Synthesis and Antitumor Activity of Panaxadiol Pyrazole and Isooxazole Derivatives

In this study, we designed and synthesized 19 nitrogen-containing heterocyclic derivatives of panaxadiol (PD). We first reported the antiproliferative activity of these compounds against four different tumor cells. The results of the MTT assay showed that the PD pyrazole derivative (compound 12b) had the best antitumor activity and could significantly inhibit the proliferation of four tested tumor cells. For A549 cells, the IC50 value was as low as 13.44±1.23 μM. Western blot analysis showed that the PD pyrazole derivative was a bifunctional regulator. On the one hand, it can down-regulate the expression of HIF-1α by acting on PI3 K/AKT signaling pathway in A549 cells. On the other hand, it can induce the decrease of CDKs protein family and E2F1 protein expression levels, thus playing a crucial role in cell cycle arrest. According to the results of molecular docking, we found that multiple hydrogen bonds were formed between the PD pyrazole derivative and two related proteins, and the docking score of the derivative was also significantly higher than that of the crude drug. In summary, the study of the PD pyrazole derivative laid a foundation for the development of ginsenoside as an antitumor agent.

Ginseng-derived panaxadiol ameliorates STZ-induced type 1 diabetes through inhibiting RORγ/IL-17A axis

Retinoic-acid-receptor-related orphan receptor γ (RORγ) is a major transcription factor for proinflammatory IL-17A production. Here, we revealed that the RORγ deficiency protects mice from STZ-induced Type 1 diabetes (T1D) through inhibiting IL-17A production, leading to improved pancreatic islet β cell function, thereby uncovering a potential novel therapeutic target for treating T1D. We further identified a novel RORγ inverse agonist, ginseng-derived panaxadiol, which selectively inhibits RORγ transcriptional activity with a distinct cofactor recruitment profile from known RORγ ligands. Structural and functional studies of receptor-ligand interactions reveal the molecular basis for a unique binding mode for panaxadiol in the RORγ ligand-binding pocket. Despite its inverse agonist activity, panaxadiol induced the C-terminal AF-2 helix of RORγ to adopt a canonical active conformation. Interestingly, panaxadiol ameliorates mice from STZ-induced T1D through inhibiting IL-17A production in a RORγ-dependent manner. This study demonstrates a novel regulatory function of RORγ with linkage of the IL-17A pathway in pancreatic β cells, and provides a valuable molecule for further investigating RORγ functions in treating T1D.

In Vivo Metabolites of Panaxadiol Inhibit HepG-2 Cell Proliferation by Inducing G1 Arrest and ROS-Mediated Apoptosis

In this study, 10 metabolites were obtained by collecting and extracting fecal samples after oral administration of panaxadiol (PD). Of these 10 metabolites, M7 (3β,21β,22α-hydroxy-24-norolean-12-ene), M8 (21β,22α-hydroxy-24-norolean-12-ene-3-one), M9 (3β,30α-hydroxy-24-norolean-22,30-epoxy-12-ene), and M10 (3β,21β-hydroxy-24-norolean-12-ene) were new compounds. MTT screening of the isolated compounds revealed that the inhibitions of cancer cells by M2, M4, M7, M8, and M10 were significantly stronger than that by the mother drug M0, with the activity of M2 being the most significant. Further, we investigated the anticancer mechanism of M2. The results showed that M2 significantly increased the level of ROS in cells; regulated the expressions of Bax, Bcl-2, and Cyt-C through the mitochondrial pathway; triggered the caspase cascade; and induced apoptosis. M2 could also induce G1 phase arrest and significantly regulate cell cycle-related proteins. In conclusion, the experimental results provide data for further study on the metabolic mechanism of PD in vivo and the potential of developing new anti-cancer drugs.

Design, Synthesis and Cytotoxicity Evaluation of Novel Indole Derivatives of Panaxadiol

Based on the well-known cytotoxicity of indole compounds, we used the 'Fisher indole synthesis' method to introduce appropriately substituted indole rings into panaxadiol (PD), generating eighteen novel Panaxadiol indole derivatives. Six human cancer cell lines (A549, HepG-2, HCT-116, SGC-7901, MDA-MB-231, PC-3 cells) and one normal ovarian cell lines (IOSE144) were designed to evaluate the anti-proliferative activity of the PD derivatives. The results showed that the majority of PD derivatives showed enhanced anti-proliferative activity, when compared with PD, with P-Methylindolo-PD exhibiting the highest cytotoxicity. In A549 cells, IC₅₀ value was 5.01±0.87 μM, which is roughly 12 times higher than the activity of PD and 5 times that of 5-FU. Moreover, cell morphology analysis and Annexin V-FITC/PI assays exhibited that P-Methylindolo-PD could induce A549 cell apoptosis (55.7 % of apoptotic cells at 20 μM). Moreover, molecular docking experiments were performed to explore the molecular mechanism underlining the binding of P-Methylindolo-PD to the active site of EGFR. The results support that P-Methylindolo-PD might be a promising lead compound for further studies.

Inhibition of JAK2/STAT3 signaling pathway by panaxadiol limits the progression of pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer-related death with the characteristics of chemoresistance and early metastasis. Panaxadiol, a triterpenoid saponin extracted from the roots of American ginseng, has been proved to display anti-tumor activity in colon cancer. In this study, we found panaxadiol significantly inhibited proliferation, and induced apoptosis in human pancreatic cancer cell lines PANC-1 and Patu8988 in a dose-dependent manner. Furthermore, the expression of apoptosis-related proteins (Bax, Bcl2, Cleaved-caspase3) was detected via western blot and immunofluorescence staining. In addition, panaxadiol was also found to inhibit the migration of pancreatic cancer cells by wound healing and transwell assays. In vivo, the growth of xenograft pancreatic cancer models was also notably suppressed by panaxadiol compared to the control group. Moreover, the down-regulation of JAK2-STAT3 signaling pathway was responsible for the underlying pro-apoptosis mechanism of panaxadiol, and this result was in good agreement with molecular docking analysis between panaxadiol and STAT3. In conclusion, our work comprehensively explored the anti-tumor ability in PANC-1 and Patu8988 cells of panaxadiol and provided a potential choice for the clinical treatment of pancreatic cancer patients.

Metabonomics Approach To Comparing the Antistress Effects of Four Panax ginseng Components in Rats

Different components of Panax ginseng have different properties and medicinal effects. Metabonomics was a prospective approach to analyze the global response of endogenous metabolites to physiological and pathological processes. In this study, an untargeted metabonomics method using GC/TOFMS combined with multivariate statistical techniques was applied to compare entire metabolite differences and the antistress variations among four components of P. ginseng, namely, total ginsenosides (TG), panaxadiol (PD), panaxatriol (PT), and ginseng polysaccharide (PS), in Wistar rats. The results of metabolite analysis showed that numerous urine metabolites involving neurotransmitters, amino acids, organic acids, and gut microbiota metabolites were changed after administration of the four components of P. ginseng, with TG having the least impact on urinary metabolites. The urinary metabolite profiling of these rats exposed to acute combined stress (forced swimming and behavior restriction) demonstrated that the four ginseng components attenuated urine metabolite changes involving gut microbiota metabolites, tricarboxylic acid (TCA) cycle and energy metabolites, and organic acids to different degrees, with TG improving most of the metabolites altered by stress.