In vitro antioxidant and anti-inflammatory activities of protocatechualdehyde isolated from Phellinus gilvus.
ABSTRACT Although various biological activities of Phellinus gilvus (PG) have been reported, the active compounds responsible for these effects are not known. Here, we evaluated the activity of various solvent extracts of PG, and found the ethyl acetate extract (Fd) to be the most active fraction, showing a strong DPPH free radical scavenging activity, and inhibitory effects on LPS-induced nitric oxide (NO) production and COX-2 mRNA expression in RAW264.7 macrophages. Six major compounds were identified from the ethyl acetate extract of PG, and protocatechualdehyde (PCA) was supposed to be the major phenolic compound of PG responsible for its DPPH free radical scavenging activity and its inhibitory effects on LPS-induced NO production in RAW264.7 cells. Further in vitro and in vivo experiments are currently underway to confirm this observation and to investigate the detailed molecular mechanisms involved in the process as well as the biological activities of other fractions of Fd.
- SourceAvailable from: Jin Boo Jeong[show abstract] [hide abstract]
ABSTRACT: Protocatechualdehyde (PCA) is a naturally occurring polyphenol found in barley, green cavendish bananas, and grapevine leaves. Although a few studies reported growth-inhibitory activity of PCA in breast and leukemia cancer cells, the underlying mechanisms are still poorly understood. Thus, we performed in vitro study to investigate if treatment of PCA affects cell proliferation and apoptosis in human colorectal cancer cells and define potential mechanisms by which PCA mediates growth arrest and apoptosis of cancer cells. Exposure of PCA to human colorectal cancer cells (HCT-116 and SW480 cells) suppressed cell growth and induced apoptosis in dose-dependent manner. PCA decreased cyclin D1 expression in protein and mRNA level and suppressed luciferase activity of cyclin D1 promoter, indicating transcriptional downregulation of cyclin D1 gene by PCA. We also observed that PCA treatment attenuated enzyme activity of histone deacetylase (HDAC) and reduced expression of HDAC2, but not HDAC1. These findings suggest that cell growth inhibition and apoptosis by PCA may be a result of HDAC2-mediated cyclin D1 suppression.Biochemical and Biophysical Research Communications 01/2013; 430(1):381-86. · 2.41 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Protocatechuic aldehyde (PAL) has been reported to bind to DJ-1, a key protein involved in Parkinson's disease (PD), and exerts potential neuroprotective effects via DJ-1 in SH-SY5Y cells. In this study, we investigated the neuroprotective pharmacological effects of PAL against neurotoxin-induced cell and animal models of PD. In cellular models of PD, PAL markedly increased cell viability rates, mitochondrial oxidation-reduction activity and mitochondrial membrane potential, and reduced intracellular ROS levels to prevent neurotoxicity in PC12 cells. In animal models of PD, PAL reduced the apomorphine injection, caused turning in 6-OHDA treated rats, and increased the motor coordination and stride decreases in MPTP treated mice. Meanwhile, in an MPTP mouse model, PAL prevented a decrease of the contents of dopamine (DA) and its metabolites in the striatum and TH-positive dopaminergic neuron loss in the substantia nigra (SN). In addition, PAL increased the protein expression of DJ-1 and reduced the level of α-synuclein in the SN of MPTP lesioned mice. PAL also increased the spine density in hippocampal CA1 neurons. The current study demonstrates that PAL can efficiently protect dopaminergic neurons against neurotoxin injury in vitro and in vivo, and that the potential mechanisms may be related to its effects in increasing DJ-1, decreasing α-synuclein and its growth-promoting effect on spine density.PLoS ONE 01/2013; 8(10):e78220. · 3.73 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Tyrosinase is responsible for the enzymatic browning of fruits and vegetables and usually catalyze the conversion of monophenols to o-diphenols and oxidation of diphenols to corresponding quinines. However, when 3,4-dihydroxymandelic acid is provided as the substrate, it catalyzes the oxidative decarboxylation reaction to generate 3,4-dihydroxybenzaldehyde (protocatechualdehyde, PA. In the present study, tyrosinase was purified from potato with 27.9 purification fold by salting out with ammonium sulfate, DEAE-Sepharose and Sephadex G-150 column chromatography. The purified tyrosinase was confirmed by tyrosinase active staining following SDS-PAGE. Tyrosinase activity was visualized in the gel as a dark band. The molecular weight of tyrosinase from potato was 38kDa as determined by SDS-PAGE. Purified tyrosinase mediated oxidative decarboxylation of 3,4-dihydroxymandelate. The identity of the reaction product, PA was confirmed by high-performance liquid chromatography (HPLC) as well as ultraviolet spectral studies. Phenol oxidase inhibitors such as potassium cyanide, sodium azide, and phenylthiourea inhibited the participation of the active site copper of the enzyme in the catalysis.Horticulture, Environment, and Biotechnology. 53(4).