Alpinia galanga (L.) Willd. commonly called as Rasna, Greater galangal or Kulinjan is a medicinally important rhizome used in Indian traditional system of medicine to cure a number of ailments. A. galanga is the main source of a galangin -a medicinally important flavanol which has a number of pharmacological properties viz. anti-mutagenic, and anti-inflammatory. Due to the high demand for the rhizome of A. galanga traders are now substituting it with rhizomes of A. calcarata and A. officinarum.
The present study aims to develop high performance thin layer chromatographic (HPTLC) fingerprinting of A. galanga with its adulterants or substitutes and to quantify bioactive galangin present thereof. Methanolic extracts were obtained from rhizomes of the three species of Alpinia used for HPTLC analysis using silica gel 60 F254 plates and hexane: ethyl acetate: acetic acid (6.2: 2.8: 1.0 v/v/v); the densitometric analysis was performed at 272 nm.
By comparison of Rf values and of the spectra of the bands with those of the standard galangin was identified in all three samples. HPTLC quantitative analysis of the methanolic extracts showed the decline trend in the quantity of the galangin in the three species of Alpinia as A. galanga (7.67 ± 0.36 mg/g) > A. officinarum (5.77 ± 0.71 mg/g) > A. calcarata (4.31 ± 0.44 mg/g). The HPTLC method was validated using International Conference on Harmonization (ICH) guidelines. The HPTLC method showed good linearity, recovery and high precision of biomarker.
Rapid and reproducible method is useful for routine analysis of galangin and quality control of Alpinia galangal along with its adulterants or substitutes.