New β-orcinol depsides from Hypotrachyna caraccensis, a lichen from the páramo ecosystem and their free radical scavenging activity. Issue 12 (18th June 2018)

• Record Type: Journal Article
• Authors: Leal, Angela; Rojas, José L.; Valencia-Islas, Norma A.; Castellanos, Leonardo
• Is Part Of: Natural product research. Volume 32:Issue 12(2018)
• Page Start: 1375
• Page End: 1382
• Publication Date: 2018-06-18
• Subjects: Lichens -- free radical scavengers -- antioxidants -- skin permeability; Natural products -- Periodicals; Natural products -- Research -- Periodicals; Biological Factors -- Periodicals; Biological Products -- Periodicals; 547
• DOI: 10.1080/14786419.2017.1346639
• Languages: English
• ISSNs: 1478-6419

Abstract

Abstract: The new hypotrachynin A (1 ) and B (2 ) along with the known (+)-(9b- R )-usnic (3 ) and methylstictic acids (4 ) were isolated for the first time from Hypotrachyna caraccensis . Additionally, their potency and reactivity as DPPH scavengers was determined by a kinetic study calculating their EC50 and second-order rate constants (k2 ). Considering1 –4 could be dermatological agents, their n -octanol-water partition coefficients and standard molar Gibbs free energies of transfer were calculated as estimation of their lipophilicity and skin penetration. Compounds1, 3 and4 were less potent than2 ( EC50 = 3.3014; 1.7540; 2.6652 vs 0.7376) as DPPH scavengers, in turn4, was the most reactive with a comparable k2 to the antioxidant BHT (k2 = (232 ± 24) × 10 −2 vs (564 ± 12) × 10 −2 M −1 s −1, respectively). Since2 and4 had an optimal lipophilicity and permeability for skin penetration, they might be developed as topical ingredients to prevent oxidative damage. Abstract :