Immunodetection of Pectic Epitopes, Arabinogalactan Proteins, and Extensins in Mucilage Cells from the Ovules of Pilosella officinarum Vaill. and Taraxacum officinale Agg. (Asteraceae).

The main aim of this study was to compare the cytological difference between ovular mucilage cells in two Asteraceae species-Pilosella officinarum and Taraxacum officinale-in order to determine whether pectic epitopes, arabinogalactan proteins, or extensins are present. The immunocytochemical technique was used. Both the Taracacum and Pilosella genera have been used recently as models for understanding the mechanisms of apomixis. Knowledge of the presence of signal molecules (pectic epitopes, arabinogalactan proteins, and extensins) can help better understand the developmental processes in these plants during seed growth. The results showed that in Pilosella officinarum, there was an accumulation of pectins in the mucilage, including both weakly and highly esterified pectins, which was in contrast to the mucilage of Taraxacum officinale, which had low amounts of these pectins. However, Taraxacum protoplasts of mucilage cells were rich in weakly methyl-esterified pectins. While the mucilage contained arabinogalactan proteins in both of the studied species, the types of arabinogalactan proteins were different. In both of the studied species, extensins were recorded in the transmitting tissues. Arabinogalactan proteins as well as weakly and highly esterified pectins and extensins occurred in close proximity to calcium oxalate crystals in both Taraxacum and Pilosella cells.

Network pharmacology-based identification of the protective mechanisms of taraxasterol in experimental colitis.

BACKGROUND AND AIM: Taraxasterol, a pentacyclic-triterpene, has been reported to exert potent anti-inflammatory activity. However, the molecular mechanisms by which taraxasterol attenuates acute experimental colitis (AEC) remain undocumented. METHODS: A network pharmacology approach was used to identify the candidate and collective targets of taraxasterol and acute colitis, and an AEC model was established by oral administration of dextran sulfate sodium (DSS) in mice. Body weight and colon lengths were then examined, the pathological scoring was assessed by using hematoxylin and eosin staining, and the expression levels of target genes were further confirmed by qRT-PCR and immunohistochemistry (IHC) analysis in taraxasterol treated AEC models. RESULTS: 14 collective targets of taraxasterol and acute colitis were identified by a network pharmacology analysis, including PPARG, JAK2, MMP3, NR1I2 and PTPN11. Further investigations in an AEC model showed that, taraxasterol alleviated the unfavorable clinical symptoms and attenuated the intestinal inflammation response by reducing the cytokines TNF-α, IL-1ß and IL-6 levels. qRT-PCR and IHC analysis evidenced that, taraxasterol decreased MMP3 expression levels, but increased PPARG expression levels in AEC models as compared with the DSS group. CONCLUSIONS: Our findings demonstrated that taraxasterol improved DSS-induced AEC through regulating MMP3 and PPARG expression, providing a new insight into the potential therapeutic strategies for acute colitis.

Organic acid component from Taraxacum mongolicum Hand.-Mazz alleviates inflammatory injury in lipopolysaccharide-induced acute tracheobronchitis of ICR mice through TLR4/NF-κB signaling pathway.

Inflammation plays an important role in the pathogenesis of acute tracheobronchitis. Taraxacum mongolicum Hand.-Mazz (TMHM) is a dietic herb for heat-clearing and detoxifying functions as well as swell-reducing and mass-resolving effect in Traditional Chinese Medicine. Studies have shown that its major ingredient organic acid component (OAC) possesses favorable anti-inflammatory activity. However, the protective effect of OAC from TMHM (TMHM-OAC) on inflammatory injury of acute tracheobronchitis and its possible mechanism remains poorly understood. In this study, HPLC-DAD was used to analyze the components of TMHM-OAC. Lipopolysaccharide of 1mg/ml was used to induce respiratory inflammation in ICR mice at the dose of 5mg/kg by intratracheally aerosol administration. Enzyme-linked immunosorbent assay (ELISA) was employed to detect the levels of inflammation factors such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and nitric oxide in serum and supernatant of trachea tissue. Western blotting (WB) and Immunohistochemistry analysis (IHC) were conducted in parallel to determine TNF-α, IL-6, inducible nitric oxide synthase (iNOS), Toll-like receptors 4(TLR4) protein expressions and nuclear factor-kappa B p65 (NF-κB p65) phosphorylation. Hematoxylin-Eosin staining (HE) was applied to evaluate pathological lesions of trachea tissue. Experimental results showed that TMHM-OAC significantly reduced the levels of the TNF-α, IL-6 and NO in serum and supernatant of tracheal of LPS-induced ICR mice. The protein expression levels of TNF-α, IL-6 and iNOS in tracheal tissue were also down-regulated significantly by the treatment of TMHM-OAC. Moreover, TMHM-OAC downregulated phosphorylation of NF-κB p65 and protein expression of TLR4. Our results indicated that TMHM-OAC could improve LPS-induced histopathological damage of tracheal tissues through the regulation of TLR4/NF-κB signaling pathway and could be beneficial for the treatment of acute tracheobronchitis.

