galangin and Arthritis--Rheumatoid

Rheumatoid arthritis (RA) is a systemic autoimmune disorder that commonly affects multiple joints of the body. Currently, there is no permanent cure to the disease, but it can be managed with several potent drugs that cause serious side effects on prolonged use. Traditional remedies are considered promising for the treatment of several diseases, particularly chronic conditions, because they have lower side effects compared to synthetic drugs. In folklore, the rhizome of Alpinia calcarata Roscoe (Zingiberaceae) is used as a major ingredient of herbal formulations to treat RA. Phytoconstituents reported in A. calcarata rhizomes are diterpenoids, sesquiterpenoid, flavonoids, phytosterol, and volatile oils. The present study is intended to understand the molecular-level interaction of phytoconstituents present in A. calcarata rhizomes with RA molecular targets using computational approaches. A total of 30 phytoconstituents reported from the plant were used to carry out docking with 36 known targets of RA. Based on the docking results, 4 flavonoids were found to be strongly interacting with the RA targets. Further, molecular dynamics simulation confirmed stable interaction of quercetin with 6 targets (JAK3, SYK, MMP2, TLR8, IRAK1, and JAK1), galangin with 2 targets (IRAK1 and JAK1), and kaempferol (IRAK1) with one target of RA. Moreover, the presence of these three flavonoids was confirmed in the A. calcarata rhizome extract using LC-MS analysis. The computational study suggests that flavonoids present in A. calcarata rhizome may be responsible for RA modulatory activity. Particularly, quercetin and galangin could be potential development candidates for the treatment of RA. Investigation of Alpinia calcarata constituent interactions with molecular targets of rheumatoid arthritis: docking, molecular dynamics, and network approach.

Topics: Alpinia; Arthritis, Rheumatoid; Chromatography, Liquid; Computational Biology; Flavonoids; Humans; Interleukin-1 Receptor-Associated Kinases; Janus Kinase 1; Janus Kinase 3; Kaempferols; Mass Spectrometry; Matrix Metalloproteinase 2; Molecular Docking Simulation; Molecular Dynamics Simulation; Phytochemicals; Plant Extracts; Quercetin; Rhizome; Syk Kinase; Toll-Like Receptor 8

Rheumatoid arthritis (RA) is a chronic autoimmune disease that significantly affects patient quality of life. Galangin is an extract with multiple health benefits, including anti‑oxidative, anti‑proliferative, immunoprotective and cardioprotective effects. However, to the best of the authors' knowledge, no detailed studies have investigated its regulatory effects on the nuclear factor (NF)‑κB/NLR family pyrin domain containing 3 (NLRP3) signaling pathway. The present study aimed to investigate the protective mechanism of galangin in RA fibroblast‑like synoviocytes with regards to the NF‑κB/NLRP3 signaling pathway. Human RA fibroblast‑like synovium cells (RAFSCs) were treated with lipopolysaccharide (LPS) to induce inflammation. The levels of interleukin (IL)‑1β, tumor necrosis factor (TNF)‑α, IL‑18, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)‑2, prostaglandin E2 (PGE2), and nitric oxide (NO) were measured by enzyme‑linked immunosorbent assay or western blotting in the absence or presence of different concentrations of galangin. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were additionally evaluated. Furthermore, factors involved in the NF‑κB/NLRP3 pathway, including NLRP3, apoptosis‑associated speck‑like protein containing A, IL‑1β, pro‑caspase‑1, caspase‑1, phosphorylated (p)‑NF‑κB inhibitor α and p‑NF‑κB, were assessed by western blotting. The results revealed that LPS significantly stimulated IL‑1β, TNF‑α, IL‑18, PGE2, NO, iNOS, COX‑2 and NF‑κB/NLRP3 factor expression, compared with the control. SOD activity was reduced. Pre‑treatment with galangin significantly attenuated the effects of LPS, and galangin was demonstrated to have effective anti‑oxidative properties. In conclusion, galangin protected RAFSCs through downregulation of the NF‑κB/NLRP3 signaling pathway. These findings suggested that galangin may provide a novel direction for the development of RA therapies in the future.

Topics: Anti-Inflammatory Agents; Arthritis, Rheumatoid; Cells, Cultured; Fibroblasts; Flavonoids; Humans; Inflammation; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Protective Agents; Signal Transduction; Synoviocytes

Rheumatoid arthritis (RA) patients usually exhibit immune complex (IC) deposition and increased neutrophil activation in the joint. In this study, we assessed how four flavonols (galangin, kaempferol, quercetin, and myricetin) modulate the effector functions of healthy individuals' and active RA patients' IC-stimulated neutrophils. We measured superoxide anion and total reactive oxygen species production using lucigenin (CL-luc)- and luminol (CL-lum)-enhanced chemiluminescence assays, respectively. Galangin, kaempferol, and quercetin inhibited CL-lum to the same degree (mean IC50=2.5 μM). At 2.5 μM, quercetin and galangin suppressed nearly 65% CL-lum of active RA patients' neutrophils. Quercetin inhibited CL-luc the most effectively (IC50=1.71±0.36 μM). The four flavonols diminished myeloperoxidase activity, but they did not decrease NADPH oxidase activity, phagocytosis, microbial killing, or cell viability of neutrophils. The ability of the flavonols to scavenge hypochlorous acid and chloramines, but not H2O2, depended on the hydroxylation degree of the flavonol B-ring. Therefore, at physiologically relevant concentrations, the flavonols partially inhibited the oxidative metabolism of IC-stimulated neutrophils without affecting the other investigated effector functions. Using these compounds to modulate IC-mediated neutrophil activation is a promising safe therapeutic strategy to control inflammation in active RA patients.

Topics: Adult; Anti-Inflammatory Agents; Antigen-Antibody Complex; Arthritis, Rheumatoid; Cell Degranulation; Cells, Cultured; Female; Flavonoids; Humans; Kaempferols; Middle Aged; Neutrophils; Oxidation-Reduction; Peroxidase; Quercetin; Reactive Oxygen Species; Structure-Activity Relationship