Neuroprotective and Antiherpetic Properties of Polyphenolic Compounds from Maackia amurensis Heartwood.

In this study, we isolated a new isoflavanostilbene maackiapicevestitol ( 1 ) as a mixture of two stable conformers 1a and 1b as well as five previously known dimeric and monomeric stilbens: piceatannol ( 2 ), maackin ( 3 ), scirpusin A ( 4 ), maackiasine ( 5 ), and maackolin ( 6 ) from M. amurensis heartwood, using column chromatography on polyamide, silicagel, and C-18. The structures of these compounds were elucidated by NMR, HR-MS, and CD techniques. Maksar ® obtained from M. amurensis heartwood and polyphenolics 1 - 6 possessed moderate anti-HSV-1 activity in cytopathic effect (CPE) inhibition and RT-PCR assays. A model of PQ-induced neurotoxicity was used to study the neuroprotective potential of polyphenolic compounds from M. amurensis . Maksar ® showed the highest neuroprotective activity and increased cell viability by 18% at a concentration of 10 μg/mL. Maackolin ( 6 ) also effectively increased the viability of PQ-treated Neuro-2a cells and the value of mitochondrial membrane potential at concentrations up to 10 μΜ. Maksar ® and compounds 1 - 6 possessed higher FRAP and DPPH-scavenging effects than quercetin. However, only compounds 1 and 4 at concentrations of 10 μM as well as Maksar ® (10 μg/mL) statistically significantly reduced the level of intracellular ROS in PQ-treated Neuro-2a cells.