Constituents from Dendrobium Aphyllum: Bibenzyls, Furfurals, Phenanthrenes, and Phenylpropanoids and Their Antioxidant and Anti-Inflammatory Potentials

Chemical investigation on the aqueous extract of Dendrobium aphyllum led to the isolation of thirty-one constituents with structures identified by analysis of the extensive spectroscopic data (1D/2D NMR, MS, UV, and ECD), including previously undescribed two bibenzyls, one furfural, and one phenolic acid, namely trigonopol D (1), trigonopol C (2), dendrofunan A (10), and 6-(4-hydroxy-3-methoxyphenyl)-3,6-dioxohexyl acetate (30), respectively, as well as twenty-seven known ones. Among them, there were one new natural product (11), seven compounds (6-7, 9, 12, 20, 28, 31) described from the genus Dendrobium for the first time, and fifteen compounds (8, 13-17, 19, 21-27, 29) isolated from D. aphyllum for the first time. Further, the antioxidant and anti-inflammatory potentials of fifteen compounds (4-5, 8, 11-12, 14-19, 22, 24, 26, and 29) with significant scavenging capacities against DPPH and hydroxyl radicals, and virtual docking activities inhibiting COX-2 and 5-LOX, respectively. Our study may draw the attention of medicinal plant taxonomists and supply potential quality markers for discrimination of D. aphyllum from other species in Dendrobium genus.