METHODS: We established an in vitro OA culture model by exposing human chondrocytes to proinflammatory cytokine and interleukin (IL)-1β for 36 hours prior to treatment with the herbals: C. quadrangularis, W. somnifera, and the combination of the two herbals. Cell viability, toxicity, and gene expression of OA modifying agents were examined. In addition, expression of survivin, which is crucial for cell growth, was analyzed. In vivo work on osteotomized rats studied the bone and cartilage regenerative effects of C. quadrangularis, W. somnifera, and the combination therapy.
RESULTS: Exposure of chondrocytes to IL-1β induced significant toxicity and cell death. However, herbal treatment alleviated IL-1β induced cell toxicity and upregulated cell growth and proliferation. C. quadrangularis inhibited gene expression of cytokines and matrix metalloproteinases, known to aggravate cartilage and bone destruction, and augmented expression of survivin by inhibiting p38 MAPK. Interestingly, osteotomized rats treated with C. quadrangularis drastically enhanced alkaline phosphatase and cartilage tissue formation as compared to untreated, W. somnifera only, or the combination of both herbals.
CONCLUSION: Our findings demonstrate for the first time the signaling mechanisms regulated by C. quadrangularis and W. somnifera in OA and osteogenesis. We suggest that the chondroprotective effects and regenerative ability of these herbals are via the upregulation of survivin that exerts inhibitory effects on the p38 MAPK signaling pathway. These findings thus validate C. quadrangularis as a potential therapeutic for rheumatic disorders.
PURPOSE: The study was carried out to investigate the molecular mechanisms underlying the anti-inflammatory properties of the standardized 80% ethanol extract of Z. zerumbet through its effect on mitogen-activated protein kinase (MyD88)-dependent nuclear factor-kappa B (NF-кB), mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/Akt (PI3K-Akt) signaling pathways in lipopolysaccharide (LPS)-induced U937 human macrophages.
METHODS: Standardization of the 80% ethanol extract of Z. zerumbet was performed by using a validated reversed-phase HPLC method, while LC-MS/MS was used to profile the secondary metabolites. The release of pro-inflammatory markers, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and prostaglandin E2 (PGE2) was evaluated by enzyme-linked immunosorbent assay (ELISA), while the Western blot technique was executed to elucidate the expression of mediators linked to MyD88-dependent respective signaling pathways. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was carried out to quantify the relative gene expression of cyclooxygenase (COX)-2 and pro-inflammatory mediators at the transcriptional level.
RESULTS: The quantitative and qualitative analyses of Z. zerumbet extract showed the presence of several compounds including the major chemical marker zerumbone. Z. zerumbet extract suppressed the release of pro-inflammatory mediators, COX-2 protein expression and downregulated the mRNA expression of pro-inflammatory markers. Z. zerumbet-treatment also blocked NF-κB activation by preventing the phosphorylation of IKKα/β and NF-κB (p65) as well as the phosphorylation and degradation of IκBα. Z. zerumbet extract concentration-dependently inhibited the phosphorylation of respective MAPKs (JNK, ERK, and p38) as well as Akt. Correspondingly, Z. zerumbet extract suppressed the upstream signaling adaptor molecules, TLR4 and MyD88 prerequisite for the NF-κB, MAPKs, and PI3K-Akt activation.
CONCLUSION: The findings suggest that Z. zerumbet has impressive role in suppressing inflammation and related immune disorders by inhibition of various pro-inflammatory markers through the imperative MyD88-dependent NF-κB, MAPKs, and PI3K-Akt activation.