sensitivity Tests , Plant Leaves/chemistry , Plant Roots/chemistry , Plants, Medicinal/chemistry , Pseudomonas aeruginosa/drug effects , Quinazolines/isolation & purification , Saccharomyces cerevisiae/drug effects , Salmonella/drug effects , Staphylococcus/drug effectsABSTRACT
gamma-Zein, a maize storage protein with an N-terminal proline-rich repetitive domain (gamma-ZNPRD), is located at the periphery of protein bodies. This domain appears to be indispensable for the aggregation of the protein on the surface of the organelle. The peptide (VHLPPP)8, spanning the gamma-ZNPRD, adopts a polyproline II (PPII) conformation that gives an amphipathic helix different from the alpha-helix. We used atomic force microscopy to study the surface organisation of the octamer, and transmission electron microscopy to visualise aggregates of the peptide in aqueous solution. We consider two self-assembly patterns that take account of the observed features. The micellar one fits best with the experimental results presented. Moreover, we found that this peptide has properties associated with surfactants, and form micelles in solution. This spontaneous amphipathic arrangement of the gamma-ZNPRD suggests a mechanism of gamma-zein deposition inside maize protein bodies.
Subject(s)
Zea mays/chemistry , Zein/chemistry , Zein/ultrastructure , Amino Acid Sequence , Micelles , Microscopy, Atomic Force , Microscopy, Electron , Models, Molecular , Organelles/chemistry , Organelles/metabolism , Protein Binding , Protein Structure, Quaternary , Protein Structure, Secondary , Protein Structure, Tertiary , Solutions , Surface-Active Agents/chemistry , Surface-Active Agents/metabolism , Zea mays/cytology , Zein/metabolismABSTRACT
Two new cyclopeptides, named discarene C (1) and discarene D (2), have been isolated from the bark of Discaria americana, along with seven known cyclopeptide alkaloids. The structures of the new compounds were determined by spectroscopic methods, mainly NMR. The stereochemistry of the ring amino acid residues have been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases.
Subject(s)
Alkaloids/isolation & purification , Peptides, Cyclic/isolation & purification , Plants, Medicinal/chemistry , Alkaloids/chemistry , Brazil , Chromatography, Gas , Chromatography, Thin Layer , Leucine/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Peptides, Cyclic/chemistry , Phenylalanine/chemistry , Plant Roots/chemistry , Spectrophotometry, Infrared , StereoisomerismABSTRACT
During maize seed development, endosperm cells synthesize large amounts of storage proteins, alpha-, beta-, and gamma-zeins, which accumulate within endoplasmic reticulum (ER)-derived protein bodies. The absence of lysine in all zein polypeptides results in an imbalance in the amino acid composition of maize seeds. We modified the maize gamma-zein gene through the introduction of lysine-rich (Pro-Lys)n coding sequences at different sites of the gamma-zein coding sequence. Maize endosperms were transiently transformed by biolistic bombardment with Lys-rich gamma-zein constructs under the control of the 1.7 kb gamma-zein seed-specific promoter and the cauliflower mosaic virus (CaMV) 35S promoter. When (Pro-Lys)n sequences were inserted contiguous to or in substitution of the Pro-Xaa region of the gamma-zein, high levels of protein were observed. In contrast, when (Pro-Lys)n sequences were inserted five residues from the C-terminal, the transcript was present but modified protein was not detected. These results suggest that only an appropriate positioning of Lys-rich inserts leads to the modified molecule displaying correct folding and stability. Subcellular localization analyses and immunoelectron microscopy studies on isolated protein bodies demonstrated that modified gamma-zeins accumulate within these organelles and co-localized with endogenous alpha- and gamma-zeins. The studies reported here show the feasibility of manipulating the gamma-zein gene in order to obtain stable and correctly targeted Lys-rich zeins in maize seeds.
