Characterization and Application of Guar Gum/Polyvinyl Alcohol-Based Food Packaging Films Containing Betacyanins from Pokeweed (Phytolacca acinosa Roxb.) Berries and Silver Nanoparticles.

Food packaging films were prepared by using guar gum/polyvinyl alcohol (GP) as the film matrix, 2% Ag nanoparticles (AgNPs) as reinforcing filler and antimicrobial agent, and 1%, 2% and 3% pokeweed betacyanins (PB) as the colorant and antioxidant agent. The structures and color-changing, barrier, mechanical, thermal and antioxidant/antibacterial properties of different films were measured. The results show that the PB were pH-sensitive pigments with pink, purple and yellow colors at pH 3-8, pH 9-11 and pH 12, respectively. PB improved the compatibility of guar gum and polyvinyl alcohol through hydrogen bonds. The films with PB showed a color-changing capacity under ammonia vapor and good color stability in chilled storage. AgNPs and PB elevated the barrier capacity of GP film to light, water vapor and oxygen gas. Meanwhile, AgNPs and PB improved the stiffness, thermal stability and antioxidant/antibacterial activity of GP film. The film with AgNPs and 3% PB showed the highest barrier capacity, stiffness, thermal stability and antioxidant/antimicrobial activity. In shrimp spoilage test, the films with AgNPs and 2% and 3% PB indicated shrimp freshness through film color changes. The results reveal the potential use of the prepared films in active and smart packaging.

Rhizospheric Lactobacillus spp. contribute to the high Cd-accumulating characteristics of Phytolacca spp. in acidic Cd-contaminated soil.

Screening high Cd-accumulating plants and understanding the interactions between plants, rhizospheric microbes and Cd are important in developing microbe-assisted phytoremediation techniques for Cd-contaminated soils. In this study, the Cd tolerance and accumulation characteristics of Phytolacca americana L., P. icosandra L. and P. polyandra Batalin growing in acidic Cd-contaminated soil were compared to evaluate their phytoremediation potential. According to Cd concentrations (root: 8.26-37.09 mg kg-1, shoot: 2.80-9.26 mg kg-1), bioconcentration factors (BCFs) and translocation factors (TFs), the three Phytolacca species exhibited high Cd-accumulation capacities, ranked in the following order: P. icosandra (root BCF: 1.25, shoot BCF: 0.31, TF: 0.25) > P. polyandra (root BCF: 0.68, shoot BCF: 0.26, TF: 0.44) > P. americana (root BCF: 0.28, shoot BCF: 0.09, TF: 0.38). Phytolacca icosandra and P. polyandra can thus be considered as two new Cd accumulators for phytoremediation. Soil pH, available Cd (ACd) concentration and certain bacterial taxa (e.g. Lactobacillus, Helicobacter, Alistipes, Desulfovibrio and Mucispirillum) were differentially altered in the rhizospheres of the three Phytolacca species in comparison to unplanted soil. Correlation analysis showed that there were significant interactions between rhizospheric ACd concentration, pH and Lactobacillus bacteria (L. murinus, L. gasseri and L. reuteri), which affected Cd uptake by Phytolacca plants. The mono- and co-inoculation of L. murinus strain D51883, L. gasseri strain D51533 and L. reuteri strain D24591 in the rhizosphere of P. icosandra altered the rhizospheric pH and ACd concentrations, in addition to increasing the shoot Cd contents by 31.9%-44.6%. These results suggest that recruitment of rhizospheric Lactobacillus spp. by Phytolacca plants contributes to their high Cd-accumulating characteristics. This study provides novel insights into understanding the interactions between plants, rhizobacteria and heavy metals.

Two new triterpene glycosides with antiproliferative activities on HepG2 from Phytolacca acinosa fruit fermentation broth.

Two new oleanane-type triterpene glycosides, phytolasides A (1) and B (2), and six known ones (3-8), were isolated from Phytolacca acinosa fruit fermentation broth. Their structures were elucidated by HR-ESI-MS and 1 D- and 2 D-NMR spectroscopic methods. Antiproliferation of compounds 1 and 2 against HepG2 cells was examined by using CCK8 assays.

