ALFATRADIOL

Details

Stereochemistry	ABSOLUTE
Molecular Formula	C18H24O2
Molecular Weight	272.382
Optical Activity	UNSPECIFIED
Defined Stereocenters	5 / 5
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

C[C@]12CC[C@H]3[C@@H](CCC4=CC(O)=CC=C34)[C@@H]1CC[C@H]2O

InChI

InChIKey=VOXZDWNPVJITMN-SFFUCWETSA-N

InChI=1S/C18H24O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3,5,10,14-17,19-20H,2,4,6-9H2,1H3/t14-,15-,16+,17-,18+/m1/s1

HIDE SMILES / InChI

Molecular Formula	C18H24O2
Molecular Weight	272.382
Charge	0
Count

Stereochemistry	ABSOLUTE
Additional Stereochemistry	No
Defined Stereocenters	5 / 5
E/Z Centers	0
Optical Activity	UNSPECIFIED

Description
Sources: https://www.ncbi.nlm.nih.gov/pubmed/22879713 | https://www.ncbi.nlm.nih.gov/pubmed/17451383

Alfatradiol (17a-estradiol, Ell-Cranell® alpha) is a stereoisomer of the female hormone 17b-estradiol. It inhibits the conversion of testosterone to the metabolite dihydrotestosterone (DHT) by suppressing 5a-reductase activity. In addition, by inhibiting 17b-dehydrogenase, it impedes the conversion process of androstenedione to testosterone, resulting in a reduction in the syntheses of testosterone and DHT. It also accelerates the conversion of testosterone to estradiol by stimulating aromatase, decreasing the level of testosterone and leading to a reduction in DHT. In addition, alfatradiol (17a-estradiol) has been reported to stimulate the generation of hair follicular matrix cells.

CNS Activity

Approval Year

Targets

Primary Target	Pharmacology	Potency
Estrogen receptor alpha 134 Target ID: CHEMBL206 Sources: https://www.ncbi.nlm.nih.gov/pubmed/9048584	Agonist 2752	0.2 nM [Ki]
Estrogen receptor beta 113 Target ID: CHEMBL3021 Sources: https://www.ncbi.nlm.nih.gov/pubmed/9048584	Agonist 2752	1.2 nM [Ki]
3-oxo-5-alpha-steroid 4-dehydrogenase activity 1 Target ID: GO:0003865 Sources: https://gr.fagron.com/sites/default/files/product/document/fadapbprb02_fad_alopecia_pharmacistphysicians_en_web.pdf	Inhibitor 8504
Cytochrome P450 19A1 39 Target ID: CHEMBL1978 Sources: https://gr.fagron.com/sites/default/files/product/document/fadapbprb02_fad_alopecia_pharmacistphysicians_en_web.pdf	Activator 1447

Conditions

Condition	Modality	Targets	Highest Phase	Product
Androgenic alopecia 8 Sources: https://www.ncbi.nlm.nih.gov/pubmed/17451383	Primary		Approved 8583	Ell-Cranell® alpha Approved Use Androgenetic alopecia in women.

Doses

Dose	Population	Adverse events
0.025 % 1 times / day multiple, topical Recommended Dose: 0.025 %, 1 times / day Route: topical Route: multiple Dose: 0.025 %, 1 times / day Sources: https://pubmed.ncbi.nlm.nih.gov/17451383/	unhealthy, ADULT Health Status: unhealthy Age Group: ADULT Sex: F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/17451383/	Sources: https://pubmed.ncbi.nlm.nih.gov/17451383/

Overview

CYP3A4	CYP2C9	CYP2D6	hERG
inhibitor 2252	inhibitor 2438	inhibitor 2507	inhibitor 2217

OverviewOther

Other Inhibitor	Other Substrate	Other Inducer
CYP2C19 2057 CYP19A1 429 CYP1A2 2153	UGT2B11 4 UGT1A10 331 UGT1A5 56 UGT1A1 479 UGT2B28 65 UGT1A8 323 UGT2A3 49 UGT1A3 470 UGT1A7 249 UGT2B10 131 UGT1A9 423 UGT1A6 343 UGT1A4 399 UGT2A2 49 UGT2A1 39 UGT2B4 278 UGT2B7 456 UGT2B15 236 UGT2B17 237

Drug as perpetrator

Target	Modality	Activity
CYP1A2 2333	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 21.0	inconclusive [IC50 20.348 uM]
CYP19A1 430	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 25.0	inconclusive [IC50 27.306 uM]
CYP3A4 2633	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 11.0	no [IC50 7.098 uM]
CYP2C9 2497	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 12.0	no [IC50 7.9641 uM]
CYP2D6 2546	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 116.0	no
CYP2C19 2141	inhibitor 4027 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 8.0	yes [IC50 4.06 uM]

