Cytochrome P450 3A4 (CYP3A4) - Noncompetitive inhibitor (IC50 = 10.79 μM, Ki = 6.16 μM) [1]
Cytochrome P450 2E1 (CYP2E1) - Competitive inhibitor (IC50 = 22.54 μM, Ki = 18.02 μM) [1]

Inhibition of CYP3A4: In pooled human liver microsomes (HLMs), Friedelin at 100 μM inhibited CYP3A4 activity to 7.5% of control activity, using testosterone 6β-hydroxylation as a probe reaction. The inhibition was concentration-dependent with an IC50 value of 10.79 μM. Enzyme kinetic studies using Lineweaver-Burk plots showed that Friedelin is a noncompetitive inhibitor of CYP3A4, with a Ki value of 6.16 μM. [1]
Inhibition of CYP2E1: In pooled HLMs, Friedelin at 100 μM inhibited CYP2E1 activity to 18.9% of control activity, using chlorzoxazone 6-hydroxylation as a probe reaction. The inhibition was concentration-dependent with an IC50 value of 22.54 μM. Enzyme kinetic studies showed that Friedelin is a competitive inhibitor of CYP2E1, with a Ki value of 18.02 μM. [1]
Lack of Inhibition of Other CYP Isoforms: At a concentration of 100 μM, Friedelin did not significantly inhibit the activities of CYP1A2, 2A6, 2D6, 2C9, 2C19, or 2C8 in pooled HLMs. [1]
Time-Dependent Inhibition (TDI) of CYP3A4: Friedelin was found to be a time-dependent inhibitor of CYP3A4. Preincubation of Friedelin (20 μM) with HLMs and NADPH for 30 minutes resulted in a time-dependent decrease in CYP3A4 activity. The inactivation parameters were determined, yielding a Kinact/KI value of 4.84 mM/min. The Kinact value indicated that approximately 5.9% of CYP3A4 is inactivated per minute at a saturating concentration of Friedelin. No time-dependent inhibition was observed for CYP2E1. [1]

CYP Enzyme Inhibition Assay in HLMs: The inhibitory effects of Friedelin on eight major CYP isoforms were investigated in human liver microsomes (HLMs) using specific probe reactions: testosterone 6β-hydroxylation for CYP3A4, phenacetin O-deethylation for CYP1A2, coumarin 7-hydroxylation for CYP2A6, chlorzoxazone 6-hydroxylation for CYP2E1, dextromethorphan O-demethylation for CYP2D6, diclofenac 4'-hydroxylation for CYP2C9, S-mephenytoin 4-hydroxylation for CYP2C19, and paclitaxel 6α-hydroxylation for CYP2C8. Incubation mixtures (200 μL final volume) contained 100 mM potassium phosphate buffer (pH 7.4), an NADPH-generating system (1 mM NADP+, 10 mM glucose-6-phosphate, 1 U/mL glucose-6-phosphate dehydrogenase, 4 mM MgCl2), HLMs, the specific probe substrate at concentrations near their Km values, and either Friedelin (100 μM for screening), a positive control inhibitor, or a solvent control (1% methanol). After a 3-minute preincubation at 37°C, the reaction was initiated by adding the NADPH-generating system and incubated for specific times as per Table 1. Reactions were terminated by adding acetonitrile (or acetonitrile/10% trichloroacetic acid for CYP2A6) with an internal standard, then placed on ice. Samples were centrifuged at 12,000 rpm for 10 minutes, and the supernatant was analyzed by HPLC to quantify metabolite formation. All incubations were performed in triplicate. [1]
Determination of IC50 and Inhibition Kinetics: For CYP3A4 and CYP2E1, which showed significant inhibition in the initial screen, secondary studies were performed to determine IC50 values. Various concentrations of Friedelin (0-50 μM) were incubated with fixed substrate concentrations. To determine inhibition constants (Ki) and the mode of inhibition, experiments were conducted with multiple concentrations of probe substrates (testosterone 20-100 μM for CYP3A4; chlorzoxazone 25-200 μM for CYP2E1) in the presence of varying concentrations of Friedelin (0-30 μM for CYP3A4; 0-50 μM for CYP2E1). Data were analyzed using Lineweaver-Burk plots and nonlinear regression to determine Ki values and inhibition mechanisms. [1]
Time-Dependent Inhibition (TDI) Assay: To assess time-dependent inhibition, Friedelin (20 μM) was preincubated with HLMs (1 mg/mL) and an NADPH-generating system at 37°C for 30 minutes. At various time points (0-30 min), an aliquot (20 μL) was transferred to a secondary incubation tube containing an NADPH-generating system and a probe substrate at a concentration approximately equal to its Km. This mixture was incubated further to measure residual enzyme activity. Reactions were terminated and analyzed by HPLC. For determining inactivation parameters (KI and Kinact) for CYP3A4, similar experiments were performed using various concentrations of Friedelin (0-50 μM) and preincubation times (0-30 min), with probe substrate concentrations at approximately 4-fold their Km values. The Kinact/KI value was calculated. [1]

