Sterols possess immunomodulatory property: Activity guided isolation and in vitro screening of phytoconstituents of Pongamia glabra and Ficus glomerata

OBJECTIVE: To isolate the phytoconstituents from the methanolic extracts of the stem bark of Pongamia glabra and Ficus glomerata, characterize spectroscopically and screen for in vitro immunomodulatory activity on human neurophils. METHODS: A flavonoid (PGF) and an alkaloidal compound (PGA) from the extract of P. glabra and a steroidal compound (FGS) and tannin fraction (FGT) from the extract of F. glomerata were isolated using column chromatography technique and were subjected for the spectroscopic (FT-IR, (1)HNMR and LC-MS) and TLC studies to identify the compounds. The isolated compounds were screened for in vitro immunomodulatory activity on human neutrophils using nitroblue tetrazolium (NBT) dye test, phagocytosis of Candida albicans and neutrophil locomotion and chemotaxis assay at the concentration range of 100, 50, 25, 12.50 and 5.00 µg/mL. RESULTS: From the spectroscopic and TLC studies data, the isolated compounds were identified as glabrin (PGA), karanjin (PGF), β-sitosterol (FGS), and tannin fraction (FGT). The isolated compounds PGA, PGF, FGS, and FGT exhibited significant (P < 0.05) in vitro immunomodulatory activity in all the parameters studied. CONCLUSION: The steroidal compound, i.e. FGS was found to be more immunopotent than all constituents alkaloid, flavonoid and tannins. Hence, these constituents could be attributed to the immunomodulatory property of the plants.