[Relationship between seedling grade of Codonopsis pilosula and yield and quality of medicinal materials].

The study is aimed to research the relationship between the seedling grade of Codonopsis pilosula and yield and quality of medicinal materials, so as to provide basis for establishing seedling standard. Thirty seedlings of C. pilosula were collected from the main production areas in Gansu province, such as Weiyuan, Minxian, Zhangxian, Dangchang and Longxi, root length and diameter and weight of all the samples were measured. According to the clustering results, seedlings were divided into 3 levels, and field experiments were conducted with three levels seedling, yield and quality were tested in laboratory. Results have showed that emergence of grades 1 was faster than that of grades 2 and 3. Yield of grades 1 was significantly higher than that of grades 2 and 3 (P<0.05). Propargyl glycoside content of grades 1 was the highest, and significantly higher than that of grades 3. Polysaccharide content of grades 3 was the highest and significantly higher than that of grades 1 and 2 (P<0.05). So considering yield, quality and investment cost of C. pilosula, planting seedlings of C. pilosula should select that root length>15.6 cm, root diameter>2.7 mm, root weight>0.56 g.

[Analysis on competitive interaction between arenobufagin and verapamil hydrochloride with serum albumin].

OBJECTIVE: The present study was performed to investigate competitive interaction between arenobufagin and verapamil hydrochloride with serum albumin. METHODS: Equilibrium dialysis and high-performance liquid chromatography were used to analyze the binding rates of the two medicines to serum protein. The interactions based on bovine serum albumin (BSA) and human serum albumin (HSA) were investigated by using spectrofluorimetry. The interaction mode of arenobufagin and verapamil hydrochloride binding to serum proteins was simulated by molecular docking. RESULTS: The rate of arenobufagin (0.1µg/mL) binding to bovine serum was (61.1±0.2)%. Verapamil hydrochloride (0.025 to 0.1µg/mL) significantly reduced the bovine serum binding rate of arenobufagin, from (60.2±3.7)% to (36.9±3.4)%. However, arenobufagin at the tested doses had no marked effects on the binding rate of verapamil hydrochloride. Furthermore, the verapamil hydrochloride had an active effect on the arenobufagin-induced fluorescence quenching of BSA and HSA. The molecular docking results showed that verapamil hydrochloride and arenobufagin binded to HSA at site I. Molecular interaction energy of verapamil hydrochloride binding to site I was stronger than that of arenobufagin. CONCLUSION: Verapamil hydrochloride reduces the binding of arenobufagin to bovine serum. The mechanism may be a competitive interaction of arenobufagin and verapamil hydrochloride at site I on HSA.

Fast magnetization tunneling in tetranickel(II) single-molecule magnets.

A series of Ni(4) cubane complexes with the composition [Ni(hmp)(ROH)Cl](4) complexes 1-4 where R= -CH(3) (complex 1), -CH(2)CH(3) (complex 2), -CH(2)CH(2)(C(4)H(9)) (complex 3), -CH(2)CH(2)CH(2)(C(6)H(11)) (complex 4), hmp(-) is the anion of 2-hydroxymethylpyridine, t-Buhmp(-) is the anion of 4-tert-butyl-2-hydroxymethylpyridine, and dmb is 3,3-dimethyl-1-butanol] and [Ni(hmp)(dmb)Br](4) (complex 5) and [Ni(t-Buhmp)(dmb)Cl](4) (complex 6) were prepared. All six complexes were characterized by dc magnetic susceptibility data to be ferromagnetically coupled to give an S = 4 ground state with significant magnetoanisotropy (D approximately equal to -0.6 cm(-1)). Magnetization hysteresis measurements carried out on single crystals of complexes 1-6 establish the single-molecule magnet (SMM) behavior of these complexes. The exchange bias observed in the magnetization hysteresis loops of complexes 1 and 2 is dramatically decreased to zero in complex 3, where the bulky dmb ligand is employed. Fast tunneling of magnetization is observed for the high-symmetry (S(4) site symmetry) Ni(4) complexes in the crystal of complex 3, and the tunneling rate can even be enhanced by destroying the S(4) site symmetry, as is the case for complex 4, where there are two crystallographically different Ni(4) molecules, one with C(2) and the other with C(1) site symmetry. Magnetic ordering temperatures due to intermolecular dipolar and magnetic exchange interactions were determined by means of very low-temperature ac susceptibility measurements; complex 1 orders at 1100 mK, complex 3 at 290 mK, complex 4 at approximately 80 mK, and complex 6 at <50 mK. This confirms that bulkier ligands correspond to more isolated molecules, and therefore, magnetic ordering occurs at lower temperatures for those complexes with the bulkiest ligands.