Anyone heard of harmalacidine?
Acid-base extraction is a widely adopted technique for isolating alkaloids from plant materials, offering enhanced selectivity and improved yield and purity compared to conventional methods [37]. However, the use of harsh acidic or basic conditions can sometimes lead to alkaloidal structure modification or degradation and reduced overall yield [38,39].
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Harmalacidine was reported to be isolated in very low yield (15 mg) using the acid-base extraction method by Wang, Zhang, Wang and He [12]. In contrast, Lamchouri, Toufik, Bouzzine, Hamidi and Bouachrine [11] identified it as the dominant alkaloid, accounting for 52 % of the total alkaloid content in P. harmala seeds from Morocco. The substantial variation in reported harmalacidine yields prompted us to investigate the impact of the extraction method on its recovery. Interestingly, the methanolic extraction method produced significantly higher yields of H3 compared to the acid-base extraction methods, as shown in the TLC chromatograms (Fig. 1). The obtained results could explain the reported low yield of harmalacidine obtained by acid-base extraction methods and the limited research attention in several phytochemical studies of P. harmala seeds [40].
The third extraction method was performed according to our previously published protocol [13]. Briefly, 2g of ground P. harmala seeds were exhaustively extracted with 98 % methanol (4 × 4 mL), followed by 75 % methanol (2 × 4 mL). The combined extracts were concentrated under reduced pressure at 45 ◦C to obtain a syrupy residue, which was subsequently dried to a dark brown residue.
This would be a big factor to consider for why I find seeds so different to A/B extract. Thanks for the tip.Very interesting, I'm reading it now and found this section interesting:
This is the method through which they extracted a sample containing harmalacidine:
This method (third in their paper) is very simple, I may try it. I'm getting some material for TLC and my seeds are from Morocco, so it could be interesting to see if I find harmalacidine as well.
It seems to be a case where harmalacidine is being destroyed by acidic or basic conditions, like yuremamine in Mimosa.
Although earlier studies also identified harmaline (H2) as a MAO inhibitor [61,62], the lower activity of H2 compared with H1 observed here is consistent with more recent findings by Kim et al., who reported Kᵢ values of 48 nM for H2 and 5 nM for H1, indicating that H1 is approximately tenfold more potent [63].
My idea (which I had forgotten about until now, so thanks for reminding me of it) was just to follow their extraction procedure and perform TLC on the residue to see if I find it there, but I didn't intend to separate it in any other way. Not that I wouldn't like to, I just have no idea about how one would go about it.@blig-blug How do you intend to extract the harmalacidine from the browinish goo/residue? Or is that considered a final 'product' ?
Maybe preparative chromatography using a full-width sample stripe on a large sheet of paper would get you somewhere. After developing, cut out the appropriate band with scissors and recover using a suitable solvent.My idea (which I had forgotten about until now, so thanks for reminding me of it) was just to follow their extraction procedure and perform TLC on the residue to see if I find it there, but I didn't intend to separate it in any other way. Not that I wouldn't like to, I just have no idea about how one would go about it.
Would columnar chromatography be a useful in this situation?Maybe preparative chromatography using a full-width sample stripe on a large sheet of paper would get you somewhere. After developing, cut out the appropriate band with scissors and recover using a suitable solvent.
YesWould columnar chromatography be a useful in this situation?