02680naa a2200265 a 450000100080000000500110000800800410001902200140006002400350007410000160010924500930012526000090021852019290022765300180215665300190217470000200219370000200221370000220223370000250225570000270228070000210230770000170232870000180234577300510236319549972018-01-29       2013    bl uuuu     u00u1 u    #d  a1420-30497 a10.3390/molecules180101782DOI1 aLIMA, E. S.  aStability and Antioxidant Activity of Semi-synthetic Derivatives of 4-Nerolidylcatechol.  c2013  a4-nerolidylcatechol (4-NC) is an unstable natural product that exhibits important antioxidant, anti-inflammatory and other properties. It is readily obtainable on a multi-gram scale through straightforward solvent extraction of the roots of cultivated Piper peltatum or P. umbellatum, followed by column chromatography on the resulting extract. Semi-synthetic derivatives of 4-NC with one or two substituent groups (methyl, acetyl, benzyl, benzoyl) on the O atoms have been introduced that have increased stability compared to 4-NC and significant in vitro inhibitory activity against the human malaria parasite Plasmodium falciparum. Antioxidant and anti-inflammatory properties may be important for the antiplasmodial mode of action of 4-NC derivatives. Thus, we decided to investigate the antioxidant properties, cytotoxicity and stability of 4-NC derivatives as a means to explore the potential utility of these compounds. 4-NC showed high antioxidant activity in the DPPH and ABTS assays and in 3T3-L1 cells (mouse embryonic fibroblast), however 4-NC was more cytotoxic (IC50 = 31.4 µM) and more unstable than its derivatives and lost more than 80% of its antioxidant activity upon storage in solution at −20 °C for 30 days. DMSO solutions of mono-O-substituted derivatives of 4-NC exhibited antioxidant activity and radical scavenging activity in the DPPH and ABTS assays that was comparable to that of BHA and BHT. In the cell-based antioxidant model, most DMSO solutions of derivatives of 4-NC were less active on day 1 than 4-NC, quercetin and BHA and more active antioxidants than BHT. After storage for 30 days at −20 °C, DMSO solutions of most of the derivatives of 4-NC were more stable and exhibited more antioxidant activity than 4-NC, quercetin and BHA and exhibited comparable antioxidant activity to BHT. These findings point to the potential of derivatives of 4-NC as antioxidant compounds.  aAntioxidantes  aPiper peltatum1 aPINTO, A. C. S.1 aNOGUEIRA, K. L.1 aSILVA, L. F. R. e1 aALMEIDA, P. D. O. de1 aVASCONCELLOS, M. C. de1 aCHAVES, F. C. M.1 aTADEI, W. P.1 aPOHLIT, A. M.  tMoleculesgv. 18, n. 1, p. 178-189, jan. 2013.