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Background: Oleanolic Acid (OA) is a ubiquitous product of triterpenoid compounds. Due to its inexpensive availability, unique bioactivities, pharmacological effects and non-toxic properties, OA has attracted tremendous interest in the field of drug design and synthesis. Furthermore, many OA derivatives have been developed for ameliorating the poor water solubility and bioavailability. Objective: Over the past few decades, various modifications of the OA framework structure have led to the observation of enhancement in bioactivity. Herein, we focused on the synthesis and medicinal performance of OA derivatives modified on A-ring. Moreover, we clarified the relationship between structures and activities of OA derivatives with different functional groups in A-ring. The future application of OA in the field of drug design and development also was discussed and inferred. Conclusion: This review concluded the novel achievements that could add paramount information to the further study of OA-based drugs.

Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-KP) have disseminated worldwide and emerged as major threats to public health. Of epidemiological significance, the international pandemic of KPC-KP is primarily associated with CG258 isolates and bla KPC-IncF plasmids. CRISPR-Cas system is an adaptive immune system that can hinder gene expansion driven by horizontal gene transfer. Because of bla KPC-IncF plasmids are favored by CG258 K. pneumoniae, it was of interest to examine the co-distribution of CRISPR and bla KPC-IncF plasmids in such isolates. We collected 459 clinical K. pneumoniae isolates in China and collected 203 global whole-genome sequences in GenBank to determine the prevalence of CRISPR-Cas systems. We observed that CRISPR-Cas system was significantly scarce in the CG258 lineage and bla KPC-positive isolates. Furthermore, the results of conjugation and plasmid stability assay fully demonstrated the CRIPSR- Cas system in K. pneumoniae could effectively hindered bla KPC-IncF plasmids invasion and existence. Notably, most bla KPC-IncF plasmids were also proved to be good targets of CRISPR owing to carry matched and functional protospacers and PAMs. Overall, our work suggests that type I-E CRISPR-Cas systems could impact the spread of bla KPC in K. pneumoniae populations, and the scarcity of CRISPR-Cas system was one of potential factors leading to the propagation of bla KPC-IncF plasmids in CG258 K. pneumoniae.

Chrysin, a flavonoid, has played a great role in the fields of anticancer, antibacterial, and antiviral drug discovery. A large number of chrysin derivatives have been synthesized recently. The fluorine atom represents an important substituent group for a great number of natural products and pharmaceuticals. Taking into account the importance of both chrysin and the fluorine atom in medicinal chemistry, the synthesis of fluorine-containing chrysin derivatives has gained great interest. Chemically, the synthetic methods for these new chrysin derivatives have also been developed rapidly. In recent years, research on their synthesis has been focused on speeding up the reaction process by changing the catalyst. Biologically, the purpose of introducing fluorine into chrysin was to improve its lipophilicity, but today it is mainly focused on the enhancement and improvement of either its anticancer or antimicrobial activities by incorporating the special properties of fluorine atoms. In this review, synthetic methods for the introduction of fluorine atoms into chrysin are summarized, and their anticancer, antibacterial, antiviral, and hypoglycemic effects are discussed.

Zehua Yang. L’utilisation de la colle d’algue et du non-tissé dans la restauration des peintures chinoises. In: Arts asiatiques, tome 68, 2013. pp. 75-80.