Effects of anthraquinones from Cassia occidentalis L. on ovalbumin-induced airways inflammation in a mouse model of allergic asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Cassia occidentalis Linn. is a traditional ayruvedic edible shrub containing anthraquinones (AQs) as the principle active constituents. In folk medicine, it has a variety of uses including treatment of whooping cough ('pertussis') and inflammatory diseases. Despite these applications, limited data are available to validate the effects of C. occidentalis AQs on airways inflammation in asthma. AIM OF THE STUDY: To explore the anti-inflammatory potential of AQs extracted from C. occidentalis using an in vivo model of ovalbumin (OVA)-induced asthma. MATERIALS AND METHODS: Extraction and optimization of AQs from C. occidentalis was performed by mechanochemistry. Allergic asthma in BALB/c mice was sensitized and challenged by OVA, and the effects of AQs investigated in a mouse model. OVA-specific IgE concentrations in serum, and Th1/Th2 cytokine (IL-4, IL-5, IL-13 and IFN-γ) concentrations, inflammatory cell counts and classification in bronchoalveolar lavage fluid (BALF) were determined. Histopathological evaluation of lung tissue was performed using hematoxylin and eosin (H&E), and periodic acid-schiff (PAS) staining. Th1/Th2 cytokine mRNA expression was analyzed using the 2-ΔΔCt method. RESULTS: Treatment with AQs decreased inflammatory cell counts and production of Th2 cytokines (IL-4, IL-5 and IL-13) in BALF, and OVA-specific IgE in serum. In contrast,Th1 cytokine IFN-γ production in BALF was promoted. AQs also decreased mRNA expression of Th1/Th2 cytokine in lung tissue. Histological studies demonstrated that AQs substantially inhibited OVA-induced cellular infiltration, mucus hypersecretion and goblet cell hyperplasia in the lung. CONCLUSIONS: These findings demonstrated the inhibitory effects of AQs, derived from C. occidentalis, on OVA-induced allergic asthma in mice. The results suggest a promising ethnopharmacological use for AQs in patients with asthma.

Extraction, partial characterization and bioactivity of polysaccharides from Senecio scandens Buch.-Ham.

Mechanochemistry was applied to improve the yield of bioactive acid polysaccharides obtained from low-cost Senecio scandens Buch.-Ham. The structural characteristics and biological activities of three novel polysaccharides from S. scandens (SP2-1, SP2-2 and SP3-2) were investigated. SP2-1 and SP2-2 with molecular weights of 267.6 and 253.1 kDa, respectively, were composed of L-rhamnose, D-arabinose, D-mannose, D-xylose, D-glucose and D-galactose in various ratios, whereas SP3-2 with molecular weight of 266.6 kDa was composed of D-arabinose, D-glucose and D-galactose. In vitro, SP3-2 presented the strongest DPPH, ABTS and O2- radicals scavenging activities, as well as Fe3+ reducibility. Immunological tests demonstrated that all polysaccharide fractions stimulated the production of nitric oxide (NO) and immunomodulatory cytokines (IL-1ß and TNF-α) without cytotoxicity in macrophages and promoted splenocyte proliferation in different degree. These findings indicated that SP2-1, SP2-2 and SP3-2 have prominent antioxidant activity and potential immune response, which proved the possibility of S. scandens polysaccharides (SSP) applied in the field of functional food or medicine.

Extraction, characterization, and biological activity of polysaccharides from Sophora flavescens Ait.

Four water-soluble polysaccharides, designated as SF1, SF2, SF3 and SF4, were efficiently extracted from the roots of Sophora flavescens by mechanochemistry under the conditions of rotational speed of 400rpm, grinding time of 10min, powder to ball weight ratio of 1:20, and Na2CO3 loading of 7wt%. The results obtained indicated that all of these four acid heteropolysaccharides are composed of rhamnose, arabinose, xylose, mannose, glucose and galactose, with the average molecular weights of 400.9, 98.6, 99.3, 42.7kDa, respectively. In vitro, SF4 showed the most significant scavenging activity on superoxide radical, ABTS, and DPPH radical, while SF3 had the most significant scavenging activity on hydroxyl radical. Immunological tests demonstrated that SF1, SF2, SF3 and SF4 significantly stimulated nitric oxide production without cytotoxicity in macrophages and promoted splenocyte proliferation. These data suggest that the four polysaccharides fractions have the potential as novel natural sources of antioxidative and immunopotentiating agents.

Identification of Pns12 as the second silencing suppressor of Rice gall dwarf virus.

RNA silencing is a conserved mechanism found ubiquitously in eukaryotic organisms. It has been used to regulate gene expression and development. In addition, RNA silencing serves as an important mechanism in plants' defense against invasive nucleic acids, such as viruses, transposons, and transgenes. As a counter-defense, most plants, and some animal viruses, encode RNA silencing suppressors to interfere at one or several points of the silencing pathway. In this study, we showed that Pns12 of RGDV (Rice gall dwarf virus) exhibits silencing suppressor activity on the reporter green fluorescent protein in transgenic Nicotiana benthamiana line 16c. Pns12 of RGDV suppressed local silencing induced by sense RNA but had no effect on that induced by dsRNA. Expression of Pns12 also enhanced Potato virus X pathogenicity in N. benthamiana. Collectively, these results suggested that RGDV Pns12 functions as a virus suppressor of RNA silencing, which might target an upstream step of dsRNA formation in the RNA silencing pathway. Furthermore, we showed that Pns12 is localized mainly in the nucleus of N. benthamiana leaf cells.

Identification of Pns6, a putative movement protein of RRSV, as a silencing suppressor.

RNA silencing is a potent antiviral response in plants. As a counterdefense, most plant and some animal viruses encode RNA silencing suppressors. In this study, we showed that Pns6, a putative movement protein of Rice ragged stunt virus (RRSV), exhibited silencing suppressor activity in coinfiltration assays with the reporter green fluorescent protein (GFP) in transgenic Nicotiana benthamiana line 16c. Pns6 of RRSV suppressed local silencing induced by sense RNA but had no effect on that induced by dsRNA. Deletion of a region involved in RNA binding abolished the silencing suppressor activity of Pns6. Further, expression of Pns6 enhanced Potato virus × pathogenicity in N. benthamiana. Collectively, these results suggested that RRSV Pns6 functions as a virus suppressor of RNA silencing that targets an upstream step of the dsRNA formation in the RNA silencing pathway. This is the first silencing suppressor to be identified from the genus Oryzavirus.