Seeds Of Phytolacca Americana Research Articles

GROWTH PARTICULARITIES OF AMERICAN POKEWEED – PLANT WITH MULTIPURPOSE UTILIZATION

American pokeweed (Phytolacca americana L.) is a good ornamental plant due to its ability to grow rapidly, broad and tall vegetation, and attractive grape-like fruits. However, American pokeweed and some useful chemical constituents, which accumulate in different parts of this plant, until present, in our opinion, are not utilised sufficient effectively. The leaves and seeds of Phytolacca americana L. produce pokeweed antiviral protein with increased antiviral and antifungal activities. Natural dyes accumulated in fruits can be used in the food, cosmetic, pharmaceutical and textile industries. The purpose of this work was to study the growth particularities of pokeweed plants propagated by seeds, and to establish the content and antioxidant activity of main constituents (polyphenols and colorant substances) in ripe fruits. American pokeweed demonstrated the excellent adaptivity of seeds and seedlings under different condition of germination, transplantation and cultivation. In season of 2019, the vegetation cycle of Phytolacca americana L. annual plants continued maximal 210 days (from March to November). The biometrical indexes of stems, racemes, fruits and seeds corresponded to similar characters reported by other scientists. The aqueous and hydroalcoholic extracts were obtained from ripe fresh fruits. The biggest amount of polyphenolic and colorant substances was found in aqueous extracts. The antioxidant activity of Phytolacca americana L. fruit extracts, evaluated in vitro by potentiometric procedure against the peroxyl free radicals, was in direct proportion to the content of polyphenols (r2=0.9563) and colorant substances (r2=0.9808). The colorant substances from American pokeweed fruits possessed the high antioxidant activity, IC50 was equal to 259.65±2.60mg/l.

Antitumor Activity of Americanin A Isolated from the Seeds of Phytolacca americana by Regulating the ATM/ATR Signaling Pathway and the Skp2-p27 Axis in Human Colon Cancer Cells.

The antiproliferative and antitumor activities of americanin A (1), a neolignan isolated from the seeds of Phytolacca americana, were investigated in human colon cancer cells. Compound 1 inhibited the proliferation of HCT116 human colon cancer cells both in vitro and in vivo. The induction of G2/M cell-cycle arrest by 1 was concomitant with regulation of the ataxia telangiectasia-mutated/ATM and Rad3-related (ATM/ATR) signaling pathway. Treatment with 1 activated ATM and ATR, initiating the subsequent signal transduction cascades that include checkpoint kinase 1 (Chk1), checkpoint kinase 2 (Chk2), and tumor suppressor p53. Another line of evidence underlined the significance of 1 in regulation of the S phase kinase-associated protein 2 (Skp2)-p27 axis. Compound 1 targeted selectively Skp2 for degradation and thereby stabilized p27. Therefore, compound 1 suppressed the activity of cyclin B1 and its partner cell division cycle 2 (cdc2) to prevent entry into mitosis. Furthermore, prolonged treatment with 1 induced apoptosis by producing excessive reactive oxygen species. The intraperitoneal administration of 1 inhibited the growth of HCT116 tumor xenografts in nude mice without any overt toxicity. Modulation of the ATM/ATR signaling pathway and the Skp2-p27 axis might be plausible mechanisms of action for the antiproliferative and antitumor activities of 1 in human colon cancer cells.

