Eleven conjugates between dihydroartemisinin (DHA) with thiols containing both ether and thioether bonds were designed, synthesized by a two-step procedure including etherification and S-alkylation. Analysis of the NMR spectral data indicated that the dimer of DHA with thiols 6-mercaptopurine and 2-mercaptoimidazole was produced with yields of 31% and 62%, respectively. Furthermore, the tautomerization of thiol 5-methoxy-2-mercaptobenzimidazole led to the formation of a mixture of two isomers in which they might be interchangeable through a dynamic tautomeric equilibrium in the solution. Screening in vitro biological activities revealed that most of the synthesized conjugates showed good cytotoxic and anti-inflammatory activity, while three of them displayed α-glucosidase inhibitory activity. Notably, two conjugates 5d and 5e of DHA with thiols 2-mercaptopyrimidine and 2-mercaptobenzothiazole had an effect in all tested activities in which conjugate 5e is the most potent.

A five-step procedure was used to synthesize four novel conjugates of AZT and adenosine with quinazolinone scaffold. In the last step, alkynes-1 of quinazolinone were coupled to adenosine azide and AZT by Click chemistry to yield the designed conjugates. Their structures were characterized by full-length data of spectra including 1H-, 13C-NMR and MS. Screening for their in vitro anti-inflammatory activity was performed using Murine macrophage RAW 264.7 cells. The relationship between structure and biological activity was also discussed.

In this research, we presented a method for preparation of four new derivatives of murrayafoline A. They were synthesized via Claisen-Schmidt reaction from two consecutive O-alkylation and N¬-alkylation reactions. Four derivatives including compounds 15-18 were tested for cytotoxic activity. The result showed that these four derivatives exhibited cytotoxic activity against to cancer cell P388 with IC50 value ranging from 22,7 to 46,96 μg/mL, however they had no cytotoxicity against to other four human cancer cells LU-1, Hep-G2, MCF7 and SW480.

As marine seaweeds are a great source of natural products, investigating biological properties for appropriate management and exploitation is a priority. For our study, we collected and extracted indigenous algal samples from marine areas of Nha Trang bay belonging to nine species of Chlorophyta, Rhodophyta, and Ochophyta to investigate their cosmeceutical activities. Results revealed tyrosinase inhibitory activity of methanolic extracts of Halimeda sp. and Ulva lactuca with 57.17 ± 1.70% and 54.32 ± 0.52% of inhibition, respectively. Additionally, methanolic extracts of U. lactuca, Sargassum mcclurei, and S. aquifolium were found to perform moderate scavenging capacity against DPPH free radicals. By the colorimetric method, the algae extracts were determined to exhibit no potent cytotoxic effect on both fibroblast cell line NIH-3T3 and keratinocyte cell line HaCaT at a test concentration of 20 µg/mL and thus considered promising for further safety evaluation. The investigation provides information on biological activities of our marine algae and highlights candidates with application significance.

Four compounds were isolated from whole plant of Taxillus chinensis (DC) Dans. including tocopherolquinon, quercetin-3-O-α-L-rhamnoside, quercetin-3-O-β- D-glucuronide and (22E)-poriferasta-5,22,25-trien-3β-ol. Their structures were elucidated by spectroscopic methods such as NMR, MS.