Therapeutic effects of total saikosaponins from Radix bupleuri against Alzheimer’s disease

Investigating the Therapeutic Mechanisms of Total Saikosaponins in Alzheimer's Disease: A Metabolomic and Proteomic Approach

Alzheimer's disease (AD) is the leading cause of dementia among the elderly, yet effective treatments remain elusive. Total saikosaponins (TSS), the primary bioactive components in Bupleurum chinense, have shown promising therapeutic effects against AD in previous studies. Methods: To delve deeper into the mechanisms underlying the therapeutic role of TSS in AD, we investigated its neuroprotective effects and associated molecular mechanisms in APP/PS1 mice. Further, we employed metabolomic and proteomic analyses, with a focus on the potential protein-level changes induced by TSS, particularly those related to metabolite accumulation in the brain. Results: Our results showed that lysophosphatidylcholine, adenosine, and sphingomyelin in plasma might serve as potential biomarkers. Compared to the control group, AD mice exhibited significantly increased expression of proteins related to neuroinflammatory pathways, whereas proteins involved in cAMP signaling, cGMP-PKG signaling, and synaptic plasticity pathways were significantly downregulated. Notably, these signaling pathways were partially reversed in APP/PS1 mice following TSS administration. Behavioral tests demonstrated that TSS effectively improved the learning and memory functions of mice. Conclusions: Our findings suggest that TSS ameliorate cognitive decline through regulating neuroinflammatory pathways, cAMP and cGMP signaling, and synaptic plasticity pathways, providing insights into its therapeutic potential in AD.

Effects of total saikosaponins on CYP3A4 and CYP1A2 in HepaRG cells

Total saikosaponins (TSS) form a group of chemically and biologically active components that can be extracted from Bupleurum, with reported antidepressive, anti-inflammatory, antiviral, antiendotoxin, antitumor, anti-pulmonary fibrosis and anti-gastric ulcer effects. Bupleurum or TSS is frequently utilized in clinical practice alongside other medications (such as entecavir, lamivudine, compound paracetamol and amantadine hydrochloride capsules), leading to an increased risk of drug-drug interactions. The cytochrome P450 (CYP) family serves a critical role in the metabolism of numerous essential drugs (such as tamoxifen, ibuprofen and phenytoin), where the majority of drug interactions involve CYP-mediated metabolism. It is therefore essential to understand the effects of key components of Bupleurum on CYPs when administering combination therapies containing TSS or Bupleurum. The present study aimed to investigate the effects of TSS on the mRNA and protein expression of CYP3A4 and CYP1A2 in HepaRG cells. The effects of TSS on the survival of HepaRG cells was investigated using the Cell Counting Kit-8 (CCK-8) method. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) analysis were used to assess the effects of different concentrations of TSS (0, 5, 10 and 15 µg/ml) on CYP3A4 and CYP1A2 mRNA and protein expression in HepaRG cells. Based on the CCK-8 assay results, it was observed that the cell viability remained above 80% when treated with 1, 5, 10 and 15 µg/ml TSS. Although there was a statistically significant reduced cell viability at TSS concentrations of 10 and 15 µg/ml compared with the control group, the findings indicated that TSS did not exhibit notable cytotoxic effects at these concentrations. Furthermore, RT-qPCR results revealed that compared with those in the control group, TSS at concentrations of 10 and 15 µg/ml reduced CYP3A4 mRNA expression but increased CYP1A2 mRNA expression in HepaRG cells at concentrations of 15 µg/ml. WB analysis found that TSS at concentrations of 10 and 15 µg/ml downregulated CYP3A4 protein expression in HepaRG cells while increasing CYP1A2 protein expression at concentrations of 15 µg/ml. Results in the present study suggest that TSS can inhibit CYP3A4 mRNA and protein expression, but exerts opposite effects on their CYP1A2 counterparts. These findings suggest that it is necessary to consider drug interactions between clinical preparations containing TSS or Bupleurum and drugs metabolized by CYP3A4 and CYP1A2 to avoid potential adverse drug reactions in clinical practice.