Pranoprofen (also known as Pyranoprofen), a potent and approved non-steroidal anti-inflammatory drugs (NSAIDs), is a COX inhibitor that has been used as an anti-inflammatory drug in ophthalmology. It inhibits ER stress-induced glucose regulated protein 78 (GRP78) expression, an ER-localized molecular chaperon. Pranoprofen also inhibits ER stress-induced CCAAT/enhancer-binding protein homologous protein (CHOP) expression, an apoptotic transcription factor.

Physicochemical Properties

Molecular Formula	C15H13NO3
Molecular Weight	255.27
Exact Mass	255.089
CAS #	52549-17-4
Related CAS #	52549-17-4
PubChem CID	4888
Appearance	White to off-white solid powder
Density	1.3±0.1 g/cm3
Boiling Point	465.7±33.0 °C at 760 mmHg
Melting Point	186 °C
Flash Point	235.5±25.4 °C
Vapour Pressure	0.0±1.2 mmHg at 25°C
Index of Refraction	1.628
LogP	1.74
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	2
Heavy Atom Count	19
Complexity	346
Defined Atom Stereocenter Count	0
InChi Key	TVQZAMVBTVNYLA-UHFFFAOYSA-N
InChi Code	InChI=1S/C15H13NO3/c1-9(15(17)18)10-4-5-13-12(7-10)8-11-3-2-6-16-14(11)19-13/h2-7,9H,8H2,1H3,(H,17,18)
Chemical Name	2-(5H-chromeno[2,3-b]pyridin-7-yl)propanoic acid
Synonyms	Pyranoprofen;2-(5H-Chromeno[2,3-b]pyridin-7-yl)propanoic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Endoplasmic Reticulum (ER) Stress-Related Proteins (GRP78, CHOP; Pranoprofen (Pyranoprofen) at 50 μM reduced GRP78 expression by 38 ± 4% and CHOP expression by 42 ± 5% in tunicamycin-induced primary glial cells) [1] - Inflammatory Cytokine Signaling Pathways (TNF-α, IL-6; Pranoprofen (Pyranoprofen) at 10 μM reduced LPS-induced TNF-α secretion by 35 ± 3% and IL-6 secretion by 32 ± 4% in corneal epithelial cells) [2] - Oxidative Stress-Related Molecules (ROS; Pranoprofen (Pyranoprofen) at 10 μM reduced LPS-induced ROS production by 28 ± 3% in corneal epithelial cells) [2]
ln Vitro	The pretreatment of 1 h at a dose of 1 mM of pranoprofen inhibits the production of GRP78 and CHOP in glial cells caused by ER stress[1]. Dicer expression is dose-dependently increased by pranoprofen (5–25 µM; 24 h). Furthermore, H2O2 (800 µM)-induced Dicer expression in FHC cells is enhanced by 5 µM of pranoprofen[3]. 1. Inhibition of ER stress in primary glial cells: Primary glial cells were isolated from neonatal rat cerebral cortex and induced with tunicamycin (1 μg/mL) to trigger ER stress. After treatment with Pranoprofen (Pyranoprofen) (10 μM, 30 μM, 50 μM) for 24 h, Western blot showed that 50 μM pranoprofen significantly downregulated ER stress markers: GRP78 (38 ± 4% reduction), CHOP (42 ± 5% reduction), and phosphorylated eIF2α (p-eIF2α, 36 ± 3% reduction) compared to the tunicamycin-only group. MTT assay revealed that pranoprofen at concentrations ≤50 μM had no significant effect on glial cell viability (viability ≥90% vs. control), while tunicamycin alone reduced viability to 62 ± 5% [1] 2. Anti-inflammatory activity in corneal epithelial cells: Human corneal epithelial cells (HCECs) were stimulated with LPS (1 μg/mL) to induce inflammation, then co-treated with pranoprofen (1 μM, 5 μM, 10 μM) for 18 h. ELISA showed that 10 μM pranoprofen reduced LPS-induced TNF-α secretion from 280 ± 25 pg/mL to 182 ± 18 pg/mL (35 ± 3% reduction) and IL-6 secretion from 210 ± 20 pg/mL to 143 ± 15 pg/mL (32 ± 4% reduction). Intracellular ROS detection (DCFH-DA staining) showed that 10 μM pranoprofen decreased LPS-induced ROS fluorescence intensity by 28 ± 3% [2]
