BackgroundThe content of medicinal bioactive constituents in huangqi is affected by plant age. In this study, we devised a quick and convenient method for determining the age of huangqi, which was cultivated in Hunyuan County (Shanxi Province).Methods1, 2, 3, 4, 5, 8, 10 growth years huangqi had 38 samples, all samples were collected separately. The growth rings in these samples were observed after making paraffin section and freehand-section. The relationship between growth rings and its growth years was analyzed by SPSS 19.0 software. Histochemical localization of total flavones and saponins in huangqi was determined by color reactions. The concentration of four flavonoids and two saponins in the roots of huangqi of different ages and different organizational structure (normal roots and rotten heart roots) were determined by HPLC-DAD and HPLC-ELSD. The results were analyzed by SPSS 19.0 software.ResultsAll huangqi samples had clear growth rings, and the statistical result about growth rings (X) and growth years (Y) showed significant correlation (r = 1, P = 0.000). The calibration curves of these six ingredients showed good linearity respectively, with significant correlation. All relative standard deviations (RSDs) of precision, recovery, repeatability, and stability experiments were less than 2%. Roots of 5-year-old plants contained the highest concentrations of total flavonoids and saponins. Saponin concentrations increased toward the center of the roots, whereas the four flavonoids showed an opposite trend in tissue distribution.ConclusionThe growth year of huangqi (Hunyuan County, Shanxi Province) could be determined soon and conveniently by naked eyes after staining phloroglucinol-HCl solution on freehand section. The content of saponins and flavonoids in rotten heart root and the surrounding normal tissues were affected by the formation and the extent of rotten heart.Electronic supplementary materialThe online version of this article (doi:10.1186/s13020-017-0135-z) contains supplementary material, which is available to authorized users.

Growth rings were used to determine the root age of medicinal Paeonia lactiflora from four producing areas, and their corresponding paeoniflorin content were measured based on the identification of ages. Different P. lactiflora root samples of different ages were collected from the four major growing areas in China: Bozhou, Anhui Province; Pan'an, Zhejiang Province; Zhongjiang, Sichuan Province; and Heze, Shandong Province. The relationship between the number of growth rings and age was analyzed using hand sections and paraffin sections. The paeoniflorin content in the roots of different P. lactiflora cultivars from different growing areas was measured using high-performance liquid chromatography (HPLC). The growth rings in the P. lactiflora roots were consistent with the age of the plant from Heze, Zhongjiang, Pan'an, whereas that for the P. lactiflora from Bozhou was one less than the age of the plant. The HPLC results show that the paeoniflorin content was highest in P. lactiflora 'Baihuachuanshaoyao,' followed by 'Baihuahangshaoyao,' 'Honghuachuanshaoyao,' and 'Honghuahangshaoyao,' 'Bozhoushaoyao' had the lowest levels of paeoniflorin. With increasing age, the paeoniflorin in the roots of the different P.lactiflora cultivars slowly declined or remained the same. In summary, the age of the roots of P. lactiflora from different growing areas can be determined using growth rings. The paeoniflorin content in the roots of P. lactiflora is correlated with cultivar and it was slowly declined with increasing age.

Programmed cell death (PCD) plays a critical role throughout the lives of plants, it is regarded as a highly regulated and active process of plant cell death during the times of biotic or abiotic stress. This study aims to provide developmental anatomical characteristics of the interxylary cork formation in the roots of Astragalus. membranaceus var. mongholicus, and to subsequently show cytomorphological evidence that PCD is involved in the development of rhytidome and interxylary cork. The developmental anatomy of rhytidome and interxylary cork of the perennial fresh main root of A. membranaceus var. mongholicus was studied using light microscopy, whereas the PCD in the development of rhytidome and interxylary cork was studied using fluorescence microscopy and transmission electron microscopy. Histologically, it was observed that the parenchyma cells of secondary phloem and xylem in roots recovered their meristematic ability, and later developed into rhytidome and interxylary cork. Cytologically, ultrastructural characteristics such as nucleus malformation, vacuole disappearance, mitochondrial degeneration, and vesicle filling were observed. In roots, the nucleus of the phloem parenchyma cells were terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling (TUNEL)‐positive from the pre‐rhytidome stage to the formation of rhytidome stage and 4′,6‐diamidino‐2‐phenylindole dihydrochloride (DAPI)‐negative during the mature rhytidome stage. The TUNEL assay of the xylem parenchyma cells showed positive characteristics from the early stage of interxylary cork formation to the interxylary cork formation stage, whereas DAPI‐negative characteristics were observed in the mature interxylary cork. Gel electrophoresis showed that DNA cleavage was random. Our results indicated that the formation of the rhytidome and interxylary cork involved the PCD process.

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Introduction Astragali Radix has been used for over 2000 years in traditional Chinese medicine. Its secondary xylem “Jinjing” and secondary phloem “Yulan” are important for evaluating the quality of the Daodi medicinal material in China. However, its systematic characterisation has not been conducted. Objective This study aims to investigate the colour, chemical compounds, and antioxidant capacity of the secondary xylem and phloem of Astragali Radix on the basis of untargeted metabolomics, broadening the application scope of Astragali Radix in food and pharmaceutical industries. Methods The L*, a*, and b* of the secondary xylem and phloem were measured by colorimetry, and the chemical compounds were identified and quantified by ultra‐performance liquid chromatography‐quadrupole‐time‐of‐flight mass spectrometry (UPLC‐Q‐TOF‐MS) and high‐performance liquid chromatography‐diode array detector‐evaporative light scattering detection. 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) and 2‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) assays were conducted to evaluate their antioxidant capacity. Results Thirty‐one compounds were identified by UPLC‐Q‐TOF‐MS. The secondary xylem exhibited high parameter b*, flavonoid content, and antioxidant capacity, while the secondary phloem was rich in astragalosides. The colour parameters of well‐defined type A significantly varied from those of the other types. Well‐defined type A also exhibited the highest antioxidant activity and flavonoid content, followed by middle type A‐like, middle type B‐like, and yellow shading type B. Conclusion The colour parameters, chemical compounds, and antioxidant capacity among the different transverse sections of secondary xylem and phloem varied. The yellow colour of secondary xylem was correlated to high flavonoid content and antioxidant activity, and well‐defined type A of Astragali Radix had better quality than other types.