Dihydrokavain (DHK) #2
Dihydrokavain is one of the six major kavalactones and is also referred to as DHK. This kavalactone required 14–15 min to travel through an HPLC column and as such was the second fastest to exit, which gave the number 2 on chemotypes [1]. Generally, this kavalactone is seen in higher percentages, usually either in the first, second, or third location on the chemotype. Although this kavalactone is prominent, few studies have focused directly on it in its purified form. One study focused on the rat brainstem and how DHK and kava extract affect the gastric vagal response. They found that the responses suggested that kava extract was superior to placebo as a symptomatic treatment for anxiety. The study identified up to 15 kavalactones, among them DHK, which they found to possess a significant anxiolytic effect. This effect was found to be due to potentiating GABA-inhibitory neurotransmission [2]. In a second study, eight-day-old chicks were screened for social separation stress. They found that chicks that were separated from the group experienced greater stress and vocalized more. This indicates a state of anxiety. The kava extract fractions containing the highest concentrations of DHK showed the greatest ability to reduce anxiety. They also found that fractions of extract containing less than 15% DHK failed to modulate anxiety levels. These studies demonstrate that dihydrokavain may be both necessary and sufficient for mediating the anxiolytic effects of kava [3].
[1] Lebot, V. and J. Levesque. “The origin and distribution of kava piper methysticum forst. f. piperaceae a phytochemical approach.” (1989).
[2] Yuan CS, Dey L, Wang A, Mehendale S, Xie JT, Aung HH, Ang-Lee MK. Kavalactones and dihydrokavain modulate GABAergic activity in a rat gastric-brainstem preparation. Planta Med. 2002 Dec;68(12):1092-6. doi: 10.1055/s-2002-36338. https://pubmed.ncbi.nlm.nih.gov/12494336/
[3] Smith, K., Dharmaratne, H., Feltenstein, M. et al. Anxiolytic effects of kava extract and kavalactones in the chick social separation-stress paradigm. Psychopharmacology 155, 86–90 (2001). https://link.springer.com/article/10.1007/s002130100686