Variation in amino acids composition through pre-column derivatisation using phenylisothiocyanate by HPLC in some economically important less explored wild Allium species of Western Himalayas

Abstract

Less explored Allium species are being used as green vegetables and as a condiment by the local inhabitant of high-altitude areas of Uttarakhand. In the present study, four economically important less explored wild Allium species viz. A. auriculatum, A. ampeloprasum, A. ascalonicum and A. rubellum have screened for their amino acid contents by High-performance liquid chromatography. The hydrochloric acid hydrolysate of these four species, the Allium amino acids were derivatised with phenylisothiocyanate resulting phenylthiocarbamyl derivatives and separated on a reverse-phase column by gradient elution with aqueous buffer and acetonitrile-water (60:40 v/v) and detected in UV region at 254 nm. The Pico-tag (3.9 × 300 mm) C18 column equilibrated with the solvents. The elution of all amino acid derivatives was achieved in 12 min using gradient elution by increasing concentration of aqueous buffer and acetonitrile-water. Total seventeen amino acids were present in these Allium species. The ratio of essential amino acids to total amino acids found 1:2.14 in Allium auriculatum, 1:2.35 in Allium ampeloprasum, 1:1.38 in A. ascalonicum and 1:3.44 in Allium rubellum. These less explored Allium species contained substantial amount of essential and non-essential amino acids. Among these Allium species, Allium auriculatum and Allium rubellum found most promising as far as essential and non-essential amino acids composition concerned.