An ultra-high-performance liquid chromatographic (UHPLC) separation was developed for six kava pyrones (methysticin, dihydromethysticin (DHM), kavain, dihydrokavain (DHK), desmethoxyyangonin (DMY), and yangonin), two unidentified components, and three Flavokavains (Flavokavain A, B, and C) in Piper methysticum (kava). The six major kavalactones and three flavokavains are completely separated (R_s > 1.5) within 15 min using a HSS T3 column and a mobile phase at 60 °C. All the peaks in the LC chromatogram of kava extract or standard solutions were structurally confirmed by LC-UV-MS/MS. The degradations of yangonin and flavokavains were observed among the method development. The degradation products were identified as cis-isomerization by MS/MS spectra. The isomerization was prevented or limited by sample preparation in a non-alcoholic solvent or with no water. The method uses the six kava pyrones and three flavokavains as external standards. The quantitative calibration curves are linear, covering a range of 0.5–75 μg/mL for the six kava pyrones and 0.05–7.5 μg/mL for the three flavokavains. The quantitation limits for methysticin, DHM, kavain, DHK, DMY, and yangonin are approximately 0.454, 0.480, 0.277, 0.686, 0.189, and 0.422 μg/mL. The limit of quantification (LOQs) of the three flavokavains are about 0.270, 0.062, and 0.303 μg/mL for flavokavain C (FKC), flavokavain A (FKA), and flavokavain B (FKB). The average recoveries at three different levels are 99.0–102.3% for kavalactones (KLs) and 98.1–102.9% for flavokavains (FKs). This study demonstrates that the method of analysis offers convenience and adequate sensitivity for determining methysticin, DHM, kavain, DHK, yangonin, DMY, FKA, FKB, and FKC in kava raw materials (root and CO₂ extract) and finished products (dry-filled capsule and tablet).

Kava and kava extracts have shown great potential as a way to minimize anxiety-associated symptoms and to help alleviate pain. Hepatoxicity has been associated with the consumption of kava products. The chemical compounds, kavalactones (KL) and flavokavains (FK) have been implicated in kava's psychotropic and possible hepatotoxic properties. To investigate the kavalactone and flavokavain content and in vitro toxicity of KAVOA™, a supercritical carbon dioxide extraction (SFE) of kava. Kavalactone and flavokavain content of SFE kava and noble kava root were determined following extraction in acetone, cell culture media, and water using ultra high-performance liquid chromatography (UHPLC). Using water extractions of the kava products, the cell viability and toxicity on the human hepatocellular carcinoma cell line (HepG2) were determined using luminescent and fluorescent assays, respectively. The half maximal inhibitory concentration (IC50) of the SFE kava and noble kava root, extracted in cell culture media, were determined utilizing a luminescent cell viability assay. Quantification of the KAVOA™, a SFE extract of kava and kava root showed similar profiles of kavalactone and flavokavain content. Water extracted SFE and root kava did not show a negative impact on cell viability and toxicity when compared to the vehicle control treated cells. IC50 values were determined for the SFE kava and kava root extracted in cell culture media in respect to cell viability, 78.63 and 47.65 µg/mL, respectively. KAVOA™, a supercritical carbon dioxide extract of kava displays a similar kavalactone profile to a noble variety of kava. In relation to total kavalactone content, KAVOA™ also has a lower content of the cytotoxic compound FKB. Aqueous extractions of KAVOA™ and noble kava root had no significant negative impact on cell viability and toxicity on HepG2 cells when compared to vehicle controlled treated cells. Results indicate KAVOA™ demonstrates a similar in vitro safety profile to that of noble kava root when experiments are normalized to kavalactone content.

This study describes a single-laboratory validation of an ultra-high-performance liquid chromatographic (UHPLC) method for the determination of key compounds like hericenones, hericenes, erinacines, and ergosterol in Hericium erinaceus (H. erinaceus, Lion’s Mane) raw materials and finished products. The expanding market for Hericium erinaceus (Lion’s Mane) has increased the need for practical, routine-ready analytical methods that can quantify characteristic marker compounds and strengthen quality control across both raw materials and finished products. In this study, an ultra-high-performance liquid chromatographic (UHPLC) separation method was developed for the determination of hericenones, hericenes, erinacines, and ergosterol in Hericium erinaceus raw materials and finished products. Under the optimized conditions, the major target analytes—hericenones, hericenes, erinacine A, and ergosterol—were fully resolved (R_s > 1.5) within 38 min using an HSS T3 column at 30 °C. All the peaks in the LC chromatogram of Hericium erinaceus samples and standard solutions were structurally confirmed by LC–UV-MS/MS based on the possible mass spectra. The quantitative calibration curves were linear, covering a range of 10–300 μg/mL for hericenone C, D and E, and hericene A, D and C; 3–100 μg/mL for deacylhericenone and deacylhericene; 1–50 μg/mL for erinacine A, and 5–200 μg/mL for ergosterol. Limits of quantification (LOQs) for hericenone C, D, and E and for hericene A, D, and C were approximately 9.263, 4.545, 4.650, 1.854, 10.72, and 11.18 µg/mL, respectively, while LOQs for deacylhericenone and deacylhericene were 1.083 and 2.109 µg/mL. Erinacine A and ergosterol showed LOQs of 0.642 and 8.352 µg/mL, respectively. The recovery of ergosterol was evaluated for the method at two different levels: 91.6~93.9% for 0.2% spiking and 93.0~102.6% for 0.08% spiking. The method was successfully validated, demonstrating inter-day Relative Standard Deviation (RSD) values between 1.1% and 5.7% for detected analytes across diverse matrices. This validated method provides a consistent quantification of hericenones, hericenes, erinacine A, and ergosterol across a range of commercial products and raw Hericium erinaceus materials, providing a sensitive and reliable tool for product characterization and quality control. This method provides QC laboratories with a robust, UV-based tool for standardized product characterization without requiring mass spectrometry.