- In A549 human lung adenocarcinoma cells, bakuchiol induces reactive oxygen species (ROS) elevation, reduces mitochondrial membrane potential (ΔΨm), activates caspase 9/3, up-regulates p53 and Bax, and down-regulates Bcl-2. [1]
- UDP-glucuronosyltransferase (UGT) 2B7: noncompetitive inhibition with Ki = 10.7 μM. [2]
- Human carboxylesterase 2 (hCE2): noncompetitive inhibition with Ki = 2.12 μM. [3]

Bakuchiol exhibited concentration-dependent cytotoxicity in A549 cells with IC50 at 72 h of 9.58 ± 1.12 μmol/l, much lower than that of resveratrol (33.02 ± 2.35 μmol/l). [1]
Bakuchiol (5, 10, 20 μmol/l for 36 h) induced apoptosis in A549 cells as shown by Annexin V/propidium iodide staining. [1]
Bakuchiol dose-dependently increased intracellular reactive oxygen species production in A549 cells (measured by H2DCFDA fluorescence). [1]
Bakuchiol reduced mitochondrial membrane potential (ΔΨm) in A549 cells in a concentration- and time-dependent manner. At 10 μmol/l, it caused a decrease in ΔΨm at 3, 6, and 12 h. [1]
Bakuchiol caused S phase arrest in A549 cells at 24 h, though less potent than resveratrol. [1]
Western blot analysis: bakuchiol (5, 10, 20 μmol/l for 24 h) resulted in decreased Bcl-2, increased Bax, increased Bax/Bcl-2 ratio, up-regulation of p53, and activation of caspase 9 and caspase 3 in A549 cells. [1]
Bakuchiol (1, 5, 10, 20, 40, 80 μM) showed concentration-dependent inhibition of recombinant UGT2B7 activity, with IC50 = 40.9 ± 0.5 μM. [2]
Bakuchiol inhibited recombinant UGT2B15 and UGT2B17 activities: at 10 μM, inhibition of UGT2B15 was 7.8% and UGT2B17 10.0%; at 100 μM, inhibition of UGT2B15 was 58.3% and UGT2B17 6.7%. [2]
Bakuchiol inhibited hCE2 activity in human liver microsomes using fluorescein diacetate (FD) as substrate, with IC50 = 7.28 μM and Ki = 2.12 μM (noncompetitive inhibition). [3]
Bakuchiol showed antifungal activity against Trichophyton mentagrophytes with minimum inhibitory concentration (MIC) of 3.91 μg/ml. [4]
Bakuchiol at 0.25×, 0.5×, and 1× MIC (3.91 μg/ml) for 24 h significantly increased membrane permeability of T. mentagrophytes conidia in a dose-dependent manner, as measured by SYTOX Green uptake. [4]
Bakuchiol at 1× MIC increased reactive oxygen species production in T. mentagrophytes cells by 11% at 0.5 h, 114% at 1 h, and 187% at 3 h (measured by carboxy-H2DCFDA). [4]

In a guinea pig model of Trichophyton mentagrophytes-induced tinea pedis, topical application of bakuchiol at 1%, 5%, or 10% (w/w) in aqueous cream once daily for 14 days significantly reduced fungal burden compared to aqueous cream control (p < 0.01–0.05). The positive control Lamisil cream (1% terbinafine hydrochloride) completely eradicated dermatophytes (fungal burden zero). [4]

For UDP-glucuronosyltransferase (UGT) inhibition assay: Recombinant UGT2B isoforms (UGT2B7, 2B15, 2B17) were incubated with 4-methylumbelliferone (4-MU) as probe substrate, 5 mM MgCl2, 5 mM UDP-glucuronic acid, 50 mM Tris-HCl (pH 7.4), and various concentrations of bakuchiol. After 5-min pre-incubation, the reaction was initiated by adding UDPGA and incubated for 120 min. The reaction was terminated with acetonitrile containing internal standard. After centrifugation at 20,000×g for 10 min, the supernatant was analyzed chromatographically. IC50 values were determined from dose-response curves. Inhibition kinetic type was determined by Dixon plot and Lineweaver-Burk plot, and Ki was calculated by nonlinear regression using equations for noncompetitive inhibition. [2]
For human carboxylesterase 2 (hCE2) inhibition assay: Human liver microsomes (HLM) were used as enzyme source. The incubation mixture (0.2 mL total volume) contained HLM (2 μg/mL), 0.1 M potassium phosphate (pH 7.4), and bakuchiol (various concentrations). After 10 min pre-incubation at 37°C, fluorescein diacetate (FD, 15 μM final concentration) was added to start the reaction. After 30 min incubation at 37°C, ice-cold acetonitrile (equal volume) was added to terminate the reaction. Mixtures were centrifuged at 20,000×g for 10 min, and the supernatant was analyzed by UFLC-UV. The residual activity (%) was calculated as (fluorescence intensity in presence of inhibitor) / (fluorescence intensity in negative control) × 100%. IC50 was evaluated by nonlinear regression. For kinetic studies, various concentrations of FD and inhibitor were used. Dixon plot and Lineweaver-Burk plots were used to determine inhibition type, and Ki was calculated from the second plot of slopes versus inhibitor concentrations. [3]