灵山湾国家森林公园垂序商陆土壤种子库时空动态及其对防除措施的响应

Soil seed banks are potential plant communities. Their temporal and spatial distribution patterns play an important role in future plant community dynamics and structure. Characteristics of the seed bank for Phytolacca americana affect the construction and function of future ecosystems in the invaded area. The ecological balance in the coastal shelterforest ecosystems in the Lingshan Bay National Forest Park has been severely affected by Phytolacca americana. Between2009 and 2014,we studied seed density and distribution pattern of Phyolacca americana in Pinus thunbergii forest,Robinia pseudoacacia forest,mixed Pinus thunbergii and R. pseudoacacia forest,and Amorpha fruticosa forest. We established five transects at 15 m intervals from the forest edge to the interior,set up 40 samples in each transect,and collected soil seed banks from the litter layer,0—2 cm soil layer,and 2—5 cm soil layer. We conducted a control trial in the R. pseudoacacia forest,which was extensively invaded by Phytolacca americana in 2009. We used physical( mowing and root cutting) and chemical( spraying herbicides) methods to control the growth of Phytolacca americana and chose A. fruticosa as the control. We investigated the seed bank in the control area,counted the number of seeds,and performed a germination test in the laboratory. The seeds of Phytolacca americana were found in all four types of forests,and the content of the seed bank decreased from the forest edge to the interior of the forest in the R. pseudoacacia and Pinus thunbergii forests. All the seeds were found within the top 5 cm of the soil layer,within which the lowest number of seeds was found in the 2—5 cm layer. We found( 1174 ± 713) seeds / m2 in one month in the seed bank from the R. pseudoacacia forest in 2009; the number of seeds increased to( 3207 ± 1072) seeds / m2 in October,in 2012 and( 4691 ± 1597) seeds / m2 in January,in2014. In the mixed forest,we found( 388 ± 713),( 1074 ± 713),and( 1767 ± 713) seeds / m2 in the seed bank in 2009,2012,and 2014,respectively. Between 2009 and 2014,less than 1000 seeds / m2 were found in the seed bank from the Pinus thunbergii and A. fruticosa forests. We compared the results of the two seed bank surveys conducted during 2009-2014: in the Pinus thunbergii and A. fruticosa forests,the number of seeds decreased by 46% and 44%,respectively,whereas in the R. pseudoacacia and mixed forests,an increase by 29. 9% and 35. 5%,respectively,was noted. The seed germination rate was less than 10% and decreased from the litter layer to the 2—5cm layer. Seedling regeneration,seed yield,and seed bank in the A. fruticosa forest were significantly lower than those in the forests where physical and chemical control methods were used. Physical and chemical control methods are useful in controlling Phytolacca americana; however,their effects are temporary and the use of biological control seems more practical. Our study showed that the seed bank of Phytolacca americana had an evident spatio- temporal heterogeneity,maintained a high reproductive potential,and can be used to control the invasion of Phytolacca americana by planting A. fruticosa. Our findings can help in the sustainable management of coastal shelter forests.

The Effect of Burial Depth on Removal of Seeds of Phytolacca americana

Although burial is known to have important effects on seed predation in a variety of habitats, the role of burial depth in affecting the removal of seeds in early- successional systems is poorly known. Phytolacca Americana (pokeweed) is a model species to examine the role of burial depth in affecting seed removal because it is common in early-successional habitats, studies suggest that seed removal is indicative of seed predation, and seed predation is related to the recruitment of mature plants. To determine how burial depth affects P. americana seed removal, 20 seeds of P. americana were buried at depths of 0, 1, or 3 cm in early-successional habitats at the Savannah River Site in South Carolina for over 6 weeks. The frequency with which seeds were encountered (as measured by the removal of at least one seed) and the proportion of seeds removed was significantly greater when seeds were on the soil surface (0 cm depth) compared to seeds that were buried 1 cm or 3 cm; there was no difference in encounter or removal between seeds at 1 cm or 3 cm. Our findings suggest that burial may have important consequences for P. americana population dynamics, because seed survival depends upon whether or not the seed is buried, and relatively shallow burial can yield large increases in seed survival. Because seed limitation is known to be an important determinant of plant community composition in early- successional systems, our work suggests that burial may play an unappreciated role in the dynamics of these communities by reducing predator-mediated seed limitation.

Crystal structure of pokeweed antiviral protein with well-defined sugars from seeds at 1.8 Å resolution

The crystal structure of pokeweed antiviral protein from seeds of Phytolacca americana (PAP-S) was solved at 1.8 Å. PAP-S is a one-chain ribosome-inactivating protein (RIP) and distinctively contains three well-defined N-acetylglucosamines, each covalently linked to an asparagine residue at positions, 10, 44, and 255, respectively. The high-resolution structure clearly shows the three mono-sugars to have either an α- or a β-conformation. Two of sugars are located on the same side of the molecule with the active pocket. Except one hydrogen bond, there are no intermolecular interactions between the polypeptide chain and the sugars. Instead the sugar conformations appear to be stabilized by intermolecular interactions. The sugar structure defined at high resolution provides a structural basis for understanding their possible biological activity. The structural comparisons of PAP-S with other PAPs reveal that the major disparity of these homologous molecules is the different charge distribution on the upper right side of the front side near the active pocket. Based on the available structure of the 50S ribosomal subunit, the possible interactions between PAPs and the ribosome are discussed.

Molecular scaffold of a new pokeweed antifungal peptide deduced by 1H nuclear magnetic resonance

The antifungal peptide from seeds of Phytolacca Americana (Pokeweed), designated PAFP-S hereinafter, is a recently found cationic peptide which consists of 38 amino acid residues and exihibites a broad spectrum of antifungal activity, including inhibition of certain saprophytic fungi and some plant pathogens. The secondary structure and three cysteine pairings have been investigated by 1H NMR analysis. The results show that the molecular scaffold of PAFP-S features a triple-stranded antiparallel β-sheet knotted by a typical disulfide bridge motif, which characterizes the knottin fold. CD spectroscopy indicates a high stability of the molecule in solution. Therefore, PAFP-S should be a new member of the knottin structural family and the first antifungal peptide that adopts the knottin-like fold.

