Leal Angela, Rojas José L, Valencia-Islas Norma A, Castellanos Leonardo
a Faculty of Sciences, Department of Chemistry , National University of Colombia , Bogotá , Colombia.
b Faculty of Sciences, Department of Pharmacy , National University of Colombia , Bogotá , Colombia.
Nat Prod Res. 2018 Jun;32(12):1375-1382. doi: 10.1080/14786419.2017.1346639. Epub 2017 Jul 10.
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 EC and second-order rate constants (k). Considering 1-4 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. Compounds 1, 3 and 4 were less potent than 2 (EC = 3.3014; 1.7540; 2.6652 vs 0.7376) as DPPH• scavengers, in turn 4, was the most reactive with a comparable k to the antioxidant BHT (k = (232 ± 24) × 10 vs (564 ± 12) × 10 M s, respectively). Since 2 and 4 had an optimal lipophilicity and permeability for skin penetration, they might be developed as topical ingredients to prevent oxidative damage.
新型次茶渍素A（1）和B（2）与已知的（+）-（9b-R）-松萝酸（3）和甲基条衣酸（4）首次从卡拉卡次茶渍（Hypotrachyna caraccensis）中分离得到。此外，通过动力学研究计算它们的半数有效浓度（EC）和二级速率常数（k），确定了它们作为1,1-二苯基-2-三硝基苯肼自由基（DPPH•）清除剂的活性和反应性。鉴于1-4可能是皮肤科用药，计算了它们的正辛醇-水分配系数和标准摩尔转移吉布斯自由能，以评估它们的亲脂性和皮肤渗透性。作为DPPH•清除剂，化合物1、3和4的活性低于2（EC分别为3.3014、1.7540、2.6652对0.7376），而4的反应性最高，其k值与抗氧化剂丁基羟基甲苯相当（k分别为(232 ± 24) × 10对(564 ± 12) × 10 M⁻¹ s⁻¹）。由于2和4具有适合皮肤渗透的最佳亲脂性和通透性，它们可能被开发为预防氧化损伤的局部用成分。
