In recent years, the incidence and mortality rate of invasive fungal infection have increased dramatically, and it is of great significance to develop novel antifungal agents with new chemical structure and new mode of action. In this review, novel antifungal lead compounds reported from 2007 to 2009 are reviewed. Moreover, their chemical structures, antifungal activities and structure-activity relationships have been summarized, which can provide useful information for future study of antifungal agents.

The Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R mutants of Candida albicans sterol 14?-demethylase (CACYP51) were constructed and heterologously expressed in D12667, the reconstructed strain with the deletion of CYP51 gene of the Y12667. With the strains obtained and microsome enzymes separated, the western blot and the ultraviolet absorption spectrophotometry were used to qualitative and quantitative detect the expressed protein, the GC-MS was used to detect the metabolism activity of the protein. The results showed that, the target protein expressed successfully in the reconstructed strains, with the expression level up to 25% of the total microsome proteins. The results also showed that, the wild type protein had the catalytic activity to its nature substrate. While after alteration the wild gene with Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R by a single base substitution, the catalytic activity of protein markedly decreased respectively. So the wild type and mutation CYP51 were expressed successfully in Saccharomyces cerevisiae and the expression products preserved the activity to metabolism their nature substrate.

Cancer is a serious threat to human life and health .Therefore, there is an emergent need to develop novel anti-cancer agents with new structural type , new mechanism of action and higher efficacy .Natural products had played a key role in the dis-covery of anticancer agents .The anti-cancer activity , mechanism of action , structure and activity relationship of several lead-com-pounds which were derived from natural products were summarized in this review .

Tyrosyl-DNA phosphodiesterase Ⅰ (TdpⅠ ) is a recently discovered proteinthat catalyzes the hydrolysis of 3′-phosphotyrosyl bonds .Such linkages form in vivo during the interaction of DNA and topoisomerase Ⅰ (TopⅠ) .TdpⅠ has been regarded as a potential therapeutic co-target of TopⅠ because it has the functions of repairing Top Ⅰ compound and coun-teracting the effects of Top Ⅰ inhibitors .TdpⅠ inhibitors can not only synergizing with Top Ⅰ-targeting drugs (camptoth-ecins) ,but also strength the function of bleomycin ,topoisomerase Ⅱ (TopⅡ ) inhibitors (etoposide ,doxorubicin) and DNA alkylating agents .We summarized the researching advance of TdpⅠ inhibitors and focused on the introduction of the mecha-nism ,bioactivity and structure-activity relationship .

With the development of science and the progress of age,medicinal chemistry is not only limited to the lead discovery and the structure-activity relationship studies,but also finding the target of bioactive small molecule drugs has be-come a tough issue to be solved.The identification and validation of bioactive small molecule targets has become the most criti-cal and difficult task,which plays a decisive role in academic and pharmaceutical research.Herein we summarize the current methods for target identification of small molecules,and mainly discuss about the target identification method by the chemical probes.Recent cases of successful application were also introduced to demonstrate the strategy of probe synthesis and design.

Objective To perform the ligand-based computer-aided drug design and construct the pharmacophore model of(1,3)-β-D-Glucan Synthase(GS)small molecule inhibitors.Method Six small molecules with diverse structures and good inhibitory activity were selected to construct the training set.The HipHop algorithm in Catalyst pharmacophore generation module was utilized to construct the pharmacophore models.The pharmacophore models were evaluated by constructed Decoy-set 3D database.Results Pharmacophore 02 has a good enrichment factor,sensitivity and specificity parameters.Pharmacoph-ore model validation with Decoyset 3D database proved that the model has good distinguishing capability.Conclusion The pharmacophore model of GS small molecule inhibitors was constructed and tested.It will provide valuable information for de-sign and discovery of novel small molecule GS inhibitors.

DNA topoisomerases (Tops) are essential enzymes that regulate the cellular processes such as replication , transcription ,recombination and repair .DNA Tops can be classified into two types ,topoisomerase Ⅰ (TopⅠ ) and topoi-somerase Ⅱ (TopⅡ) .They catalyze the breakage and religation of DNA ,maintaining the topological changes of DNA and va-rious DNA metabolic processes .Due to their important role in DNA metabolism ,the ability to interfere with the functions of Tops or generating Top-mediated DNA damage is an effective strategy for cancer chemotherapy .Tops have been considered as the most important targets for tumor chemotherapy .In this review ,we used examples to describe the development of dual to-poisomerase Ⅰ and Ⅱ inhibitors .

Objective To improve the synthesis process of chlorine f (1).Methods A "one-pot"method was applied to prepare Photosensitizer component (1),using pheophorbide a (3) as raw material by oxidating and cracking of the E-ring of (3) with bubbling oxygen in alcoholic solution of potassium hydroxide at 0 ℃ followed by refluxing in nitrogen atmosphere.In order to obtain the optimal synthetic procedure,the orthogonal experimental design of L9 (34 ) was adopted to investigate three different levels of four main factors i.e.ring opening reaction time,alcoholic variety,alkali concentration and refluxing reaction time.Results The target compound (1) was optimizedly synthesized through treatment of raw material (3) with bubbling oxy-gen in 25% ethanol solution of potassium hydroxide at 0℃ for 30 min,followed by refluxing in nitrogen atmosphere for 20 min in yield of 40.8%.Conclusion The procedure developed has some advantages of simple and safty operation,and high synthetic yield.

Objective To design and prepare 13 ,15-cycloimides chlorin p6 (1) ,a class of chlorin related antitumor photo-sensitizers ,which contain a more stable six-membered cyclic imide comparing to the exocyclic anhydride ring of purpurin-18 (2) .Compounds (1) exhibit strong absorption at long wavelengths near λmax 700 nm to take full advantage of greater tissue penetration .Methods Pheophorbide a (3) was obtained by acid hydrolysis of chlorophyll a ,which was from crude chlorophyll extracts of Chinese traditional herb named Silkworm excrement .Purpurin-18 (2) was prepared by air oxidation and alkali open loop simultaneously on five-membered beta-keto carboxylic ester ring of pheophorbide a (3) .Finally ,the target compounds 1a~1j were synthesized via condensation of its anhydride ring with various amines including carboxyl-protected amino acids . Results Target compounds 1a~1j were successfully synthesized in yields ranged from 32 .6% to 65 .2% .Their structures were confirmed by elemental analysis ,ESI-MS and 1 H NMR spectra .Conclusion Treatment of purpurin-18 (2) with amines can produce target compounds 1a~1j .The starting raw material was inexpensive and readily available .The reaction conditions were mild and workup was convinient .

Targeted protein degradation (TPD) techniques eliminate pathogenic proteins by hijacking the intracellular proteolysis machinery which includes the ubiquitin-proteasome system (UPS) and the lysosomal degradation pathway, holding promise to overcome the limitations of traditional inhibitors and further broaden the target space including many “undruggable” targets, and provide new targeted treatments for drug discovery. In this review, recent advances in a variety of promising TPD strategies were summarized, such as proteolysis targeting chimera (PROTAC), molecular glue, lysosome-targeting chimaera (LYTAC), autophagosome-tethering compound (ATTEC), autophagy-targeting chimera AUTAC and AUTOTAC, particularly. The representative case studies, potential applications and challenges were analyzed.