Solution structure of PAFP-S: a new knottin-type antifungal peptide from the seeds of Phytolacca americana.

The three-dimensional solution structure of PAFP-S, an antifungal peptide extracted from the seeds of Phytolacca americana, was determined using 1H NMR spectroscopy. This cationic peptide contains 38 amino acid residues. Its structure was determined from 302 distance restraints and 36 dihedral restraints derived from NOEs and coupling constants. The peptide has six cysteines involved in three disulfide bonds. The previously unassigned parings have now been determined from NMR data. The solution structure of PAFP-S is presented as a set of 20 structures using ab initio dynamic simulated annealing, with an average RMS deviation of 1.68 A for the backbone heavy atoms and 2.19 A for all heavy atoms, respectively. For the well-defined triple-stranded beta-sheet involving residues 8-10, 23-27, and 32-36, the corresponding values were 0.39 and 1.25 A. The global fold involves a cystine-knotted three-stranded antiparallel beta-sheet (residues 8-10, 23-27, 32-36), a flexible loop (residues 14-19), and four beta-reverse turns (residues 4-8, 11-14, 19-22, 28-32). This structure features all the characteristics of the knottin fold. It is the first structural model of an antifungal peptide that adopts a knottin-type structure. PAFP-S has an extended hydrophobic surface comprised of residues Tyr23, Phe25, Ile27, Tyr32, and Val34. The side chains of these residues are well-defined in the NMR structure. Several hydrophilic and positively charged residues (Arg9, Arg38, and Lys36) surround the hydrophobic surface, giving PAFP-S an amphiphilic character which would be the main structural basis of its biological function.

A new antifungal peptide from the seeds of Phytolacca americana: characterization, amino acid sequence and cDNA cloning

An antifungal peptide from seeds of Phytolacca americana, designated PAFP-s, has been isolated. The peptide is highly basic and consists of 38 residues with three disulfide bridges. Its molecular mass of 3929.0 was determined by mass spectrometry. The complete amino acid sequence was obtained from automated Edman degradation, and cDNA cloning was successfully performed by 3′-RACE. The deduced amino acid sequence of a partial cDNA corresponded to the amino acid sequence from chemical sequencing. PAFP-s exhibited a broad spectrum of antifungal activity, and its activities differed among various fungi. PAFP-s displayed no inhibitory activity towards Escherichia coli. PAFP-s shows significant sequence similarities and the same cysteine motif with Mj-AMPs, antimicrobial peptides from seeds of Mirabilis jalapa belonging to the knottin-type antimicrobial peptide.

Crystal structure of pokeweed antiviral protein from seeds ofPhytolacca americana at 0.25 nm

Crystals of pokeweed antiviral protein (PAP) from seeds ofPhytolacca americana with high diffraction ability were grown from high protein concentration (100 mg/mL) solution at high temperature (33 degrees C). The crystal structure was solved by use of molecular replacement method and refied by use of molecular dynamic method at 0.25 nm to anR factor of 18.15% with standard deviations from standard geometry of 0.001 6 nm and 2.04 for bond lengths and bond angles, respectively. Comparison with two other PAPS revealed, near the active center, a sequence- and structure-variable region, consisting of the loop connecting the fifth beta-strand with the second alpha-helix and including a proposed active residue, suggesting this loop probably to be related to difference in activity.

Photoactivation of toxin conjugates.

A novel photocleavable protein cross-linking reagent has been used for conjugation of the ribosome-inactivating protein pokeweed antiviral protein from seeds of Phytolacca americana (PAP-S), with either the monoclonal antibody 5E9 directed against the human transferrin-receptor or the B-chain of ricin that binds to cell-surface oligosaccharides bearing terminal D-galactose residues. When irradiated with near-UV light (350 nm), the linker of these conjugates undergoes photolytic degradation, resulting in the release of native toxin that is fully functional. The cytotoxicities of these 5E9-PAP-S and ricin B-chain-PAP-S conjugates for HeLa cells could be enhanced by irradiating the cells with light after they had internalized the conjugates.

Structures of americanol A and isoamericanol A having a neurotrophic property from the seeds of Phytolacca americana.

The structures of new neo-lignans, isoamericanol A (1) and americanol A (2) isolated from the seeds of Phytolacca americana have been elucidated on the basis of spectroscopic data and then confirmed by chemical correlation with the previously known isoamericanin A (3) and americanin A (4). Isoamericanol A, americanol A, and americanin A have been found to enhance choline acetyltransferase activity at 10(-5) M in a cultured neuronal cell system derived from fetal rat hemisphere.

