Structural Characterization and Anti-Inflammatory Effects of 24-Methylcholesta-5(6), 22-Diene-3ß-ol from the Cultured Marine Diatom Phaeodactylum tricornutum; Attenuate Inflammatory Signaling Pathways.

In the present investigation, 24-methylcholesta-5(6), 22-diene-3ß-ol (MCDO), a major phytosterol was isolated from the cultured marine diatom, Phaeodactylum tricornutum Bohlin, and in vitro and in vivo anti-inflammatory effects were determined. MCDO demonstrated very potent dose-dependent inhibitory effects on the production of nitric oxide (NO) and prostaglandin E2 (PGE2) against lipopolysaccharide (LPS)-induced RAW 264.7 cells with minimal cytotoxic effects. MCDO also demonstrated a strong and significant suppression of pro-inflammatory cytokines of interleukin-1ß (IL-1ß) production, but no substantial inhibitory effects were observed on the production of cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) at the tested concentrations against LPS treatment on RAW macrophages. Western blot assay confirmed the suppression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expressions against LPS-stimulated RAW 264.7 cells. In addition, MCDO was assessed for in vivo anti-inflammatory effects using the zebrafish model. MCDO acted as a potent inhibitor for reactive oxygen species (ROS) and NO levels with a protective effect against the oxidative stress induced by LPS in inflammatory zebrafish embryos. Collectively, MCDO isolated from the cultured marine diatom P. tricornutum exhibited profound anti-inflammatory effects both in vitro and in vivo, suggesting that this major sterol might be a potential treatment for inflammatory diseases.

Mechanistic Insight into Apoptotic Induction in Human Rhabdomyosarcoma and Breast Adenocarcinoma Cells by Chnoospora minima: A Sri Lankan Brown Seaweed.

The current study determined the cytotoxic and apoptotic potential of the polyphenol-rich methanol extract of Chnoospora minima (C. minima) and its fractions against human breast adenocarcinoma (MCF-7) and rhabdomyosarcoma (RMS) cells. MTT and neutral red assays were used to determine cytotoxicity. The clonogenic assay evaluated the antineoplastic activity, while the apoptotic activity was determined by cellular morphological changes, caspase 3/7 activity, and DNA fragmentation. Morphological alterations in apoptosis were observed by an inverted phase-contrast microscope and Hoechst 33342 staining methods. The total phenolic, flavonoids, alkaloids, and antioxidant activity in the hexane and chloroform fractions were determined, based on their cytotoxic activity. The hexane fraction of C. minima effectively reduced the cell growth that is concentration-dependent in human RMS and MCF-7 cell lines. It also exhibited low cytotoxicity on Vero cells. The characteristic cellular and nuclear apoptotic morphological features were observed. A noticeable caspase 3/7 activation and the fragmented DNA were detected only in the hexane fraction treated RMS cells, whereas MCF-7 cells showed low caspase 3/7 activation due to a lack of caspase 3 and no evidence of having a typical ladder pattern of apoptosis. Further analysis revealed that the hexane fraction-treated RMS cells upregulated the p53 gene twofold (2.72) compared to the p21 (0.77) gene, whereas in the MCF-7 cells, a 2.21-fold upregulation of p53 was observed compared to the p21 (0.64) gene. The hexane fraction exhibited moderate total phenolics, flavonoids, alkaloids content, and antioxidant activity. According to the different antioxidant mechanisms, hexane and chloroform fractions showed the highest antioxidant activities by FRAP and ORAC assays, respectively. GC-MS analysis of hexane fraction revealed the presence of methyl tetradecanoate (38.314%) as the most abundant compound. The study's findings highlighted that the non-polar compounds present in the hexane fraction of C. minima suppressed cell proliferation and induced apoptosis-mediated cell death in RMS and MCF-7 cells, mainly via the activation of the p53 gene. Hence, the isolation of compounds is warranted. However, more studies are required to understand the mechanistic insights of these observations.

Antidiabetic Potential of Marine Brown Algae-a Mini Review.

Marine algae are an important source of bioactive metabolites in drug development and nutraceuticals. Diabetes mellitus is a metabolic disorder and the third leading cause of death worldwide due to lifestyle changes associated with rapid urbanization. Due to the adverse side effects of currently available antidiabetic drugs, search for an effective natural-based antidiabetic drug is important to combat diabetes and its complications. Therefore, in lieu with herbal drug development, it is important to find the potential benefits of seaweeds for the management of type 2 diabetes as they are underexplored yet in Sri Lanka. Among the marine seaweeds, natural bioactive compounds are abundant in brown algae with potentials in application as active ingredients in drug leads and nutraceuticals. Bioactive secondary metabolites are derived from numerous biosynthetic pathways of marine algae which contribute to various chemical and biological properties. Phlorotannins present in marine brown algae exhibited antidiabetic activities through different mechanisms such as the inhibitory effect of enzyme targets mainly by inhibiting the enzymes such as α-amylase, α-glucosidase, angiotensin-converting enzymes (ACE), aldose reductase, dipeptidyl peptidase-4, and protein tyrosine phosphatase 1B (PTP 1B) enzyme. In addition, phlorotannins derived from brown algae have the ability to reduce diabetic complications. Hence, the present review focuses on the different antidiabetic mechanisms of secondary bioactive compounds present in marine brown algae.