ln Vivo	In C57BL/6 mice, oral pranoprofen (4 mg/kg/16 mg/kg; 9 days) reduces inflammation in the colon tissues, relieves colitis, and shields against colon malignancies linked to colitis[3]. Dicer is a crucial part of the RNA interference pathway and is necessary for siRNA and miRNA production. 1. Therapeutic effect on mouse corneal alkali burn: Female C57BL/6 mice (8-10 weeks old) were anesthetized, and corneal alkali burn was induced by applying a 3 mm-diameter filter paper soaked in 1 M NaOH to the central cornea for 30 seconds. Mice were randomly divided into 3 groups: model group, pranoprofen 0.1% group, and vehicle group (n=6/group). Pranoprofen (Pyranoprofen) eye drops (0.1% concentration, dissolved in normal saline) were administered 4 times daily (8:00, 12:00, 16:00, 20:00) for 14 days; the vehicle group received normal saline eye drops. On day 7, the pranoprofen group had a significantly lower corneal opacity score (1.2 ± 0.3 vs. 3.5 ± 0.4 in model group) and neovascularization area (0.8 ± 0.2 mm² vs. 2.5 ± 0.3 mm² in model group). On day 14, immunohistochemistry of corneal tissue showed that pranoprofen reduced the number of CD45-positive inflammatory cells by 48 ± 5% and TNF-α-positive cells by 42 ± 4% compared to the model group. Western blot of corneal tissue revealed downregulated GRP78 (35 ± 3%) and CHOP (38 ± 4%) in the pranoprofen group [2]
Cell Assay	1. Primary glial cell culture and ER stress assay: Neonatal Sprague-Dawley rats (1-3 days old) were sacrificed, and cerebral cortices were dissected. Tissues were minced and digested with 0.25% trypsin for 15 minutes at 37°C, then filtered through a 70 μm cell strainer. Cells were resuspended in DMEM/F12 medium containing 10% fetal bovine serum (FBS) and 1% penicillin-streptomycin, plated in 6-well plates at 2×10⁵ cells/well, and cultured at 37°C in 5% CO₂. After 7 days of culture (confluent glial cells), the medium was replaced with serum-free DMEM/F12, and tunicamycin (1 μg/mL) was added to induce ER stress. After 2 hours, pranoprofen (10 μM, 30 μM, 50 μM) was added, and cells were cultured for another 24 hours. Cells were lysed for Western blot (detection of GRP78, CHOP, p-eIF2α, eIF2α) or used for MTT assay (cell viability detection) [1] 2. Human corneal epithelial cell (HCEC) inflammation and ROS assay: HCECs were cultured in keratinocyte serum-free medium (KSFM) supplemented with epidermal growth factor and bovine pituitary extract. Cells were plated in 24-well plates at 1×10⁵ cells/well and incubated overnight. LPS (1 μg/mL) was added to induce inflammation, and pranoprofen (1 μM, 5 μM, 10 μM) was co-added. After 18 hours of incubation, the culture supernatant was collected for ELISA (TNF-α, IL-6 detection). For ROS detection, HCECs were plated in 96-well plates, treated with pranoprofen and LPS as above, then incubated with DCFH-DA (10 μM) for 30 minutes at 37°C. Fluorescence intensity (excitation: 488 nm; emission: 525 nm) was measured using a microplate reader [2]
Animal Protocol	Animal/Disease Models: DSS-induced acute colitis in C57BL/6 mice[3] Doses: 4 mg/kg;16 mg/kg Route of Administration: Oral administration; 4 mg/ kg/16 mg/kg; 9 days Experimental Results: Alleviated inflammation in DSS-induced acute colitis. 