Fisetin

Published research context

Fisetin has an extensive peer-reviewed literature. The studies below are provided as technical context for formulators evaluating this raw material. These entries summarise what the cited publications report. They are not claims about Nutrition BioTech material, and no health, therapeutic or cosmetic outcome is claimed or implied for any finished product. Buyers are responsible for the claims they make on their own labels and for confirming what is permitted in their market.

1. Degradation kinetics as a function of pH, temperature and co-existing proteinsMeasured first-order degradation in buffered solution by a spectroscopic method. Raising the medium pH from 6.0 to 7.5 at 37 °C increased the fisetin rate constant from 8.30 × 10⁻³ to 0.202 h⁻¹; at pH 6.8 the rate constant rose from 3.58 × 10⁻² h⁻¹ at 37 °C to 0.124 h⁻¹ at 50 °C and 0.490 h⁻¹ at 65 °C. Casein, soy protein isolate and whey protein isolate at 0.10 g/L lowered the rate constant to 2.28 × 10⁻²–2.98 × 10⁻² h⁻¹, an effect the authors attributed to hydrophobic interactions. Fisetin was more stable than quercetin in all conditions tested.Wang J, Zhao XH. Journal of the Serbian Chemical Society. 2016;81(3):243–253. DOI 10.2298/JSC150706092W — source
2. Cocrystal forms and measured solubility changeIdentified new cocrystalline phases by solvent-drop grinding with FT-Raman and X-ray powder diffraction, isolated them as single crystals and characterised their structures and thermal stability. Dissolution measurements gave a 2.5-fold increase in fisetin solubility for the nicotinamide 1:2 hemiethanolate, and 1.8-fold and 1.5-fold increases for the caffeine and isonicotinamide phases respectively.Sowa M, Ślepokura K, Matczak-Jon E. CrystEngComm. 2014;16:10592–10601. DOI 10.1039/C4CE01713G — source
3. Disposition and metabolite identification in miceCharacterised fisetin disposition and metabolism in mice and identified geraldol, a methylated metabolite, in plasma. Relevant to analytical method design where methylated metabolites may need to be resolved from the parent compound.Touil YS, Auzeil N, Boulinguez F, Saighi H, Regazzetti A, et al. Biochemical Pharmacology. 2011;82(11):1731–1739. PMID 21840301 — source
4. First human pharmacokinetic study of fisetinReported the first human pharmacokinetic data for fisetin, in a randomised, double-blinded, comparative crossover study in fifteen healthy adults (twelve male, three female, aged 22–55, BMI 18–25), comparing unformulated fisetin with a fenugreek-galactomannan hydrogel formulation at a 1000 mg dose with a 10-day washout, with results normalised for the difference in fisetin content between the two arms. For unformulated fisetin the reported C max was 9.97 ng/ml at a t max of 0.88 h, AUC 0–12 h was 12.67 ng·h/ml, and plasma fisetin was quantifiable for only 2 hours. For the formulated arm the reported values were C max 238.2 ng/ml, t max 1.24 h, AUC 0–12 h 341.4 ng·h/ml, with plasma levels quantifiable to 8 hours. The paper also reports the geraldol-to-fisetin AUC ratio as 1.62 for the unformulated material and 0.67 for the formulated material. The formulation studied is a third-party proprietary material and is not a Nutrition BioTech product; these data are cited as published pharmacokinetic context for the compound, not as a claim about any Nutrition BioTech grade.Krishnakumar IM, Jaja-Chimedza A, Joseph A, Balakrishnan A, Maliakel B, Swick A. J Nutr Sci. 2022;11:e74. PMID 36304817. DOI 10.1017/jns.2022.72 — source