In-Vitro Antioxidant, Hypoglycemic Activity, and Identification of Bioactive Compounds in Phenol-Rich Extract from the Marine Red Algae Gracilaria edulis (Gmelin) Silva.

Obesity and diabetes are major metabolic disorders which are prevalent worldwide. Algae has played an important role in managing these disorders. In this study, Gracilaria edulis, a marine red algae, was investigated for antioxidant and hypoglycemic potential using in vitro models. De-polysaccharide methanol extract of G. edulis was sequentially partitioned with hexane, chloroform, ethyl acetate, and antioxidants, and hypoglycemic potentials were evaluated using multiple methods. High antioxidant potential was observed in the ethyl acetate fraction in terms of ferric reducing antioxidant power, iron chelating, and DPPH and ABTS radical scavenging activities, while the crude methanol extract exhibited potent oxygen radical-absorbance capacity. Potent α-amylase inhibitory activity was observed in the ethyl acetate fraction, while the ethyl acetate fraction was effective against α-glucosidase inhibition. Glucose diffusion was inhibited by the ethyl acetate fraction at 180 min, and the highest antiglycation activity was observed in both chloroform and ethyl acetate fractions. Additionally, gas chromatography-mass spectrometry analysis of the ethyl acetate fraction revealed the presence of several potent anti-diabetic compounds. In conclusion, G. edulis exhibited promising antidiabetic potential via multiple mechanisms. The ethyl acetate fraction exhibited the strongest hypoglycemic and antiglycation potential among the four fractions, and hence the isolation of active compounds is required to develop leads for new drugs to treat diabetes.

Antioxidant and anti-inflammatory functionality of ten Sri Lankan seaweed extracts obtained by carbohydrase assisted extraction.

Enzyme-assisted extraction is a cost-effective, safe, and efficient method to obtain bioactives from plant materials. During this study, 10 different marine algae from Sri Lanka were individually extracted by using five commercial food-grade carbohydrases. The enzymatic and water extracts of the seaweeds were analyzed for their antioxidant and anti-inflammatory activities. The highest DPPH, hydrogen peroxide (H2O2) and intracellular H2O2 scavenging abilities were observed from the Celluclast extract of Sargassum polycystum (CSp). CSp exerted protective effects against oxidative stress-induced cell death in hydrogen peroxide-induced Chang cells and in model zebrafish. The Celluclast extract of Chnoospora minima (CCm) showed the strongest anti-inflammatory activity against lipopolysaccharide (LPS)-induced NO production in RAW 264.7 macrophages (IC50 = 44.47 µg/mL) and in model zebrafish. CCm inhibited the levels of iNOS, COX-2, PGE2, and TNF-α in LPS stimulated RAW 264.7 macrophages. Hence, CSp and CCm could be utilized in developing functional ingredients for foods, and cosmeceuticals.

A fucoidan fraction purified from Chnoospora minima; a potential inhibitor of LPS-induced inflammatory responses.

Fucoidans are an interesting group of bioactive sulfated polysaccharides abundant in brown seaweeds. The current study highlights the enrichment and extraction of fucoidan from Chnoospora minima by means of enzyme-assistant extraction using Celluclast and evaluation of its anti-inflammatory potential through in vitro and in vivo studies. The purified C. minima fucoidan (F2,4) inhibited the nitrous oxide (NO) production (IC50=27.82±0.88µg/ml) and expression of PGE2 through the subsequent downregulation of iNOS and COX-2 expression in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophages. F2,4 downregulated TNF-α, IL1-ß, and IL-6 in RAW 264.7 macrophages in a dose-dependent manner and suppressed NO and ROS production in LPS stimulated zebrafish embryos while exerting a protective effect against the cell damage caused by LPS. Polysaccharide structural characterization was performed using FTIR, HPAE-PAD analysis of the monosaccharide content and NMR spectroscopy. Current findings confirm the potential anti-inflammatory activity of fucoidan purified from C. minima and elaborate its potential application as a functional ingredient in consumer products.

Evaluation of the antioxidant, anti-inflammatory, and anticancer activities of Euphorbia hirta ethanolic extract.

This study evaluated the chemical composition, antioxidant, anti-inflammatory and anticancer activities of a Euphorbia hirta L. extract. The antioxidant activities of whole E. hirta ethanol extract were determined by electron spin resonance spectrophotometric analysis of 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl, and alkyl radical levels and by using an online high-performance liquid chromatography (HPLC)-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay. The E. hirta ethanol extract (0.5 mg/mL) exhibited DPPH-scavenging activity of 61.19% ± 0.22%, while the positive control (0.5 mg/mL ascorbic acid) had 100% ± 0.22% activity. The concentration of the extract required to trap 50% of DPPH (IC50) was 0.205 mg/mL. Online HPLC analysis of the extract also showed strong antioxidant activity. The anti-inflammatory activity of the E. hirta extract was assessed in lipopolysaccharide-induced RAW 264.7 macrophages. The anti-inflammatory activity was highest in the presence of 200 µg/mL E. hirta extract, and nitric oxide production was decreased significantly (p < 0.05). The extract also showed selective anticancer activity at a concentration of 100 µg/mL (p < 0.05). These results indicated that E. hirta may warrant further investigation for the development of antioxidant, anti-inflammatory, and anticancer herbal medications.

