Young-Min Han

Young-Min Han, Hye-Rin Ahn, Da-Young Lee, Moon-Young Song, Seung-Won Lee, You-Kyung Jang, Byeong Yeob Jeon, Eun-Hee Kim. J Cancer Prev 2024;29:165-74. https://doi.org/10.15430/JCP.24.029

Globally, the edible insect industry is emerging due to its potential contributions to food security and environmental sustainability. Edible insects are rapidly being integrated into the development of alternative foods and new pharmaceuticals. Silkworms, known for their high protein content, are not only a potential new source of human food and animal feed but have also been traditionally used for medicinal purposes. However, conventional silkworms are difficult to ingest. To address this, we have developed a steamed and freeze-dried mature silkworm larva powder (SMSP), and it is essential to investigate its potential toxicity and food safety for further studies and applications. Therefore, this study aimed to evaluate the toxicity of SMSP. A toxicity assessment of SMSP was conducted according to OECD guidelines. An oral repeat-administration study was performed on male and female SD rats at doses of 625, 1250, and 2500 mg/kg/day for 4 and 13 weeks. No toxicological changes were observed in clinical signs, body weight, water and food intake, urine tests, hematology, clinical biochemistry, gross findings, or histopathological examination. In conclusion, the no observed adverse effect level (NOAEL) of SMSP was 2500 mg/kg/day, with no target organs identified in either sex of the rats. These results suggest that SMSP is safe, is without side effects and has potential for use as an edible ingredient and in health functional food applications.

Cinnamomum cassia (cassia) is a tropical aromatic evergreen tree of the Lauraceae family well known for its fragrance and spicy flavor and widely used in Asian traditional medicine. It has recently garnered attention for its diverse potential health benefits, including anti-inflammatory, anti-cancer, and anti-diabetic properties. However, the gastroprotective effect of C. cassia, particularly against ethanol-induced gastric damage, remains unclear. We investigated the potential gastroprotective property of C. cassia and the underlying mechanisms of action in a rat model of ethanol-induced gastric injury. To assess its effectiveness, rats were fed C. cassia for a 14-day period prior to inducing gastric damage by oral administration of ethanol. Our results indicated that pre-treatment with C. cassia mitigated ethanol-induced gastric mucosal lesions and bleeding. Reduced gastric acid secretion and expression of acid secretion-linked receptors were also observed. Additionally, pretreatment with C. cassia led to decreased levels of inflammatory factors, including TNF-α, p-p65, and IκBα. Notably, C. cassia upregulated the expressions of HO1 and HSP90, with particular emphasis on the enhanced expression of PAS and MUC, the crucial gastric mucosa defense molecules. These findings suggest that C. cassia has protective effects on the gastric mucosa and can effectively reduce oxidative stress and inflammation.

Gastric mucosa is important to protect the gastric damage against external factors. We previously reported the gastro-protective effects of steamed and freeze-dried mature silkworm larval powder (SMSP) in ethanol-treated rats. However, the factors that promote mucosal formation still remain unclarified. In this study, we evaluated the effect of SMSP on the restoration and maintenance of gastric mucosal layer as well as anti-inflammatory response in ethanol-induced stomach injury in rats. A significant decrease of ulcer indexes, histopathological scores and pro-inflammatory cytokine levels was observed in SMSP-treated group. In addition, SMSP protected the mucosal layer from ethanol-induced gastric damage by increasing the expression of nitric oxide synthases and heat shock proteins, along with promoting genes related gastric mucosal protection and biosynthesis including mucin 5AC and trefoil factors. These results demonstrate that SMSP attenuates the pro-inflammatory responses and strengthens the gastric mucosal layer, thus exhibiting gastro-protective effect against ethanol-induced gastric injury in rats.

