Mining Xanthine Oxidase Inhibitors from an Edible Seaweed Pterocladiella capillacea by Using In Vitro Bioassays, Affinity Ultrafiltration LC-MS/MS, Metabolomics Tools, and In Silico Prediction

The prevalence of gout and the adverse effects of current synthetic anti-gout drugs call for new natural and effective xanthine oxidase (XOD) inhibitors to target this disease. Based on our previous finding that an edible seaweed Pterocladiella capillacea extract inhibits XOD, XOD-inhibitory and anti-inflammatory activities were used to evaluate the anti-gout potential of different P. capillacea extract fractions. Through affinity ultrafiltration coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS), feature-based molecular networking (FBMN), and database mining of multiple natural products, the extract's bioactive components were traced and annotated. Through molecular docking and ADMET analysis, the possibility and drug-likeness of the annotated XOD inhibitors were predicted. The results showed that fractions F4, F6, F4-2, and F4-3 exhibited strong XOD inhibition activity, among which F4-3 reached an inhibition ratio of 77.96% ± 4.91% to XOD at a concentration of 0.14 mg/mL. In addition, the P. capillacea extract and fractions also displayed anti-inflammatory activity. Affinity ultrafiltration LC-MS/MS analysis and molecular networking showed that out of the 20 annotated compounds, 8 compounds have been previously directly or indirectly reported from seaweeds, and 4 compounds have been reported to exhibit anti-gout activity. Molecular docking and ADMET showed that six seaweed-derived compounds can dock with the XOD activity pocket and follow the Lipinski drug-like rule. These results support the value of further investigating P. capillacea as part of the development of anti-gout drugs or related functional foods.

Mertensene, a Halogenated Monoterpene, Induces G2/M Cell Cycle Arrest and Caspase Dependent Apoptosis of Human Colon Adenocarcinoma HT29 Cell Line through the Modulation of ERK-1/-2, AKT and NF-κB Signaling

Conventional treatment of advanced colorectal cancer is associated with tumor resistance and toxicity towards normal tissues. Therefore, development of effective anticancer therapeutic alternatives is still urgently required. Nowadays, marine secondary metabolites have been extensively investigated due to the fact that they frequently exhibit anti-tumor properties. However, little attention has been given to terpenoids isolated from seaweeds. In this study, we isolated the halogenated monoterpene mertensene from the red alga Pterocladiella capillacea (S.G. Gmelin) Santelices and Hommersand and we highlight its inhibitory effect on the viability of two human colorectal adenocarcinoma cell lines HT29 and LS174. Interestingly, exposure of HT29 cells to different concentrations of mertensene correlated with the activation of MAPK ERK-1/-2, Akt and NF-κB pathways. Moreover, mertensene-induced G2/M cell cycle arrest was associated with a decrease in the phosphorylated forms of the anti-tumor transcription factor p53, retinoblastoma protein (Rb), cdc2 and chkp2. Indeed, a reduction of the cellular level of cyclin-dependent kinases CDK2 and CDK4 was observed in mertensene-treated cells. We also demonstrated that mertensene triggers a caspase-dependent apoptosis in HT29 cancer cells characterized by the activation of caspase-3 and the cleavage of poly (ADP-ribose) polymerase (PARP). Besides, the level of death receptor-associated protein TRADD increased significantly in a concentration-dependent manner. Taken together, these results demonstrate the potential of mertensene as a drug candidate for the treatment of colon cancer.

Health-promoting ingredients from four selected Azorean macroalgae

This study presents, for the first time, the nutritional and health promoting aspects of four selected Azorean macroalgae (Ulva compressa, Ulva rigida, Gelidium microdon and Pterocladiella capillacea) in terms of total lipids, fatty acids (FA) profile, n6/n3 and hypocholesterolemic (h)/hypercholesterolemic (H) FA ratios, minerals, total essential amino acids (AA), anti-ageing and anti-phenylketonuria AA content, coenzyme Q₁₀, α-tocopherol, total phenolics, antioxidant properties and energy value, on a dry weight basis. The results revealed low lipid content (1.02-4.32%) but significant PUFA content (29.57-69.22% of total FA), suitable FA ratios (0.48-9.49 for n6/n3 and 1.26-4.22 for h/H), balanced macromineral ratios (0.27-1.91 for Na/K and 0.15-1.07 for Ca/Mg), appreciable amount of essential AA (45.27-58.13% of total AA), high amount of anti-ageing AA, low Phe content, coenzyme Q₁₀ (1.25-8.27μg/g), α-tocopherol (2.61-9.14mg/100g), high total phenolic content (27.70-55.07mg of gallic acid equivalents/g extract), significant free radical scavenging activity (29.32-47.73%) and valuable energy content (6.80-9.80kJ/g). A regular consumption of these algae either directly or through food supplements may improve human health or may have a protective effect on some diseases and ageing process. They can also be used for producing pharmaceuticals and cosmeceuticals with potential economic value.