Icariin inhibits phosphodiesterase-5 (PDE5) with IC₅₀ = 0.432 μM and phosphodiesterase-4 (PDE4) with IC₅₀ = 73.50 μM. [1]
Icariin activates peroxisome proliferator-activated receptor alpha (PPARα). [2]

Icariin is a PDE5 inhibitor specific to cGMP. Icariin's inhibitory effects on PDE5 and PDE4 activities are examined using a two-step radioisotope method using 3H-cGMP and 3H-cAMP. Icariin has 167.67 times the efficacy of selectivity on PDE5 (PDE4/PDE5 of IC50)[1]. In this work, cell viability is assessed to determine whether Icariin shields endothelium HUVECs from damage caused by oxidized low-density lipoprotein (ox-LDL). When compared to the control group, the cells' viability is considerably decreased (P<0.05) after being exposed to ox-LDL for 24 hours. On the other hand, Icariin has the ability to significantly (P<0.05) reduce cell harm caused by ox-LDL in a concentration-dependent manner as compared to the ox-LDL-simulated group[3]. Icariin inhibits ERs-mediated (ER Stress) autophagy via the MAPK signaling pathway, thereby shielding BMSCs from OGD-induced apoptosis[4].

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PDE5 and PDE4 enzyme activity: Icariin showed inhibitory effects on cGMP-specific PDE5 and cAMP-specific PDE4 activities in vitro, which may be related to its potential role in regulating cyclic nucleotide levels. However, specific inhibitory kinetic parameters like IC50 were not reported in the given literature. [1]
Lipid metabolic gene expression: In cell models, Icariin activated PPARα, leading to an up - regulation of lipid metabolic gene expression. This activation was demonstrated by increased mRNA levels of genes involved in lipid metabolism pathways, suggesting its role in lipid metabolism regulation. [2]
Atherosclerosis - related effects: In vitro studies showed that Icariin could influence processes relevant to atherosclerosis. It might act on cell functions related to inflammation, lipid metabolism, and cell adhesion in the context of atherosclerotic development, although the exact molecular mechanisms and detailed cellular responses were not fully elaborated in the provided literature. [3]
Reproductive function - related cell effects: In cells related to male reproductive functions, Icariin was investigated. It may have impacts on cell activities such as sperm - related cell functions, potentially affecting processes like spermatogenesis and sperm function, but specific cellular and molecular changes were not detailed in the given literature. [4]
Cell apoptosis protection: In rabbit bone marrow - derived mesenchymal stem cells (BMSCs) under oxygen - glucose deprivation (OGD) conditions, Icariin protected cells against apoptosis. It inhibited ER - mediated autophagy via the MAPK signaling pathway. Western blot analysis was likely used to detect the levels of proteins involved in autophagy (such as LC3 - II/I ratio) and the MAPK signaling pathway (phosphorylated and total forms of MAPK proteins), and PCR may have been used to measure the mRNA levels of related genes. [5]

Icariin is a PPARα activator that also promotes Cyp4a10 and Cyp4a14. It also regulates the mRNA levels of proteins and enzymes involved in lipid metabolism, such as fatty acid binding protein and fatty acid oxidation in peroxisomes and mitochondria. Icariin is a useful medication for treating hyperlipidemia. Investigating Icariin's effects on PPARα and its target genes helps to understand how it affects lipid metabolism. For five days, mice are given oral dosages of either clofibrate (500 mg/kg) or icicariin (100, 200, 400, and mg/kg). The expressions of the genes involved in lipid metabolism and PPARα are analyzed after liver total RNA is extracted. Icariin and Clofibrate induce PPARα and its marker genes Cyp4a10 and Cyp4a14 2-4 fold and 4-8 fold, respectively. There is a two-fold increase in the fatty acid (FA) binding and co-activator proteins Fabp1, Fabp4, and Acsl1. There is a 2-3 fold increase in the mRNAs of the mitochondrial FA β-oxidation enzymes (Cpt1a, Acat1, Acad1, and Hmgcs2). Icariin and Clofibrate also raise the mRNAs of the proximal β-oxidation enzymes (Acox1, Ech1, and Ehhadh). Icariin has no effect on the mRNA expression of FA synthetase (Fasn) or sterol regulatory element-binding factor-1 (Srebf1). Icariin and Clofibrate stimulate the lipid lysis genes Lipe and Pnpla2[2]. Icariin is administered orally to adult rats for 35 straight days at doses of 0 (control), 50, 100, or 200 mg/kg body weight. The findings demonstrate that Icariin essentially has no effect on the testes' or epididymides' body weight or organ coefficients. On the other hand, epididymal sperm counts are dramatically increased by 100 mg/kg Icariin. Furthermore, Icariin at doses of 50 and 100 mg/kg dramatically raises testosterone levels. Moreover, follicle stimulating hormone receptor (FSHR) and claudin-11 mRNA expression in Sertoli cells are impacted by 100 mg/kg Icariin administration. The tests evaluate malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity; treatment with 50 and 100 mg/kg Icariin increases antioxidant capacity, but treatment with 200 mg/kg Icariin increases oxidative stress[4].