Cytotoxicity assay (MTT): A549 cells were seeded in 96-well plates (5000 cells/well). After 24 h, cells were treated with various concentrations of bakuchiol for 72 h. MTT solution (0.5 mg/ml final) was added for 4 h, then DMSO was added and absorbance at 570 nm was measured. Viability was expressed compared to control cells. [1]
Reactive oxygen species production assay: A549 cells were treated with bakuchiol (5, 10, 20 μmol/l) for 1 h, then washed twice with PBS and incubated with 50 μmol/l H2DCFDA for 30 min in the dark. Fluorescence was monitored by flow cytometry (excitation 488 nm, emission 530 nm). Relative fluorescence intensity units were recorded. [1]
Mitochondrial membrane potential (ΔΨm) measurement: A549 cells (5×10^4/ml) were treated with bakuchiol for 6 h (concentration-dependent) or 10 μmol/l for 3, 6, 12 h (time-dependent). Cells were stained with JC-1 dye (5 μg/ml for 30 min at room temperature in the dark), then analyzed by flow cytometry. Loss of ΔΨm was indicated by switch from red to green fluorescence. [1]
Apoptosis detection by Annexin V/propidium iodide staining: A549 cells were treated with bakuchiol (5, 10, 20 μmol/l for 36 h), then washed twice with PBS, resuspended in Annexin V binding buffer, incubated with Annexin V-FITC and propidium iodide for 5 min at room temperature in the dark, and analyzed by flow cytometry within 1 h. [1]
Cell cycle analysis: A549 cells (5×10^4 cells/ml) were cultured with or without bakuchiol (5, 10, 20 μmol/l for 24 h), harvested, washed, resuspended in 0.1% sodium citrate containing propidium iodide (0.05 mg) and RNase (50 μg) for 30 min at room temperature in the dark, then analyzed by flow cytometry. [1]
Western blot: A549 cells were treated with bakuchiol (5, 10, 20 μmol/l for 24 h). Proteins were extracted with lysis buffer (50 mmol/l NaCl, 50 nmol/l Tris, 1% Triton X-100, 1% sodium deoxycholate, 0.1% SDS). 40 μg total protein per lane was fractionated on 12.5% Tris-glycine gels, transferred to nitrocellulose membrane, probed with primary antibodies (p53, Bcl-2, Bax, pro-caspase 9, cleaved caspase 3, β-actin), then HRP-labeled secondary antibodies, and visualized by enhanced chemiluminescence. [1]
Fungal membrane permeability assay (SYTOX Green): T. mentagrophytes cells (1×10^4 conidia/ml) were incubated at 37°C for 24 h with bakuchiol at 1× MIC or PBS (control). SYTOX Green was added (final 5 μM). After 10 min, fluorescence was measured (excitation 488 nm, emission 540 nm). [4]
Fungal ROS production assay: T. mentagrophytes cells were treated with bakuchiol at 1× MIC for 0.5, 1, and 3 h. Carboxy-H2DCFDA was used as probe, and fluorescence was measured according to kit instructions. [4]
DNA fragmentation assay (TUNEL): T. mentagrophytes cells (1×10^4 conidia/ml) were treated with bakuchiol at 1× MIC for 3 h, washed, fixed with 4% paraformaldehyde in PBS (pH 7.4) for 1 h at 20°C, permeabilized for 2 min on ice, then labeled using the In Situ Cell Death Detection Kit. Results were examined with a fluorescence spectrometer. [4]

