Measuring sulforaphane plasma compounds

This 2020 Australian human study investigated methods of measuring sulforaphane plasma compounds:

“A simplified methodology to allow high-throughput LC–MS [Liquid Chromatography-Mass Spectrometry] analysis of plasma samples for the measurement of sulforaphane and its metabolites is described. Analysis time is greatly reduced by employing fast chromatography and simple plasma extraction procedure.”

“The participants were observed consuming four Broccomax capsules, each containing 30 mg of broccoli seed extract and a dose of 8 mg of sulforaphane, as per manufacturer certificate of analysis, resulting in a total dose of 32 mg of sulforaphane (120 mg of broccoli seed extract).

The mean peak of combined metabolites from our study (0.9 and 1 μM) using 120 mg of broccoli seed extract (~32 mg of SFN) was similar to work by Fahey et al. who investigated the pharmacokinetics of 350 mg of purified broccoli seed powder (mean 1.3 μM ± 0.5 μM), though our dose was almost three-times less. The pharmacokinetic profiles of our study mirrored those of Fahey et al. in that excretion was complete 8 hrs after consumption. Our intervention peaked slightly later (~2hrs), than that of Fahey (~1 hr), likely due to our use of a capsule rather than liquid.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070302/ “Measuring Sulforaphane and Its Metabolites in Human Plasma: A High Throughput Method”


The study was thin on comparing their 2-person results to previous work. I filled in other comparables from Broccoli or Sulforaphane: Is It the Source or Dose That Matters?


The current study set up a strawman by stating a false comparison:

“Our dose was almost three-times less.”

The compared study was the n = 10 subjects row above, which stated its dose as:

“200 μmol of SF was contained in about 350 mg of SF-αCD powder dissolved in 25 mL of distilled water, which subjects were given to drink upon arrival at the clinic.”

If the current study wanted a true comparison, they would measure and compare sulforaphane dose weights or amounts:

  • https://pubchem.ncbi.nlm.nih.gov/compound/sulforaphane lists sulforaphane’s molecular weight as 177.3 g / mol.
  • A 5.64 μmol sulforaphane amount (.001 / 177.3) equals a 1 mg weight of sulforaphane.
  • 200 μmol / 5.64 μmol = 35 mg sulforaphane used in the compared study.

But these researchers couldn’t even do that. They asserted a 32 mg sulforaphane dose “per manufacturer certificate of analysis” when they had the resources to do otherwise.

Why would a study that went to all the trouble of measuring sulforaphane not test their process by measuring their dose? Had they closely read the compared study, they may have also noticed that its commercial supplement, Prostaphane, was tested to verify stated dosage. These researchers could have done the same with Broccomax.

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