Fibrosis has various biological processes and affects almost every organ, especially in patients with inflammatory bowel disease, including Crohn’s disease, who experience discomfort caused by intestinal fibrosis, which is a problem that needs to be resolved. TGF-β signaling is known to act as a key regulator of intestinal fibrosis, and its modulation could be an excellent candidate for fibrosis therapy. Xanthohumol (XN) has various effects, including anti-inflammation and anti-cancer; however, the detailed mechanism of TGF-β signaling has not yet been studied. The purpose of this study was to investigate the mechanism underlying the anti-fibrotic effect of XN on TGF-β1-induced intestinal fibrosis using primary human intestinal fibroblasts (HIFs). In this study, to check the anti-fibrotic effects of XN on intestinal fibrosis, we assessed the expression of fibrosis-related genes in TGF-β1-stimulated HIFs by qPCR, immunoblotting, and immunofluorescence staining. As a result, XN showed the ability to reduce the expression of fibrosis-associated genes increased by TGF-β1 treatment in HIFs and restored the cell shape altered by TGF-β1. In particular, XN repressed both NF-κB- and Smad-binding regions in the α-SMA promoter, which is important in fibrosis. In addition, XN inhibited NF-κB signaling, including phosphorylated-IkBα and cyclooxygenase-2 expression, and TNF-α-stimulated transcriptional activity of NF-κB. XN attenuated TGF-β1-induced phosphorylation of Smad2 and Smad3, and the transcriptional activity of CAGA. Particularly, XN interfered with the binding of TGF-Receptor I (TβRI) and Smad3 by binding to the kinase domain of the L45 loop of TβRI, thereby confirming that the fibrosis mechanism did not proceed further. In conclusion, XN has an inhibitory effect on TGF-β1-induced intestinal fibrosis in HIFs, significantly affecting TGF-β/Smad signaling.

Propolis, a natural resinous substance obtained from a variety of buds and plants, has been reported to possess various biological functions. Several recent studies have demonstrated the inhibitory effects of propolis on the growth of Helicobacter pylori (H. pylori) in vitro; however, current research efforts on Korean propolis (KP) remain insufficient especially in vivo. Our study aims to investigate the anti-inflammatory effect and molecular mechanism of KP on mouse gastric mucosa during H. pylori infection. We examined an in vivo H. pylori-induced gastric mucosal injury mice model. We found that KP inhibited the growth of H. pylori and attenuated the expression of H. pylori virulence factors such as cytotoxin-associated gene A, encoding urease A subunit, surface antigen gene and neutrophil-activating protein A. Moreover, KP reduced both gross lesions and pathological scores in H. pylori-challenged mice. In addition, KP markedly restrained the production of pro-inflammatory cytokines and nitric oxide levels compared with an untreated H. pylori-infected group. In particular, we found that KP repressed the phosphorylation of IκBα and NF-κB p65 subunit, and subsequently suppressed their downstream target genes. Taken together, these findings demonstrate the beneficial effects of KP on inflammation through the inhibition of NF-κB signaling as well as inhibition of H. pylori growth in a mouse model infected with H. pylori. This suggests the potential application of KP as a natural supplement for patient’s suffering from gastric mucosal injury caused by H. pylori infection.

Background: Proton pump is an integral membrane protein that is ubiquitous ATP binding cassette (ABC) involved in many transport processes in all living organisms, among which a specialized form of pump, so called p-type proton pump, exists in the parietal cells of stomach. Though proton pump inhibitors (PPIs) are frequently prescribed to prevent nonsteroidal anti-inflammatory drugs (NSAIDs)-induced gastric damage, the acid suppressive actions do not suffice to explain. Methods: In order to document the effects of pantoprazole, one of PPIs, on the NSAIDs-induced gastric damage, in vitro and in vivo studies were performed. Immunocytochemistry, Western blot analysis, electrophoretic mobility shift assay and RT-PCR were conducted to evaluate the induction of heme oxygenase-1 (HO-1) through Nrf2 activation in normal gastric mucosal RGM-1 cells or in vivo stomach tissues from rats treated with indomethacin and/or pantoprazole. Results: Pantoprazole activated Nrf2 through inactivation of Keap1, after which the expression of HO-1 was significantly increased in a dose-dependent manner in RGM-1 cells. Increased ARE-DNA binding activity was observed maximally at 1 h with 300 μM of pantoprazole. The expression of HO-1 induced by pantoprazole was significantly associated with the increased in vitro tube formation (P < 0.05) and angiogenic factors including VEGF, bFGF, and HIF-1α. Indomethacin markedly increased the expressions of TNF-α, IL-1ß, IL-8, NOX-1, ICAM-1 and VCAM, whereas pantoprazole significantly decreased the expressions of indomethacin-induced these inflammatory mediators in accord with pantoprazole-induced HO-1 (P < 0.05) as documented with HO-1 inhibitor. In vivo model of indomethacin-induced gastric damage could validate in vitro-drawn results that pantoprazole remarkably protected against indomethacin-induced gastric damage, in which zinc protoporphyrin (5 mg/kg, ip) significantly abolished the protective efficacy of pantoprazole. Conclusion: These results demonstrate that Nrf2-mediated HO-1 induction of PPIs afforded a significant protective effect against NSAIDs-induced gastric damage beyond acid suppressive actions.