Bioactive-Rich Piper sarmentosum Aqueous Extract Mitigates Osteoarthritic Pathology by Enhancing Anabolic Activity and Attenuating NO-Driven Catabolism in Human Chondrocytes.

Background: Osteoarthritis (OA) is a prevalent degenerative joint disease often causing functional disability. Current therapies provide only temporary relief and can cause adverse effects that frequently result in pain and disability. Current pharmacological options offer only temporary symptom relief and may cause adverse effects. Piper sarmentosum (PS), a plant traditionally used for its medicinal properties, has demonstrated antioxidant and anti-inflammatory activities that may counteract OA-related degeneration. This study provides preliminary insight into the therapeutic potential of PS aqueous extract in human OA chondrocytes. Methods: Compounds in the PS aqueous extract were profiled using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Primary human OA chondrocytes (HOCs) were treated with 0.5, 2, and 4 µg/mL of PS aqueous extract for 72 h. Key OA-related parameters were assessed, including anabolic markers (sulfated glycosaminoglycan (sGAG), collagen type II (COL II), aggrecan core protein (ACP), SRY-box transcription factor 9 (SOX9)), catabolic markers (matrix metalloproteinase (MMP) 1, MMP13, cyclooxygenase 2 (COX2)), oxidative stress (nitric oxide (NO) production, inducible NO synthase (iNOS) expression), and inflammatory responses (interleukin (IL) 6). Gene expression was quantified using qPCR, and protein levels were evaluated using the colorimetric method, immunocytochemistry, and Western blot. Results: A total of 101 compounds were identified in the extract, including vitexin, pterostilbene, and glutathione-bioactives known for antioxidant, anti-inflammatory, and chondroprotective functions. PS-treated chondrocytes maintain healthy polygonal morphology. PS aqueous extract significantly enhanced anabolic gene expression (COL2A1, ACP, SOX9) and sGAG production, while concurrently suppressing COX2 expression and NO synthesis. Additionally, PS aqueous extract reduced COX2 and iNOS protein levels, indicating inhibition of the NO signaling pathway. Catabolic activity was attenuated, and inflammatory responses were partially reduced. Conclusions: PS aqueous extract exhibits promising chondroprotective, antioxidant, and anti-inflammatory effects in human OA chondrocytes, largely through the suppression of NO-mediated catabolic signaling. The presence of multiple bioactive compounds supports its mechanistic potential. These findings highlight PS aqueous extract as a potential therapeutic candidate for OA management. Further ex vivo and in vivo studies are warranted to validate its efficacy and clarify its mechanism in joint-tissue environments.