Physiological and rhizospheric response characteristics to cadmium of a newly identified cadmium accumulator Coreopsis grandiflora Hogg. (Asteraceae).

Screening for superior cadmium (Cd) phytoremediation resources and uncovering the mechanisms of plant response to Cd are important for effective phytoremediation of Cd-polluted soils. In this study, the characteristics of Coreopsis grandiflora related to Cd tolerance and accumulation were analyzed to evaluate its Cd phytoremediation potential. The results revealed that C. grandiflora can tolerate up to 20 mg kg-1 of Cd in the soil. This species showed relatively high shoot bioconcentration factors (1.09-1.85) and translocation factors (0.46-0.97) when grown in soils spiked with 5-45 mg kg-1 Cd, suggesting that C. grandiflora is a Cd accumulator and can potentially be used for Cd phytoextraction. Physiological analysis indicated that antioxidant enzymes (i.e., superoxide dismutase, peroxidase, and catalase) and various free amino acids (e.g., proline, histidine, and methionine) participate in Cd detoxification in C. grandiflora grown in soil spiked with 20 mg kg-1 of Cd (Cd20). The overall microbial richness and diversity remained similar between the control (Cd0) and Cd20 soils. However, the abundance of multiple rhizospheric microbial taxa was altered in the Cd20 soil compared with that in the Cd0 soil. Interestingly, many plant growth-promoting microorganisms (e.g., Nocardioides, Flavisolibacter, Rhizobium, Achromobacter, and Penicillium) enriched in the Cd20 soil likely contributed to the growth and vitality of C. grandiflora under Cd stress. Among these, some microorganisms (e.g., Rhizobium, Achromobacter, and Penicillium) likely affected Cd uptake by C. grandiflora. These abundant plant growth-promoting microorganisms potentially interacted with soil pH and the concentrations of Cd and AK in soil. Notably, potassium-solubilizing microbes (e.g., Rhizobium and Penicillium) may effectively solubilize potassium to assist Cd uptake by C. grandiflora. This study provides a new plant resource for Cd phytoextraction and improves our understanding of rhizosphere-associated mechanisms of plant adaptation to Cd-contaminated soil.

Nitrogen deficiency maintains the yield and improves the antioxidant activity of Coreopsis tinctoria Nutt.

Nitrogen (N) deficiency levels were investigated for their potential to maintain the yield and improve antioxidant activity of Coreopsis tinctoria. Inflorescences and leaves at 0, 10, 20, 30, 40, and 50 d after flowering were frozen at -80 °C and plant growth, antioxidant activity, bioactive substance, enzyme activity, and gene expression were evaluated. N deficiency maintained the total number of flowers, promoted phenol and flavonoid accumulation, and enhanced antioxidant activity. Moreover, N deficiency stimulated activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate:coenzyme A ligase (4CL), and induced CtPAL, CtC4H and Ct4CL gene expression. The data also suggest that N-deficiency-induced phenolic and flavonoid accumulation occurs due to the activation of biosynthetic pathways in C. tinctoria. We characterize the unique features of C. tinctoria under N-deficiency conditions and provide valuable information for the cultivation of high-N use efficiency varieties with low input and high output.

Protective Effects of Anthocyanins from Coreopsis tinctoria against Oxidative Stress Induced by Hydrogen Peroxide in MIN6 Cells.

Anthocyanins (AC) from Coreopsis tinctoria possesses strong antioxidant properties, while the effects of AC on cells damage induced by reactive oxygen species (ROS) in diabetes mellitus diseases progression have not been reported. The present study was carried out to evaluate the protective property of AC against cellular oxidative stress with an experimental model, H2 O2 -exposed MIN6 cells. AC could reverse the decrease of cell viability induced by H2 O2 and efficiently suppressed cellular ROS production and cell apoptosis. In addition, Real-time PCR and Western blot analyses indicated that AC could protect MIN6 cells against oxidative injury through increasing the translocation of Nrf2 into nuclear, decreasing the phosphorylation level of p38 and up-regulating the protein expression of antioxidant enzyme (SOD1, SOD2 and CAT). Thus, this study provides evidence to support the beneficial effect of AC in inhibiting MIN6 cells from H2 O2 -induced oxidative injury.

Anti-Lipid Peroxidation, α-Glucosidase and α-Amylase Inhibitory Effects of the Extract of Capitula of Coreopsis tinctoria Nutt. and Protection Effects on High-Fat/High-Sugar and Streptozotocin-Induced Type 2 Diabetes in Mice.

