Anti-inflammatory agents that are safer and more effective than the currently used non-steroidal anti-inflammatory drugs are urgently needed. The dicaffeoylquinic acid (diCQA) isomer 4,5-diCQA exhibits antioxidant activity and various other health-promoting benefits; however, its anti-inflammatory properties require further investigation. This study was conducted to evaluate the anti-inflammatory properties of 4,5-diCQA in vitro and in vivo using RAW264.7 cells and a carrageenan-induced inflammation model, respectively. In RAW264.7 cells, 4,5-diCQA pretreatment significantly inhibited lipopolysaccharide-induced expression of nitric oxide, prostaglandin E₂, nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α, interleukin-1β, and interleukin-6, without inducing cytotoxicity. The inhibitory effects of 4,5-diCQA were mediated by the suppression of nuclear factor-κB nuclear translocation and mitogen-activated protein kinase (MAPK) phosphorylation. Oral administration of 4,5-diCQA at doses of 5, 10, and 20 mg/kg of the body weight suppressed carrageenan-induced edema and the expression of nitric oxide synthase, cyclooxygenase-2, and tumor necrosis factor-α in a dose-dependent manner. Collectively, our results suggest that 4,5-diCQA exerts anti-inflammatory effects by suppressing activation of the nuclear factor-κB and MAPK pathways in vitro and reducing carrageenan-induced edema in vivo. Therefore, 4,5-diCQA shows potential as a natural alternative to non-steroidal anti-inflammatory drugs.

Osteoarthritis (OA) is characterized by cartilage degradation, inflammation, and pain. The dicaffeoylquinic acid (diCQA) isomer, 4,5-diCQA, exhibits antioxidant activity and various other health-promoting benefits, but its chondroprotective effects have yet to be elucidated. In this study, we aimed to investigate the chondroprotective effects of 4,5-diCQA on OA both in vitro and in vivo. Primary rat chondrocytes were pre-treated with 4,5-diCQA for 1 h before stimulation with interleukin (IL)-1β (5 ng/mL). The accumulation of nitrite, PGE₂, and aggrecan was observed using the Griess reagent and ELISA. The protein levels of iNOS, COX-2, MMP-3, MMP-13, ADMATS-4, MAPKs, and the NF-κB p65 subunit were measured by Western blotting. In vivo, the effects of 4,5-diCQA were evaluated for 2 weeks in a destabilization of the medial meniscus (DMM)-surgery-induced OA rat model. 4,5-diCQA significantly inhibited IL-1β-induced expression of nitrite, iNOS, PGE₂, COX-2, MMP-3, MMP-13, and ADAMTS-4. 4,5-diCQA also decreased the IL-1β-induced degradation of aggrecan. It also suppressed the IL-1β-induced phosphorylation of MAPKs and translocation of the NF-κB p65 subunit to the nucleus. These findings indicate that 4,5-diCQA inhibits DMM-surgery-induced cartilage destruction and proteoglycan loss in vivo. 4,5-diCQA may be a potential therapeutic agent for the alleviation of OA progression. In this study, diclofenac was set to be administered once every two days, but it showed an effect on OA. These results may be used as basic data to suggest a new dosing method for diclofenac.

Seul Ah Lee, Seul Hee Han, Ji Yun Jang, Bo-Ram Park, and Chun Sung Kim. Prev Nutr Food Sci 2023;28:43-9. https://doi.org/10.3746/pnf.2023.28.1.43

Osteoarthritis (OA), caused by the long-term use of joints, is a representative degenerative disease in the elderly. However, recently, the age of onset has been decreasing owing to excessive activities among young people in their 20s and 30s. Gynostemma pentaphyllum (Thunb.) Makino (GP), a perennial herb of the Cucurbitaceae family, has been used since the Ming dynasty as a medicinal material to treat various ailments, such as rheumatism, liver disease, and diabetes. In this study, we investigated the anti-arthritic effects of heat-processed Gynostemma pentaphyllum extract (Actiponin (AP)) and its derivatives, damulin A (DA) and damulin B (DB), using in vitro (primary rat chondrocytes and SW1353 cells) and in vivo (destabilization of the medial meniscus (DMM)-induced OA model) systems. Histological analysis results from the in vivo study showed that the group that underwent DMM surgery induced degeneration by the loss of proteoglycan and the destruction of cartilage (OARSI score 14 ± 0.57), whereas the group that received AP daily for 8 weeks maintained an intact condition (OARSI score 5 ± 0.28 at 200 mg/kg, p < 0.001). In addition, cartilage thickness and chondrocytes were reduced in the DMM group, but were restored in the AP-administered group. Furthermore, the von Frey analysis results showed that the pain threshold of the DMM group was considerably low (54.5 g at 8 weeks), whereas that of the AP group was dose-dependently increased (65.5, 69.5, 70.3, and 71.8 at 8 weeks for 30, 50, 100, and 200 mg/kg, respectively). In vitro studies showed that AP, DA, and DB reduced the expression of interleukin-1β alone-induced nitrite; inducible nitric oxide synthase; cyclooxygenase-2; matrix metallopeptidase 1/3/13; and a disintegrin and metalloproteinase with thrombospondin motifs 4/5. They also restored the expression of collagen type II and aggrecan, which are components of the extracellular matrix. The anti-arthritic effects of AP, DA, and DB were confirmed to be mediated by the mitogen-activated protein kinase and nuclear factor kappa-light-chain-enhancer of activated B cell signaling pathways. Collectively, these results suggest that AP is a potential therapeutic agent for mitigating OA progression and chondroprotection.

Campylaephora hypnaeoides (C. hypnaeoides) was extracted using fermented ethanol. The effect of fermented ethanol extract of C. hypnaeoides (FeCH) on chondrocyte viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-iphenyltetrazolium bromide assay, which showed no cytotoxicity at 2 mg/mL. FeCH pretreatment in IL-1β-stimulated chondrocytes significantly inhibited the accumulation of nitric oxide and prostaglandin E₂, which was analyzed using the ELISA assay. In addition, protein expression levels of inflammatory-related factors, such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6, tumor necrosis factor-alpha, and cartilage-degrading-related enzymes, such as matrix metalloproteinases-1, -3, and -13, and a disintegrin and metalloproteinase with thrombospondin motifs-4 and -5 were significantly decreased in IL-1β-stimulated chondrocytes pretreated with FeCH, which were analyzed using western blot analysis. In addition, as a result of analyzing the content of collagen type II (Col II) and proteoglycan through western blot analysis and alcian blue staining, FeCH pretreatment prevented the degradation of Col II and proteoglycan. It was analyzed through western blot analysis that the chondroprotective effect of FeCH may be mediated through MAPKs and NF-κB-signaling mechanisms. In an in vivo study, an osteoarthritis experimental animal model with damaged medial meniscus (DMM) was utilized and orally administered daily for 8 weeks after surgery. At the study end point, knee joints were harvested and subjected to histological analysis with safranin O staining. As a result, articular cartilage was significantly protected in the FeCH group compared to the DMM group. These results suggest FeCH as a candidate material for the development of pharmaceutical materials for the treatment or prevention of degenerative arthritis.