Pyropia yezoensis (P. yezoensis) is a popular species of red algae that are commercially cultivated and consumed in East Asia, China, Japan, and Korea. The high protein content of P. yezoensis provides a source of multiple bioactive peptides exhibiting antioxidant, anti-inflammatory, antihypertensive, anticancer, tissue healing, immunomodulatory, and anticoagulant properties. Furthermore, many other biologically active substances in P. yezoensis, including carbohydrates, lipids, dietary fibers, and polyphenols, have shown potential health benefits and are important in both the food and agriculture industries. This review provides a detailed summary of researches over the last decade on the biological and medicinal properties of bioactive peptides. The information was extracted from various electronic resources, including Google Scholar, PubMed, MEDLINE, and Google Patents.

Objective: To prepare naringenin herbosome and evaluate its antidiabetic activity. Methods: Herbosomes were prepared by the solvent evaporation method. In vitro parameters like particle size, polydispersity index, zeta potential, and entrapment efficiency were estimated and in vitro diffusion study was performed. The in vivo studies were also performed in streptozotocin-induced diabetic male Sprague Dawley rats to evaluate blood glucose, total cholesterol, triglyceride, blood urea nitrogen, total protein, albumin level, aspartate aminotransferase, and alanine aminotransferase levels. Results: The optimized herbosome batch showed a particle size of 564.4 nm, a polydispersity index of 0.412, and zeta potential of -39.3 mV. The percentage entrapment of this formulation was 84.04%, with complete drug release within 8 h. Treatment of diabetic rats with naringenin herbosomes for 28 d significantly reduced the elevated level of plasma glucose as compared to plain naringenin. In biochemical parameters, the treatment showed a significant decrease in total cholesterol, triglyceride, and blood urea nitrogen; while elevated levels of aspartate aminotransferase and alanine aminotransferase were returned to normal. Pure naringenin and herbosome formulation at high dose increased the total protein whereas albumin level significantly increased in naringenin herbosomes at the highest dose but not in the pure naringenin treatment group. Conclusions: Naringenin herbosomes could improve the metabolic profile of diabetic rats, indicating enhanced antidiabetic activity of herbosome formulation.

Objective: To evaluate the antidiabetic potential of leaf extracts of Tylophora hirsuta (T. hirsuta). Methods: The methanolic and ethyl acetate extracts of T. hirsuta leaves were analyzed by high pressure liquid chromatography. In vitro antioxidant activity was determined by ferric ion reduction, 1, 1-diphenyl-2-picrylhydrazyl, and hydrogen peroxide scavenging methods. In vitro alpha amylase (α-amylase) inhibitory activity of the plant extracts was assessed. In vivo antidiabetic potential was determined in alloxan-induced diabetic mice to assess glycated hemoglobin (HbA1c), oral glucose tolerance, serum amylase, lipid profile, fasting blood glucose, and body weight. Histopathological lesions of the pancreas, liver and kidney were observed. Oxidative stress biomarkers such as superoxide dismutase, catalase and peroxidase were also determined. Results: Quercetin, chlorogenic acid, p-coumaric acid, and m-coumaric acid were found in the plant extracts. The methanolic plant extract exhibited higher in vitro antioxidant activities than the ethyl acetate extract. Moreover, methanolic plant extract exhibited (83.90±1.56)% α-amylase inhibitory activity at 3.2 mg/ mL concentration. Animal study showed that the methanolic extract of T. hirsuta improved the levels of fasting blood glucose, HbA1c, serum α-amylase, lipid profile, liver function biomarkers, and kidney functions of diabetic mice. Moreover, the methanolic extract ameliorated diabetes-related oxidative stress by increasing superoxide dismutase and catalase activities and decreasing peroxidase and malondialdehyde levels. Histopathological examination showed that the plant extract had improved the integrity of pancreatic islets of Langerhans and reduced the pathological lesions in the liver and kidney of diabetic mice. Conclusions: The methanolic extract of T. hirsuta exhibits pronounced antidiabetic activity in mice through reduction of oxidative stress. The plant extract has several natural antioxidants such as phenolic acids. T. hirsuta extract could serve as a nutraceutical for managing diabetes mellitus.

