|Jmol-3D images||Image 1|
|Molar mass||254.24 g mol−1|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Chrysin is a naturally occurring flavone, a type of flavonoid. It is found in the passion flowers Passiflora caerulea and Passiflora incarnata, and in Oroxylum indicum. It is also found in chamomile, in the mushroom Pleurotus ostreatus, and in honeycomb.
At high concentrations, chrysin is reported to be an aromatase inhibitor in vitro. However, studies performed in vivo show that orally administered chrysin does not have clinical activity as an aromatase inhibitor.
Chrysin is available as a bodybuilding supplement and it is taken with the hope of raising testosterone levels or stimulating testosterone production; however, there is no clinical evidence for this effect.
Studies show that chrysin has no effect on estrogen levels in either animals or humans.[medical citation needed] Early evidence was reported in the early 1980s through in vitro studies. Follow-up studies determined that cell membranes effectively block chrysin from entering the cells and having any effect at all on estrogen levels in organisms.
In vivo studies lend support to the observation that chrysin has no effect on estrogen levels, but may have other detrimental effects to the body, particularly to thyroid function. For instance, a 30 day study administered chrysin to four groups of mice both orally and via injection to examine chrysin's effect on serum estrogen levels. The results showed that chrysin had no effect on estrogen levels. Further, the mice treated with chrysin became considerably fatter, possibly due to chrysin's ability to disrupt thyroid function.[full citation needed][unreliable source?] Another study on rats administered 50 mg of chrysin per kg body weight, considerably more than found in dietary supplements. Chrysin was found to have no ability to inhibit aromatase, possibly due to poor absorption or bioavailability.
- Peak plasma chrysin concentrations after oral dose of 400 mg = 3–16 ng mL−1 
- AUC = 5–193 ng mL−1 h 
- Plasma chrysin sulfate concentrations were 30-fold higher (AUC 450–4220 ng mL−1 h).
- Excretion: urine peak concentration = 0.2–3.1 mg. Most of the dose appeared in feces as chrysin.
In a 1997 rodent study, chrysin injections displayed dose-dependent anxiolytic effects similar to that of diazepam. Unlike diazepam, the training and test performance of rats injected with chrysin was not significantly reduced. The authors proposed that chrysin does not produce the cognitive impairment usually associated with benzodiazepine medications. However, oral bioavailability of chrysin is still very poor.
- Wolfman C, Viola H, Paladini A, Dajas F, Medina JH (January 1994). "Possible anxiolytic effects of chrysin, a central benzodiazepine receptor ligand isolated from Passiflora coerulea". Pharmacol. Biochem. Behav. 47 (1): 1–4. doi:10.1016/0091-3057(94)90103-1. PMID 7906886.
- Brown E, Hurd NS, McCall S, Ceremuga TE (October 2007). "Evaluation of the anxiolytic effects of chrysin, a Passiflora incarnata extract, in the laboratory rat". AANA J 75 (5): 333–7. PMID 17966676.
- Anandhi R, Annadurai T, Anitha TS, Muralidharan AR, Najmunnisha K, Nachiappan V et al. (2012). "Antihypercholesterolemic and antioxidative effects of an extract of the oyster mushroom, Pleurotus ostreatus, and its major constituent, chrysin, in Triton WR-1339-induced hypercholesterolemic rats.". J Physiol Biochem. doi:10.1007/s13105-012-0215-6. PMID 23104078.
- van Meeuwen JA, Korthagen N, de Jong PC, Piersma AH, van den Berg M. (2007). "(Anti)estrogenic effects of phytochemicals on human primary mammary fibroblasts, MCF-7 cells and their co-culture". Toxicol Appl Pharmacol. 221 (3): 372–83. doi:10.1016/j.taap.2007.03.016. PMID 17482226.
- Kellis JT Jr, Vickery LE. (1984). "Inhibition of human estrogen synthetase (aromatase) by flavones". Science 225 (4666): 1032–4. doi:10.1126/science.6474163. PMID 6474163.
- Saarinen N, Joshi SC, Ahotupa M, Li X, Ammälä J, Mäkelä S, Santti R. (2001). "No evidence for the in vivo activity of aromatase-inhibiting flavonoids". J Steroid Biochem Mol Biol. 78 (3): 231–9. doi:10.1016/S0960-0760(01)00098-X. PMID 11595503.