Drug as victim

Target	Modality	Activity
UGT1A5 56	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT1A6 343	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT1A9 423	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT2A3 49	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT2B10 131	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT2B11 4	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT2B17 237	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT2B28 65	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	no
UGT1A1 479	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 11.2 uM]
UGT1A4 399	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 21.7 uM]
UGT1A10 331	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 21.8 uM]
UGT2B15 236	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 26.1 uM]
UGT1A3 470	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 34.2 uM]
UGT1A7 249	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 37.1 uM]
UGT2B4 278	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 4.77 uM]
UGT2A1 39	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km 99 uM]
UGT2B7 456	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes [Km <0.5 uM]
UGT1A8 323	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes
UGT2A2 49	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/18719240/	yes

Tox targets

Target	Modality	Activity	Metabolite	Clinical evidence
hERG 2263	inhibitor 2237 Sources: https://pubchem.ncbi.nlm.nih.gov/compound/68570#section=Biological-Test-Results Page: 116.0

PubMed

Title	Date	PubMed
17beta-estradiol inhibits cyclic strain-induced endothelin-1 gene expression within vascular endothelial cells.	2004-09	15130882
Direct action of estradiol on gonadotropin-releasing hormone-1 neuronal activity via a transcription-dependent mechanism.	2004-07-14	15254088
Estrogen content of dairy and swine wastes.	2004-07-01	15296306
Rapid yeast estrogen bioassays stably expressing human estrogen receptors alpha and beta, and green fluorescent protein: a comparison of different compounds with both receptor types.	2004-07	15276617
Profiling of sulfoconjugates in urine by using precursor ion and neutral loss scans in tandem mass spectrometry. Application to the investigation of heavy metal toxicity in rats.	2004-06	15236304
The unusual binding properties of the third distinct teleost estrogen receptor subtype ERbetaa are accompanied by highly conserved amino acid changes in the ligand binding domain.	2004-06	15001543
Aromatase inhibition in the treatment of advanced breast cancer: is there a relationship between potency and clinical efficacy?	2004-05-04	15150604
Estrogen suppresses IL-1beta-mediated induction of COX-2 pathway in rat cerebral blood vessels.	2004-05	14684367
Free energy simulations and MM-PBSA analyses on the affinity and specificity of steroid binding to antiestradiol antibody.	2004-04-01	14997538
Synthetic polymers adsorbing bisphenol A and its analogues prepared by covalent molecular imprinting using bisphenol A dimethacrylate as a template molecule.	2004-04	14762648
Involvement of insulin/phosphoinositide 3-kinase/Akt signal pathway in 17 beta-estradiol-mediated neuroprotection.	2004-03-26	14711819
Estradiol binding to maxi-K channels induces their down-regulation via proteasomal degradation.	2004-01-09	14555652
The difluoromethylene group as a replacement for the labile oxygen in steroid sulfates: a new approach to steroid sulfatase inhibitors.	2004-01-05	14684318
Chemical synthesis of two novel diaryl ether dimers of estradiol-17beta.	2004-01	14715378
Alpha and beta estradiol protect neuronal but not native PC12 cells from paraquat-induced oxidative stress.	2004	15325966
Manure-borne estrogens as potential environmental contaminants: a review.	2003-12-15	14717153
The use of estrogens and related compounds in the treatment of damage from cerebral ischemia.	2003-12	14993044
Estrogen modulation of G-protein-coupled receptor activation of potassium channels in the central nervous system.	2003-12	14993035
Characterization of a membrane-associated estrogen receptor in a rat hypothalamic cell line (D12).	2003-12	14709794
Estrogen modulates xanthine dehydrogenase/xanthine oxidase activity by a receptor-independent mechanism.	2003-12	14588143
Estradiol modulates acetylcholine-induced Ca2+ signals in LHRH-releasing GT1-7 cells through a membrane binding site.	2003-11	14622151
Characterization of an organic anion transport system in a placental cell line.	2003-11	12902320
Protective effects of estrogens on polyglutamine-expanded androgen receptor aggregation in mice.	2003-10-16	12962912
Estrogen-induced changes in the microtubular system correlate with a decreased susceptibility of aging neurons to beta amyloid neurotoxicity.	2003-10	14572470
Short-term activation by low 17beta-estradiol concentrations of the Na+/H+ exchanger in rat aortic smooth muscle cells: physiopathological implications.	2003-10	12959986
17Beta-estradiol as a receptor-mediated cardioprotective agent.	2003-10	12893838
Role of steroid sulfatase in local formation of estrogen in post-menopausal breast cancer patients.	2003-09	14623544
Estrogens inhibit l-glutamate uptake activity of astrocytes via membrane estrogen receptor alpha.	2003-09	12950458
[Anti-arrhythmia activity of estradiol valerate and estradiol nitrate].	2003-08-20	12924228
[New and established methods in therapy of hair diseases].	2003-08	12942187
Stationary phase with specific surface properties for the separation of estradiol diastereoisomers.	2003-07-25	12860035
Estradiol regulates the slow Ca2+-activated K+ current in hippocampal pyramidal neurons.	2003-07-16	12867518
Estrogen in the adult male reproductive tract: a review.	2003-07-09	12904263
17beta-estradiol downregulates angiotensin-II-induced endothelin-1 gene expression in rat aortic smooth muscle cells.	2003-07-02	14730207
Equine estrogens differentially prevent neuronal cell death induced by glutamate.	2003-07	12853093
Potential role of the interaction between equine estrogens, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in the prevention of coronary heart and neurodegenerative diseases in postmenopausal women.	2003-06-20	12848896
Estrogens and menopause: pharmacology of conjugated equine estrogens and their potential role in the prevention of neurodegenerative diseases such as Alzheimer's.	2003-06	12943738
Reciprocal effects of C/EBPalpha and PKCdelta on JunB expression and monocytic differentiation depend upon the C/EBPalpha basic region.	2003-05-15	12522006
17beta-estradiol inhibits NADPH oxidase activity through the regulation of p47phox mRNA and protein expression in THP-1 cells.	2003-05-12	12729920
Repeated estradiol treatment prevents MPTP-induced dopamine depletion in male mice.	2003-04	12766322
17beta-estradiol inhibits the production of interferon-induced protein of 10 kDa by human keratinocytes.	2003-03	12603854
17beta-estradiol and tamoxifen regulate a maxi-chloride channel from human placenta.	2003-01-01	12532277
Estradiol prevents amyloid-beta peptide-induced cell death in a cholinergic cell line via modulation of a classical estrogen receptor.	2003	14580942
Estradiol inhibits atp-induced intracellular calcium concentration increase in dorsal root ganglia neurons.	2003	12732239
Estrogen prevents the loss of CA1 hippocampal neurons in gerbils after ischemic injury.	2003	12573724
17Alpha-estradiol and 17beta-estradiol treatments are effective in lowering cerebral amyloid-beta levels in AbetaPPSWE transgenic mice.	2002-12	12515896
Nuclear receptor agonists stimulate release of arachidonic acid from rat liver cells.	2002-12	12468267
Testosterone metabolism in human skin cells in vitro and its interaction with estradiol and dutasteride.	2002-07-26	14528059
Dehydroepiandrosterone and alpha-estradiol limit the functional alterations of rat brain mitochondria submitted to different experimental stresses.	2002	12421607
Tamoxifen eliminates estrogen's neuroprotective effect upon MPTP-induced neurotoxicity of the nigrostriatal dopaminergic system.	2001-07	15111254

