Kava Science Kavalactones and Flavokavins Profiles Contribute to Quality Assessment of Kava

[kasa_balavu]

A new study has just been published by Vincent Lebot 1, Serge Michalet, and Laurent Legendre:
Kavalactones and Flavokavins Profiles Contribute to Quality Assessment of Kava (Piper methysticum G. Forst.), the Traditional Beverage of the Pacific
It's an Open Access paper so you can download it from that page.

Abstract
Kava (Piper methysticum) is increasingly traded internationally and there is need for a rapid method to analyze kava raw material before export. The objectives of the present study were: (i) to develop a simple and robust protocol for high throughput simultaneous quantification of kavalactones (KLs) and flavokavins (FKs) in kava and (ii) to assess its potential for quality control. Methysticin; dihydromethysticin; kavain; desmethoxyyangonin; dihydrokavain; yangonin; and flavokavin A, B and C were quantified using HPTLC in acetonic extracts of 174 kava varieties. UHPLC analysis was conducted on a subset of six varieties representing the genetic variation of the species. The genetically distinct groups of nobles, two-day and wichmannii varieties were clearly differentiated and multivariate analyses of UHPLC and HPTLC data were congruent. Noble varieties have significantly low FKs/KLs (0.13) and high kavain/flavokavin B (K/FKB = 7.31). Two-day and wichmannii varieties are characterized by high FKs/KLs (0.36, 0.21) and low K/FKB (1.5, 1.7). A high-throughput HPTLC protocol was developed with a total analytical time of 50 min for 20 samples and only 10 mL of mobile phase. The use of acetone, sonication and two different detection wavelengths improves the accuracy compared to previous HPLC studies and confirms that kava varieties exhibit distinct chemotypes clearly differentiated by their FKs/KLs profiles. These results will strengthen the use of Codex Alimentarius regional standards.

I haven't read it yet (and a lot of it will probably go over my head), but would love to hear what our resident chemistry geeks think. @verticity?

Curiously, it seems they've changed the name "Flavokavains" to "Flavokavins".

 

[verticity]

Pretty cool. A couple points that stand out on first skimming this:

- It appears to be a improved and refined version of existing protocols for measuring kavalactones and flavokavains, the goals being to be able to more easily, quickly, and accurately measure KLs and FKs at the same time. In short, the way they do that is by using acetone as a solvent, which is more efficient at extracting both KLs and FKs than other things such as methanol or chloroform that are normally used, and also by looking at the HPTLC slides with two different wavelengths of UV light in order to get more accurate peak heights for all the KLs that absorb UV light at different wavelengths.

- They confirm what is already known about kavain and FKs: namely that noble kava is relatively higher in kavain and lower in FKs than tudei and wild kava.

- But the most interesting thing is what they say about yangonin and DMY. They conclude that Y and DMY might have been underestimated by a lot in the chemotypes that we are all familiar with using the current standard methods:

"...The present results also give much higher Y and DMY values, due to the use of a different wavelength (355 nm) for their quantification, rather than the same (240 nm) as used for other metabolites in previous HPLC study [7]. A recent HPLC protocol based on methanol extraction of 0.2 g raw material also confirmed that when these two KLs are quantified using a proper wavelength (355 nm), their values are significantly increased compared to their measurements at 240 nm [22].
...
Our findings reveal chemotype groups different than those previously described because we have used two different detection wavelengths that allow for a better quantification of yangonin and desmethoxyyangonin. It appears that these two compounds were underestimated in previous HPLC studies because they were quantified at 240 nm."​

 

[Alia]

Pretty cool. A couple points that stand out on first skimming this:

- It appears to be a improved and refined version of existing protocols for measuring kavalactones and flavokavains, the goals being to be able to more easily, quickly, and accurately measure KLs and FKs at the same time. In short, the way they do that is by using acetone as a solvent, which is more efficient at extracting both KLs and FKs than other things such as methanol or chloroform that are normally used, and also by looking at the HPTLC slides with two different wavelengths of UV light in order to get more accurate peak heights for all the KLs that absorb UV light at different wavelengths.

- They confirm what is already known about kavain and FKs: namely that noble kava is relatively higher in kavain and lower in FKs than tudei and wild kava.

- But the most interesting thing is what they say about yangonin and DMY. They conclude that Y and DMY might have been underestimated by a lot in the chemotypes that we are all familiar with using the current standard methods:

"...The present results also give much higher Y and DMY values, due to the use of a different wavelength (355 nm) for their quantification, rather than the same (240 nm) as used for other metabolites in previous HPLC study [7]. A recent HPLC protocol based on methanol extraction of 0.2 g raw material also confirmed that when these two KLs are quantified using a proper wavelength (355 nm), their values are significantly increased compared to their measurements at 240 nm [22].
...
Our findings reveal chemotype groups different than those previously described because we have used two different detection wavelengths that allow for a better quantification of yangonin and desmethoxyyangonin. It appears that these two compounds were underestimated in previous HPLC studies because they were quantified at 240 nm."​

Increased yangonin? Has been there all along could be good, somewhat related--Phytomedicine paper entitled "Yangonin protects against non-alcoholic fatty liver disease through farnesoid X receptor" Vol. 53 February 2019, 134-142.

 

[verticity]

Increased yangonin? Has been there all along could be good, somewhat related--Phytomedicine paper entitled "Yangonin protects against non-alcoholic fatty liver disease through farnesoid X receptor" Vol. 53 February 2019, 134-142.

Yes, "apparently increased", or just "measured more accurately" would be a better way to phrase that..

An interesting implication of this result for us kava drinkers is that yangonin and DMY might be more important for kava's effects than we had known before. I think of both of them as sort of mysterious, and can't really say what they "feel" like. Is yangoin "heady"? Is DMY "heavy"? Maybe, but who knows? It's hard to say because the chemotypes we thought we knew were usually dominated by others KLs.. But now that there is a way to measure Y and DMY more accurately, and thus get more accurate chemotypes, it might be possible to figure out what they actually do by comparing the effects of various cultivars where that we actually know to be high or low in Y/DMY..

 

[kasa_balavu]

This is going to muddy the water for a while as labs slowly switch to this method (if indeed that happens), making it impossible to accurately compare chemotypes published by different labs.