Aqueous extract of Polygonum bistorta modulates proteostasis by ROS-induced ER stress in human hepatoma cells.[Pubmed: 28134285]

Hepatocellular carcinoma (HCC) remains the leading cause of cancer mortality with limited therapeutic targets. The endoplasmic reticulum (ER) plays a pivotal role in maintaining proteostasis in normal cells. However, alterations in proteostasis are often found in cancer cells, making it a potential target for therapy. Polygonum bistorta is used in traditional Chinese medicine owing to its anticancer activities, but the molecular and pharmacological mechanisms remain unclear. Using hepatoma cells as a model system, this study demonstrated that P. bistorta aqueous extract (PB) stimulated ER stress by increasing autophagosomes but by blocking degradation, followed by the accumulation of ubiquitinated proteins and cell apoptosis. In addition, an autophagy inhibitor did not enhance ubiquitinated protein accumulation whereas a reactive oxygen species (ROS) scavenger diminished both ubiquitinated protein accumulation and ligand-stimulated epidermal growth factor receptor (EGFR) expression, suggesting that ROS generation by PB may be upstream of PB-triggered cell death. Nevertheless, PB-exerted proteostasis impairment resulted in cytoskeletal changes, impairment of cell adhesion and motility, and inhibition of cell cycle progression. Oral administration of PB delayed tumour growth in a xenograft model without significant body weight loss. These findings indicate that PB may be a potential new alternative or complementary medicine for HCC.

Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.[Pubmed: 26183112]

Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover will not necessarily result in greater tundra productivity.

Xanthine oxidase inhibitory activity of extracts prepared from Polygonaceae species.[Pubmed: 25510560]

The xanthine oxidase (XO) inhibitory activity of aqueous and organic extracts of 27 selected species belonging in five genera (Fallopia, Oxyria, Persicaria, Polygonum and Rumex) of the family Polygonaceae occurring in the Carpathian Basin were tested in vitro. From different plant parts (aerial parts, leaves, flowers, fruits and roots), a total of 196 extracts were prepared by subsequent extraction with methanol and hot H2O and solvent-solvent partition of the MeOH extract yielding n-hexane, chloroform and 50% MeOH subextracts. It was found that the chloroform subextracts and/or the remaining 50% MeOH extracts of Fallopia species (F. bohemica, F. japonica and F. sachalinensis), Rumex species (R. acetosa, R. acetosella, R. alpinus, R. conglomeratus, R. crispus, R. hydrolapathus, R. pulcher, R. stenophyllus, R. thyrsiflorus, R. obtusifolius subsp. subalpinus, R. patientia) and Polygonum bistorta, Polygonum hydropiper, Polygonum lapathifolium and Polygonum viviparum demonstrated the highest XO inhibitory activity (>85% inhibition) at 400 µg/mL. The IC50 values of the active extracts were also determined. On the basis of the results, these plants, and especially P. hydropiper and R. acetosella, are considered worthy of activity-guided phytochemical investigations.

Effect of Pakistani medicinal plants on IgE/antigen- and ionophore-induced mucosal mast cells degranulation.[Pubmed: 25016264]

Cumulative evidence has now demonstrated the stimulation of mucosal mast cells by both allergic and non-allergic triggers and their inhibition as a potential therapeutic target in many diseases like food allergy and ulcerative colitis. Hence, we screened medicinal plants from Pakistan against antigen- and ionophore-induced degranulation of mucosal mast cells. Aqueous ethanol extracts were screened. IgE/antigen- and A23187-induced degranulation of mucosal-type murine bone marrow derived mast cells (mBMMCs) were screening assays and β-hexosaminidase released from degranulated mBMMCs was measured. Real time-polymerase chain reaction was employed to examine the expression of TNF-α and IL-4 mRNA. Acetoxychavicol acetate, was examined by degranulation assays and real time-PCR. Among the ten plants screened against IgE/antigen stimulated degranulation, five plants; Alpinia galangal, Mentha arvensis, Myrtus communis, Polygonum bistorta and Syzygium aromaticum demonstrated significant (p<0.01) suppression of the degranulation at 100 μg/ml. Of them, Alpinia galangal showed significant (p<0.01) inhibition at 32 mg/ml. In A23187-induced degranulation, all plants showed significant (p<0.01) inhibition at 100 μg/ml except Tamarix dioica. Again Alpinia galangal exhibited significant (p<0.01) suppression at 32 μg/ml. In a concentration dependent assay, Alpinia galangal revealed significant suppression at 10 μg/ml against A23187-stimulated degranulation. Acetoxychavicol acetate demonstrated significant (p<0.01) inhibition at 3.2 μM in IgE/antigen-treated cells and at 10 μM in A23187-treated cells. Furthermore, both Alpinia galangal and acetoxychavicol acetate suppressed the IgE/antigen- and A23187-enhanced mRNA expression of inflammatory cytokines, TNF-a and IL-4, in mBMMCs. Our findings revealed the suppressive effect of Alpinia galangal and acetoxychavicol acetate on degranulation of mBMMCs by allergic and non-allergic stimuli, which can be utilized for future drug development against food allergy or ulcerative colitis.

Evaluation of direct antiviral activity of the Deva-5 herb formulation and extracts of five Asian plants against influenza A virus H3N8.[Pubmed: 25012588]

The herb formulation Deva-5 is used in traditional medicine to treat acute infectious diseases. Deva-5 is composed of five herbs: Gentiana decumbens L., Momordica cochinchinensis L., Hypecoum erectum L., Polygonum bistorta L., and Terminalia chebula Retz. Deva-5 and its five components were investigated for in vitro antiviral activity against avian influenza A virus subtype H3N8.

Determination of the volatile fraction of Polygonum bistorta L. at different growing stages and evaluation of its antimicrobial activity against two major honeybee (Apis mellifera) pathogens.[Pubmed: 22344911]

The composition of the volatile fraction of Polygonum bistorta L. (also known as bistort or snakeroot) was investigated. Fresh aerial parts of this plant species were collected in the Western Italian Alps during the summer at three different phenological stages, namely vegetative, flowering, and fruiting, and steam-distilled in a Clevenger-type apparatus. The oils accounted for 0.004 to 0.010% of the fresh plant material, and their compositions were determined by GC/FID and GC/MS. The composition of the oils during the vegetative period varied both in quantity and quality; several classes of compounds were found with a predominance of alcohols in the vegetative phase, terpenes and linear-chained saturated hydrocarbons in the flowering phase, while saturated aliphatic acids and their methyl esters were predominant in fruiting phase. The most abundant compounds were 3-methylbut-3-en-1-ol in the vegetative phase, linalool in the flowering phase, and dodecanoic acid and its methyl ester in the fruiting phase. The obtained essential oils were then tested against two major bee pathogens, i.e., Paenibacillus larvae and Melissococcus plutonius, and against a reference bacterial species, Bacillus subtilis. Data were compared to those obtained with reference standards used against those pathogens such as the essential oils obtained from leaves and bark of Cinnamomum zeylanicum (cinnamon), and the antibiotic oxytetracyclin.