New enantiomers from Ficus variolosa Lindl. ex Benth. and their anti-inflammatory and neuroprotective activities

Chemical investigation of the whole plant of Ficus variolosa Lindl. ex Benth. led to the discovery of two pairs of previously unreported enantiomers, 1a/1b and 2a/2b, which were separated by chiral HPLC. Their structures were characterised through detailed spectroscopic interpretation, and the stereochemical assignments were achieved by matching the experimental ECD spectra with those calculated at the TDDFT level. Notably, to the best of our knowledge, 2a/2b represents the first enantiomerically resolved example of this type of furocoumarin. The isolates were evaluated for their inhibitory effects on nitric oxide production in LPS-stimulated RAW264.7 macrophages and for their protective effects against 6-hydroxydopamine-induced injury in PC12 cells. At 50 μM, compounds 2a and 2b moderately reduced nitrite accumulation by 33.30% and 35.11%, respectively, and slightly increased the viability of injured PC12 cells by 8.16% and 10.28%, respectively.