New Anthracenone and Xanthenones From Tricholaena teneriffae With Antioxidant Activity: In Vitro and In Silico Studies

Three novel phenolic compounds, namely, 6-hydroxy-3-methoxy-7H-benzo[d]anthracen-7-one (1), 3-hydroxy-12H-benzo[a] xanthen-12-one (2), and 10-hydroxy-12H-benzo[a]xanthen-12-one (3), have been isolated from the aerial parts of Tricholaena teneriffae along with a known benzoxanthenone, 12H-benzo[a]xanthen-12-one (4). All structures were elucidated through 1D- and 2D-nuclear magnetic resonance (NMR) and UV analysis. The results revealed that Compounds (1-3) possess significant antioxidant capacity, slightly weaker but still comparable to that of vitamin C, whereas Compound (4), which lacks hydroxyl substituents, exhibited negligible antioxidant activity. Moreover, the antioxidant properties of the isolated compounds were confirmed by in silico docking analysis against lipoxygenase-3, and it revealed that the isolated compounds effectively bind to the enzyme's active site with favorable binding energies, forming stable hydrogen bonds and hydrophobic interactions. These findings could enhance the understanding of this species rich in natural antioxidants and encourage its potential applications in the development of agricultural and industrial goods.