No abstract

Marine red algae of genus Laurencia are becoming the most important resources to produce unique natural metabolites with wide bioactivities. However, reports related to Laurencia undulata, an edible species used as folk herb, are rarely found to date. In this research, 5-hydroxymethyl-2-furfural (5-HMF) was isolated and characterized by nuclear magnetic resonance (NMR) from Laurencia undulata as well as other marine algae. The following characteristics of 5-HMF were systematically evaluated: its antioxidant activities, such as typical free-radicals scavenging in vitro by electron spin resonance spectrometry (ESR) and intracellular reactive oxygen species (ROS) scavenging; membrane protein oxidation; oxidative enzyme myeloperoxidase (MPO) inhibition; as well as expressions of antioxidative enzymes glutathione (GSH) and superoxide dismutase (SOD) on the gene level using the polymerase chain reaction (PCR) method. The results demonstrated that 5-HMF could be developed as a novel marine natural antioxidant or potential precursor for practical applications in the food, cosmetic, and pharmaceutical fields.

In the present study, hydroxyapatite (HAp) was isolated from Thunnus obesus bone using alkaline hydrolysis and thermal calcination methods. The obtained ceramic has been characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction analysis (XRD), field-emission scanning electron microscopy, energy-dispersive x-ray analysis, transmission electron microscopy (TEM), selected area diffraction analysis, cytotoxic analysis and cell proliferation analysis. The results indicate that there are significant differences between the ceramics and T. obesus bone. FT-IR and TGA results affirmed that the collagen and organic moieties have been eliminated by both the proposed methods. XRD results were in agreement with JCPDS data. TEM and selective area diffraction images have signified that the thermal calcination method produces good crystallinity with dimensions 0.3-1.0 µm, whereas the alkaline hydrolysis method produces nanostructured HAp crystals with 17-71 nm length and 5-10 nm width. Biocompatibility of HAp crystals was evaluated by cytotoxicity and cell proliferation with human osteoblast-like cell MG-63.

Recent research has revealed the role of metalloproteinases in a number of severe pathological illnesses, including cardiac, cartilage, neurological, and cancer-related diseases that are fatal to humans. Metalloproteinases are a subclass of endopeptidases that comprise structurally identical enzymes known as Matrix Metalloproteinases [MMPs] that are solely involved in extracellular matrix degradation and play a significant regulatory function in tissue remodeling. Improper regulation and expression of MMPs have been linked to several life-threatening pathological conditions in humans. Hence there is an ever-growing interest in various research communities to identify and report the Matrix Metalloproteinase Inhibitors [MMPIs]. In spite of several chemically synthesized MMPIs being available currently, several unpleasant side effects, un-successful clinical trials have made use of synthetic MMPIs as a risky strategy. Several natural product researchers have strongly recommended and reported many natural resources like plants, microorganisms, and animals as greater resources to screen for bioactives that can function as potential natural MMPIs. Marine environment is one of the vast and promising resources that harbor diverse forms of life known to synthesize biologically active compounds. These bioactive compounds from marine organisms have been reported for their unparalleled biological effects and have profound applications in cosmeceutical, nutraceutical, and pharmaceutical research. Several research groups have reported an umpteen number of medicinally unmatched compounds from marine flora and fauna, thus driving researchers to screen marine organisms for natural MMPIs. In this review, our group has reported the potential MMPIs from marine organisms.