Neuroprotective Effects of Water Extract from Brown Algae Petalonia binghamiae in an Experimental Model of Focal Cerebral Ischemia In Vitro and In Vivo.

Focal cerebral ischemia (fCI) can result in brain injury and sensorimotor deficits. Brown algae are currently garnering scientific attention as potential therapeutic candidates for fCI. This study investigated the therapeutic effects of the hot water extract of Petalonia binghamiae (wPB), a brown alga, in in vitro and in vivo models of fCI. The neuroprotective efficacy of wPB was evaluated in an in vitro excitotoxicity model established using HT-22 cells challenged with glutamate. Afterward, C57/BL6 mice were administered wPB for 7 days (10 or 100 mg/kg, intragastric) and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) operation, which was used as an in vivo fCI model. wPB co-incubation significantly inhibited cell death, oxidative stress, and apoptosis, as well as stimulated the expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, and the nuclear translocation of its upstream regulator, nuclear factor erythroid 2-related factor 2 (Nrf2) in HT-22 cells challenged with glutamate-induced excitotoxicity. Pretreatment with either dose of wPB significantly attenuated infarction volume, neuronal death, and sensorimotor deficits in an in vivo fCI model. Furthermore, the attenuation of oxidative stress and apoptosis in the ischemic lesion accompanied the wPB-associated protection. This study suggests that wPB can counteract fCI via an antioxidative effect, upregulating the Nrf2/HO-1 pathway.

Rubus fruticosus leaf extract inhibits vascular dementia-induced memory impairment and neuronal loss by attenuating neuroinflammation.

Vascular dementia (VaD) is characterized by progressive memory impairment, which is associated with microglia-mediated neuroinflammation. Polyphenol-rich natural plants, which possess anti-inflammatory activities, have attracted scientific interest worldwide. This study investigated whether Rubus fruticosus leaf extract (RFLE) can attenuate VaD. Sprague-Dawley rats were separated into five groups: SO, sham-operated and treated with vehicle; OP, operated and treated with vehicle; RFLE-L, operated and treated with low dose (30 mg/kg) of RFLE; RFLE-M, operated and treated with medium dose (60 mg/kg) of RFLE; and RFLE-H, operated and treated with high dose (90 mg/kg) of RFLE. Bilateral common carotid artery and hypotension were used as a modeling procedure, and the RFLE were intraorally administered for 5 days (preoperative 2 and postoperative 3 days). The rats then underwent memory tests including the novel object recognition, Y-maze, Barnes maze, and passive avoidance tests, and neuronal viability and neuroinflammation were quantified in their hippocampi. The results showed that the OP group exhibited VaD-associated memory deficits, neuronal death, and microglial activation in hippocampi, while the RFLE-treated groups showed significant attenuation in all above parameters. Next, using BV-2 microglial cells challenged with lipopolysaccharide (LPS), we evaluated the effects of RFLE in dynamics of proinflammatory mediators and the upstream signaling pathway. RFLE pretreatment significantly inhibited the LPS-induced release of nitric oxide, TNF-α, and IL-6 and upregulation of the MAPKs/NF-κB/iNOS pathway. Collectively, we suggest that RFLE can attenuate the histologic alterations and memory deficits accompanied by VaD, and these roles are, partly due to the attenuation of microglial activation.

Regioselective Synthesis of 6-O-Acetyl Dieckol and Its Selective Cytotoxicity against Non-Small-Cell Lung Cancer Cells.

Dieckol, a phlorotannin from Ecklonia cava, has shown potential for use as an anticancer agent that selectively kills cancer cells. However, it is necessary to amplify its potency without damaging its inherent safety in order to develop it as a competitive chemotherapeutic. Here, we explored the controlled O-acylations of dieckol. Acyl groups could be consistently introduced to the 6-O position of dieckol with a high regioselectivity, which was confirmed by NOESY, HMBC and HSQC spectroscopies. In cytotoxicity studies on the newly synthesized 6-O-acetyl, 6-O-benzoyl dieckols and previously synthesized 6-O-alkyl dieckols against A549 vs. normal cells, all of the derivatives showed low cytotoxicity in normal cells with an IC50 of 481-719 µM, and highly structure-dependent cytotoxicity in A549 cells with an IC50 of 7.02 (acetyl)-842.26 (benzyl) µM. The selectivity index also showed a large structure dependency in the range of 0.67 (benzyl)-68.58 (acetyl). An analysis of the structure-activity relationship indicated that the activity was dramatically reduced in the presence of a benzene ring and was highly increased in the presence of small polar substituents. Conclusions: Controlled mono-O-modifications of dieckol could be a powerful tool to enhance the anticancer activity of dieckol, thus contributing to the development strategy for dieckol-based chemotherapeutics.

