Crystal structure and Hirshfeld surface analysis of (1H-imidazole-κN3)[4-methyl-2-({[2-oxido-5-(2-phenyl-diazen-1-yl)phen-yl]methyl-idene}amino)penta-noate-κ3O,N,O']copper(II).

The title copper(II) complex, [Cu(C18H19N3O3)(C3H4N2)], consists of a tridentate ligand synthesized from l-leucine and azo-benzene-salicyl-aldehyde. One imidazole mol-ecule is additionally coordinated to the copper(II) ion in the equatorial plane. The crystal structure features N-H⋯O hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions to the packing are from H⋯H (52.0%) and C⋯H/H⋯C (17.9%) contacts.

Seasonal variation of alkaloids and polyphenol in Ephedra sinica cultivated in Japan and controlling factors.

We investigated the seasonal variation of alkaloids (ephedrine and pseudoephedrine), total polyphenol, and sugar contents in Ephedra sinica cultivated in Japan and elucidated the controlling factors for the variation. In 2018, alkaloids and polyphenol contents increased dramatically from May to July, decreased to their lowest in October, and slightly increased again in November. The reduction of alkaloids and polyphenol contents in the autumn may be affected by precipitation in summer. In 2020, alkaloids and polyphenol contents started to decrease in late July when rainfall was abundant from July to August. In contrast, sucrose and starch contents continued to increase until September and remained high until October. Vascular bundles and fiber developed, and herbal stem weight increased from August to October. Alkaloids and total polyphenol contents tended to increase in November. At the same time, starch and sucrose contents decreased dramatically, whereas glucose and fructose contents increased. Sugar content decreased from October and was lowest in November. The seasonal variation of alkaloids and total polyphenol contents exhibited a contrasting tendency to the seasonal variation of sugar content and tissue development. The seasonal variation of alkaloids and total polyphenol contents was caused by the seasonal variation of sugar content and tissue development. In addition, it is suggested that anatomy may be used for alkaloids content estimation in Ephedra plants.

Evaluation of rooting characteristics of Ephedra cuttings by anatomy and promising strain selection based on rooting characteristics and alkaloid content.

The differences in rooting characteristics of cuttings prepared from E. sinica strains were investigated and found that cuttings prepared from strains with high rooting characteristics showed approximately 90% of the cuttings were rooted, whereas cuttings prepared from low rooting characteristics did not root. To understand the reason for this substantial difference, the anatomy of nodes was examined and found that adventitious roots were generated from the cortex and parenchyma in pith. Calculations of the correlation coefficients between the rooting rate and the value of anatomy indicated that the rooting rate was positively correlated with the parenchyma in pith in the node. On the basis of the positive correlation, it is possible to estimate the rooting characteristics of new strains without having to prepare cuttings. Next, we conducted a screening for E. sinica strains on the basis of total alkaloids content [ephedrine (E) + pseudoephedrine (PE)] and selected strains having no less than 0.7% total alkaloids content as defined by the Japanese Pharmacopoeia 18th edition. Strains having characteristic E or PE content were uncovered: E-rich strains had 100% E content and PE-rich strains had 99% PE content. We were able to select E. sinica strains on the basis of two factors: high rooting rate of cuttings and high or characteristic alkaloid content. These strains are valuable for breeding.