Cell experiment:

To investigate the cytotoxic effect of Procyanidin B1, viability of THP1 cells is assessed using CCK8 assay. THP1 cells are treated with Procyanidin B1 for 18 h, and 10 μL of CCK8 solution is then added to each well and the cultures are incubated for 4 h at 37℃. The optical density (OD) at 450 nm is measured using an ELx808 Absorbance Microplate Reader. The Procyanidin B1 concentration tested ranges from 50 to 200 μg/mL. Each sample is tested in triplicate[1].

Procyanidin B1 is a polyphenolic flavonoid isolated from commonly eaten fruits, binds to TLR4/MD-2 complex, and has anti-inflammatory activity.

Procyanidin B1 is a polyphenolic flavonoid isolated from fruits and fruit juices, binds to TLR4/MD-2 complex, and has anti-inflammatory activity. Procyanidin B1 causes cellular toxicity at concentrations >100 μg/mL. Procyanidin B1 (100 μg/mL) inhibits LPS-induced TNF-α production, and expression of MD-2, TRAF6, NF-κB mRNA, phosphorylated p38 MAPK and NF-κB protein in THP1 cells[1]. Procyanidin B1 (50-100 μM) protects against Aβ oligomer-induced neuronal death. Procyanidin B1 potently inhibits the activation of caspase-3 at 100 μM, caspase-8 at concentrations of 30, 50, and 100 μM and caspase-9 at concentrations of 10, 30, 50, and 100 μM[2]. Procyanidin B1 (10, 20, 30 μM) significantly and dose-dependently induces expression of ACO and CPT1, with no obvious effect on mRNA expression of PPARα[3].

References:
[1]. Xing J, et al. Anti-inflammatory effect of procyanidin B1 on LPS-treated THP1 cells via interaction with the TLR4-MD-2 heterodimer and p38 MAPK and NF-κB signaling. Mol Cell Biochem. 2015 Sep;407(1-2):89-95.
[2]. Kanno H, et al. Protective effects of glycycoumarin and procyanidin B1, active components of traditional Japanese medicine yokukansan, on amyloid β oligomer-induced neuronal death. J Ethnopharmacol. 2015 Jan 15;159:122-8.
[3]. Shimada T, et al. Flavangenol (pine bark extract) and its major component procyanidin B1 enhance fatty acid oxidation in fat-loaded models. Eur J Pharmacol. 2012 Feb 29;677(1-3):147-53.