Xiangxiang Fu

Integrated effects of light intensity and fertilization on growth and flavonoid accumulation in Cyclocarya paliurus.

Cyclocarya paliurus has been used for drug formulations and ingredients in functional foods in China. Field studies were conducted to examine the relationships between environmental factors and flavonoid accumulation. A split-plot randomized design was used to establish three shading treatments and three fertilization levels, and growth parameters and flavonoid contents were detected. The greatest biomass production was achieved in intermediate shade and fertilization treatment, and leaf production per seedling increased by 139.5% compared to the treatment without shade and fertilization. Overall, shade and fertilization had a significantly negative effect on contents of total flavonoid, kaempferol, quercetin, and isoquercitrin in leaves of C. paliurus. However, the greatest accumulation of total flavonoid in the leaves was observed in intermediate shade and fertilization treatment, achieving 364.4 g/plant. The results suggest that manipulating the field growing conditions and optimizing the silvicultural system would be important for obtaining the greatest yield of targeted health-promoting substances.

Seasonal and genotypic variation of water-soluble polysaccharide content in leaves of Cyclocarya paliurus

Cyclocarya paliurus (Batal) Iljinskaja is an important medicinal woody plant due to numerous bioactive natural products in its leaves. As an important bioactive natural product, water-soluble polysaccharides (WSP) in leaves of C. paliurus possess diverse biological activities, such as hypoglycemic, anticancer and free-radical-scavenging activities. To better understand accumulation patterns of WSP in C. paliurus leaves, seasonal, genotypic and positional variations of WSP content were investigated in this study. The results showed that the mean content of WSP in leaves from three crown positions (upper, middle and lower) within an individual was 38.5 mg g−1. ANOVA and Duncans multiple range test indicated that WSP content in leaves of the upper crown was significantly higher than that in the middle and lower crowns, whereas no significant difference was observed between the middle and the lower positions. Seasonal variation of WSP content in the leaves was revealed as a bimodal temporal pattern with the maximum (38.3 mg g−1) observed in April and the second peak (32.3 mg g−1) in October, whereas the lowest WSP content was observed in June (20.12 mg g−1) or in fallen leaves (17.71 mg g−1). Generally, higher contents of WSP accumulated in the maturity/senescence period (from September to mid-November) than during the rapid growth phase (from May to August). Moreover, WSP content varied significantly among 12 provenances, ranging from 22.09 to 34.56 mg g−1, in leaves sampled in October. Our results not only provide knowledge of the accumulative dynamics and genotypic variation of WSP, but also establish a basis for determining the optimal time for harvesting and for extensive selection and breeding programs to improve the content of beneficial compounds in the leaves of C. paliurus in the future.

Chemical Fingerprint and Multicomponent Quantitative Analysis for the Quality Evaluation of Cyclocarya paliurus Leaves by HPLC–Q–TOF–MS

Cyclocarya paliurus is an edible and medicinal plant containing various bioactive components with significant health benefits. A combinative method using high-performance liquid chromatography (HPLC) fingerprint and quantitative analysis was developed and successfully applied for characterization and quality evaluation of C. paliurus leaves collected from 18 geographical locations of China. For the fingerprint analysis, 21 common peaks were observed among the 18 samples, and these peaks were identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC–Q–TOF–MS), while a simultaneous quantification of 16 markers was conducted to interpret the variations of contents of these bioactive compounds among the C. paliurus leaves from different geographical locations. Quantification results showed that the contents of these sixteen investigated compounds varied greatly among the leaves from different locations. The developed new method would be a valuable reference for further study and development of this bioactive plant.

Seasonal variation of microelement contents in leaves of Cyclocarea paliurus among the provenances

Cyclocarya paliurus as a multiple function plant can accumulate biologically important microelement elements. To reveal the variation of selected microelement concentrations in leaves of C. paliurus provenances during the growing season, 12 C. paliurus provenances in the field trial were sampled five times at approximately 1-month intervals. The method of inductively coupled plasma optical emission spectrometer (ICP-OES) was employed to determinate average concentrations of Fe, Mn, Zn, Cu and Se in leaves of 12 C. paliurus provenances. The results show that on average, the concentrations of five microelement in the leaves follows an order of Fe > Mn > Zn > Cu > Se. Variance analysis shows that there are significant differences in Fe, Mn and Zn concentrations among the twelve provenances (p<0.05), while there is no significant difference between Cu and Se concentrations. A significant difference was also observed in the concentrations of five microelements at the different sampling times (p<0.001), but the mean concentrations for each microelement showed different temporal dynamic patterns. Meanwhile, a significant correlation between concentrations of Se and other measured microelements was detected in the leaves of C. paliurus, except for Mn. Obtained results not only demonstrated that leaves of C. paliurus exhibited higher levels of microelements (Fe, Mn, Cu, Zn and Se), but also provided a basis for breeding strategies of superior provenances with rich content of microelements, and choosing optimum harvesting time for food industry in future.

