Bacopasides III-V: Three New Triterpenoid Glycosides from Bacopa monniera.

Abstract

In continuation of our studies 1,2) on the bioactive glycosidic fraction of Bacopa monniera, a herb having confirmed nervine tonic activity, [3][4][5] we undertook a reinvestigation of the n-butanol soluble fraction of the methanol extract of the plant. Earlier workers reported six saponins, viz. bacopasaponins A-F from the same fraction. [6][7][8] During the present investigation, we have extensively used HPLC for isolation of the minor constituents and finally have been able to isolate three new triterpenoid glycosides, designated as bacopaside III (1), bacopaside IV (2) and bacopaside V (3). We report herein the isolation and structure determination of these three saponins. Results and DiscussionThe n-butanol soluble fraction of the methanol extract of the plant was dissolved in minimum volume of methanol, adsorbed on silica gel and fractionated by successive extraction with hot solvents, such as chloroform, ethyl acetate, acetone and methanol-chloroform (1 : 4) in a Soxhlet apparatus. The acetone extract was subjected to column chromatography (CC) over silica gel and the combined saponin-containing fractions was then subjected to prep. HPLC. The minor peaks were collected to give the saponins 1-3. All the compounds gave positive froth test for saponins and Libermann-Burchard test for triterpenes.The sugar constituents present in the saponins were identified as glucose and arabinose by paper chromatography of their acid hydrolysates. Gas chromatography (GC) of the alditol acetates derived from the hydrolysates showed that glucose and arabinose were present in 1 : 1 ratio in all the saponins (1-3). The absolute configuration of the sugars were determined to be D and L respectively by the specific rotations of the sugars isolated by prep. paper chromatography of the acid hydrolysates of the saponins.High-resolution positive ion FAB mass spectrum (FAB-MS) of all the three saponins (1-3) showed [MϩH] ϩ at m/z 767.4601 corresponding to the molecular formula C 41 H 66 O 13 . 13 C-NMR spectrum (Table 1) of each of the saponins (1-3) displayed signals for 41 carbons, of which 30 were assigned to the aglycone moiety and the remaining 11 must be due to one glucose and one arabinose units. A comparison of the 13 C chemical shifts of the three saponins revealed that the

Estimation of Twelve Bacopa Saponins in Bacopa monnieri Extracts and Formulations by High-Performance Liquid Chromatography

“…Identity and purity (Ͼ95%) of the isolated compounds were confirmed by chromatographic (TLC, HPLC) and spectral (IR, Mass and NMR) data. [17][18][19][20][21][22][23][24] Bacopa monnieri plant materials, extracts analyzed in this study were supplied by M/s Laila Impex, Vijayawada, India and commercial formulations containing Bacopa monnieri were procured from the local market and Australia. Methanol and acetonitrile (HPLC grade), sodium sulphate and sulphuric acid (analytical grade) were purchased from Qualigens (Mumbai, India).…”

Effects of a Standardized Bacopa monnieri Extract on Cognitive Performance, Anxiety, and Depression in the Elderly: A Randomized, Double-Blind, Placebo-Controlled Trial

“…28 Chemical characterizations of the plant have been carried out by many investigators. [29][30][31][32][33][34][35][36][37][38][39][40] There are no data currently available on the pharmacokinetics of Bacopa or its saponins. Phase I clinical studies confirmed the safety of bacosides in healthy male volunteers at both single and chronic dosing administered over a period of 4 weeks 7 and 6 weeks with a dose of up to 450 mg of dried water extract.…”

Brahmi (<italic>Bacopa monnieri</italic>): Up-to-date of memory boosting medicinal plant: A review

“…The major chemical constituents isolated and characterized from B. monnieri are dammaranes of triterpenoid saponins with pseudojujubogenin glycosides or jujubogenin glycosides (Chakravarty et al, 2001(Chakravarty et al, , 2003Hou et al, 2002;Kamonwannasit et al, 2008).…”

“…Neuroprotective activity: The active constituents responsible for B. monnieri's cognitive effects are bacosides A and B, moreover, triterpenoid saponins are responsible to enhance nerve impulse transmission (Mahato et al, 2000;Hou et al, 2002;Chakravarty et al, 2001;2003). The bacosides also aid in repair of damaged neurons by enhancing kinase activity, neuronal synthesis, restoration of synaptic activity, and nerve impulse transmission (Singh and Dhawan, 1997).…”