Tinea pedis model in guinea pigs: Female Hartley guinea pigs (8-10 weeks old) were infected by fixing an adhesive bandage wetted with 500 μl of Trichophyton mentagrophytes conidial suspension (1×10^8 conidia/ml) onto the right hind foot for 7 days. After infection, the bandage was removed. Bakuchiol was dissolved in ethanol and mixed with aqueous cream to final concentrations of 1%, 5%, or 10% (w/w). These were applied topically on the infected feet once daily for 2 consecutive weeks. Positive control: 1% terbinafine hydrochloride cream (Lamisil). Negative control: aqueous cream. At the end of experiment, animals were euthanized, foot skin samples were excised, and fungal burden was determined. [4]

Bakuchiol showed selective cytotoxicity: it markedly inhibited growth of A549 human lung adenocarcinoma cells but did not change growth rate of non-tumorous cells including endothelial cell lines EA.hy926, HUVEC, and primary cultured mouse embryonic fibroblasts (MEF) at 5, 10, 20 μmol/l for 72 h. [1]
Based on in vitro inhibition of UGT2B7 (Ki = 10.7 μM) and reported maximum plasma concentration (16 μM), the [I]/Ki ratio was calculated as 1.5, indicating high risk of in vivo drug-drug interaction when bakuchiol is co-administered with drugs metabolized by UGT2B7. [2]

[1]. Anti-tumor effects of bakuchiol, an analogue of resveratrol, on human lung adenocarcinoma A549 cell line. Eur J Pharmacol. 2010 Sep 25;643(2-3):170-9.

[2]. In vitro evidence for bakuchiol's influence towards drug metabolism through inhibition of UDP-glucuronosyltransferase (UGT) 2B7. Afr Health Sci. 2014 Sep;14(3):564-9.

[3]. Fructus Psoraleae contains natural compounds with potent inhibitory effects towards human carboxylesterase 2. Fitoterapia. 2015 Jan 13;101C:99-106.

[4]. Anti-dermatophytic activity of bakuchiol: in vitro mechanistic studies and in vivo tinea pedis-inhibiting activity in a guinea pig model. Phytomedicine. 2014 Jun 15;21(7):942-5.

[5]. Anti-Allergic and Anti-inflammatory Effects of Bakuchiol on Ovalbumin-Induced Allergic Rhinitis in Mice. Appl Biochem Biotechnol. 2024;196(6):3456-3470.

Bakuchiol is currently being studied in the clinical trial NCT03112863 (comparison of the cosmetic effects of bakuchiol and retinol). It has been reported that bakuchiol is found in Spiraea taiwanensis, Plumbago stenoptera, and other organisms with relevant data. See also: Plumbago stenoptera fruit (partial).

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Bakuchiol is an analogue of resveratrol, sharing the same "4-hydroxystyryl moiety". It exhibits more potent cytotoxicity against A549 cells than resveratrol, with IC50 at 72 h of 9.58 μM vs. 33.02 μM for resveratrol. The anti-tumor mechanism involves ROS elevation, mitochondrial membrane potential loss, S phase arrest, and p53/Bax up-regulation with Bcl-2 down-regulation. [1]
Bakuchiol is a major constituent of Fructus Psoraleae (Psoralea corylifolia L.). The Chinese Pharmacopoeia recommends an oral dosage of Fructus Psoraleae up to 30 g/day for humans, which would correspond to a combined dosage of its bioactive compounds (including bakuchiol) exceeding 600 mg/day. [3]

C18H24O

256.3826

256.182

10309-37-2

5468522

Colorless to yellow liquid

1.0±0.1 g/cm3

391.4±21.0 °C at 760 mmHg

176.6±11.7 °C

0.0±0.9 mmHg at 25°C

1.555

6.4

1

1

6

19

328

1

O([H])C1C([H])=C([H])C(=C([H])C=1[H])/C(/[H])=C(\[H])/[C@@](C([H])=C([H])[H])(C([H])([H])[H])C([H])([H])C([H])([H])/C(/[H])=C(\C([H])([H])[H])/C([H])([H])[H]

LFYJSSARVMHQJB-QIXNEVBVSA-N

InChI=1S/C18H24O/c1-5-18(4,13-6-7-15(2)3)14-12-16-8-10-17(19)11-9-16/h5,7-12,14,19H,1,6,13H2,2-4H3/b14-12+/t18-/m1/s1

4-[(1E,3S)-3-ethenyl-3,7-dimethylocta-1,6-dienyl]phenol

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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

DMSO : ~62.5 mg/mL (~243.78 mM)

Solubility in Formulation 1: ≥ 2.17 mg/mL (8.46 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 21.7 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 2: ≥ 2.17 mg/mL (8.46 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 21.7 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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