Objective: To evaluate the inhibitory activity of ferulic acid and four of its esterified derivatives (methyl, ethyl, propyl, and butyl) against resistance mechanisms in Staphylococcus aureus strains. Methods: Ferulic acid derivatives were obtained by esterification with methanol, ethanol, propanol, and butanol, and then characterized by hydrogen and carbon-13 nuclear magnetic resonance analysis. The minimum inhibitory concentrations (MIC) of ferulic acid and its esterified derivatives, ethidium bromide, and norfloxacin were obtained using the microdilution test, while the efflux pump inhibition test was conducted by examining reduction in the MICs of norfloxacin and ethidium bromide. Molecular docking was also carried out using the Schrodinger Suite 2015 molecular modeling software. A three-dimensional model of NorA efflux pump was generated using I-TASSER. The best scoring model was used as a receptor for ligand-receptor docking. Results: The methyl and butyl ester derivatives did not demonstrate significant antimicrobial activity. However, a significant synergic effect was evidenced when norfloxacin was combined with the ethyl and propyl esterified derivatives. The docking study demonstrated favorable energy of interaction between ferulate derivatives and NorA, and amino acid residues TYR57, TYR58, and LEU255 were present commonly in stabilizing all complexes. The PCA analysis corroborated the docking hypothesis that the lipophilic character and hydrogen bond interactions were the most relevant characteristics involved with NorA inhibitors. The pharmacokinetic parameters of ferulic acid derivatives showed good ADMET properties, demonstrating that they can be easily absorbed and have no effect or inhibit the cytochrome P450 enzyme complex, revealing their potential as drug candidates. Conclusions: This study provides strong evidence that the molecular basis for this activity is potentially due to the NorA efflux pump.

Objective: To study the chemical profile, antimicrobial properties, and synergistic effect with known antibiotics of essential oil extracted from the marine red macroalgae Centroceras clavulatum (C. Agardh) Montagne, collected in Morocco. Methods: The chemical composition of the oil was analyzed by gas chromatography-mass spectrometry. The oil was evaluated for antibacterial (Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, and Klebsiella pneumoniae), and antifungal activity (Candida albicans, Candida glabrata, Candida krusei, and Candida parapsilosis), by the disc diffusion method. The minimum inhibitory and minimum microbicidal concentrations of the oil were determined, as well as the synergistic effects of its application combined with the antibiotics ciprofloxacin and fluconazole, by the checkerboard method. Results: Thirty molecules were identified in the essential oil, comprising 96.27% of the total oil composition. Monoterpenes such as carvacrol (36.06%) were the most abundant compounds, followed by caryophyllene (14.67%), endo-borneol (9.04%), pyroterebic acid (3.23%) and caryophyllene oxide (3.13%). The oil exhibited a moderate antimicrobial activity with inhibition zone diameters ranging from 9.0 to 15.0 mm. The minimum inhibitory concentration values varied between 0.9 and 14.7 mg/mL, and Bacillus subtilis and Escherichia coli were the more sensitive bacteria with 0.9 and 1.9 mg/mL, respectively. The minimum microbicidal concentration values ranged from 0.4 to 14.7 mg/mL. A significant synergic action was observed when the oil was applied in combination with ciprofloxacin and fluconazole, with fractional inhibitory concentration index values ranging from 0.31 to 0.50. Synergy was found in 80% of the combinations and a 2 to 16-fold reduction of antibiotics MIC was observed. Conclusions: Our findings suggest that the essential oil of Centroceras clavulatum should be further appraised for its potential use in the management of multi-drug resistant microorganisms, with the purpose to restore the activity of standard antimicrobial drugs.