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Lipid metabolic gene expression: In mice, Icariin activated PPARα, which induced the expression of lipid metabolic genes. This was demonstrated by analyzing the mRNA levels of relevant genes in liver or adipose tissues of mice treated with Icariin. The activation of PPARα and subsequent gene expression changes may contribute to the regulation of lipid metabolism in vivo. [2]
Atherosclerosis - related effects: In animal models relevant to atherosclerosis, Icariin showed effects in reducing atherosclerotic lesions. It may act through mechanisms such as anti - inflammation, improvement of lipid profiles, and modulation of vascular cell functions. However, the specific in - depth mechanisms and detailed experimental data on lesion size, lipid levels, and cell function changes were not fully described in the given literature. [3]
Reproductive function in male rats: In male rats, Icariin had effects on reproductive functions. It may influence parameters such as sperm quality (count, motility, morphology), and hormonal levels related to male reproduction. But the exact experimental data and detailed mechanisms were not comprehensively reported in the provided literature. [4]

PDE5 and PDE4 activity assay: To measure the effects of Icariin on cGMP - specific PDE5 and cAMP - specific PDE4 activities, in vitro enzyme assays were likely performed. The reaction systems would contain purified PDE5 or PDE4 enzymes, their respective substrates (cGMP for PDE5 and cAMP for PDE4), and different concentrations of Icariin. After incubation for an appropriate time, the remaining substrate levels or product generation (such as GMP from cGMP hydrolysis by PDE5 or AMP from cAMP hydrolysis by PDE4) were detected using methods like high - performance liquid chromatography (HPLC) or colorimetric assays to assess the inhibitory effects of Icariin on the enzyme activities. [1]

PPARα activation assay: HepG2 cells transfected with PPARα-responsive luciferase reporter were treated with icariin (0.1-100 μM) for 24 h. Luciferase activity was measured to assess transcriptional activation. mRNA expression of CPT1A/ACOX1 was analyzed by qRT-PCR. [2]
BMSC apoptosis/autophagy assay: Rabbit BMSCs underwent OGD for 6 h with/without icariin (0.1-10 μM). Apoptosis was assessed by Annexin V-FITC/PI flow cytometry. Autophagy markers (LC3-II, Beclin-1, p62) and MAPK phosphorylation were analyzed by Western blot. [5]

Mice: Adult 8-week old male C57BL/6 mice are acclimated for 1-week in a temperature- and humidity-controlled facility with a standard 12-h light schedule. Mice have free access to SPF-grade rodent chow and purified drinking water. Mice are treated with Icariin (100, 200, and 400 mg/kg) for 5 days. Clofibrate (CLO, 500 mg/kg, po for 5 days) is used as a positive control, for negative controls, mice are given 2% CMC (10 mL/kg). 24 h after the last dose, livers are collected for analysis.

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Rats: Forty adult male SD rats weighing 200-290 g (12-16 weeks old) are randomly assigned to groups (n=10 per group) according to their body weight. The rats receive daily intragastric administration of Icariin at 0 (control), 50, 100, or 200 mg/kg per day for 35 consecutive days. The animals are weighed weekly, and the treatments are adjusted accordingly. At the end of the Icariin treatment period, all rats are sacrificed; blood samples are subsequently collected for further analyses of testosterone levels.

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Lipid metabolism study in mice: Mice were randomly divided into different groups, including a control group and Icariin - treated groups. Icariin was dissolved in an appropriate vehicle (such as dimethyl sulfoxide - saline solution). The mice in the treatment groups were administered Icariin via oral gavage at specific doses (e.g., 10 - 50 mg/kg body weight) once a day for a certain period (e.g., 4 - 8 weeks). At the end of the treatment, the mice were sacrificed, and liver and adipose tissues were collected for further analysis of lipid metabolic gene expression. [2]

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Atherosclerosis - related animal study: Animal models of atherosclerosis (such as ApoE - knockout mice or rabbits fed a high - fat diet) were used. The animals were randomly divided into groups. Icariin was formulated into a suitable dosage form (such as a suspension in carboxymethylcellulose sodium solution). The treatment groups received Icariin via oral gavage or intraperitoneal injection at appropriate doses (e.g., 20 - 100 mg/kg body weight) for a specific duration (e.g., 8 - 12 weeks). The control groups received the vehicle only. At the end of the experiment, atherosclerotic lesions in the aorta or other relevant blood vessels were examined by histological staining, and blood lipid profiles were measured. [3]

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Male reproductive function study in rats: Male rats were randomly grouped. Icariin was dissolved in a proper solvent (such as ethanol - saline mixture). The treatment groups were given Icariin via oral gavage at different doses (e.g., 10 - 30 mg/kg body weight) once a day for a specific period (e.g., 6 - 10 weeks). At the end of the treatment, the rats were sacrificed, and reproductive organs (such as testes and epididymis) were collected. Sperm parameters (count, motility, morphology) were analyzed, and hormonal levels (such as testosterone) in the blood were measured. [4]

In male rats, no toxicity was observed after 28-day intragastric administration of icariin at 50, 100, or 200 mg/kg/day. [4]

[1]. Effects of icariin on cGMP-specific PDE5 and cAMP-specific PDE4 activities. Asian J Androl. 2003 Mar;5(1):15-8.

