Simultaneous Densitometric Determination of 6-Gingerol, 8-Gingerol, 10-Gingerol, and 6-Shogaol in Some Commercial Gingers

Abstract

A simple and rapid densitometric method has been developed for determination of 6-gingerol, 8-gingerol, 10-gingerol, and 6-shogaol in some commercial gingers. After extracting the samples four times with methanol, the solutions were spotted on precoated Lichrosphere Si 60F254 HPTLC plates, which were eluted with a mixture of toluene–ethyl acetate (3:1, v/v). Quantitative evaluation was performed by measuring the absorbance reflectance of the analyte spots at λ = 577 nm after being sprayed with anisaldehyde-H₂SO₄ reagent. The HPTLC-densitometric method is cheap, selective, precise, and accurate and can be used for routine analysis of gingers in the herbal drugs industry quality control laboratories.

Keywords:

• Densitometry
• Ginger
• 6-Gingerol
• 8-Gingerol
• 10-Gingerol
• 6-Shogaol
• HPTLC
• Zingiber officinale

ACKNOWLEDGMENTS

The authors are very grateful to Camag, Muttenz, Switzerland for providing method MOA 010, and Mr. Fajar Zulkarnain Lubis (Assessment, Service Unit, Faculty of Pharmacy, Airlangga University) for preparing the figures.

Notes

^a Caculated by using winCats 1.4.2 (Camag).

^b Relative process standard deviation of the linear curve.^{[ 17 ]}

^c F_calculated of ANOVA linearity testing (p < 0.0001).

^d Test value for homogeneity of the linear curve^{[ 17 ]} (p < 0.05).

^e Detection Limit (ng spot⁻¹), calculated from Xp value.^{[ 17 ]}

^f Quantification Limit (ng spot⁻¹), calculated as 3 times of DL value.^{[ 19 ]}

^a DW = dry weight.

^b Values were expressed as Mean (% dry weight; n = 3); values in parentheses showed RSD (in %).

^c % from original content.

^a Data presented as RSD (%) for n = 3.

^b Each measurement was performed by a different analyst on the different days, and HPTLC plates within one laboratory.

^a Values were expressed as Mean (% dry weight; n = 3); values in parentheses showed RSD (in %).

^b Number after the code of the varieties (G, E, M) means samples from different markets.

^a Mobile phase composition presented in v/v.

^b Values were expressed as Mean (% dry weight; n = 3); values in parentheses showed RSD (%).

^a Calculated from data presented on Table 5.

^b Calculation was performed by using Unscrambler 9.6 software (CAMO) NS = not significant (for p = 0,05); p = probability value.