Monoclonal anti-human T cell antibody and PAP-s conjugate —Preparation and selective cytotoxic properties on leukemic cell

Pokeweed antiviral protein (PAP-s) was prepared from seeds of Phytolacca americana. Monoclonal antibody against human pan-T lymphocyte Wu71 was linked to PAP-s by a disulfide bond. The results of SDS-PAGE, double immunodiffusion of active monoclonal antibody and PAP-s showed that the conjugate was highly cytotoxic to the human T-leukemic cell line CEM, but not to antigen-negative cell line SP2/O. At a concentration of 10(-9) mol/L, 76.4% of the target cells were killed, as compared with 10.1% at 10(-9) mol/L of free PAP-s. Treatment of the CEM cells with conjugate at 10(-9) mol/L reduced their rate of protein synthesis by 72.4%, as determined with 14C-leucine incorporation. The immunotoxin may be useful for the in-vitro eradication of leukemic cells in autologous bone marrow transplantation to leukemia patients.

Structure of Isoamericanin A, a Prostaglandin I2 Inducer, Isolated from the Seeds of Phytolacca americana L.

Abstract A new neo-lignan, isoamericanin A was isolated as a prostaglandin I2 inducer from the seeds of Phytolacca americana L. and its structure was fully characterized by extensive 2D NMR and long range selective proton decoupling (LSPD) techniques.

NOVEL PHOTOCLEAVABLE PROTEIN CROSSLINKING REAGENTS AND THEIR USE IN THE PREPARATION OF ANTIBODY‐TOXIN CONJUGATES

Abstract— Two photolabile heterobifunctional protein crosslinking reagents have been synthesized and used for the conjugation of a protein toxin to an antibody. o‐Nitrobenzyl alcohol derivatives containing protected sulfhydryl groups were converted to o‐nitrobenzyloxycarbonyl chlorides and covalently attached to pokeweed antiviral protein (PAP‐S) obtained from the seeds of Phytolacca americana. The sulfhydryl groups were deprotected and the modified toxins were reacted with J5 antibody (specific for the common acute lymphoblastic leukemia antigen, CALLA) that had been functionalized with maleimido groups. Antibody‐toxin conjugates were formed predominantly in the ratio of 1:1, and were purified from unconjugated antibody and PAP‐S. Irradiation of the conjugates with light having a peak intensity at 365 nm effected photolytic fragmentation, and PAP‐S was released in fully active form. The methods described here may prove useful for the release of drugs or toxins at sites accessible to light.

Antiinflammatory activity of americanin a

Americanin A from the seeds ofPhytolacca americana, was investigated for the antiinflammatory activity. The compound significantly inhibited edema induction, granuloma formation, arthritis induction and leucocyte emigration in CMC-pouch. But its anticarrageenin activity was not exhibited in adrenalectomized rats. These findings together with decrease in the contents of ascorbic acid and cholesterol in adrenals by administration of the compound suggest that its activity is mediated through stimulation of the pituitary-adrenal axis. The acute toxicity of the compound is very weak and gastric ulceration was not produced by the compound.

Effect of ribosome-inactivating proteins on virus-infected cells. Inhibition of virus multiplication and of protein synthesis.

HEp-2 cells were infected with herpes simplex virus-1 (HSV-1) or with polio-virus I in the presence of plant proteins which inactivate ribosomes in cell-free systems, while exerting scarce effect on whole cells. Ribosome-inactivating proteins used were gelonin, from seeds of Gelonium multiflorum, an inhibitor from the seeds of Momordica charantia, dianthin 32, from the leaves of Dianthus caryophyllus (carnation), and PAP-S, from the seeds of Phytolacca americana (pokeweed). All proteins tested had the following effects: 1. They reduced viral yield; 2. They decreased HSV-1 plaque-forming efficiency; 3. They inhibited protein synthesis more in infected than in uninfected cells. These results strongly suggest that ribosome-inactivating proteins impair viral replication by inhibiting protein synthesis in virus-infected cells, in which presumably they enter more easily than in uninfected cells.

Acetonylidene americanin A, an artefact isolated fromPhytolacca americana

From the seeds ofPhytolacca americana, acetonylidene americanin A was isolated and its structure elucidated mainly by spectroscopic methods. This compound is not a genuine constitutent but formed in the tissue on heating with acetone.

The structure of new lignans from the seeds of phytolacca americana

From the seeds of Phytolacca americana two new lignans, Americanin B and D, have been isolated and their structures elucidated mainly by spectroscopic methods

3-acetyloleanolic acid from Phytolacca americana seeds

3-Acetyloleanolic acid has been obtained from the seeds of Phytolacca americana L. It has not been detected in other parts of the plant. Oleanolic acid has been detected in the roots.