Invasive Plants Have Higher Resistance to Native Generalist Herbivores Than Exotic Noninvasive Congeners.

Research on the invasive plant Phytolacca americana (L.) mostly focuses on its medicinal value and enrichment of heavy metals. However, little is known regarding its impact on native herbivorous insects. In this study, we explored the effects of P. americana and the exotic noninvasive Phytolacca icosandra (L.) on the Spodoptera litura (Fabricius) (native tobacco cutworm) via bioassay, oviposition preference, detoxifying enzyme activity analysis, and phytochemical determination. We found that the oviposition preference index (OPI) of S. litura feeding on P. icosandra was higher than that of P. americana. The developmental duration of S. litura feeding on P. icosandra was shorter than that of P. americana. Additionally, the Acetylcholinesterase (AchE) and Glutathione-S-transferase (GST) activities of S. litura feeding on P. americana were higher than that of S. litura feeding on artificial diets or P. icosandra. The content of lignin and flavonoids in P. americana was relatively high, whereas starch content was relatively low. These findings suggest invasive plants have higher resistance to herbivores, thereby suffering less damage than exotic noninvasive plants.

Increase of P and Cd bioavailability in the rhizosphere by endophytes promoted phytoremediation efficiency of Phytolacca acinosa.

The information about the spatial distribution of bioavailable phosphorus (P) and heavy metal (HM) in the rhizosphere could aid in the precise phytoremediation regulation. In this study, a rhizobox system was adapted to study soil-root interactions and used to access the endophyte inoculation variation on bioavailable P and cadmium (Cd) spatial distribution during phytoremediation of Cd contaminated soils. Results showed that endophyte PE31 Bacillus cereus inoculation enhanced Cd uptake of P. acinosa by 52.70% and 46.73% in low and high Cd contaminated soils, increasing the phytoremediation hotspot area from 45.78% and 15.29% to 60.97% and 21.80%, respectively. Available P and Cd significantly diminished because root activities depleted large amounts of bioavailable P and Cd concentrations. However, PE31 increased bioavailable P and Cd concentration in the rhizosphere soil. The bioavailable P enhancement in the rhizosphere was positively correlated to plant growth and Cd accumulation. Overall, endophyte inoculation compensated the diminution of bioavailable P and Cd in the rhizosphere to improve plant biomass and HM absorption, and thus promote phytoremediation efficiency. This study helped to better understand bioavailable P and Cd spatial distribution under endophyte inoculation, which could provide effective management strategies for the precise regulation of phytoremediation.

Reutilization of manganese enriched biochar derived from Phytolacca acinosa Roxb. residue after phytoremediation for lead and tetracycline removal.

This study aimed to evaluate the chemical form variation of Mn in Phytolacca acinosa Roxb. residue under different pyrolysis temperatures and its contribution to decontamination efficacy of lead (Pb(II)) and tetracycline (TC). The results illuminated that pyrolysis temperature is a crucial factor of fraction and bioavailability of Mn and other heavy metals in the resultant biochar and pyrolysis temperature under 450 °C may be most suitable for reutilization without potential risk. The Mn-enriched phytolaccaceae biochar (PSB450) exhibited more preferential sorption toward Pb(II) (279.33 mg/g) and TC (47.51 mg/g) than pristine phytolaccaceae biochar in the single system, mainly due to the formation of MnOx and Mn minerals via pyrolysis. Binary adsorption showed that Pb(II) would serve as a bridge between PSB450 and TC by complexation within a limited concentration range, thus facilitating their joint decontamination. This study provided an efficient alternative approach for reutilization of Mn-contaminated biomass.

Rapid Screening and Characterization of Triterpene Saponins from the Root of Phytolacca acinosa Roxb by High-Performance Liquid Chromatography Coupled to Electrospray Ionization and Quadrupole Time-of-Flight Mass Spectrometry.

