Isoquinoline

Isoquinoline is an analog of pyridine. Isoquinoline-based alkaloids, such as p-tolyl bisisoquinoline, phthaloyl isoquinoline, and naphthyl isoquinoline, exhibit anticancer activity. Berberine, an isoquinoline alkaloid, exerts anti-inflammatory effects in diabetic mice by downregulating the gene expression ratios of pro-/anti-inflammatory and Th1/Th2 cytokines. Additionally, some isoquinoline-based compounds also possess antidepressant, antibacterial, antimalarial, and anti-HIV activities^{[1][2][3][4][5][6]}. In Vitro:Isoquinoline alkaloids exhibit inhibitory activity against Plasmodium falciparum (drug-resistant mutant strain K1). Among them, dehydrodiscretine and berberine have IC₅₀ values of less than 1 μM, while sallocrytopine, columbamine, dehydroocoteine, jatrorrhizine, norcorydine, thalifendine, and ushinsuninehad have IC₅₀ values ranging from 1 to 10 μM^[5].
Berberine (A kind of Isoquinoline) (20-80 μM, 14 days) exerts neuroprotective effects against brain ischemia by modulating apoptotic protein changes and reducing microglial activation^[6].
In Vivo:The isoquinoline compound, 7-fluoro-1,3-diphenylisoquinoline-1-amine (FDPI) (0.1 and 1 mg/kg, i.g., once daily for 35 days) abolishes chronic unpredictable mild stress-induced depressive-like behavior in adult Swiss mice^[3].
The isoquinoline alkaloid berberine (50-500 mg/kg, i.g., once daily for 14 weeks) exerts a protective effect on spontaneous inflammation in the spleen, liver, and kidney of mice (non-obese diabetic (NOD) mice that spontaneously develop type 1) diabetes by downregulating the gene expression ratios of pro-/anti-inflammatory and Th1/Th2 cytokines^[4].