[1]. In vitro inhibitory effects of Friedelin on human liver cytochrome P450 enzymes. Pharm Biol. 2018 Dec;56(1):363-367.

Friedelin is a pentacyclic triterpenoid compound belonging to the perhydro-adenosylene family. Its 3-position is substituted with a carbonyl group, and its 4, 4a, 6b, 8a, 11, 12b, and 14a positions are substituted with methyl groups (4R, 4aS, 6aS, 6bR, 8aR, 12aR, 12bS, 14aS, 14bS enantiomers). It is the main triterpenoid component of cork. Friedelin possesses anti-inflammatory, non-anesthetic analgesic, antipyretic, and plant metabolic-regulating effects. It is a pentacyclic triterpenoid compound and also a cyclic terpene ketone. Friedelin has been reported to exist in Erythrophleum fordii, Phellinus pomaceus, and other organisms with relevant data.

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Friedelin is a triterpenoid isolated from plants such as Maytenus ilicifolia and possesses various biological activities including antioxidant, anti-inflammatory, antiulcer, anti-obesity, and in vitro cytotoxic effects. [1]
This study was the first to investigate the effects of Friedelin on major human liver cytochrome P450 enzymes. The results indicate that Friedelin can inhibit CYP3A4 and CYP2E1 in vitro, suggesting it has the potential to cause pharmacokinetic drug-drug interactions when co-administered with drugs metabolized by these enzymes. [1]
The study notes that while in vitro data is essential, it does not automatically predict clinically relevant interactions. Factors such as the in vivo concentration of Friedelin and the contribution of the inhibited pathway to total drug clearance will influence the clinical significance. Further in vivo studies are needed. [1]

C30H50O

426.73

426.386

559-74-0

91472

White to off-white solid powder

1.0±0.1 g/cm3

477.2±13.0 °C at 760 mmHg

262-265ºC(lit.)

233.9±12.1 °C

0.0±1.2 mmHg at 25°C

1.503

10.87

0

1

0

31

781

9

C[C@H]1C(=O)CC[C@@H]2[C@@]1(CC[C@H]3[C@]2(CC[C@@]4([C@@]3(CC[C@@]5([C@H]4CC(CC5)(C)C)C)C)C)C)C

OFMXGFHWLZPCFL-SVRPQWSVSA-N

InChI=1S/C30H50O/c1-20-21(31)9-10-22-27(20,5)12-11-23-28(22,6)16-18-30(8)24-19-25(2,3)13-14-26(24,4)15-17-29(23,30)7/h20,22-24H,9-19H2,1-8H3/t20-,22+,23-,24+,26+,27+,28-,29+,30-/m0/s1

(4R,4aS,6aS,6aS,6bR,8aR,12aR,14aS,14bS)-4,4a,6a,6b,8a,11,11,14a-octamethyl-2,4,5,6,6a,7,8,9,10,12,12a,13,14,14b-tetradecahydro-1H-picen-3-one

Friedelin UNII-AK21264UAD EINECS 209-205-1

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

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

THF : 7.14 mg/mL (~16.73 mM)
DMSO :< 1 mg/mL

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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