724434-08-6

A series of dihydroflavonol derivatives (4a–4l) were synthesized from chalcones via classical Algar–Flynn–Oyamada (AFO) reaction and characterized on the basis of spectroscopic analyses. All synthesized compounds were evaluated for their inhibitory activity against the pro-inflammatory-inducible TNF-alpha, IL-1beta, and IL-6 in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell lines and showed various efficiency. Furthermore, compounds 4d and 4k were selected to examine their in vivo anti-inflammatory activity by using two classical models. Herein compound 4k showed maximum anti-inflammatory activity of 32.98% inhibition in mice ear-swelling model and 40.06% inhibition at the 2 h intervals in rat paw edema model in comparison to the two references: aspirin and meloxicam. Similar effect was observed at a lower dose. In addition, the compound 4k was docked against cyclooxygenases-2 to validate the attained pharmacological data and provide understandable evidence for the observed anti-inflammatory activity.

The invention relates to a synthesis method of a bulk drug, in particular to a preparation method of kaempferol. The preparation method of the kaempferol is provided in order to solve the technical problems that in the prior art, when purified kaempferol is separated from plants, waste of plant resources and solvents is large, and a total-synthesis method of the kaempferol is long in synthesis route, many in step, low in yield, and difficult to meet the requirements of industrial production are difficult to meet. According to the preparation method, dihydromyricetin is selected as a starting raw material, a kaempferol crude product is obtained through three step reactions of hydrolysis, catalytic closed-loop and oxidation, and the kaempferol crude product is purified and refined to obtainkaempferol refined product with the qualified quality. According to the preparation method of the kaempferol, raw materials are easy to obtain, operation is easy, the cost is low, and the preparationmethod is suitable for industrial production.

Thirty dihydroflavonol derivatives (D1–D30) were designed and synthesized, meanwhile the synthesized compounds were characterized on the basis of spectroscopic analyzes. Their inhibitory activity against the pro-inflammatory inducible interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages were evaluated and showed various efficiency. Compounds D1–D30 showed no toxic effects on RAW 264.7 cells at the concentration 20 μM; among them, compounds D9, D13, and D19 exhibited best anti-inflammatory activity through decreasing IL-1β, IL-6, and TNF-α. Furthermore, their structure–activity relationships were discussed preliminarily.

To explore the structure-activity relationships on the inhibitory activity of flavanonols against nitric oxide (NO) production in inflammatory cells, we synthesized 19 flavanonols which shared a common 3,5,7-trihydroxychroman scaffold. A range of substitutions was included in the B ring in order to investigate the structure-activity relationship. We also succeeded in isolating stereoisomers from 16 of the flavanonols using chiral column chromatography. The inhibitory effects of these compounds on NO production were examined in RAW 264.7 cells (a murine macrophage-like cell line), which were activated by lipopolysaccharide (LPS). We only observed inhibitory activity against NO production in (2R,3R) stereoisomers, while the inhibitory activities of (2S,3S) stereoisomers were significantly weaker. We also evaluated the free radical scavenging potential of the flavanonols using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Each stereoisomer indicated the equivalent DPPH scavenging potential as expected. The radical scavenging activity was not correlated with the inhibitory activity against NO. The inhibition of NO production by flavanonols is stereospecific and cannot simply be explained by their radical scavenging activity. We propose the possible existence of a 'target' molecule for flavanonols which is involved in the production and/or regulation of NO in RAW 264.7 cells.

A practical synthesis of polyhydroxy- and regiospecifically methylated flavone-3-ols which are components of commercial 'seabuckthorn flavone' has been achieved by modified Algar-Flynn-Oyamada method. Antioxidant activities of seabuckthorn extracts, isolated products and a number of flavone-3-ols have been determined. Structure-activity relationships have been discussed. Amongst the compounds tested, gallic acid, which is also present in seabuckthorn, was found to be the most effective antioxidant and radioprotectant.