以考试这一重要的教学环节为切入点，由每位同学出两道题并阐明出题动机和考查点，将全体宾老师在习题课上逐一深入分析后作为期末考试题库。这种考试改革方案极大地调动了学生的学习积极性，激发了学生的学习热情，给学生充分的创造空间。该方法在有机化学教学实践中已取得了非常好的效果。

Vitamin C (L-ascorbic acid) protects human health by scavenging toxic free radicals and other reactive oxygen species formed in cell metabolism. The surplus supplementation of vitamin C, however, may be harmful to health because the level of 8-oxoguanine and 8-oxoadenine in lymphocyte DNA varies remarkably. In the process of the kinetic investigation on the 2,20-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced autoxidation of glycerol trioleate (GtH) in the micelles of cetyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and Triton X-100, the addition of vitamin C accelerates the autoxidation of GtH even in the absence of the free radical initiator, AAPH. The initiating rate, Ri, of vitamin C (VC)-induced autoxidation of GtH is related to the micelle charge, i.e. Ri=14.4×10-6 [VC] s-1 in SDS (anionic micelle), Ri＝1961×10-6 [VC] s-1 in Triton X-100 (neutral micelle) and Ri is a maximum in CTAB (cationic micelle) when the vitamin C concentration is ～300μM. Thus, vitamin C can initiate autoxidation of GtH in micelles, especially in the neutral one. Moreover, the attempt to explore whether -tocopherol (TocH) could rectify vitamin C-induced autoxidation of GtH leads us to find that the rate constant of TocH reacting with the anionic radical of vitamin C (VC.), k inh, is 103 M-1 s-1, which is less than that of the-tocopherol radical (Toc.) with vitamin C (kinh=105 M-1 s1). Thus, the equilibrium constant of the reaction Toc.þVC ÐTocH=VC. is prone strongly to the regeneration of Toc. by vitamin C rather than the reverse reaction

This work focused on assessing the antioxidant capacity of two hydroxyl-substituent Schiff bases, 2-(o-hydroxylphenylimino)methylphenol (OsH) and 2-(p-hydroxylphenylimino)methylphenol (PsH) used alone or in combination with a-tocopherol (TocH) and 6-hydroxyl-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) in 2,2’-azobis(2-amidinopropane hydrochloride) (AAPH)-induced peroxidation of triolein (GtH) dispersed in cetyl trimethyl ammonium Bromide (CTAB, a cationic micelle), sodium dodecyl sulfate (SDS, an anionic micelle), and Triton X-100 (a neutral micelle), respectively. The present findings indicate that OsH and PsH are not only concentration-dependent antioxidants, but also protect GtH with Trolox and TocH synergistically. Especially, the reason for the higher antioxidant capacity of OsH than PsH can be ascribed to the fact that OsH contains a hydroxyl group adjacent to the nitrogen atom. Furthermore, the number of trapped peroxyl radicals by Schiff base, n, can be calculated on the basis of chemical kinetic deduction. As a result, n of OsH and PsH increase in SDS micelle but decrease in CTAB, implicating that their antioxidant capacities are not only related to their structures but also to the charge property of micelles, dispersed GtH also affect their antioxidant behavior prominently. In addition, the synergistic antioxidant capacities of OsH and PsH used in conjuction with Trolox and TocH were investigated in the above micelles, and, it was found that PsHþTrolox in Triton X-100 and CTAB exhibited a mutual promoting effect, whereas OsHþTrolox in SDS plays a mutual demoting effect. Nevertheless, the n of Schiff bases or other antioxidants in the mixed usage are rather different from that used alone, implying that an interaction among these compounds exists in protecting GtH against AAPH-induced peroxidation.

Since the research on antioxidants provides theoretical information for the medicinal development, and supplies some in vitro methods for quick-optimizing drugs, it attracts more scientific attention from bioorganic and medicinal chemists. In addition to the traditional O–H bond-type antioxidant, carbazole and its related tricyclic amines (Ar2NHs), in which N–H bond functioned as the antioxidant, have attracted much research attention because Ar2NHs have always been the central structure in many currently used drugs. Thus, the investigation on the structure–activity relationship (SAR) between Ar2NHs and their free-radical-scavenging capacities in detail will benefit the development of novel radical-scavenging drugs containing Ar2NHs as the central structure. Therefore, carbazole (CazNH) and its structural analogues including phenoxazine (PozNH), phenothiazine (PtzNH), iminostilbene (IsbNH) together with diphenylamine (DpaNH) were applied to protect human erythrocytes against 2,20-azobis(2-amidinopropane hydrochloride) (AAPH)-induced hemolysis in vitro. By introducing the chemical kinetic formula related to free radical reaction, namely, the quantitative relationship between inhibition period (tinh) and the concentration of antioxidant (AH), tinh=(n/Ri)[AH], into AAPH-induced hemolysis, the values of stoichiometric factor (n) of Ar2NHs indicated that the free-radical-scavenging sequence of Ar2NHs is PozNH > DpaNH > CazNH > IsbNH > PtzNH > a-tocopherol (TocH). Another aim of this work was to investigate the antioxidative effect of Ar2NHs used together with other antioxidants including Trolox (TroH), VC, L-ascorbyl-6-laurate (VC-12), and TocH. The obtained data revealed that n value of PozNH when used together with all the other antioxidants decreases, whereas, n values of CazNH, DpaNH, IsbNH, and PtzNH when used in combination with TroH increase, demonstrating that two different interaction styles existed in the case of Ar2NHs used with other antioxidants. These findings may be useful for the development of agents for various ROS-mediated diseases in vivo.