Effects of NaCl Stress on Seed Germination, Leaf Gas Exchange and Seedling Growth of Pteroceltis tatarinowii

Effects of NaCl on seed germination, leaf gas exchange and seedling growth were investigated. The germination of P. tatarinowii seeds was delayed in the presence of NaCl, and was significantly inhibited when NaCl concentration exceeded 17 mM (1.0 g·L−1). NaCl treatments induced reductions of transpiration rate, stomatal conductance and net photosynthetic rate and their reductions were significant with the increasing of NaCl concentration. However, intercellular CO2 concentration in seedling leaves under salt stress was significantly higher than that of controls. There was a significant reduction in survival, basal diameter increment and height increment with increasing NaCl concentration 50 days after NaCl treatment, and a significant reduction in the dry weight increment of roots, stems, and leaves was also observed in the NaCl treatments. The deleterious effect on the biomass increment was more evident in the case of stems and leaves. Results from this study suggest that P. tatarinowii is sensitive to salinity stress and the salinity threshold for seedling growth might be less 34 mM (2.0 g·L−1).

Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus

Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearsons correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials.

Antidiabetic Effect of Cyclocarya paliurus Leaves Depends on the Contents of Antihyperglycemic Flavonoids and Antihyperlipidemic Triterpenoids

Cyclocarya paliurus has been used commonly to treat diabetes in China. However, the effective components and the effect of plant origin remain unclear. In this study, C. paliurus leaves with different chemical compositions were selected from five geographical locations, and their effects on streptozotocin (STZ)-induced diabetic mice were evaluated with both ethanol and aqueous extracts. Glucose levels, lipid levels, and biomarkers of liver and kidney function were measured. The principal components of both C. paliurus ethanol and aqueous extracts from different geographical locations differed quantitatively and qualitatively. Results showed that C. paliurus extracts with better antihyperglycemic effects were characterized by higher contents of total flavonoids, especially quercetin-3-O-glucuronide and kaempferol-3-O-glucuronide. Furthermore, significantly negative correlations were found between triterpenoids contents and lipid levels. These results revealed the potential antihyperglycemic capacity of C. paliurus flavonoids and the antihyperlipidemic effect of C. paliurus triterpenoids. Thus, we suggest that the composition of C. paliurus compounds might help to design therapeutic alternatives for the treatment of diabetes mellitus. However, geographic origins and the extraction solvents can also affect the effectiveness of the treatment as these factors influence the chemical compositions and thereby the biological activities.

Influence of provenance and shade on biomass production and triterpenoid accumulation in Cyclocarya paliurus

Cyclocarya paliurus is a well-known multiple function tree species and has been used for ingredients in functional foods and drug formulations in China. A split-plot randomized design was used to grow three provenances at three different shade levels and effects of provenance and shading on growth and triterpenoid accumulation were assessed. Shading caused significant variation in photosynthetic photon flux density, air temperature and relative humidity, and moreover influenced total triterpenoid content in leaves. However, contents of cyclocaric acid B, cyclocarioside I, and arjunolic acid in the leaves were mainly affected by provenance. A significant seasonal variation of triterpenoid contents was observed in the leaves and the highest content appeared in September. Two-way analysis of variance revealed a significant provenance effect, shading effect and integrated effect between provenance and shading on biomass production. The highest accumulation of total triterpenoid and cyclocarioside I per plant was achieved in Muchuan provenance without shading, while the biggest accumulations of cyclocaric acid B and arjunolic acid were observed in Muchuan provenance with one-layer shading net. The data obtained suggest a complex relationship between environment, genotype and triterpenoid production but highlight that selecting suitable provenance of C. paliurus and optimizing cultivation system would be crucial for a high triterpenoid production.

Geographic Variation in the Chemical Composition and Antioxidant Properties of Phenolic Compounds from Cyclocarya paliurus (Batal) Iljinskaja Leaves

Cyclocarya paliurus has been widely used as an ingredient in functional foods in China. However, the antioxidant properties of phenolic compounds and the effect of the plant origin remain unclear. The present study evaluated the geographical variation of this plant in term of its phenolic composition and antioxidant activities based on leaf materials collected from five regions. high-performance liquid chromatography (HPLC) analysis showed that there are three major components, quercetin-3-O-glucuronide, kaempferol-3-O-glucuronide, and kaempferol-3-O-rhamnoside, and their contents varied significantly among sampling locations. The investigated phenolic compounds showed substantial antioxidant activities, both in vitro and in vivo, with the highest capacity observed from Wufeng and Jinzhongshan. Correlation analysis revealed that quercetin and kaempferol glycosides might be responsible for the antioxidant activities. Our results indicate the importance of geographic origin, with sunny hours and temperature as the main drivers affecting the accumulation of C. paliurus phenolics and their antioxidant properties.

Genotypic variation in tree growth and selected flavonoids in leaves of Cyclocarya paliurus

Cyclocarya paliurus is a valuable medicinal tree species in China. However, limited information is available on its genotype selection and cultivation for improvement of growth and health-promoting phytochemicals. To contribute to improved knowledge of the potential use of the species, 33 families of C. paliurus were assessed with respect to genotype on growth and flavonoid content in the leaves, and the relationship between growth and flavonoid accumulation was examined. Growth and flavonoid content varied significantly among different families, and isoquercitrin was the main component of the individual flavonoids, followed by kaempferol and quercetin. Both total and individual flavonoids showed seasonal variation, with the mean highest contents of quercetin and isoquercitrin in July but the highest kaempferol content in October. Correlation analysis showed that tree height and diameter at breast height of C. paliurus were negatively correlated with the contents of quercetin and kaempferol in the leaves, whereas no significant correlation between tree growth and total flavonoid content was detected. Hierarchical cluster analysis based on the parameters of tree growth and leaf flavonoid contents indicated that 33 families of C. paliurus were classified into four distinct groups. Results from this study are valuable for identifying superior families for a specific site and provide a basis for C. paliurus breeding strategies for flavonoid production.