Triterpene saponins (TSs) are important bioactive constituents with structural diversity widely distributed in many plants. The root of Phytolacca acinosa Roxb (RPa) has been used as a traditional Chinese medicine. However, TSs as the main active ingredients in RPa have not been fully characterized. Here, we profiled TSs from RPa by high-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS). We tentatively identified 29 TSs, including 13 that had not been reported previously from this plant. This study indicates that HPLC-ESI-QTOF-MS/MS is an effective and rapid method for the characterization of complicated TSs in herbal extracts.

Endophyte inoculation redistributed bioavailable Cd and nutrient in soil aggregates and enhanced Cd accumulation in Phytolacca acinosa.

Plant growth and heavy metal (HM) accumulation is affected by heavy metal bioavailability and nutrient content in soil aggregates during endophyte-assisted phytoremediation. In this study, we evaluated the influence of endophytes inoculation on P. acinosa HM accumulation and soil aggregate physicochemical properties and explored the correlation among them. Endophyte inoculation increased the plant growth and Cd accumulation by 7.95-25.13% and 3.27-19.22%, respectively and the soil aggregate was redistributed with a decrease of 1.88-5.41% of the clay fraction. The available nitrogen, phosphorus and potassium, and organic matter in macro-aggregate and micro-aggregate were significantly improved with endophyte inoculation. In addition, compared to the no inoculation group, endophytes inoculation enhanced the bioavailability of Cd in macro-aggregates by 4.92-15.00% and in micro-aggregate by 0-9.37%. Both multiple linear regression analysis and the structural equation modeling (SEM) analysis showed that the Cd accumulation in P. acinosa was mainly depended on the Cd bioavailability in macro-aggregates and micro-aggregates. In general, this study helped to improve our understanding of soil aggregate HM bioavailability and nutrient content distribution characteristics under endophyte inoculation, which could further explain the mechanisms of endophytes in plant growth promoting and HM accumulation improving.

Preparation of magnetic hydrochar derived from iron-rich Phytolacca acinosa Roxb. for Cd removal.

Considering that hyperaccumulators can accumulate high concentrations of iron salt, they can successfully obtain magnetic hydrochar from iron-rich hyperaccumulators. In this study, iron-rich biomass was obtained by irrigating Phytolacca acinosa Roxb. using iron salt. Magnetic nano-Fe3O4 hydrochar was prepared from iron-rich Phytolacca acinosa Roxb. via hydrothermal carbonization to remove Cd. The characterization results showed that the synthesized magnetic nanoparticles had an average size of 2.62 ± 0.56 nm and N elements were doped into magnetic nano-Fe3O4 hydrochar with abundant oxygenic groups. Cd adsorption on magnetic nano-Fe3O4 hydrochar was better fitted using the Langmuir isotherm and the pseudo-second-order kinetic model. The maximum adsorption capacity was 246.6 mg g-1 of Cd. The research confirmed that Cd adsorption was controlled by multiple mechanisms from the jar test, transmission electron microscopy mapping, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. CdCO3 crystals can be formed after adsorption, indicating that surface precipitation played an important role in Cd adsorption. The abundance of O atoms and the doping of N atoms on the hydrochar surface were conducive to Cd adsorption, indicating that the mechanisms were related to surface complexation and electrostatic attraction. In addition, the significant decrease in Na+ content after Cd adsorption illustrated that ion exchange had a non-negligible effect on Cd adsorption. This study not only provides a strategy for preparing magnetic nano-Fe3O4 hydrochar derived from iron-rich plants but also verifies multiple Cd adsorption mechanisms using magnetic nano-Fe3O4 hydrochar.

Esculentosides: Insights into the potential health benefits, mechanisms of action and molecular targets.

