Today’s fact of the day deals with a curious cultivar of kava that originates in Papua New Guinea in the Madang region. This kava is known as “Isa” pronounced "E-SAH" or Madang Short. Isa is a tall, hearty, disease-resistant plant with green woody stalks and vigorous growth. Kavalactone contents usually run higher than standard drinking kava with a chemotype around 254631. Isa has an unusual history. Dr. Lebot brought a sample from PNG to Hawaii for botanical purposes. This sample “escaped” the nursery and became a commercial kava in Hawaii. Isa is an interesting cultivar because it falls into what research classifies as a group outside of the three common cultivar classifications we are used to, Noble, Tudei, and Wild. Isa is unique in that it is quite close to Piper Wichmannii and is still officially classified as Piper Methysticum. Many have referred to this kava as a “tudei” kava, which is incorrect. Isa’s genomic classification puts it in an entirely different category than those found in the three standard categories. Isa is also not considered "tudei" because the kava must originate from Vanuatu to receive that label; however, it remains “non-noble”. According to Lebot and Levesque (1989), this kava was served at funerals in the Madang Province of PNG. It was seen to have a “toxic” effect and to cause those who drank it to immediately fall asleep. This kava is also locally known as “Koniak”. The only other kava in the group it shares this category with is a cultivar known as Iwi.
Kavalactone Differences: Between the Noble Hawaiian cultivar Mahakea and Isa, Isa routinely has double the total kavalactone content in the root portion; however, the corm area of the Isa plant presented approximately equal levels of kavalactones as those of the corm of Mahakea, given that the rhizome is peeled. The ratio of kavalactones in Isa is distinctly different with DHM being further towards the front being of a higher ratio. DHM is the kavalactone shown as being long-acting and sedative with a propensity to cause nausea at higher doses.
Flavokavain Differences: Flavokavains, the topics of several facts of the day about cancer treatment, and hepatotoxicity occur in higher proportions in Isa than in beverage grade or “Noble” kava. Flavokavains in Isa were found to be approximately double that of standard noble varieties. Keep in mind that these chemicals in the Isa extract are present only slightly in standard preparations and are of little concern to the average kava drinker. Really gnarly non-beverage grade or “Tudei” kava can contain many times more of these chemicals and can become a source of nausea and hangover if consumed regularly and with some cultivars, even one session. These types of Tudei kava are not available for purchase on the regular kava market.
Qualitative Differences: Isa is known to be a heavy, sedating, long-acting kava. This is because of the higher concentrations of DHM and DHK. The majority of DHM and DHK are found in stump peelings. A relatively unknown quality regarding Isa is that when only the well-peeled corm of the plant is used, flavokavain levels drop drastically. It has been observed that Isa corm that has been meticulously peeled can pass the acetonic test as noble. If unpeeled roots or corm are used, the powder will fail the acetone test.
Health Issues: We normally do not see any reported health issues that specifically stem from the Isa plant; however, higher kavalactone concentrations in kava may bring about the reported kava dermopathy, or skin drying effect more quickly. Nausea can also be an issue when consumed in large amounts. This kava may make it a bit more difficult to get moving in the mornings because DHK and DHM have much longer half-lives than kavain. It is generally agreed by most to limit this variety to sporadic consumption. This kava is a “weekend kava” because of its ability to last much longer than your daily drinking kava. This kava has shown popularity in relieving pain related to menstrual cramps, and may be better than other kava in terms of specific pain-relief properties.
Henri Vandenbroucke, Pierre Mournet, Roger Malapa, Jean-Christophe Glaszmann, Hana Chaïr, and Vincent Lebot. Comparative analysis of genetic variation in kava (Piper methysticum) assessed by SSR and DArT reveals zygotic foundation and clonal diversification. Genome. 58(1): 1-11. https://doi.org/10.1139/gen-2014-0166
Lebot, V., Kaoh, J. & Legendre, L. High-Throughput Analysis of Flavokawains in Kava (Piper methysticum Forst. f.) Roots, Chips and Powders and Correlations with Their Acetonic Extracts Absorbance. Food Anal. Methods 13, 1583–1593 (2020).
https://doi.org/10.1007/s12161-020-01781-9
Lebot, V., and J. Lèvesque. 1989. “THE ORIGIN AND DISTRIBUTION OF KAVA (PIPER METHYSTICUM FORST. F., PIPERACEAE): A PHYTOCHEMICAL APPROACH.” Allertonia 5 (2): 223–81. http://www.jstor.org/stable/23187398.
Wang, J., Qu, W., Bittenbender, H.C. et al. Kavalactone content and chemotype of kava beverages prepared from roots and rhizomes of Isa and Mahakea varieties and extraction efficiency of kavalactones using different solvents. J Food Sci Technol 52, 1164–1169 (2015). https://doi.org/10.1007/s13197-013-1047-2