Silencing and heterologous expression of ppo-2 indicate a specific function of a single polyphenol oxidase isoform in resistance of dandelion (Taraxacum officinale) against Pseudomonas syringae pv. tomato.

Dandelion (Taraxacum officinale) possesses an unusually high degree of disease resistance. As this plant exhibits high polyphenol oxidase (PPO) activity and PPO have been implicated in resistance against pests and pathogens, we analyzed the potential involvement of five PPO isoenzymes in the resistance of dandelion against Botrytis cinerea and Pseudomonas syringae pv. tomato. Only one PPO (ppo-2) was induced during infection, and ppo-2 promoter and ß-glucuronidase marker gene fusions revealed strong induction of the gene surrounding lesions induced by B. cinerea. Specific RNAi silencing reduced ppo-2 expression only, and concomitantly increased plant susceptibility to P. syringae pv. tomato. At 4 days postinoculation, P. syringae pv. tomato populations were strongly increased in the ppo-2 RNAi lines compared with wild-type plants. When the dandelion ppo-2 gene was expressed in Arabidopsis thaliana, a plant having no PPO gene, active protein was formed and protein extracts of the transgenic plants exhibited substrate-dependent antimicrobial activity against P. syringae pv. tomato. These results clearly indicate a strong contribution of a specific, single PPO isoform to disease resistance. Therefore, we propose that specific PPO isoenzymes be included in a new family of pathogenesis-related (PR) proteins.

Sesquiterpene lactone mix patch testing supplemented with dandelion extract in patients with allergic contact dermatitis, atopic dermatitis and non-allergic chronic inflammatory skin diseases.

We investigated the value of patch testing with dandelion (Compositae) extract in addition to sesquiterpene lactone (SL) mix in selected patients. After we detected a case of contact erythema multiforme after patch testing with dandelion and common chickweed (Caryophyllaceae), additional testing with common chickweed extract was performed. A total of 235 adults with a mean age of 52.3 years were tested. There were 66 men and 169 women: 53 consecutive patients with allergic contact dermatitis (ACD); 43 with atopic dermatitis (AD); 90 non-atopics suffering from non-allergic chronic inflammatory skin diseases; 49 healthy volunteers. All were tested with SL mix 0.1% petrolatum (pet.) and diethyl ether extracts from Taraxacum officinale (dandelion) 0.1 and 3.0% pet. and from Stellaria media (common chickweed) 0.1 and 3% pet. A total of 14 individuals (5.9%) showed allergic reaction (AR) to at least 1 of the plant allergens, 4 (28.6%) to common chickweed extract, and 11 (78.6%) to Compositae allergens. These 11 persons made the overall prevalence of 4.7%: 8 (3.4%) were SL-positive and 3 (1.3%) reacted to dandelion extract. 5 persons (45.5%) had AD, 2 had ACD, 2 had psoriasis and 2 were healthy controls. The Compositae allergy was relevant in 8 cases (72.7%). The highest frequency of SL mix sensitivity (9.3%) was among those with AD. Half the SL mix-sensitive individuals had AD. ARs to dandelion extract were obtained only among patients with eczema. A total of 9 irritant reactions (IRs) in 9 individuals (3.8%) were recorded, 8 to SL mix and 1 to common chickweed extract 3.0% pet. No IR was recorded to dandelion extract (P = 0.007). Among those with relevant Compositae allergy, 50.0% had AR to fragrance mix and balsam of Peru (Myroxylon pereirae resin) and colophonium. SLs were detected in dandelion but not in common chickweed. Our study confirmed the importance of 1 positive reaction for emerging, not fully established, Compositae allergy. In conclusion, the overall prevalence of 4.7% in our study represents a basal SL mix detection rate of 3.4% reinforced and safely supplemented by testing with the dandelion extract.