BACKGROUND: Esculentosides and related phytolaccosides form a group of oleanene-type saponins isolated from plants of the Phytolaccaceae family, essentially Phytolacca esculenta, P. americana and P. acinosa. This chemical family offers a diversity of glycosylated compounds, including molecules with a mono-, di- or tri-saccharide unit at position C-3, and with or without a glucose residue at position C-28. The esculentosides, which derive essentially from the sapogenin jaligonic acid or its 30-methyl ester phytolaccagenin, exhibit anti-inflammatory, antifungal and anticancer activities. PURPOSE: The objective of the review was to identify the 26 esculentosides (ES) and phytolaccosides known to date, including 16 monodesmosidic and 10 bidesmosidic saponins, and to review their pharmacological properties and molecular targets. METHODOLOGY: The retrieval of potentially relevant studies was done by systematically searching of scientific databases like Google Scholar and PubMed in January-May 2020. The main keywords used as search terms were related to esculentosides, phytolaccosides and Phytolaccaceae. The systematic search retrieved about 110 papers that were potentially relevant and after an abstract-based selection, 68 studies were analyzed in details and discussed. RESULTS: The structural relationship between the compounds and their sapogenin precursors has been studied. In addition, the pharmacological properties of the main ES, such as ES-A, -B and -H, have been analyzed to highlight their mode of action and potential targets. ES-A is a potent inhibitor of the release of cytokines and this anti-inflammatory activity contributes to the anticancer effects observed in vitro and in vivo. Potential molecular targets of ES-A/B include the enzymes cyclooxygenase 2 (COX-2) and casein kinase 2 (CK2). In addition, the targeting of the protein high-mobility group box 1 (HGMB1) by ES-A/B is proposed, based on molecular modeling and the structural analogy with the related saponin glycyrrhizin, a potent HGMB1 alarmin inhibitor. CONCLUSION: More work is needed to properly characterize the molecular targets but otherwise compounds like ES-A and ES-H emerge as potent anti-inflammatory and anticancer agents and ES-B as an antifungal agent. A preclinical development of these three compounds should be considered.

Antiviral Activity of PD-L1 and PD-L4, Type 1 Ribosome Inactivating Proteins from Leaves of Phytolacca dioica L. in the Pathosystem Phaseolus vulgaris-Tobacco Necrosis Virus (TNV).

Using the pathosystem Phaseolus vulgaris-tobacco necrosis virus (TNV), we demonstrated that PD-L1 and PD-L4, type-1 ribosome inactivating proteins (RIPs) from leaves of Phytolacca dioica L., possess a strong antiviral activity. This activity was exerted both when the RIPs and the virus were inoculated together in the same leaf and when they were inoculated or applied separately in the adaxial and abaxial leaf surfaces. This suggests that virus inhibition would mainly occur inside plant cells at the onset of infection. Histochemical studies showed that both PD-L1 and PD-L4 were not able to induce oxidative burst and cell death in treated leaves, which were instead elicited by inoculation of the virus alone. Furthermore, when RIPs and TNV were inoculated together, no sign of H2O2 deposits and cell death were detectable, indicating that the virus could have been inactivated in a very early stage of infection, before the elicitation of a hypersensitivity reaction. In conclusion, the strong antiviral activity is likely exerted inside host cells as soon the virus disassembles to start translation of the viral genome. This activity is likely directed towards both viral and ribosomal RNA, explaining the almost complete abolition of infection when virus and RIP enter together into the cells.

Full-length transcriptome analysis of Phytolacca americana and its congener P. icosandra and gene expression normalization in three Phytolaccaceae species.

BACKGROUND: Phytolaccaceae species in China are not only ornamental plants but also perennial herbs that are closely related to human health. However, both large-scale full-length cDNA sequencing and reference gene validation of Phytolaccaceae members are still lacking. Therefore, single-molecule real-time sequencing technology was employed to generate full-length transcriptome in invasive Phytolacca americana and non-invasive exotic P. icosandra. Based on the transcriptome data, RT-qPCR was employed to evaluate the gene expression stability in the two plant species and another indigenous congener P. acinosa. RESULTS: Total of 19.96 Gb and 19.75 Gb clean reads of P. americana and P. icosandra were generated, including 200,857 and 208,865 full length non-chimeric (FLNC) reads, respectively. Transcript clustering analysis of FLNC reads identified 89,082 and 98,448 consensus isoforms, including 86,989 and 96,764 high-quality ones. After removing redundant reads, 46,369 and 50,220 transcripts were obtained. Based on structure analysis, total 1675 and 1908 alternative splicing variants, 25,641 and 31,800 simple sequence repeats (SSR) as well as 34,971 and 36,841 complete coding sequences were detected separately. Furthermore, 3574 and 3833 lncRNA were predicted and 41,676 and 45,050 transcripts were annotated respectively. Subsequently, seven reference genes in the two plant species and a native species P. acinosa were selected and evaluated by RT-qPCR for gene expression analysis. When tested in different tissues (leaves, stems, roots and flowers), 18S rRNA showed the highest stability in P. americana, whether infested by Spodoptera litura or not. EF2 had the most stable expression in P. icosandra, while EF1-α was the most appropriate one when attacked by S. litura. EF1-α showed the highest stability in P.acinosa, whereas GAPDH was recommended when infested by S. litura. Moreover, EF1-α was the most stable one among the three plant species whenever germinating seeds or flowers only were considered. CONCLUSION: Full-length transcriptome of P. americana and P. icosandra were produced individually. Based on the transcriptome data, the expression stability of seven candidate reference genes under different experimental conditions was evaluated. These results would facilitate further exploration of functional and comparative genomic studies in Phytolaccaceae and provide insights into invasion success of P. americana.

