Discovery of triterpenoids as potent dual inhibitors of pancreatic lipase and human carboxylesterase 1.

Pancreatic lipase (PL) is a well-known key target for the prevention and treatment of obesity. Human carboxylesterase 1A (hCES1A) has become an important target for the treatment of hyperlipidaemia. Thus, the discovery of potent dual-target inhibitors based on PL and hCES1A hold great potential for the development of remedies for treating related metabolic diseases. In this study, a series of natural triterpenoids were collected and the inhibitory effects of these triterpenoids on PL and hCES1A were determined using fluorescence-based biochemical assays. It was found that oleanolic acid (OA) and ursolic acid (UA) have the excellent inhibitory effects against PL and hCES1A, and highly selectivity over hCES2A. Subsequently, a number of compounds based on the OA and UA skeletons were synthesised and evaluated. Structure-activity relationship (SAR) analysis of these compounds revealed that the acetyl group at the C-3 site of UA (compound 41) was very essential for both PL and hCES1A inhibition, with IC50 of 0.75 µM and 0.014 µM, respectively. In addition, compound 39 with 2-enol and 3-ketal moiety of OA also has strong inhibitory effects against both PL and hCES1A, with IC50 of 2.13 µM and 0.055 µM, respectively. Furthermore, compound 39 and 41 exhibited good selectivity over other human serine hydrolases including hCES2A, butyrylcholinesterase (BChE) and dipeptidyl peptidase IV (DPP-IV). Inhibitory kinetics and molecular docking studies demonstrated that both compounds 39 and 41 were effective mixed inhibitors of PL, while competitive inhibitors of hCES1A. Further investigations demonstrated that both compounds 39 and 41 could inhibit adipocyte adipogenesis induced by mouse preadipocytes. Collectively, we found two triterpenoid derivatives with strong inhibitory ability on both PL and hCES1A, which can be served as promising lead compounds for the development of more potent dual-target inhibitors targeting on PL and hCES1A.

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications.

Tyrosinase (TYR, E.C. 1.14.18.1), a critical enzyme participating in melanogenesis, catalyzes the first two steps in melanin biosynthesis including the ortho-hydroxylation of L-tyrosine and the oxidation of L-DOPA. Previous pharmacological investigations have revealed that an abnormal level of TYR is tightly associated with various dermatoses, including albinism, age spots, and malignant melanoma. TYR inhibitors can partially block the formation of pigment, which are always used for improving skin tone and treating dermatoses. The practical and reliable assays for monitoring TYR activity levels are very useful for both disease diagnosis and drug discovery. This review comprehensively summarizes structural and enzymatic characteristics, catalytic mechanism and substrate preference of TYR, as well as the recent advances in biochemical assays for sensing TYR activity and their biomedical applications. The design strategies of various TYR substrates, alongside with several lists of all reported biochemical assays for sensing TYR including analytical conditions and kinetic parameters, are presented for the first time. Additionally, the biomedical applications and future perspectives of these optical assays are also highlighted. The information and knowledge presented in this review offer a group of practical and reliable assays and imaging tools for sensing TYR activities in complex biological systems, which strongly facilitates high-throughput screening TYR inhibitors and further investigations on the relevance of TYR to human diseases.

Network Pharmacology-Based Study on the Mechanism of Bushen-Jianpi Decoction in Liver Cancer Treatment.

To investigate the mechanism of a Bushen-Jianpi decoction (BSJPD) in liver cancer (LC) treatment, we analyzed clinical therapy data, conducted network pharmacology analysis, and performed pharmacological experimental verification in vitro and in vivo. The univariate analysis of clinical therapy showed that the BSJPD was protective factor (p < 0.05). The network pharmacology analysis showed that 9 compounds were important nodes of BSJPD-LC therapy network. In experimental verification, the rate of apoptosis increased in the liver tumors of mice treated with the BSJPD (p < 0.05); drug serum with 20 % BSJPD inhibited cell viability (p < 0.05) and reduced the expression of PI3K, the Bcl-xL/BAD ratio, and the levels of p53 and p-Akt in HepG2 cells. Moreover, licochalcone A, alisol B, and hederagenin inhibited cell viability (p < 0.05), induced cell apoptosis (p < 0.01), reduced p-Akt levels, and increased cleaved-CASP3 (p < 0.05) and p53 expression levels in HepG2 cells. These data suggest that the BSJPD prolongs the survival of LC patients and induces apoptosis and that it may be associated with the regulation of PI3K, Akt, p53, CASP3, and Bcl-xL/BAD expression.