Resveratrol and piceid enhance efferocytosis by increasing the secretion of MFG-E8 in human THP-1 macrophages.

The process of apoptotic cell clearance by phagocytes, known as efferocytosis, plays an essential role in maintaining homeostasis. Defects in efferocytosis can lead to inflammatory diseases such as atherosclerosis and autoimmune disorders. Therefore, the maintenance and promotion of efferocytosis are considered crucial for preventing these diseases. In this study, we observed that resveratrol, a representative functional food ingredient, and its glycoside, piceid, promoted efferocytosis in both human THP-1 macrophages differentiated with phorbol 12-myristate 13-acetate and peritoneal macrophages from thioglycolate-elicited mice. Resveratrol and piceid significantly increased mRNA expression and protein secretion of MFG-E8 in THP-1 macrophages. Furthermore, the activation of efferocytosis and the increment in MFG-E8 protein secretion caused by resveratrol or piceid treatment were canceled by MFG-E8 knockdown in THP-1 macrophages. In conclusion, we have demonstrated for the first time that resveratrol and piceid promote efferocytosis through the upregulation of MFG-E8 excretion in human THP-1 macrophages.

Inhibitory effects of cyanidin-3-O-glucoside in black soybean hull extract on RBL-2H3 cells degranulation and passive cutaneous anaphylaxis reaction in mice.

Black soybean hull extract (BSHE) exhibits a variety of biological activities. However, little is known about the effects of BSHE on immunoglobulin E (IgE)-mediated type I allergic reactions. The anti-allergic effect of BSHE was assessed with the degranulation assay using rat basophilic leukemia RBL-2H3 cells and the passive cutaneous anaphylaxis (PCA) reaction in mice. An active compound in BSHE was identified by ultra-performance liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry analysis. BSHE inhibited the release of ß-hexosaminidase and histamine in RBL-2H3 cells, and cyanidin-3-O-glucoside (C3G) was identified as one of its active compounds. Oral administering of 200 µmol/kg of C3G to IgE-sensitized mice prior to antigen injection suppressed the PCA reaction, as compared with control (p < 0.01). Intravenous administration of BSHE (C3G content, 5.4%) more strongly inhibited PCA responses at lower doses (100 mg/kg, p < 0.01) than oral administration (1,000 mg/kg, p = 0.059). Intravenous C3G also suppressed PCA response at a low dose (40 mg/kg, p < 0.05), showing the same trend as BSHE. This information can be useful to design appropriate formulations of anthocyanin-based drug products to suppress allergic reactions. This study provides evidence for the potential use of BSHE and C3G for the prevention or the treatment of type I allergies.

Antioxidant compounds of Petasites japonicus and their preventive effects in chronic diseases: a review.

Petasites japonicus (P. japonicus) is a plant of the Asteraceae family. Its roots and stems have been used for the treatment or the prophylaxis of migraine and tension headache as a traditional Chinese medicine in Japan and Korea. Sesquiterpenoids, lignans, and flavonoids are components of P. japonicus. Regarding the biological activity of P. japonicus, its anti-allergic effect has been researched extensively using IgE antigen-stimulated degranulation of RBL-2H3 cells or passive cutaneous anaphylaxis reaction in experimental animal models. The study of the antioxidant activity of P. japonicus was initiated approximately 15 years ago using in vitro assays. In addition, its in vivo effect has also been examined in animal models with induced oxidative injury. Moreover, recently, many types of antioxidant compounds have been rapidly and simultaneously identified using the liquid chromatography-mass spectrometry technique. The number of reports on the other functions of this plant, such as its neuroprotective and anti-inflammatory effects, has been increasing. In this review, I summarized the studies of functional foods derived from P. japonicus, which may provide a basis for the development of potential functional foods. Finally, I discuss the future research avenues in this field.

In vitro and in vivo evaluation of antioxidant activity of Petasites japonicus Maxim. flower buds extracts.

The antioxidant activity of Petasites japonicus flower buds cultivated in Tokushima, Japan, was examined in vitro and in vivo. The flower bud extracts were assayed using either oxygen radical absorbance capacity or 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Antioxidants in the 80% ethanol extract were investigated using online high-performance liquid chromatography-DPPH and were identified as caffeic acid, 3-O-caffeoylquinic acid, fukinolic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid using liquid chromatography-mass spectrometry. Fukinolic acid was the most active compound based on its activity and abundance. Administering the extracts orally to ICR mice prior to iron injection significantly suppressed plasma thiobarbituric acid reactive substance (TBARS) production. Moreover, TBARS and triglyceride concentrations in the plasma of C57BL/6 mice fed with a high fat diet were also significantly decreased by the extract. The results suggest that antioxidative compounds in P. japonicus can be used in the management of oxidative stress.

Cloning of a cDNA encoding the Gly m Bd 28K precursor and its vacuole transport in tobacco BY2 suspension-cultured cells.

Gly m Bd 28K (Gm28K), a soybean allergen, is formed as a preproprotein consisting of a predicted signal peptide, Gm28K, and the 23-kDa peptide (Gm23K). Gm28K and Gm23K are found in the protein-storage vacuoles (PSVs) of developing soybean seeds. However, the complete structure of Gm28K has not yet been identified and its processing and transport to the vacuoles has never been clarified. In the present study, we elucidated the 5'-nucleotide sequence of cDNA encoding the Gm28K precursor and identified a putative signal peptide (SP) with 24 N-terminal amino acid residues. We expressed peptides from the Gm28K precursor as fusion proteins with enhanced green fluorescent protein (EGFP) in tobacco BY2 suspension-cultured cells. BY2 cells transformed by an expression vector for SP-EGFP-Gm28-Gm23K (SP-EGFP-Gm28-Gm23K/BY2 cells) and SP-Gm28-Gm23K-EGFP/BY2 cells produced the EGFP fused-Gm28K precursor, and the EGFP-fluorescence in their vacuoles were recorded. In the experiments with SP-EGFP/BY2 and SP-EGFP-Gm28K/BY2 cells, large amounts of the EGFP segments were secreted into the medium. On the other hand, the fluorescence of EGFP in SP-EGFP-Gm23K/BY2 cells was shown to accumulate only in the endoplasmic reticulum without secretion into the medium. These findings show that the SP signals the precursor to enter the lumen of the endoplasmic reticulum and that both the Gm28K and Gm23K components may be involved in the transport from the endoplasmic reticulum (ER) lumen via the Golgi to the vacuoles in a proprotein form.