Coreopsis tinctoria capitula (CTC) of the Compositae family has been used traditionally to treat various diseases in China, particularly type 2 diabetes mellitus (T2DM). This study evaluated the anti-lipid peroxidation, α-glucosidase and α-amylase inhibitory effects of CTC extracts, and analyzed its chemical composition by HPLC. Moreover, the antioxidant activity and protection effects of CTC extracts were investigated on high-fat/high-sugar and streptozotocin-induced T2DM mice. In vitro study, the ethyl acetate extract (EAE) and butanol extract (BE) of CTC exhibited anti-lipid peroxidation (IC50 : BHA>BE or EAE>ascorbic acid, p<0.05) and α-glucosidase inhibitory activity (IC50 : BE>EAE, p<0.05). In vivo, the BE at the dose of 600 mg/kg was intragastrically given to T2DM mice, which exhibited a certain extent of repair and improvement of the levels of CAT, GSH, GSH-PX , SOD, as well as plasma biomarkers, compared with those in the model group (p<0.05). These results demonstrated that CTC extracts have a positive effect to treat T2DM and it can be used for the treatment of T2DM in the future.

Structural elucidation and bioactivities of a novel arabinogalactan from Coreopsis tinctoria.

Coreopsis tinctoria is being widely cultivated in Xinjiang of China, whose consumption is known to prevent diabetes and neurodegenerative diseases. To elucidate the bioactive ingredients responsible for these benefits, the alkaline soluble crude polysaccharide (CTB) was isolated from C. tinctoria. In vitro experiments showed that the inhibition of α-amylase and α-glucosidase by CTB was 13407-fold and 906-fold higher than that by positive control, respectively. Then, a novel arabinogalactan, CTBP-1, was isolated and purified from CTB. Structural analysis showed that CTBP-1 possessed a 1,6-linked ß-d-Galp and 1,5-linked α-l-Araf backbone with branches substituted at the C-3 position of the 1,6-linked ß-d-Galp, and the side chains included 1,5-linked α-l-Araf, T-linked ß-d-Galp and T-linked α-l-Araf. The inhibitory effects of CTBP-1 on α-amylase and α-glucosidase were 2.7 and 17.9 times that of acarbose, respectively. CTBP-1 could avoid indigestion and similar side effects. In addition, CTBP-1 remarkably inhibited the release of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. In summary, CTBP-1 is a novel arabinogalactan with great potential as a treatment for type 2 diabetes and Alzheimer's disease.

Coreopsis Tinctoria Modulates Lipid Metabolism by Decreasing Low-Density Lipoprotein and Improving Gut Microbiota.

BACKGROUND/AIMS: The prevalence of hyperlipidemia is increasing rapidly. The role of Coreopsis tinctoria (CT) in amending lipid metabolism in hyperlipidemia patients has not been reported. This study aims to evaluate the role of CT in altering lipid metabolism in hyperlipidemia patients and to explore the possible mechanisms mediated by gut microbiota in hyperlipidemia mice models. METHODS: A retrospective analysis in 40 hyperlipidemia patients was conducted, in which 20 patients took fenofibrate and another 20 patients normatively drank water with CT. Hyperlipidemia mice models were also established. Blood biochemical tests were performed using an automatic biochemical analyzer. Liver histopathology was observed by hematoxylin and eosin staining. Ileocecal samples were collected from mice, and bacterial DNA was extracted and sequenced by MiSeq sequencing. Bacterial composition and differences were analyzed. RESULTS: In hyperlipidemia patients, CT was associated with decreased triglyceride and low-density lipoprotein (LDL) levels without liver injury. The experimental hyperlipidemia model also verified a similar result. Gut microbial richness and diversity were significantly decreased in hyperlipidemic mice, but increased after CT treatment. Bacterial communities were significantly differentiated between normal controls and hyperlipidemic mice. CT administration improved gut microbiota composition to an approximately normal status. Meanwhile, CT administration attenuated bacterial alterations at the class, order, family, and genus levels in hyperlipidemic mice. Importantly, the genera Barnesiella, Lactobacillus, and Helicobacter achieved high discriminatory power in hyperlipidemic mice relative to normal controls. CONCLUSIONS: CT can modulate blood lipid metabolism with improvement of liver function by decreasing LDL and improving gut microbiota compositions. These findings may provide novel therapeutic strategies for patients with hyperlipidemia.

Effects of the arbuscular mycorrhizal fungus Glomus mosseae on growth and metal uptake by four plant species in copper mine tailings.

A greenhouse experiment was conducted to evaluate the potential role of arbuscular mycorrhizal fungi (AMF) in encouraging revegetation of copper (Cu) mine tailings. Two native plant species, Coreopsis drummondii and Pteris vittata, together with a turf grass, Lolium perenne and a leguminous plant Trifolium repens associated with and without AMF Glomus mosseae were grown in Cu mine tailings to assess mycorrhizal effects on plant growth, mineral nutrition and metal uptake. Results indicated that symbiotic associations were successfully established between G. mosseae and all plants tested, and mycorrhizal colonization markedly increased plant dry matter yield except for L. perenne. The beneficial impacts of mycorrhizal colonization on plant growth could be largely explained by both improved P nutrition and decreased shoot Cu, As and Cd concentrations. The experiment provided evidence for the potential use of local plant species in combination with AMF for ecological restoration of metalliferous mine tailings.