RP-thin layer chromatographic method for the quantification of three gingerol homologs of ultrasonic-assisted fresh rhizome extracts of Zingiber officinale collected from North Western Himalayas

A rapid and sensitive RP high-performance thin-layer chromatographic (RP-HPTLC) methodology was developed and validated for the quantitative estimation of gingerols in methanolic extract of fresh ginger rhizome. The samples were chromatographed on RP-TLC glass plates pre-coated with RP-18 60F(254) as the stationary phase. Linear ascending development was carried out in twin trough glass chamber saturated with ternary-solvent system consisting of acetonitrile-water-formic acid (7:2:1 v/v/v) at room temperature (25 +/- 2 degrees C) and plates were scanned at 500 nm. The system was found to give compact spots for gingerols (R-f values of 6-gingerol 0.73 +/- 0.04, 8-gingerol 0.59 +/- 0.08 and 10-gingerol 0.36 +/- 0.05). Linearity was found to be in the range of 140-840 ng/spot for 6-gingerol, 168-1008 ng/spot for 8-gingerol and 136-816 ng/spot for 10-gingerol with significantly high value of correlation coefficient. The linear regression analysis data for the calibration plots showed linear relationship (r(2)) and ranged from 0.9992 to 0.9937 for 6-, 8- and 10-gingerol. The method was used for routine analyses and to obtain relative amounts of the gingerols in the fresh rhizomes of the ginger cultivated in different locations of Uttarakhand and Himachal Pradesh of North Western Himalayas (India).