Osteoarthritis (OA), a common degenerative joint disease, is characterized by the progressive degradation of articular cartilage and inflammation. Hederagenin (HE) is a pentacyclic triterpenoid saponin extracted from many herb plants. It has anti-inflammatory, anti-lipid peroxidative, anti-cancer, and neuroprotective activities. However, its effect on OA has not been investigated. Our study found that HE may be a potential anti-OA drug. In vitro, HE could suppress extracellular matrix (ECM) degradation via up-regulating aggrecan and Collagen II levels as well as downregulating MMPs and ADAMTS5 levels. It could also reduce proinflammatory and inflammatory cytokines or enzymes production, including TNF-α, IL-6, iNOS, COX-2, NO, and PGE2. Besides, HE markedly reduced IL-1β-induced C28/I2 cell apoptosis and ROS accumulation. Mechanistically, HE exerted chondroprotective and anti-inflammatory effects by partly inhibiting JAK2/STAT3/MAPK signalling pathway and the crosstalk of the two pathways. Also, HE exhibited anti-apoptotic and anti-oxidative effect via targeting Keap1-Nrf2/HO-1/ROS/Bax/Bcl-2 axis. In vivo, HE significantly reduced monosodium iodoacetate (MIA) induced cartilage destruction of rats with a lower OARSI score and inflammatory cytokine levels, further demonstrating its protective effects in OA progression. These results suggest that HE is a potential compound for the development of drugs to treat OA.

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated for simultaneous quantification of oleanolic acid and hederagenin in rat plasma. After the two analytes were extracted with liquid-liquid extraction, chromatographic separation was performed on a C18 column with acetonitrile and water (85:15, v/v) as mobile phase at a flow rate of 0.4 mL/min. Calibration curves exhibited good linearity (r > 0.995) over the ranges of 0.41-82.0 ng/mL for oleanolic acid and 0.32-64.0 ng/mL for hederagenin, respectively. The lower limit of quantifications (LLOQs) in plasma were 0.41 ng/mL for oleanolic acid and 0.32 ng/mL for hederagenin. The established LLOQs were within the concentration needed for the assay in plasma, which met the requirements to evaluate their pharmacokinetics of oleanolic acid and hederagenin. This developed assay was successfully applied in the pharmacokinetic study of oleanolic acid and hederagenin in rats after oral administration of Rhizoma Clematidis extract.

Two high-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) mass spectrometry methods were developed and validated for the simultaneous determination of asperosaponin VI (A-VI) and hederagenin (HG) in rats\' various tissues. Biological samples were processed with methanol extraction, and glycyrrhetinic acid was chosen as the internal standard (IS). The analytes were separated on a C18 column with two gradient elution programs for different rat tissue samples. The MS/MS detection was carried out by monitoring the transitions of m/z [MH](-) 927.5→603.4 for A-VI, m/z [MH](-) 471.3→471.3 for HG and m/z [MH](-) 469.4→425.4 for the IS, respectively. The lower limits of quantification (LLOQ) for the two analytes in different rat tissues were 2-6ng/mL, respectively. The methods were successfully applied to a tissue distribution study of A-VI and its active metabolite HG in rats. The results of the tissue distribution study showed that the highest concentration of A-VI was in the gastrointestinal (GI) tract. Besides, A-VI was mainly distributed in lung, liver, fat and ovary. HG was almost undetectable in most tissues except for the GI tract.