Patents

Sample Use Guides

In Vivo Use Guide

Ell-Cranell® alpha was applied once a day at 3 ml/application using a pre-dosed applicator, and the head was massaged for approximately one minute to facilitate the absorption of the drug.

Route of Administration: Topical

In Vitro Use Guide

17a- and 17b-estradiol caused a concentration-dependent inhibition of spontaneous rat uterine contractility, with an IC50 value of 89.39 and 8.42 uM, respectively.

Substance Class	Chemical Created by `admin` on `Wed Apr 02 06:52:45 GMT 2025` Edited by `admin` on `Wed Apr 02 06:52:45 GMT 2025`
Record UNII	3VQ38D63M7
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

ALFATRADIOL

Official Name

English

.ALPHA.-ESTRADIOL [MI]

Preferred Name

English

ESTRA-1,3,5(10)-TRIENE-3,17.ALPHA.-DIOL

Systematic Name

English

ESTRADIOL, .ALPHA.-

Common Name

English

ALFATRADIOL [MART.]

Common Name

English

17ALPHA-ESTRADIOL

Common Name

English

ESTRADIOL, ALPHA-

Common Name

English

ETHINYLESTRADIOL IMPURITY L [EP IMPURITY]

Common Name

English

17.ALPHA.-ESTRADIOL

Common Name

English

17a-estradiol [WHO-DD]

Common Name

English

alfatradiol [INN]

Common Name

English

ESTRADIOL HEMIHYDRATE IMPURITY B [EP IMPURITY]

Common Name

English

ESTRADIOL 17-.ALPHA.

Common Name

English

Classification Tree Code System Code

NCI_THESAURUS

C1740