Perilla frutescens Leaf Extract Attenuates Vascular Dementia-Associated Memory Deficits, Neuronal Damages, and Microglial Activation.

Vascular dementia (VaD) is characterized by a time-dependent memory deficit and essentially combined with evidence of neuroinflammation. Thus, polyphenol-rich natural plants, which possess anti-inflammatory properties, have received much scientific attention. This study investigated whether Perilla frutescens leaf extract (PFL) exerts therapeutic efficacy against VaD. Sprague Dawley rats were divided into five groups: SO, sham-operated and vehicle treatment; OP, operated and vehicle treatment; PFL-L, operated and low-dose (30 mg/kg) PFL treatment; PFL-M, operated and medium-dose (60 mg/kg) PFL treatment; and PFL-H, operated and high-dose (90 mg/kg) PFL treatment. Two-vessel occlusion and hypovolemia (2VO/H) were employed as a surgical model of VaD, and PFL was given orally perioperatively for 23 days. The rats underwent the Y-maze, Barnes maze, and passive avoidance tests and their brains were subjected to histologic studies. The OP group showed VaD-associated memory deficits, hippocampal neuronal death, and microglial activation; however, the PFL-treated groups showed significant attenuations in all of the above parameters. Using lipopolysaccharide (LPS)-stimulated BV-2 cells, a murine microglial cell line, we measured PFL-mediated changes on the production of nitric oxide (NO), TNF-α, and IL-6, and the activities of their upstream MAP kinases (MAPKs)/NFκB/inducible NO synthase (iNOS). The LPS-induced upregulations of NO, TNF-α, and IL-6 production and MAPKs/NFκB/iNOS activities were globally and significantly reversed by 12-h pretreatment of PFL. This suggests that PFL can counteract VaD-associated structural and functional deterioration through the attenuation of neuroinflammation.

Characterization and identification of distinct Mycobacterium massiliense extracellular proteins from those of Mycobacterium abscessus.

Mycobacterium massiliense is an emerging pathogen and very similar to Mycobacterium abscessus of rapidly growing mycobacteria in the phenotype and genotype. Pathogenic bacteria secrete a diversity of factors into extracellular medium which contribute to the bacterial pathogenicity. In the present study, we performed the comparative proteome analysis of culture filtrate proteins from a clinical isolate of M. massiliense and M. abscessus strains using two-dimensional gel electrophoresis and liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). Interestingly, 9 proteins of M. massiliense were distinctly expressed from those of M. abscessus. Bioinformatic analysis of the identified proteins revealed that 3 unique proteins corresponded to serine/arginine rich protein, membrane protein from Streptomyces coelicolor, and one hypothetical protein from Corynebacterium efficiens YS-314, respectively. Culture filtrate proteins from M. massiliense induced the release of pro-inflammatory cytokines from macrophages in a dose-dependent manner but not that from M. abscessus. Taken together, the functional study on the identified proteins uniquely produced from M. massiliense may provide not only the clues for the different pathogensis, but also help develop the diagnostic tools for the differentiation between two mycobacterial species.

Induction of macrophage death by clinical strains of Mycobacterium kansasii.

Mycobacterium kansasii is a facultative intracellular pathogen causing pulmonary disease in immunocompetent patients. Little is known about the host defense against M. kansasii and its intracellular survival strategy inside macrophages. In the present study, we obtained six clinical isolates from patients with M. kansasii pulmonary disease and investigated the intracellular growth and cytotoxic effects of M. kansasii inside mouse bone marrow-derived macrophages (BMDM) as well as cytokine secretion from BMDM. Interestingly, two isolates, SM-1 and 2693-20, displayed faster growth rates and higher levels of TNF-alpha secretion from macrophages when compared to the other strains. In addition, SM-1 and 2693-20 also induced massive cell death in BMDM and THP-1 acute monocytic leukemia cells, while the slow growing strains induced significantly lower levels of cell death. This cytotoxicity was mainly caused by necrosis, not apoptosis and it was TNF-alpha-independent. Caspase inhibitors failed to block M. kansasii-induced macrophage death. In addition, necrosis caused by the fast growing strains was accompanied by the loss of mitochondrial membrane potential (DeltaPsi(m)). When dissipation of DeltaPsi(m) was inhibited by the classical mitochondrial permeability transition (MPT) inhibitor cyclosporine A (CsA), macrophage necrosis was reduced. These results suggest that clinical isolates of M. kansasii that grow faster in macrophages induce higher levels of necrosis in a DeltaPsi(m) loss-dependent manner.