- Int J Sport Nutr Exerc Metab. (2000). "Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men". Int J Sport Nutr Exerc Metab. 10 (3): 340–59. PMID 10997957.
- Dean, W. "Chrysin: Is It An Effective Aromatase Inhibitor?". Vitamin Research Products.
- Kellis JT, Vickery LE (September 1984). "Inhibition of human estrogen synthetase (aromatase) by flavones". Science 225 (4666): 1032–4. doi:10.1126/science.6474163. PMID 6474163.
- Ibrahim AR, Abul-Hajj YJ (October 1990). "Aromatase inhibition by flavonoids". J. Steroid Biochem. Mol. Biol. 37 (2): 257–60. doi:10.1016/0960-0760(90)90335-I. PMID 2268557.
- Campbell DR, Kurzer MS (September 1993). "Flavonoid inhibition of aromatase enzyme activity in human preadipocytes". J. Steroid Biochem. Mol. Biol. 46 (3): 381–8. doi:10.1016/0960-0760(93)90228-O. PMID 9831487.
- Wang C, Mäkelä T, Hase T, Adlercreutz H, Kurzer MS (August 1994). "Lignans and flavonoids inhibit aromatase enzyme in human preadipocytes". J. Steroid Biochem. Mol. Biol. 50 (3–4): 205–12. doi:10.1016/0960-0760(94)90030-2. PMID 8049151.
- Pelissero C, Lenczowski MJ, Chinzi D, Davail-Cuisset B, Sumpter JP, Fostier A (February 1996). "Effects of flavonoids on aromatase activity, an in vitro study". J. Steroid Biochem. Mol. Biol. 57 (3–4): 215–23. doi:10.1016/0960-0760(95)00261-8. PMID 8645631.
- Le Bail JC, Laroche T, Marre-Fournier F, Habrioux G (November 1998). "Aromatase and 17β-hydroxysteroid dehydrogenase inhibition by flavonoids". Cancer Lett. 133 (1): 101–6. doi:10.1016/S0304-3835(98)00211-0. PMID 9929167.
- Jeong HJ, Shin YG, Kim IH, Pezzuto JM (June 1999). "Inhibition of aromatase activity by flavonoids". Arch. Pharm. Res. 22 (3): 309–12. doi:10.1007/BF02976369. PMID 10403137.
- King DS, Sharp RL, Vukovich MD, et al. (June 1999). "Effect of oral androstenedione on serum testosterone and adaptations to resistance training in young men: a randomized controlled trial". JAMA 281 (21): 2020–8. doi:10.1001/jama.281.21.2020. PMID 10359391. [see comments]
- Koehrle J, Auf'mkolk M, Spanka M, Irmscher K, Cody V, Hesch RD (1986). "Iodothyronine deiodinase is inhibited by plant flavonoids". Prog. Clin. Biol. Res. 213: 359–71. PMID 3086894.
- Shibayama, J. The Oral Bioavailability and In Vivo Activity of Chrysin in Exercising and Non-Exercising Mice. Submitted for publication, as reported by VRP article (by W. Dean)
- Walle T, Otake Y, Brubaker JA, Walle UK, Halushka PV (February 2001). "Disposition and metabolism of the flavonoid chrysin in normal volunteers". Br J Clin Pharmacol 51 (2): 143–6. doi:10.1111/j.1365-2125.2001.01317.x. PMC 2014445. PMID 11259985.
- Woo KJ, Jeong YJ, Inoue H, Park JW, Kwon TK (January 2005). "Chrysin suppresses lipopolysaccharide-induced cyclooxygenase-2 expression through the inhibition of nuclear factor for IL-6 (NF-IL6) DNA-binding activity". FEBS Lett. 579 (3): 705–11. doi:10.1016/j.febslet.2004.12.048. PMID 15670832.
- Tsuji PA, Walle T. (2008). "Cytotoxic effects of the dietary flavones chrysin and apigenin in a normal trout liver cell line". Chem Biol Interact 171 (1): 37–44. doi:10.1016/j.cbi.2007.08.007. PMC 2219546. PMID 17884029.