Planta Med 2008; 74(14): 1756-1763
DOI: 10.1055/s-0028-1088311
Original Paper
Analytical Studies
© Georg Thieme Verlag KG Stuttgart · New York

Stability Studies of Saponins in Bacopa monnieri Dried Ethanolic Extracts

Watoo Phrompittayarat1 , Sakchai Wittaya-areekul1 , Kanchalee Jetiyanon2 , Waraporn Putalun3 , Hiroyuki Tanaka4 , Kornkanok Ingkaninan1
  • 1Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand
  • 2Faculty of Agriculture Natural Resources and Environmental Science, Naresuan University, Phitsanulok, Thailand
  • 3Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • 4Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
Further Information

Publication History

Received: May 7, 2008 Revised: July 3, 2008

Accepted: July 30, 2008

Publication Date:
24 October 2008 (online)


Bacopa monnieri (L.) Wettst. (Brahmi) is currently used as a drug and food supplement for memory improvement. However, studies on the physical and chemical stability of the extract components, especially on the lead compound important for pre-formulation, have not yet been reported. In this study, the stabilities of the crude extract and the diluted crude extract were investigated at various temperatures using saponin glycosides, bacopaside I and bacoside A3 as markers for quantitative analysis. The stability testing of bacopaside I and bacoside A3 standard solution was performed at various temperatures and pH values. The quantity of both compounds under all conditions was analyzed using HPLC techniques. The moisture adsorption of the crude extract was determined at 5, 40, 60 and 80 °C at 75 % relative humidity using gravimetric methods. The results revealed that the crude extract quickly adsorbed moisture up to 54 % w/w at both 40 and 80 °C, while it only slowly adsorbed moisture at 5 °C. The amounts of intact bacopaside I and bacoside A3 in the crude extract decreased drastically at 80 °C, slowly at 40 and 60 °C, and remained unchanged at 5 °C during the period of investigation. Moreover, the amount of both compounds in the standard solution dropped sharply at a pH of 1.2 but slowly at pH 6.8 and 9.0, respectively. The pre-formulation data could be further used for improvement of the final product quality.


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Sakchai Wittaya-areekul, Ph. D.

Faculty of Pharmaceutical Sciences

Naresuan University

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