Chemical constituents of the lichen Usnea baileyi (Stirt.) Zahlbr

α‐Glucosidase Inhibition by Usnic Acid Derivatives

“…From the HSQC and HMBC spectra, signals at δ H 13.52, 5.82, 1.95, and 7.9 ppm represented 6‐OH, H‐2, H 3 ‐14, and H 3 ‐11, respectively. The presence of a benzofuran moiety (rings A and B) was further supported by comparing the NMR results with those of usnic acid [16] . The absence of both 10‐OH and H 3 ‐15 of usnic acid suggested that an oxidation reaction occurred at C‐1 and C‐4.…”

“…The 1 H‐NMR spectrum of 1g displayed three singlets of signals at δ H 14.01, 11.18, and 6.11 representing 8‐OH, 10‐OH, and H‐4, respectively, ten aromatic protons [δ H 7.71 (dd, J =5.5, 2.0, 2H), 7.66 (dd, J =7.5, 4.0, 2H), 7.46–7.47 (m, 3H), and 7.45–7.46 (m, 3H)], and two trans double bond [δ H 8.29 (d, J =15.5, 1H), 8.07 (d, J =15.5, 1H), 7.95 (d, J =15.0, 1H), 7.89 (d, J =15.0, 1H)] indicated two aldolizations occurred at C‐15 and C‐18. NMR comparison of 1g and other similar derivatives 1a – 1e [14–16] indicated they shared the same skeleton ( Figure 1). Furthermore, NMR data of 4c was highly similar to those of 4b , except for the absence of chlorine atoms in phenyl groups.…”

Lichen-Derived Diffractaic Acid Inhibited Dengue Virus Replication in a Cell-Based System

“…The two depsides and 14 depsidones were extracted from Usnea aciculifera [ 29 ], Usnea baileyi [ 30 ], Parmotrema dilatatum [ 31 ], and Parmotrema tsavoense [ 23 ] ( Table 1 ). The compounds were identified using 1 H, 13 C, and 2D NMR methods as described previously.…”

Biotransformation of Betulonic Acid by the Fungus Rhizopus arrhizus CGMCC 3.868 and Antineuroinflammatory Activity of the Biotransformation Products

“…Betulonic acid ( 1 ) is a pentacyclic triterpene belonging to the lupane group isolated from many plants. − As one of the most important oxo-derivatives of betulin, betulonic acid exhibits a broad spectrum of biological activities, such as anti-inflammatory, antimelanoma, antiviral, and antioxidant activities. , Additionally, betulonic acid can serve as a key pharmaceutical intermediate for the production of new drugs. It has attracted significant interest in the pharmaceutical, cosmetic, and food industries …”