Extraction and Characterization of Bioactive Compounds from Diverse Marine Microalgae and Their Potential Antioxidant Activities.

This study compared free and bound phenolic compounds in various marine microalgae species. It assessed total phenolic content (TPC), total flavonoid content (TFC) and total condensed tannin content (TCT) and their antioxidant capacities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⋅+ ) radical cation-based assay and ferric ion reducing antioxidant power assay. Liquid chromatography-mass spectrometry (LC-MS) was also employed to characterize the phenolic profiling. Results showed that free phenolic compounds ranged from 1.83-6.45 mg GAE/g d. w., while bound phenolic compounds ranged from 4.03-26.03 mg GAE/g d. w., indicating significant differences. These variations were consistent across assays, highlining unique profiles in different species. A total 10 phenolics were found in these seven microalgae, including 1 phenolic acid, 6 flavonoids, 1 other polyphenol and 2 lignans. 4'-O-methyl-(-)-epigallocatechin 7-O-glucuronide and chrysoeriol 7-O-glucoside in microalgae were firstly reported in microalgal samples. These findings have implications for future applications in industries.

Bioaccessibility and bioactivities of phenolic compounds from microalgae during in vitro digestion and colonic fermentation.

Microalgae are a developing novel source of carbohydrates, phenolic compounds, carotenoids and proteins. In this study, in vitro digestion and colonic fermentation were conducted to examine the total phenolic content and potential antioxidant activity of four microalgal species (Chlorella sp., Spirulina sp., Dunaliella sp., and Isochrysis sp.). The bioaccessibility of targeted phenolic compounds and the short-chain fatty acid (SCFA) production were also estimated. Particularly, Spirulina sp. exhibited the highest total phenolic content (TPC) and free radical scavenging (2,2'-diphenyl-1-picrylhydrazyl, DPPH) capacity after gastrointestinal digestion of 7.93 mg gallic acid equivalents (GAE) per g and 2.35 mg Trolox equivalents (TE) per g. Meanwhile, it had the highest total flavonoid content (TFC) of 1.07 quercetin equivalents (QE) per g after 8 h of colonic fermentation. Dunaliella sp. and Isochrysis sp. showed comparable ferric reducing antioxidant power (FRAP) of 4.96 and 4.45 mg QE per g after 4 h of faecal reaction, respectively. p-hydroxybenzoic and caffeic acid almost completely decomposed after the intestine and fermented in the colon with the gut microflora. In Dunaliella sp. and Isochrysis sp., these phenolic acids were found in the colonic fermented residual, probably due to the presence of dietary fibre and the interactions with other components. All four species reached the highest values of SCFA production after 16 h, except Spirulina sp., which displayed the most increased total SCFA production after 8 h of fermentation. It is proposed that Spirulina sp. could be more beneficial to gut health.

Immunohistochemical Characterization of Gingival Fibromas.

PURPOSE: Gingival fibromas (GFs) are fibrous lesions of the gingiva that are not well defined in the literature. They are histologically similar to peripheral ossifying fibromas (POFs), both being characterized as cellular proliferations of dense fibrous tissue, with POFs differing in that they demonstrate foci of calcification. This study aims to expand upon the immunohistochemical characterization of GFs, and to confirm their osteoblastic phenotype. METHODS: Formalin fixed, paraffin embedded GFs, POFs and fibroepithelial polyps (FEPs) of the gingiva were examined. Immunohistochemical staining was performed for special AT-rich sequence binding protein 2 (SATB2), runt-related transcription factor 2 (RUNX2), osteocalcin and alpha-smooth muscle actin (αSMA). Sections were evaluated by light microscopy and the immunohistochemical staining patterns were assigned immunoreactive scores (IRS) based on percentage of stained cells and intensity of staining. RESULTS: GFs, POFs, and FEPs of the gingiva expressed osteoblastic markers SATB2, RUNX2 and osteocalcin. GFs and POFs expressed αSMA while FEPs of the gingiva did not. GFs and POFs had similar staining patterns of SATB2, RUNX2 and αSMA. DISCUSSION: These findings demonstrate that GFs and POFs exhibit a similar immunohistochemical profile, and supports a theory that GFs are osteoblastic lesions possibly related to POFs.

Activation of Mast Cells Promote Plasmodium berghei ANKA Infection in Murine Model.

Malaria, a mosquito-borne infectious disease, is a severe health problem worldwide. As reported, some anti-malarial drugs with anti-parasitic properties also block mast cells (MCs) activities. It is hypothesized that MCs activity may be correlated with the pathogenesis of malaria. Thus, the role of MCs on malarial pathogenesis and the involved physiological action and pathways need to be further investigated. This study aimed to investigate the effect of MCs activation on malaria disease severity using KunMing mice with Plasmodium berghei ANKA (PbANKA) infection treated with MCs degranulator (compound 48/80, C48/80) or MCs stabilizer (disodium cromoglycate, DSCG). PbANKA infection caused a dramatic increase in MCs density and level of MCs degranulation in cervical lymph node (CLN) and skin. Compared with infected control, C48/80 treatment had shortened survival time, increased parasitemia, exacerbated liver inflammation and CLN hyperplasia, accompanied with increase in vascular leakage and leukocyte number. The infected mice with C48/80 treatment also elevated the release of CCL2, CXCL1, and MMP-9 from MCs in CLN and skin, and TNF-α, IFN-γ, CCR2, and CXCR2 mRNA expression in CLN and liver. In contrast, the infected mice treated with DSCG showed longer survival time, lower parasitemia, improved liver inflammation and CLN hyperplasia, followed by a decline of vascular leakage and leukocyte number. Decreased MCs-derived CCL2, CXCL1, and MMP-9 from CLN and skin, mRNA expression in CLN and liver (TNF-α, IFN-γ, CCR2, and CXCR2) were also observed in infected mice with DSCG treatment. Our data indicated that MCs activation may facilitate the pathogenesis of PbANKA infection.