Development of an ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry method for comparative pharmacokinetics of six triterpenoids in rat plasma and application to different forms of Phytolacca acinosa.

Phytolacca acinosa is an herb for treatment of ascites and tumor. Two forms of P. acinosa, i.e. raw and vinegar-processed herb, have been used in clinic. However, pharmacokinetic difference between the two forms of P. acinosa has not been fully understood. Herein, a comparative pharmacokinetic method based on liquid chromatography with tandem mass spectrometry was developed for quantification of six bioactive triterpenoids, including esculentoside H, esculentoside T, esculentoside A, esculentoside B, phytolaccagenic acid, and phytolaccagenin in rat plasma after oral administration of different forms of P. acinosa. Separation was performed on an Acquity BEH C18 column (1.7 µm, 2.1 mm × 50 mm). The method was validated over a linear range of 2.0-5000 ng/mL. Intraday and interday bias were within ±5%. Besides, all triterpenoids were stable in plasma during different storage conditions. The described method was successfully applied to a comparative pharmacokinetic study of raw and vinegar-processed P. acinosa in rats. Notably, double peak phenomenon for six triterpenoids of P. acinosa was observed for the first time. AUC0→t and Cmax values of esculentoside H, esculentoside T, phytolaccagenic acid, and phytolaccagenin were significantly lower in vinegar-processed group than that of raw group, indicating the oral bioavailability of the four triterpenoids was decreased after vinegar processing.

Accumulation and fractionation of rare earth elements are conserved traits in the Phytolacca genus.

Rare earth elements (REEs) are now considered emerging pollutants in the environment. Phytolacca americana, an REE hyperaccumulating plant, has been proposed for the remediation of REE-contaminated soils. However, there is no REE-related information for other Phytolacca species. Here, we examined five species (P. americana, P. acinosa, P. clavigera, P. bogotensis, and P. icosandra) for their response to REEs. REE accumulation and fractionation traits both occurred on the same order of magnitude among the five species. Heavy REEs were preferentially transferred to leaves relative to light REEs. Regardless of the species, lateral root length and chlorophyll content decreased under REE exposure, and lateral roots and foliar anthocyanins increased. However, plants did not experience or only slightly experienced oxidative stress. Finally, REE exposure strongly modulated the ionome of roots and, to a lesser extent, that of leaves, with a negative correlation between REE and Mn contents. In conclusion, our study provides new data on the response of several Phytolacca species to REEs. Moreover, we highlighted that the REE accumulation trait was conserved among Phytolacca species. Thus, we provide valuable information for the phytoremediation of REE-contaminated sites since the most appropriate Phytolacca species could be selected depending on the climatic/pedological area to be remediated.

The antifungal activity and mechanisms of action of quantified extracts from berries, leaves and roots of Phytolacca tetramera.

