RESUMEN
Sclareol, a bioactive diterpene alcohol isolated from Salvia sclarea, was subjected to structural modification and cytotoxic evaluation. Boron-Heck-coupled analogs of manoyl oxide were prepared from sclareol in a two-step reaction scheme. In the first step manoyl oxide was prepared from sclareol using cerium (IV) ammonium nitrate. Further the structural modification of manoyl oxide via Palladium (II) catalysed Boron-Heck coupling reaction produced a new series of compounds. All the synthesised compounds were screened for in vitro cytotoxic evaluation against four cancer cell lines HCT-116, MCF-7, MDA-MB231and MDA-MB468. The results showed that manoyl oxide is less active than sclareol. Sclareol shows an IC50 of 2.0 µM compared to manoyl oxide with an IC50 of 50 µM against the MCF-7 cell line. From the results it was inferred that the presence of two tertiary hydroxyls in sclareol are necessary for its cytotoxic activity and Heck coupled analogs are more active than sclareol and manoyl oxide.
RESUMEN
An efficient strategy towards N-formylation of amides and oxidation of indolines to isatins is described. This method employs readily available (NH4)2S2O8, I2, and DMSO. The given method features operational simplicity, excellent functional group tolerance, broad substrate scope, and fast kinetics. Moreover, the method was applied to the synthesis of the natural product alatamide. Notably, DMSO plays three vital roles: a formyl group source, an oxidant, and a solvent.
Asunto(s)
Yodo , Isatina , Amidas , Dimetilsulfóxido , YodurosRESUMEN
AIM: To evaluate the antimicrobial capability of sclareol and its derivatives against Staphylococcus aureus and its Methicillin-resistant strain (MRSA). METHODS AND RESULTS: A new series of Boron-Heck-coupled sclareol analogues were prepared by structural modifications at the C-15 terminal double bond of sclareol using ultrasonication. The structural modifications were designed to keep the stereochemistry of all the five chiral centres of sclareol intact. A two-step reaction scheme consisting of Boron-Heck coupling of sclareol followed by Wittig reaction was carried out to produce novel sclareol congeners for antimicrobial evaluation. Three compounds SAJ-1, SAJ-2 and SB-11 exhibited strong antibacterial activity against S. aureus and Methicillin-resistant strain (MRSA) with MIC values between 3 and 11 µM. Among all the screened compounds, SAJ-1 and SAJ-2 showed the best antibiofilm profiles against both strains. Moreover, SAJ-1 and SAJ-2 acted synergistically with streptomycin against S. aureus while creating varying outcomes in combination with ciprofloxacin, penicillin and ampicillin. SAJ-1 also acted synergistically with ampicillin against S. aureus, while SB-11 showed synergism with ciprofloxacin against both pathogens. Moreover, SAJ-1 and SAJ-2 also inhibited staphyloxanthin production in S. aureus and MRSA and induced postantibiotic effects against both pathogens. CONCLUSIONS: It can be inferred that SAJ-1, SAJ-2 and SB-11 may act as potential chemical entities for the development of antibacterial substances. The study revealed that SAJ-1 and SAJ-2 are the most suitable sclareol analogues for further studies towards the development of antibacterial substances. SIGNIFICANCE AND IMPACT OF THE STUDY: SAJ-1, SAJ-2 and SB-11 show promising antibacterial properties against Staphylococcus aureus. Efforts should be made and more research should be done utilizing in vivo models to determine their efficacy as antibiotics.