[CAS NO. 530-57-4]  Syringic acid

Syringic acid ameliorates the expressions of TH, DAT and VMAT2 and also significantly attenuates MPTP/p2 induced increased inflammatory markers expression. SYRA pretreatment obviously inhibits H2O2-induced RGC-5 cell injury and also decreases H2O2-induced ROS production and MDA content. Syringic acid may protect RGC-5 cells against apoptosis induced by H2O2 through the activation of PI3K/Akt signaling pathway. Syringic acid shows a time- and dose-dependent (IC50 = 0.95-1.2 mg/mL) antimitogenic effect against cancer cells with little cytotoxicity on normal fibroblasts (≤20%). SYRA alters cell cycle (S/G2-M or G1/G2-M phases) in a time-dependent manner, induces apoptosis, inhibits DNA-binding activity of NFκB (p ≤ 0.0001), chymotrypsin-like/PGPH (peptidyl-glutamyl peptide-hydrolyzing) (p ≤ 0.0001) and the trypsin-like (p ≤ 0.002) activities of 26S proteasome and angiogenesis. SYRA also differentially sensitizes cancer cells to standard chemotherapies with a marked increase in their sensitivity to camptothecin (500-fold), 5FU (20,000-fold), doxorubicin (210-fold), taxol (3134-fold), vinblastine (1000-fold), vincristine (130-fold) and amsacrine (107-fold) compared to standard drugs alone. SYRA exerts its chemotherapeutic and chemo-sensitizing effects through an array of mechanisms including cell-cycle arrest, apoptosis induction, inhibition of cell proliferation, cell migration, angiogenesis, NFκB DNA-binding and proteasome activities.