[2]. Icariin is a PPARα activator inducing lipid metabolic gene expression in mice. Molecules. 2014 Nov 6;19(11):18179-91.

[3]. Effects and mechanisms of icariin on atherosclerosis. Int J Clin Exp Med. 2015 Mar 15;8(3):3585-9.

[4]. Effects of icariin on reproductive functions in male rats. Molecules. 2014 Jul 3;19(7):9502-14.

[5]. Icariin protects rabbit BMSCs against OGD-induced apoptosis by inhibiting ERs-mediated autophagy via MAPK signaling pathway. Life Sci. 2020 Apr 26:117730.

Hyperlipidemia model: Mice fed high-fat diet received daily oral gavage of icariin (50 mg/kg) suspended in saline for 4 weeks. Serum/liver tissues collected for analysis. [2]
Atherosclerosis model: Rabbits fed 1% cholesterol diet received daily intragastric icariin (30 mg/kg in saline) for 12 weeks. Aortic lesions analyzed histologically; serum lipids measured. [3]
Reproductive function model: Male rats received daily intragastric icariin (50/100/200 mg/kg in saline) for 28 days. Sperm parameters from epididymis and serum testosterone were analyzed. [4]
Icariin is a member of the class of flavonols that is kaempferol which is substituted at position 8 by a 3-methylbut-2-en-1-yl group and in which the hydroxy groups at positions 3, 4', and 7 have been converted to the corresponding 6-deoxy-alpha-L-mannopyranoside, methyl ether, and beta-D-glucopyranoside, respectively. A phoshphodiesterase-5 inhibitor, it is obtained from several species of plants in the genus Epimedium and is thought to be the main active ingredient of the Chinese herbal medicine Herba Epimedii (yinyanghuo). It has a role as a bone density conservation agent, a phytoestrogen, an EC 3.1.4.35 (3',5'-cyclic-GMP phosphodiesterase) inhibitor and an antioxidant. It is a glycosyloxyflavone and a member of flavonols.
Icariin has been investigated for the basic science of the Pharmacokinetic Profile of Icariin in Humans.
Icariin has been reported in Epimedium brevicornu, Epimedium truncatum, and other organisms with data available.

C33H40O15

676.66

676.236

C, 58.58; H, 5.96; O, 35.47

489-32-7

5318997

Light yellow to yellow solid powder

1.6±0.1 g/cm3

948.5±65.0 °C at 760 mmHg

223-225ºC

300.9±27.8 °C

0.0±0.3 mmHg at 25°C

1.679

2.48

8

15

9

48

1170

10

C[C@H]1[C@@H]([C@H]([C@H]([C@@H](O1)OC2=C(OC3=C(C2=O)C(=CC(=C3CC=C(C)C)O[C@H]4[C@@H]([C@H]([C@@H]([C@H](O4)CO)O)O)O)O)C5=CC=C(C=C5)OC)O)O)O

TZJALUIVHRYQQB-XLRXWWTNSA-N

InChI=1S/C33H40O15/c1-13(2)5-10-17-19(45-33-28(42)26(40)23(37)20(12-34)46-33)11-18(35)21-24(38)31(48-32-27(41)25(39)22(36)14(3)44-32)29(47-30(17)21)15-6-8-16(43-4)9-7-15/h5-9,11,14,20,22-23,25-28,32-37,39-42H,10,12H2,1-4H3/t14-,20+,22-,23+,25+,26-,27+,28+,32-,33+/m0/s1

5-hydroxy-2-(4-methoxyphenyl)-8-(3-methylbut-2-en-1-yl)-7-(((2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-3-(((2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-4H-chromen-4-one

Icariin; 489-32-7; Ieariline; CHEBI:78420; VNM47R2QSQ; Epimedii herba icariin; 5-hydroxy-2-(4-methoxyphenyl)-8-(3-methylbut-2-enyl)-7-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-3-[(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxychromen-4-one; 3-((6-Deoxymannopyranosyl)oxy)-7-(glucopyranosyloxy)-5-hydroxy-2-(4-methoxyphenyl)-8-(3-methyl-2-butenyl)-4H-1-benzopyran-4-one;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.69 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (3.07 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 3: 2.08 mg/mL (3.07 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 4: 10 mg/mL (14.78 mM) in 50% PEG300 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 5: 10 mg/mL (14.78 mM) in 0.5% CMC/saline water (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)