BACKGROUND: Phytolacca tetramera is an endemic plant from Argentina that is currently at serious risk because its environment is subjected to a high anthropic impact. A previous study has shown that berry extracts obtained from this plant display antifungal activity against multiple human-pathogenic fungi when tested with a non-standardized method. Further evidences of the antifungal properties of other parts of the plant and studies of mechanism of antifungal action of the antifungal chemically characterized extracts are required. PURPOSE: This study aimed to gain further evidence of the antifungal activity of P. tetramera berry, leaf and root extracts in order to find the most active extract to be developed as an Herbal Medicinal Antifungal Product. The medicinal usefulness of P. tetramera extracts as antifungal agents will serve as an important support to create concience and carry out actions tending to the preservation of this threatened species and its environment. MATERIALS AND METHODS: Chemical analysis of all P. tetramera extracts, including quantitation of selected markers, was performed through UHPLC-ESI-MS/MS and UPLC-ESI-MS techniques according to the European Medicines Agency (EMA). The antifungal activity of the quantified extracts was tested with the standardized CLSI microbroth dilution method against Candida spp. Antifungal mechanisms of the most active extract were studied by examination of morphological changes by phase-contrast and fluorescence microscopies and both, cellular and enzymatic assays targeting either the fungal membrane or the cell wall. RESULTS: The antifungal activity of twelve P. tetramera extracts was tested against Candida albicans and Candida glabrata. The dichloromethane extract from berries (PtDEb) showed the best activity. Phytolaccagenin (PhytG) and phytolaccoside B (PhytB) were selected as the main active markers for the antifungal P. tetramera extracts. The quantitation of these active markers in all extracts showed that PtDEb possessed the highest amount of PhytG and PhytB. Finally, studies on the mechanism of antifungal action showed that the most active PtDEb extract produces morphological changes compatible with a damage of the cell wall and/or the plasma membrane. Cellular and enzymatic assays showed that PtDEb would not damage the fungal cell wall by itself, but would alter the plasma membrane. In agreement, PtDEb was found to bind to ergosterol, the main sterol of the fungal plasma membrane. CONCLUSION: Studies of the anti-Candida activity of P. tetramera extracts led to the selection of PtDEb as the most suitable extract, confirming the antifungal properties of the threatened species P. tetramera. The new data give a valuable reason for the definitive protection of this sp. and its natural environment thus allowing further studies for the future development of an Herbal Medicinal Antifungal Product.

Homeopathic medicine of Melissa officinalis combined or not with Phytolacca decandra in the treatment of possible sleep bruxism in children: A crossover randomized triple-blinded controlled clinical trial.

PURPOSE: The present randomized controlled clinical trial evaluated the efficacy of homeopathic medicines of Melissa officinalis (MO), Phytolacca decandra (PD), and the combination of both in the treatment of possible sleep bruxism (SB) in children. STUDY DESIGN: Patients (n = 52) (6.62 ± 1.79 years old) were selected based on the parents report of SB. The study comprised a crossover design that included 4 phases of 30-day treatment (Placebo; MO 12c; PD 12c; and MO 12c + PD 12c), with a wash-out period of 15 days between treatments. METHODS: At baseline and after each phase, the Visual Analogic Scale (VAS) was used as the primary outcome measure to evaluate the influence of treatments on the reduction of SB. The following additional outcome measures were used: a children's sleep diary with parent's/guardian's perceptions of their children's sleep quality, the trait of anxiety scale (TAS) to identify changes in children's anxiety profile, and side effects reports. Data were analyzed by ANOVA with repeated measures followed by Post Hoc LSD test. RESULTS: Significant reduction of SB was observed in VAS after the use of Placebo (-1.72 ± 0.29), MO (-2.36 ± 0.36), PD (-1.44 ± 0.28) and MO + PD (-2.21 ± 0.30) compared to baseline (4.91 ± 1.87). MO showed better results compared to PD (p = 0.018) and Placebo (p = 0.050), and similar result compared to MO+PD (p = 0.724). The sleep diary results and TAS results were not influenced by any of the treatments. No side effects were observed after treatments. CONCLUSION: MO showed promising results in the treatment of possible sleep bruxism in children, while the association of PD did not improve MO results.

Chemical composition and enzyme inhibition of Phytolacca dioica L. seeds extracts.

