Activity-guided isolation of sesquiterpene coumarins from Ferula assa-foetida as monoamine oxidase inhibitors: Investigation on their therapeutic implications in a mice model of Parkinson's disease

Ethnopharmacological relevance

Ferula assa-foetida, has been used for centuries as a spice, is well acknowledged as a traditional medicine in Ayurveda, and as a folklore medicine across the globe for its neurological benefits. In recent years, modern pharmacological studies have augmented its potential against various neurological disorders, thus signifying its therapeutic importance against neurological disorders in both ethnic and modern medicinal aspects.

Aim of the study: We aimed to identify Monoamine oxidase (MAO)-inhibiting sesquiterpene coumarins from Ferula assa-foetida through activity-guided isolation and evaluate them using in vitro and in vivo models relevant to Parkinson's disease (PD).

Materials and methods

LC-MS² was used for the detection of the sesquiterpene coumarins, followed by chromatographic fractionation, and semi-preparative HPLC-mediated purification of the 19 compounds; their structures were established by the combined use of MS, 1D, and 2D NMR techniques. MAO assay identified two active compounds for further study. Toxicity was evaluated in SH-SY5Y cells, Drosophila, and C57BL/6 mice. Effects on mice brain MAO activity and striatal dopamine were examined by LC-MS/HPLC. Finally, neuroprotective effects were validated in an MPTP-induced PD mouse model.

Results

LC-MS² analysis confirmed the presence of naturally occurring sesquiterpene coumarin hybrids with significant structural diversity in Ferula assa-foetida oleo-gum-resin, and 19 compounds were isolated for characterization. After preliminary in vitro MAO assays karatavicinol and farnesiferol C were selected for further evaluation. Both compounds exhibited BBB permeability, inhibited MAO activity in mice brain, and effectively elevated dopamine levels in the striatum. Additionally, these compounds demonstrated their therapeutic potential against PD in a mice model.

Conclusions

The 7 substituted coumarins with the structurally diverse sesquiterpene moieties displayed varying degrees of MAO inhibition. Further detailed investigation on karatavicinol and farnesiferol C confirmed that both compounds holds significant therapeutic potential to address PD related dopamine deficiency, motor incoordination, and neurodegeneration.