Antioxidant Aryl-Substituted Phthalan Derivatives Produced by Endophytic Fungus Cytospora rhizophorae

Abstract

Six new phthalan derivatives cytorhizophins D-I (1-6) as well as three known derivatives cytorhizophin C, pestacin and rhizophol B were isolated from Cytospora rhizophorae. Among them, cytorhizophins D-E (1-2) and F-G (3-4) were two pairs of diastereoisomers, all of them featuring a 1-phenyl-1,3-dihydroisobenzofuran scaffold with a highly oxygenated O-linked isopentenyl unit. Besides, cytorhizophins H-I (5-6) represent the first examples of phthalide family with fascinating 6/6/6/5 tetracyclic ring system fusing as unprecedented furo [4,3,2-kl]xanthen-2 (10bH)-one skeleton. The structures of the new phthalan derivatives were extensively confirmed by detail spectroscopic analysis. The partial absolute configurations of compounds 1-6 were established through electronic circular dichroism (ECD) calculations. Moreover, compounds 1-4 showed remarkable antioxidant activities with EC50 values ranging from 5.86 to 26.80 μM, which were better than or comparable to that of ascorbic acid (positive control).

Synthesis of 14H-dibenzoxanthenes in green media using Sn(II)/nano silica as an efficient catalyst

“…Moreover, some uridine- and xanthene-based drugs are used for treatment of heart problems ( Dai et al, 2022 ). They also have antioxidant ( Liu et al, 2022 ) and antibacterial activities ( Marona et al, 2009 ) and can be employed in biomembranes ( Torrisi et al, 2022 ), dyes ( Cesaratto et al, 2019 ), and solar cells ( Maciejczyk et al, 2016 ). These structures have interesting deep-red and near-infrared adsorption potencies, which make them valuable candidates for cell imaging ( Niu et al, 2016 ).…”

Synthesis of 1,1,4,5-Tetrasubstituted Phthalans via Pd-Catalyzed Three-Component Reactions of Haloarenes, Alkynes, and Protic Nucleophiles

“…Phthalans represent an important class of benzenoids, , which are found in a wide range of bioactive molecules, including pharmaceuticals, therapeutic agents, and natural products (Figure ). − For example, escitalopram is a clinically prescribed antidepressant drug of the selective serotonin reuptake inhibitor class .…”