|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 an 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.
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- 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.
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- 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.
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