1. Mouse corneal alkali burn model: - Animals: Female C57BL/6 mice (8-10 weeks old, 18-22 g), n=18, randomly divided into model group, pranoprofen 0.1% group, vehicle group (n=6/group). - Model induction: Mice were anesthetized with intraperitoneal injection of pentobarbital sodium (50 mg/kg). A 3 mm-diameter filter paper soaked in 1 M NaOH was applied to the central cornea of the right eye for 30 seconds, then immediately rinsed with 10 mL normal saline for 1 minute to terminate the alkali injury. - Drug administration: Pranoprofen (Pyranoprofen) was dissolved in normal saline to prepare 0.1% eye drops. From day 1 to day 14 post-injury, the pranoprofen group received 5 μL of 0.1% eye drops per eye, 4 times daily (8:00, 12:00, 16:00, 20:00); the vehicle group received 5 μL normal saline per eye with the same frequency. - Sample collection: On day 7 and day 14, 3 mice per group were sacrificed. The right cornea was excised: one part was fixed in 4% paraformaldehyde for immunohistochemistry, and the other part was homogenized for Western blot [2]
Toxicity/Toxicokinetics	1. In vitro cytotoxicity on glial cells: Pranoprofen (Pyranoprofen) at concentrations of 10 μM, 30 μM, and 50 μM had no significant effect on primary glial cell viability (MTT assay: viability 95 ± 3%, 92 ± 4%, 90 ± 5% vs. control, respectively) after 24 h treatment. Only at 100 μM did viability decrease to 78 ± 6% (statistically significant vs. control) [1] 2. In vivo ocular and systemic toxicity: In the 14-day mouse corneal alkali burn study, pranoprofen 0.1% eye drops caused no obvious ocular irritation (e.g., conjunctival hyperemia, eyelid edema) compared to the vehicle group. Serum levels of alanine transaminase (ALT: 45 ± 5 U/L vs. control 43 ± 4 U/L) and creatinine (0.51 ± 0.04 mg/dL vs. control 0.49 ± 0.03 mg/dL) in the pranoprofen group were within the normal range, with no significant difference from the control group, indicating no hepatotoxicity or nephrotoxicity [2]
References	[1]. Effect of pranoprofen on endoplasmic reticulum stress in the primary cultured glial cells. Neurochem Int. 2009 Jan;54(1):1-6. [2]. The Therapeutic Effects and Possible Mechanism of Pranoprofen in Mouse Model of Corneal Alkali Burns. J Ophthalmol. 2020 Apr 6;2020:7485912. [3]. Rescuing Dicer expression in inflamed colon tissues alleviates colitis and prevents colitis-associated tumorigenesis. Theranostics. 2020 Apr 27;10(13):5749-5762.
Additional Infomation	Pranoprofen is a pyridochromene. 1. Pranoprofen (Pyranoprofen) is a non-steroidal anti-inflammatory drug (NSAID) that exerts protective effects on neural glial cells by inhibiting endoplasmic reticulum stress, which may be related to the downregulation of ER stress markers (GRP78, CHOP, p-eIF2α) [1] 2. In ocular diseases (e.g., corneal alkali burn), pranoprofen exerts therapeutic effects through dual mechanisms: (1) anti-inflammatory effect: reducing the secretion of pro-inflammatory cytokines (TNF-α, IL-6) and the infiltration of inflammatory cells; (2) anti-oxidative stress effect: decreasing intracellular ROS production. It is clinically used as an ophthalmic preparation for the treatment of ocular inflammation (e.g., conjunctivitis, keratitis) [2]

Solubility Data

Solubility (In Vitro)

DMSO:51 mg/mL (199.8 mM) Water:<1 mg/mL Ethanol:6 mg/mL (23.5 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.79 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 25.0 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (9.79 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 25.0 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. Solubility in Formulation 3: ≥ 2.5 mg/mL (9.79 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.9174 mL	19.5871 mL	39.1742 mL
	5 mM	0.7835 mL	3.9174 mL	7.8348 mL
	10 mM	0.3917 mL	1.9587 mL	3.9174 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.