Phytolacca, which belongs to the family of Phytolaccaceae, are known for their use in popular medicine. Bioactivity of five extracts from Phytolacca dioica seeds were evaluated in four bioassays. A selected group of compounds from the extract that displayed the best bioactivity was analysed. The ethyl acetate extract (EAE) possessed the highest content of phenolics, the highest inhibitory activity on the tyrosinase and xanthine oxidase enzymes and showed a high antioxidant activity. HPLC-DAD-MS was employed to identify the phenolics profile of the most active one (EAE). HSCCC analysis of the EAE led to the isolation of phytolaccoside B and a mixture of 4 isomers, isoamericanol B1, B2, C1 and C2. These isoamericanol isomers presented activity against tyrosinase and xanthine oxidase. Our results revealed for the first time an interesting biological activity of the extract and isolated compounds from P. dioica seeds, which could be considered as a source of bioactive molecules.

[Triterpenoid saponins from roots of Phytolacca acinosa].

A new triterpenoid saponin named esculentoside U(1), along with the five known compounds, was isolated and characterized from the roots of Phytolacca acinosa, a commonly used traditional Chinese medicine with anti-inflammatory and anti-rheumatoid activities. The structure of the new saponin was elucidated as 3-O-[ß-D-glucopyranosyl-(1→4)]-ß-D-xylopyranosyl]-2, 23-dihydroxyolean-11, 13(18)-diene-28, 29-dioic acid 29-methyl ester(1). The assignment of all NMR signals of 1 was performed by means of 2D-NMR experiments.

Novel bioactive peptides from PD-L1/2, a type 1 ribosome inactivating protein from Phytolacca dioica L. Evaluation of their antimicrobial properties and anti-biofilm activities.

Antimicrobial peptides, also called Host Defence Peptides (HDPs), are effectors of innate immune response found in all living organisms. In a previous report, we have identified by chemical fragmentation, and characterized the first cryptic antimicrobial peptide in PD-L4, a type 1 ribosome inactivating protein (RIP) from leaves of Phytolacca dioica L. We applied a recently developed bioinformatic approach to a further member of the differently expressed pool of type 1 RIPs from P. dioica (PD-L1/2), and identified two novel putative cryptic HDPs in its N-terminal domain. These two peptides, here named IKY31 and IKY23, exhibit antibacterial activities against planktonic bacterial cells and, interestingly, significant anti-biofilm properties against two Gram-negative strains. Here, we describe that PD-L1/2 derived peptides are able to induce a strong dose-dependent reduction in biofilm biomass, affect biofilm thickness and, in the case of IKY31, interfere with cell-to-cell adhesion, likely by affecting biofilm structural components. In addition to these findings, we found that both PD-L1/2 derived peptides are able to assume stable helical conformations in the presence of membrane mimicking agents (SDS and TFE) and intriguingly beta structures when incubated with extracellular bacterial wall components (LPS and alginate). Overall, the data collected in this work provide further evidence of the importance of cryptic peptides derived from type 1 RIPs in host/pathogen interactions, especially under pathophysiological conditions induced by biofilm forming bacteria. This suggests a new possible role of RIPs as precursors of antimicrobial and anti-biofilm agents, likely released upon defensive proteolytic processes, which may be involved in plant homeostasis.

Novel Flavones from the Root of Phytolacca acinosa Roxb.

Two new flavones, 6,7-methylenedioxy-4-hydroxypeltogynan-7'-one (1), cochliophilin B (2), as well as two known ones, cochliophilin A (3) and 6-methoxy-7-hydroxy flavone (4), were isolated from the ethanol extract of the root of Phytolacca acinosa Roxb. Compound 1 is a flavanol framework with one δ-lactone unit, which is rather rare in nature. The structures of the new compounds were determined on the basis of extensive spectroscopic (IR, MS, 1D- and 2D-NMR) analyses, the absolute configuration of 1 was established by comparing experimental and calculated electronic circular dichroism spectra. The structures of known compounds were fixed by comparison with literatures data. Compounds 2 and 4 showed modest inhibitory activities against BEL-7402 cell line, with IC50 values of 28.22 and 39.16 µmol/L, respectively.