Asimilobine

Asimilobine, also known as (R)-1-methoxy-2-hydroxynoraporphine, is a noraporphine alkaloid with various known pharmacological actions. It has been found to act as a selective biased partial agonist of the serotonin 5-HT2C receptor, with an EC50Tooltip half-maximal effective concentration of 308 nM and EmaxTooltip maximal efficacy of 86% for activation of Gq signaling and no β-arrestin2 recruitment. Conversely, asimilobine was inactive as an agonist of the serotonin 5-HT2A and 5-HT2B receptors, but did show weak antagonism of these receptors at very high concentrations (IC50Tooltip half-maximal inhibitory concentration = >10,000 nM). Derivatives and analogues of asimilobine with more potent serotonin 5-HT2C receptor agonism, such as 11-chloroasimilobine, have been studied and described. In addition, derivatives with dual highly potent serotonin 5-HT2A and 5-HT2C receptor agonism, such as 11-methoxyasimilobine, have been described. Although asimilobine is inactive as an agonist of the serotonin 5-HT2A and 5-HT2C receptors, the racemic form of the compound has been found to act as an agonist of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors, with EC50 (Emax) values of 318 nM (55%), 794 nM (25%), and 51 nM (94%), respectively. The 1-propoxy homologue shows more potent serotonin 5-HT2A and 5-HT2B receptor agonism and less potent serotonin 5-HT2C receptor agonism (EC50 (Emax) = 43 nM (91%), 53 nM (81%), and 197 nM (98%), respectively).

Asimilobine

Names
IUPAC name 1-Methoxy-12-nor-6aβ-aporphin-2-ol
Systematic IUPAC name (6aR)-1-methoxy-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinolin-2-ol
Other names 1857; (R)-Asimilobine; (R)-1-Methoxy-2-hydroxynoraporphine
Identifiers
CAS Number	6871-21-2[1] N
3D model (JSmol)	Interactive image
ChEBI	CHEBI:70637
ChEMBL	ChEMBL469423
ChemSpider	23282723
PubChem CID	160875
UNII	Q4H26TGS8S
CompTox Dashboard (EPA)	DTXSID101045654
InChI InChI=1S/C17H17NO2/c1-20-17-14(19)9-11-6-7-18-13-8-10-4-2-3-5-12(10)16(17)15(11)13/h2-5,9,13,18-19H,6-8H2,1H3/t13-/m1/s1 Key: NBDNEUOVIJYCGZ-CYBMUJFWSA-N
SMILES COC1=C(C=C2CCN[C@H]3C2=C1C4=CC=CC=C4C3)O
Properties
Chemical formula	C17H17NO2
Molar mass	267.328 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chemical compound

Asimilobine, also known as (R)-1-methoxy-2-hydroxynoraporphine, is a noraporphine alkaloid with various known pharmacological actions.^[2][3] It has been found to act as a selective biased partial agonist of the serotonin 5-HT_2C receptor, with an EC₅₀Tooltip half-maximal effective concentration of 308 nM and E_maxTooltip maximal efficacy of 86% for activation of G_q signaling and no β-arrestin2 recruitment.^[4] Conversely, asimilobine was inactive as an agonist of the serotonin 5-HT_2A and 5-HT_2B receptors, but did show weak antagonism of these receptors at very high concentrations (IC₅₀Tooltip half-maximal inhibitory concentration = >10,000 nM).^[4] Derivatives and analogues of asimilobine with more potent serotonin 5-HT_2C receptor agonism, such as 11-chloroasimilobine, have been studied and described.^[5][6] In addition, derivatives with dual highly potent serotonin 5-HT_2A and 5-HT_2C receptor agonism, such as 11-methoxyasimilobine, have been described.^[5][6]

Although asimilobine is inactive as an agonist of the serotonin 5-HT_2A and 5-HT_2C receptors, the racemic form of the compound has been found to act as an agonist of the serotonin 5-HT_2A, 5-HT_2B, and 5-HT_2C receptors, with EC₅₀ (E_max) values of 318 nM (55%), 794 nM (25%), and 51 nM (94%), respectively.^[7][8] The 1-propoxy homologue shows more potent serotonin 5-HT_2A and 5-HT_2B receptor agonism and less potent serotonin 5-HT_2C receptor agonism (EC₅₀ (E_max) = 43 nM (91%), 53 nM (81%), and 197 nM (98%), respectively).^[7][9]

See also

[edit]

• Noraporphine
• Aporphine alkaloid
• Nornuciferine
• 11-Chloroasimilobine
• 11-Methoxyasimilobine
• MQ02-439

References

[edit]

1. ^ "KNApSAcK Metabolite Information - C00025231". www.knapsackfamily.com.
2. ^ Shoji, N; Umeyama, A; Saito, N; Iuchi, A; Takemoto, T; Kajiwara, A; Ohizumi, Y (1987). "Asimilobine and lirinidine, serotonergic receptor antagonists, from Nelumbo nucifera". Journal of Natural Products. 50 (4): 773–4. Bibcode:1987JNAtP..50..773S. doi:10.1021/np50052a044. PMID 3430176.
3. ^ Jin, CM; Lee, JJ; Kim, YK; Ryu, SY; Lim, SC; Hwang, BY; Lee, CK; Lee, MK (2008). "Effects of asimilobine on dopamine biosynthesis and l-DOPA-induced cytotoxicity in PC12 cells". Journal of Asian Natural Products Research. 10 (7–8): 747–55. doi:10.1080/10286020802030892. PMID 18696327. S2CID 47473525.
4. ^ ^{a b} Zhang B, Zhao S, Yang D, Wu Y, Xin Y, Cao H, Huang XP, Cai X, Sun W, Ye N, Xu Y, Peng Y, Zhao S, Liu ZJ, Zhong G, Wang MW, Shui W (February 2020). "A Novel G Protein-Biased and Subtype-Selective Agonist for a G Protein-Coupled Receptor Discovered from Screening Herbal Extracts". ACS Cent Sci. 6 (2): 213–225. doi:10.1021/acscentsci.9b01125. PMC 7047268. PMID 32123739.
5. ^ ^{a b} Qin W, Zhang B, Wang Q, Jiang G, Cui J, Chen F, Wang L, Chen J, Tian S, Zhen XC, Shui W, Ye N (November 2025). "Discovery of New N-H Aporphine Derivatives As Brain-Penetrant Gq-Biased 5-HT2C Receptor Agonists and Dual 5-HT2C/5-HT2A Receptor Agonists". Journal of Medicinal Chemistry. 68 (21): 23300–23323. doi:10.1021/acs.jmedchem.5c02115. PMID 41108743.
6. ^ ^{a b} "Aporphine derivative and preparation method and application thereof". Google Patents. 14 June 2022. Retrieved 4 April 2026.
7. ^ ^{a b} Mao Q, Zhang B, Tian S, Qin W, Chen J, Huang XP, Xin Y, Yang H, Zhen XC, Shui W, Ye N (June 2022). "Structural optimizations and bioevaluation of N-H aporphine analogues as Gq-biased and selective serotonin 5-HT2C receptor agonists". Bioorg Chem. 123 105795. doi:10.1016/j.bioorg.2022.105795. PMID 35430417.
8. ^ "1-Methoxy-5,6,6a,7-tetrahydro-4H-dibenzo[de,g]quinolin-2-ol". PubChem. Retrieved 7 April 2026.
9. ^ Bergwerf, Herman. "MolView". MolView. Retrieved 7 April 2026.