The Monoamine Oxidase Inhibitory Activity of Essential Oils Obtained from Peperomia Ruiz. & Pav. (Piperaceae) Species and Their Chemical Composition

Divergent Synthesis of Natural Benzyl Salicylate and Benzyl Gentisate Glucosides

“…IR spectra were recorded on neat samples using an Agilent Cary 630 FTIR spectrometer with attenuated total reflectance (ATR). 1 H and 13 C NMR spectra were acquired for solutions in CDCl 3 , DMSO-d 6 , or methanol-d 4 on a Bruker AVANCE III HD instrument (400 and 101 MHz for 1 H and 13 C, respectively). The 1 H NMR chemical shifts are referenced to the residual signal of CHCl 3 (δ H 7.26), DMSO-d 5 (δ H 2.50), methanol-d 3 (δ H 3.31), acetone-d 5 (δ H 2.05), or HDO (δ H 4.79), and the 13 C NMR shifts are referenced to the central line of the CDCl 3 signal (δ C 77.00), DMSO-d 6 (δ C 39.52), acetone-d 6 (δ C 29.84), and methanol-d 4 (δ C 49.00).…”

“…The crude product was purified by silica gel column chromatography (toluene/ acetone, 6:1, → toluene/acetone, 1:1, 0.05% (v/v) HOAc) to give the product as an off-white solid: 86 mg (39%), purity >95%; R f = 0.30 (hexanes/EtOAc, 7:2); mp 155−156 °C (lit. 171−173 °C from EtOAc); 31 UV (EtOH) λ max 232, 320 nm; ATR-FTIR ν max 3426 (br), 2920, 2851, 1667, 1584, 1490, 1261, 1206, 1180, 890, 814, 749, 676 cm −1 ; 1 H NMR (400 MHz, acetone-d 6 , δ, ppm, J, Hz) 3.99 (s, 3H, OMe), 7.06 (dd, 1H, J 3.0, J 8.9, H-6), 7.11 (d, 1H, J 8.9, H-5), 7.43 (d, 1H, J 3.0, H-2), 8.35 (s, 1H, OH), 10.98 (s, 1H, OH); 13 C NMR (101 MHz, acetone-d 6 , δ, ppm) 57.5, 115.0, 118.8, 120.4, 121.9, 152.3, 152.9, 165.9. The spectroscopic data are in agreement with the literature.…”

“…The precipitate was filtered, washed with cold toluene (2 × 30 mL), and air-dried to give the title compound as white needles (11.57 g, 93%, purity >95%): R f = 0.48 (toluene/EtOH, 9:1); mp 102−103 °C (lit. 104.5 °C, 18 102−103 °C47 ); UV (EtOH) λ max 230, 290 nm; ATR-FTIR ν max 3227 (br), 2940, 2873, 1654, 1616, 1483, 1194, 1071, 779, 695 cm −1 ; 1 H NMR (400 MHz, CDCl 3 , δ, ppm, J, Hz) 5.35 (s, 2H, CH 2 ), 6.88 (d, 1H, J 8.9, H-5), 7.00 (dd, 1H, J 3.0, J 8.9, H-6), 7.32 (d, 1H, J 3.0, H-2), 7.36−7.41 (m, 5H, C 6 H 5 ), 10.39 (s, 1H, OH); 13 18,48 Benzyl 5-acetoxy-2-hydroxybenzoate (13). Phenol 4 (4.88 g, 20 mmol) was dissolved in Ac 2 O (6.8 mL, 72 mmol).…”

“…Phenol 4 (4.88 g, 20 mmol) was dissolved in Ac 2 O (6.8 mL, 72 mmol). The reaction mixture was stirred at room temperature (∼20 °C) for 24 h, the solvent was evaporated in vacuo, and the residue was purified by silica gel column chromatography (toluene → toluene/EtOAc, 7:1) to give the title compound as a white solid (4.75 g, 83%, purity >95%): R f = 0.88 (toluene/EtOAc, 20:1); mp 55−56 °C; UV (EtOH) λ max 237, 314 nm; ATR-FTIR ν max 3201 (br), 3073, 1758, 1671, 1485, 1204, 743, 681 cm −1 ; 1 H NMR (400 MHz, CDCl 3 , δ, ppm, J, Hz) 2.27 (s, 3H, CH 3 , Ac), 5.37 (s, 2H, CH 2 ), 6.99 (d, 1H, J 9.0, H-5), 7.19 (dd, 1H, J 2.9, J 9.0, H-6), 7.37−7.45 (m, 5H, C 6 H 5 ), 7.57 (d, 1H, J 2.9, H-2), 10.68 (s, 1H, OH); 13 Benzyl 5-hydroxy-2-methoxybenzoate (14). From acid 10: Benzylation of 10 (100 mg, 0.6 mmol) was carried out under the same conditions as for 4; yield of 14, 145 mg (94%).…”

“…Benzyl salicylate ( 3 ) has been identified as one of the main constituents of Walter’s dogwood ( Cornus walteri ) and other plants, including Notopterygium incisium , Ocotea pulchella , Friesodielsia enghiana , and several species of the Aniba genus . Benzyl salicylate ( 3 ) has been shown to display significant nephroprotective and monoamine oxidase inhibitory effects, while it is also commonly used in the fragrance industry and as an active component in sunscreens . Gentisic acid ( 2 ) and its esters have been found in numerous plants and showed prominent wound healing and skin lightening properties .…”