Bromelain Extract Exerts Antiarthritic Effects via Chondroprotection and the Suppression of TNF-α-Induced NF-κB and MAPK Signaling.

Bromelain, a mixture of proteases in pineapple rhizome, has beneficial biological properties. Following absorption, the compound remains biologically active in mammalian blood and tissues. Bromelain has multiple clinical and therapeutic applications because of its anti-arthritic activities. Anti-inflammation is one of the putative therapeutic effects of bromelain on osteoarthritis (OA) and rheumatoid arthritis (RA), but the molecular mechanisms in cartilage and synovial fibroblast has not been reported. Thus, in this study, interleukin (IL)-1ß/oncostatin M-induced porcine cartilage and TNF-α-induced synovial fibroblast were used as the inflamed OA and RA models, respectively. The results demonstrated the chondroprotective effects of bromelain on cartilage degradation and the downregulation of inflammatory cytokine (tumor necrosis factor (TNF)-α, IL-1ß, IL-6, IL-8) expression in TNF-α-induced synovial fibroblasts by suppressing NF-κB and MAPK signaling. The evidence from this study supported and explained the anti-inflammatory and analgesic effects of bromelain on arthritis in animal models and clinical studies.

Anti-Inflammatory Effect of Pineapple Rhizome Bromelain through Downregulation of the NF-κB- and MAPKs-Signaling Pathways in Lipopolysaccharide (LPS)-Stimulated RAW264.7 Cells.

Bromelain is a mixture of proteolytic enzymes derived from pineapple (Ananas comosus) fruit and stem possessing several beneficial properties, particularly anti-inflammatory activity. However, the molecular mechanisms underlying the anti-inflammatory effects of bromelain are unclear. This study investigated the anti-inflammatory effects and inhibitory molecular mechanisms of crude and purified rhizome bromelains on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophage cells. RAW264.7 cells were pre-treated with various concentrations of crude bromelain (CB) or purified bromelain (PB), and then treated with LPS. The production levels of pro-inflammatory cytokines and mediators, including nitric oxide (NO), interleukin (IL)-6, and tumor necrosis factor (TNF)-α were determined by Griess and ELISA assays. The expressions of inducible nitric oxide synthetase (iNOS), cyclooxygenase (COX)-2, nuclear factor kappa B (NF-κB), and mitogen-activated protein kinases (MAPKs)-signaling pathway-related proteins were examined by western blot analysis. The pre-treatment of bromelain dose-dependently reduced LPS-induced pro-inflammatory cytokines and mediators, which correlated with downregulation of iNOS and COX-2 expressions. The inhibitory potency of PB was stronger than that of CB. PB also suppressed phosphorylated NF-κB (p65), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha, extracellular signal-regulated kinases, c-Jun amino-terminal kinases, and p38 proteins in LPS-treated cells. PB then exhibited potent anti-inflammatory effects on LPS-induced inflammatory responses in RAW264.7 cells by inhibiting the NF-κB and MAPKs-signaling pathways.

Analgesic, anti-inflammatory, and chondroprotective activities of Cryptolepis buchanani extract: in vitro and in vivo studies.

Cryptolepis buchanani Roem. & Schult. is widely used in folk medicine in Southeast Asia for treating muscle tension and arthritis. This study aimed to investigate an analgesic activity of the methanol extract of C. buchanani (CBE) in acetic acid-induced writhing response in mice, and to examine its anti-inflammatory activity in ethyl phenylpropiolate- (EPP-) induced ear edema and carrageenan-induced paw edema in rats. Its effects on cartilage degradation induced by interleukin-1ß (IL-1ß) in porcine cartilage explant culture were also determined. This study demonstrated that CBE significantly reduced acetic acid-induced writhing response. It also inhibited edema formation in both EPP-induced ear edema and carrageenan-induced paw edema models. In cartilage explant culture, CBE significantly reduced the sulfated glycosaminoglycan and hyaluronan released into culture media while it reserved the uronic acid and collagen within the cartilage tissues. It also suppressed the matrix metalloproteinase-2 activity with no effect on cell viability. In conclusion, CBE shows analgesic, anti-inflammatory, and chondroprotective effects in this preliminary study. Therefore, CBE may be useful as an alternative treatment for osteoarthritis.

Active compound of Zingiber cassumunar Roxb. down-regulates the expression of genes involved in joint erosion in a human synovial fibroblast cell line.

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovium. It is involved in up-regulation of pro-inflammatory cytokines and matrix metalloproteinases (MMPs), resulting in joint inflammation and erosion. Zingiber cassumunar Roxb. has long been used to reduce joint pain and inflammation. This study aimed to investigate the inhibitory activities of an active compound of Z. cassumunar, (E)-4-(3',4'-dimethoxyphenyl)but-3-en-1-ol (compound D), against cytokine-induced up-regulation of catabolic genes involved in cartilage degradation in RA. Synovial fibroblast cell line, SW982, was cultured in media containing interleukin-1ß (IL-1ß), in the presence or absence of compound D at the concentration range of 1 to 100 µM. After 24 hours, the cells were analyzed for the expressions of MMPs, IL-1ß and interleukin-1ß-converting enzyme (ICE) by RT-PCR. MMPs activities in the culture media were analyzed by zymographic techniques. Dexamethasone was used as the positive control. It was found that compound D at the concentration of 10 - 100 µM significantly decreased the mRNA expressions of MMP-1, -2, -3, and -13 which was induced by IL-1ß (P<0.05) concomitantly with a decrease in activities of these MMPs in the culture media. An increase in the mRNA expression of IL-1ß and ICE was also suppressed by compound D. The results suggest that the potent activities of this compound may be involved in the reduction of IL-1ß protein synthesis in both pro-form and active form which played an important role in up-regulation of MMPs. This study first revealed the chondroprotective activity of Z. cassumunar in the transcriptional level by suppressing cytokine-induced catabolic genes which caused cartilage erosion in RA.