Quantitative thin layer chromatographic analysis of the saponins in tea seed meal.
BACKGROUND
The defatted seed meal of Camellia oleifera Abel., which contains saponins, is used extensively in aquaculture to eliminate unwanted fish and harmful insects during the cultivation of prawns, and as a molluscicide to control Pomacea canaliculata Lamarck. For the quality control of such tea seed meal products, a method for the determination of saponin content is required.


OBJECTIVE
To develop a simple, sensitive and specific method for the quantitative determination of saponins in tea seed meal using high-performance thin layer chromatography and densitometry.


METHODS
Powdered tea seed meal samples were extracted with methanol, filtered, evaporated to dryness and the residue taken up in methanol. Samples, together with methanolic solutions of saponin standard, were analysed by HPTLC on silica gel layers eluted with ethyl acetate:methanol:water (6:3:1.5, v/v/v) and detected at 214 nm. The amounts of saponins were determined from the respective calibration curves obtained by plotting the concentrations of saponin standard against peak area.


RESULTS
Tea saponin peaks were detected at about R(f )0.40. Good linearity was observed in the range of 0.9-22.2 microg/spot with a correlation coefficient of 0.9978. The limits of detection and quantification were 0.87 and 2.90 microg/spot, respectively. The content of tea saponins in 10 tested samples was found to be between 13.1 and 21.1% w/w.


CONCLUSIONS
The assay proved to be a specific, sensitive and inexpensive method for the quality control of saponins in tea seed meal.
Chaicharoenpong
Chanya
C
Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand. Chanya.C@Chula.ac.th
Petsom
Amorn
A