In vitro and in vivo antioxidant activities of polysaccharide purified from aloe vera (Aloe barbadensis) gel.

The in vitro and in vivo antioxidant potentials of a polysaccharide isolated from aloe vera gel were investigated. Enzymatic extracts were prepared from aloe vera gel by using ten digestive enzymes including five carbohydrases and five proteases. Among them, the highest yield was obtained with the Viscozyme extract and the same extract showed the best radical scavenging activity. An active polysaccharide was purified from the Viscozyme extract using ethanol-added separation and anion exchange chromatography. Purified aloe vera polysaccharide (APS) strongly scavenged radicals including DPPH, hydroxyl and alkyl radicals. In addition, APS showed a protective effect against AAPH-induced oxidative stress and cell death in Vero cells as well as in the in vivo zebrafish model. In this study, it is proved that both the in vitro and in vivo antioxidant potentials of APS could be further utilized in relevant industrial applications.

Preparative isolation of sargachromanol E from Sargassum siliquastrum by centrifugal partition chromatography and its anti-inflammatory activity.

Centrifugal partition chromatography (CPC) can be used to isolate various bioactive compounds from natural materials by one-step. We confirmed antioxidative compounds existed in chloroform (CHCl3) fraction of Sargassum siliquastrum using online-HPLC. Fractions (A, B, C, D and E) were separated from the CHCl3 fraction by preparative CPC (n-hexane:ethyl acetate:methanol:water, 5:5:7:3, v/v). In this study, we proved that the isolated compounds exhibit anti-inflammatory activities using lipopolysaccharide (LPS) stimulated RAW 264.7 macrophages. The fraction A which exhibited the strongest inhibitory effect on nitric oxide (NO) production level, was confirmed as sargachromanol E by LC-MS-ESI, (1)H NMR and (13)C NMR data. The sargachromanol E significantly reduced the inflammatory response in LPS induced macrophages, decreasing LPS-induced transcription factor of pro-inflammatory cyclooxygenase-2, NO synthase, phosphate P38, phosphate ERK1/2, LPS-stimulated tumor-necrosis factor alpha, interleukin-1 beta and prostaglandin E2 release. In conclusion, it was suggested that sargachromanol E inhibited inflammation in LPS induced RAW 264.7 cells via MAPK pathway.

Protective effect of a marine polyphenol, dieckol against carbon tetrachloride-induced acute liver damage in mouse.

In this study, the hepatoprotective effect of dieckol on carbon tetrachloride (CCl4) induced hepatic damages in ICR mice liver was investigated. Mice were randomly divided into 4 groups such as saline treated (negative control), CCl4 treated (positive control), CCl4+dieckol (5mg/kg mouse) and CCl4+dieckol (25mg/kg mouse), respectively. The body weights and survival rates of mice, followed by dieckol treatments were significantly increased compared to the positive control. The level of GOT, GPT and MDA in the serum of the dieckol treated groups were reduced dose dependently than the control, significantly. The antioxidant enzymes including CAT, and GSH-px levels were increased significantly compared to the positive control. However, no significant differences were observed on hepatic histophathological analysis in dieckol treated groups dose dependently. Down-regulation of Bax and up-regulation of Bcl-xl protein expressions were observed in liver tissues of the dieckol administered groups. These results suggested that, dieckol can be developed as a therapeutic agent for liver disease by oxidative stress.

Purification and determination of two novel antioxidant peptides from flounder fish (Paralichthys olivaceus) using digestive proteases.

We investigated the effects of bioactive-peptides from hydrolysates of flounder fish muscle (FFM) on antioxidant activity. The hydrolysates were prepared by enzymatic reactions of FFM using eight commercial proteases such as papain, pepsin, trypsin, neutrase, alcalase, kojizyme, protamex, and α-chymotrypsin. The α-chymotrypsin hydrolysate showed the strongest antioxidant activity among the eight enzymatic hydrolysates. Further separation of the α-chymotrypsin hydrolysate was performed by ultrafiltration, gel filtration, and reverse-phase high performance liquid chromatography. Consequently, two novel peptides with high antioxidant activity were purified, and their amino acid sequences were determined (Val-Cys-Ser-Val [VCSV] and Cys-Ala-Ala-Pro [CAAP], respectively). The two peptides showed good scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical (IC(50) values, 111.32 and 26.89 µM, respectively) and high cytoprotective activities against 2,2-azobis-(2-amidino-propane) dihydrochloride (AAPH) without cytotoxicity and scavenged total reactive oxygen species in Vero cells. In particular, apoptotic bodies produced by AAPH dose-dependently decreased following treatment with the CAAP peptide. These results revealed firstly the two peptides with strong antioxidative effects from FFM.

Antibacterial effect of citrus press-cakes dried by high speed and far-infrared radiation drying methods.

In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization.