Kadsura japonica fruits exert immunostimulatory and anti-obesity activity in RAW264.7 and 3T3-L1 cells

Chromatographic and Biological Screening of Chosen Species of Schisandraceae Family: Schisandra chinensis, S. rubriflora, S. sphenanthera, S. henryi and Kadsura japonica

HPLC and TLC profiling was carried out for leaf and fruit extracts of five Schisandraceae species: Schisandra chinensis, S. rubriflora, S. spehenanthera, S. henryi and Kadsura japonica. HPLC measurements confirmed presence of lignans and phenolic compounds in fruits and leaves of all tested species. The most abundant in lignans was S. chinensis fruit extract in which 15 compounds were detected (e. g.: schisandrol A, schisanhenol, γ-schisandrin, gomisin N). The effect-directed detection, i. e., TLC-direct bioautography against Bacillus subtilis, showed exceptionally high activity for S. chinensis and S. rubriflora fruit extracts. On the other hand, TLC-DB enzyme tests (α-glucosidase, lipase, tyrosinase and acetylcholinesterase (AChE) inhibition assays) showed that all fruit and leaf extracts have ability to inhibit the above-mentioned enzymes (except for the K. japonica fruit). The leaf extracts showed much stronger antioxidant activity than the fruit ones, which were assessed and compared using both TLC-direct bioautography and spectrophotometric measurements based on ABTS, DPPH and FRAP tests.

Effect of Ginseng Sapogenin Protopanaxadiol-Enriched Rice (DJ-PPD) on Immunomodulation

Protopanaxadiol (PPD), a gut microbiome-induced ginseng metabolite, has positive immune effects. We previously reported the immune-boosting and anti-inflammatory effects of PPD-enricshed rice seed extracts in normal and inflammatory cell environments, respectively. In the present study, the immunomodulatory activity of PPD-enriched transgenic rice seed extract (DJ-PPD), which exhibited the highest immune-related activity among all available extracts, was compared with that of commercially synthesized 20s-PPD (S-PPD) and natural ginseng root extract (GE), in RAW264.7 cells. Compared with S-PPD and GE treatment, DJ-PPD treatment (i) significantly promoted NF-κB p65 and c-Jun N-terminal protein kinase (JNK) phosphorylation; (ii) upregulated IL-1β, IL-6, COX-2, TLR-4, and TNF-α expression; (iii) and increased prostaglandin E₂ (PGE₂) production. However, there were no significant differences in the effects of the three treatments containing PPD-type sapogenin or saponins on nitric oxide (NO) production and phagocytic activity. In the inflammatory cell environment, DJ-PPD treatment markedly decreased the production of LPS-induced inflammatory factors, including NO and PGE₂, as well as proinflammatory cytokine expression, by decreasing phosphorylated (p-)NF-κB p65, p-p38 MAPK, and p-JNK levels. Thus, DJ-PPD that does not require complex intestinal microbial processes to exert higher anti-inflammatory effects compared with S-PPD and GE. However, DJ-PPD exerted similar or higher immune-boosting effects (depending on inflammatory biomarkers) than S-PPD and GE. These findings indicate the potential of PPD-enriched transgenic rice as an alternative immunomodulatory agent.

Identification of TLR2/4-mediated phagocytosis and immune response activation pathways by vacuoles isolated from Saccharomyces cerevisiae

The vacuoles of the yeast Saccharomyces cerevisiae are closely related to mammalian lysosomes and play a role in macromolecular degradation due to the hydrolytic enzymes present inside. The vacuoles also regulate osmotic pressure and control cellular homeostasis. In previous results, vacuoles were shown to activate the immune response of macrophages by promoting the production of immune-mediated transporters nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory cytokines. In this study, the effects of vacuoles on the phagocytosis activity of RAW264.7 cells and their potential as immune enhancers were evaluated, and receptors capable of recognizing vacuoles were examined. An investigation using the phagocytes assay showed that phagocytosis activity increased by the vacuole. Besides, after treatment with TLR2/4 inhibitor, the expression of pro-inflammatory cytokines by vacuoles was significantly reduced and the inducible nitric oxide synthase (iNOS) protein was also significantly reduced. However, treatment with a TLR2 inhibitor did not reduce the production of interleukin-6 (IL)-6, a pro-inflammatory cytokine. As a result of confirming the activation of TLR2/4 using Western blot and immunofluorescence (IF), the TLR2/4 protein expression and fluorescence intensity increased depending on the concentration of vacuoles. Yeast vacuoles significantly upregulate protein expression of p-p65/p-p38 MAPKs. In summary, the vacuoles isolated from S. cerevisiae in macrophages have increased phagocytic ability at a concentration of 20 (µg/ml) and can function as immune-enhancing agent suggesting that TLR2/4 mediated the p38 MAPK/nuclear factor kappa B signaling pathway.

Transgenic Rice Seed Extracts Exert Immunomodulatory Effects by Modulating Immune-Related Biomarkers in RAW264.7 Macrophage Cells

Protopanaxadiol (PPD), a native active triterpenoid present in Panax ginseng, has been reported to exert immune-related effects. We previously created PPD-producing transgenic rice by introducing the P. ginseng protopanaxadiol synthase and dammarenediol-II synthase genes into Dongjin rice. In the present study, the seeds of the T₄ generation of this transgenic rice were tested for their immunomodulatory effects in RAW264.7 macrophage cells. Treatment with transgenic rice seed extract in RAW264.7 cells (i) significantly enhanced nitric oxide (NO) production in a dose-dependent manner without any cytotoxicity (up to 100 µg/mL), (ii) upregulated the expression of immune-related genes and increased production of the inflammation mediator prostaglandin E₂ (PGE₂), and (iii) activated nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) by promoting the phosphorylation of NF-κB p65, p38 MAPK, and c-Jun N-terminal protein kinase (JNK). In lipopolysaccharide (LPS)-treated RAW264.7 cells used to mimic the inflammation condition, treatment with transgenic rice seed extract significantly reduced NO production, proinflammatory cytokine expression, and PGE₂ production, all of which are LPS-induced inflammation biomarkers, by inhibiting the phosphorylation of NF-κB p65, p38 MAPK, and JNK. Collectively, these results indicate that PPD-producing transgenic rice has immunomodulatory effects.