Extraction and recovery of karanjin: A value addition to karanja (Pongamia pinnata) seed oil

Karanja (Pongamia pinnata) seed oil contains karanjin, a bioactive molecule with important biological
attributes. The objective of this study was to develop a facile method for efficient recovery of karanjin.
The seed oil was subjected to liquid–liquid extraction with methanol. The extract was further purified by
chromatography on alumina followed by crystallization to afford karanjin, whose purity was ascertained
by HPLC. The recovery of karanjin was ∼20% with >95% purity. The structure of the compound was elucidated
by MS and NMR spectral analysis. Mass spectrum for the compound in ESI+ mode showed signals
at 293 and 315 corresponding to (M+H+) and (M+Na+) adducts, respectively, confirming the molecular
weight to be 292. 1H and 13C spectral data established the structure of the molecule to be a furanoflavonoid
compound with the furan ring signals appearing at 7.78 (H�)/145.4 (C�) and 7.20 (H�)/103.9
(C�). 1H COSY, HMBC (H→C) and DEPT spectral data showed the annelation of furan and flavonoid
rings to be at C7/C8 and C9/C10 positions, respectively, and a phenyl ring substitution at 2 (1�) position.
Karanjin’s recovery in pure form and high yield affords value addition to the seed oil for pharmaceutical
applications.