I thought that a little discussion of the composition of bacopa might be useful to aid in choosing good products (and for research, of course ^^).
This first paper provides a summary of the 12 saponins known before the paper posted in this thread (grand total of 15, now). They also analyze the amount of all compounds found in whole plant material and several products.
Estimation of twelve bacopa saponins in Bacopa monnieri extracts and formulations by high-performance liquid chromatography.
Murthy PB, Raju VR, Ramakrisana T, Chakravarthy MS, Kumar KV, Kannababu S, Subbaraju GV.
Bacosides are a complex mixture of structurally closely related compounds, glycosides of either jujubogenin or pseudojujubogenin (Fig. 1)...Major saponins found in Bacopa monnieri are derivatives of two aglycones, jujubogenin and pseudojujubogenin. The saponins, in two groups, differ only in their sugar moieties. Bacopasaponins possess a weak chromophore.
An extraction procedure for plant materials was evaluated by extracting the plant material (PM-1) with 3x30 ml of 70% methanol, which is sufficient for complete extraction of bacopa saponins 1—12.
The results presented in Table 4 reveal that the compounds Bacoside A3 (3), Bacopaside II (4), Bacopaside I (5), Bacopaside X (6) and Bacopasaponin C (7) were major components and the remaining were minor, but, in quantifiable amounts in Bacopa monnieri plant materials (PM) and total saponins are in the range 5.1—6.0%. Compounds 3—12 were the major peaks whereas Bacopasaponin F (1) and Bacopasaponin E (2) have been detected as minor components in Bacopa monnieri extracts (EM). Major part of the saponin content was contributed by compounds 3—10 in all commercial formulations analyzed. Bacopaside IV (11) and Bacopaside V (12) were not present in commercial formulations (FM-1 and FM-2) procured in the domestic market. The total saponin content of the formulations are in the range 1.47—66.03 mg per capsule or tablet.
Himalaya is a notable exception in the products tested, containing only 1.5mg total saponin content, and missing 5 of the 12 compounds. This may be a whole-plant product, rather than extract, and the missing compounds may simply have been below the detection threshold when only looking at a single pill. The Himalaya product I have ("Bacopa mental alertness") contains ~66.5mg saponins, which is in line with the other extracts here. It is also standardized via chromatography (see below).
The previous study did not list the familiar Bacoside A and B in the list of compounds. These were identified in the 60s by the Chatterji/Basu group [
1] [
2] [
3]; only ten years later was it discovered that what are called A and B are each mixtures of several saponins [
4]. But it wasn't until 2004 that the identity of bacoside A [
5] and B [
6] were finally defined (ID #s from study above):
Bacoside A (triglycosidic saponins)
bacoside A3 (3)
bacopaside II (4)
bacopaside X (6)
bacopa saponin C (7)
Bacoside B (diglycosidic saponins)
bacopaside N1 (8)
bacopaside N2 (9)
bacopaside IV (11)
bacopaside V (12)
Bacoside A group are the major constituents, accounting for ~80% of the saponin content in the extracts and plants tested tested.
The study above used a simple three-fold extraction of methanol to extract the saponins; an earlier study determined this method to extract 98.3%+ of each of the compounds [
7]. Reflux in methanol is also exhaustive [6]. The simplicity of extraction makes it a lot harder to flub up, and more likely that any given extract will contain the full range of active ingredients. Among the last 4 extract products tested in the study above, the ratio of the 12 compounds is fairly consistent, with deviations in the ballpark of those seen in the plant material itself.
However, it was noted in [6] that one of the commercial samples tested in [7] was standardized to 50% A+B by UV method, and actually contained less than 20%
total saponin content. So while the relative ratios may be fairly predictable, the total content may be less accurate. Products standardized by chromatography are greatly preferred, for this reason.
There seems to be some conflicting data on the amount of saponins in whole plants. Study [7] found the total saponin content to be 1.06% for stems, and 1.74-1.99% for leaves. However, the first study above found amounts from 5.1-6%. This
may be explained by the structure of the major components being identified only after [7] was published, though in theory I don't believe this is necessary for determining total saponin content.
Edited by chrono, 10 October 2011 - 12:38 PM.
