ABSTRACT
Silibinin is a kind of flavonoid extracted from the dried ripe fruit of Silybum marianum，a plant of compositae. It has a variety of pharmacological activities and can effectively prevent and treat diabetes and its complications. This paper reviews the research progress on the mechanism of silibinin in the prevention and treatment of diabetes and its complications. It is found that silibinin can prevent and treat diabetes by up-regulating the expression of estrogen receptor-α，activating the duodenum-brain-liver axis pathway and stabilizing the protein structure. It can prevent and cure the nervous system diseases of diabetes by activating glucagon-like peptide-1 receptor/protein kinase A signal pathway and inhibiting the hyperphosphorylation of tau protein. It can prevent and treat diabetic retinopathy by down-regulating the expression and activity of pro-inflammatory，pro-oxidative factors and histone deacetylase 6. It can prevent diabetic nephropathy by activating protein kinase B signal pathway and reducing the level of transforming growth factor-β1，and prevent and treat diabete’s obesity by inhibition of hepatobiliary transporter CD36 expression， and suppressing nuclear factor-κB pathway and its downstream expression of pro-inflammatory cytokines（tumor necrosis factor-α and interleukin-1β），etc.
ABSTRACT
Toll-like receptor 4(TLR4)is a member of the TLRs superfamily,mainly capable of identifying bacterial endotoxin,lipopolysaccharides and lipooligosaccharides of Gram-negative bacte?ria cell walls to prevent microbial invasion. Activation of TLR4 can induce production of proinflammato?ry cytokines and inflammatory chemokines and regulate natural immunity. However,dysregulation of TLR4 can lead to autoimmune diseases. This review summarized the biological structure of TLR4 and recognition mechanisms between TLR4 and its ligands,surveyed TLR4 ligands including lipid A ana?logues,natural products and synthetic small molecules,discussed the structure-activity relationship of TLR4 modulators and the ligand-receptor and protein-protein interactions in the complex,and outlined the prospect of future research and development of TLR4 ligands.
ABSTRACT
Thirteen novel oleanolic acid (OA) derivatives were designed and synthesized with modification at positions of C-3, C-12 and C-28 of OA. Their structures were confirmed by MS, 1H NMR and elemental analysis. Their in vitro cytotoxicities against various cancer cell lines (SGC7901, MCF-7 and A549) were evaluated by MTT assay. The results indicated that the tested derivatives were found to have stronger cell growth inhibitory activity than OA. Among them, compounds II2 and II3 showed more potent cytotoxicity on MCF-7 and A549 tumor cells than gefitinib (positive control). They are worthy to be studied further.
ABSTRACT
Structural modifications were performed with natural product of oleanolic acid to search for novel anticancer drugs. Ten oleanolic acid derivatives were designed and obtained by the reaction of oxidation, acylation or hydrolyzation, etc. The cytotoxic activity of derivatives was evaluated against HeLa, HepG2 and BGC-823 cells in vitro by MTT assay, gefitinib and etoposide used as a positive control. The results showed that compound 5a was particularly active to inhibit HepG2 cells growth, and anti-tumor activity of compound 7 on HeLa cells was significantly stronger than oleanolic acid. They are worthy to be studied further.
ABSTRACT
Structure of natural product-ursolic acid was modified for increasing its antitumor activity. Ursolic acid was acylated, esterified, hydrolized or oxidized to obtain target pentacyclic triterpenoid compounds with different substitutes. Sixteen derivatives of ursolic acid were designed and synthesized including eleven new compounds. Anti-tumor activities of ursolic acid and these derivatives against HeLa, SKOV3 and BGC-823 cells in vitro were investigated by MTT assay. The results indicated that compounds 7a and 8a were found to have stronger cell growth inhibitory than ursolic acid on HeLa cells and SKOV3 cells separately, and are worth to be intensively studied further.