Quang Van Ta

Marine organisms as a therapeutic source against herpes simplex virus infection.

Herpes simplex virus (HSV) is a member of the Herpesviridae family that causes general communicable infections in human populations throughout the world, the most common being genital and orolabial disease. The current treatments for HSV infections are nucleoside analogs such as acyclovir, valacyclovir and famciclovir. Despite the safety and efficacy, extensive clinical use of these drugs has led to the emergence of resistant viral strains, mainly in immunocompromised patients. To counteract these problems, alternative anti-HSV agents from natural products have been reported. Recently, a great deal of interest has been expressed regarding marine organisms such as algae, sponges, tunicates, echinoderms, mollusks, shrimp, bacteria, and fungus as promising anti-HSV agents. This contribution presents an overview of potential anti-HSV agents derived from marine organisms and their promising application in HSV therapy.

Inhibitory Effect of Chitooligosaccharides on Matrix Metalloproteinase-9 in Human Fibrosarcoma Cells (HT1080)

Matrix metalloproteinase-9 (MMP-9) has gelatinase activity and plays an important role in cancer invasion and metastasis. Therefore, inhibition of specific types of MMPs including MMP-9 has become an attractive target for therapeutic intervention. The aim of this study was to investigate the effect of chitooligosaccharides (COS) on activity and expression of MMP-9 in HT1080 cells. The inhibitory effect of COS with different molecular masses was examined by gelatin zymography, reverse transcriptase-polymerase chain reaction (RT-PCR), gene reporter assay, and Western blot analysis. MMP-9 inhibition in the presence of COS was clearly observed in gelatin zymography. Specifically, 1- to 3-kDa COS (COS-I) exhibited the highest inhibitory effect on MMP-9 activity in HT1080 cells among tested molecular mass fractions. It was also found that COS-I was capable of inhibiting both gene and protein expression of MMP-9 (P < 0.01). These results suggest that low molecular mass COS can be considered as a potent inhibitor of MMP-9.

Physcion from marine-derived fungus Microsporum sp. induces apoptosis in human cervical carcinoma HeLa cells.

Recently, the relationship between apoptosis and cancer has been emphasized and the induction of apoptosis is recognized as one of the key mechanisms of anti-cancer agents. Marine-derived fungi are valuable sources of structurally diverse bioactive anticancer agents. In the present study, a marine-derived fungus, Microsporum sp. was cultured and an anthraquinone derivative, physcion (11.8 mg) was isolated from the culture broth extract (1710 mg). Physcion has shown cytotoxic effect on human cervical carcinoma HeLa cells and its apoptosis induction in HeLa cells was investigated by the expressions of p53, p21, Bax, Bcl-2, caspase-9, and caspase-3 proteins. The Western blot analysis has revealed that physcion could significantly induce cell apoptosis through down-regulating of Bcl-2 expression, up-regulating of Bax expression, and activating the caspase-3 pathway. Furthermore, physcion induced the formation of reactive oxygen species (ROS) in HeLa cells. Collectively, these results suggest that physcion could be a potential candidate in the field of anticancer drug discovery against human cervical cancer.

Protective effect of chitin oligosaccharides against lipopolysaccharide-induced inflammatory response in BV-2 microglia

Chitin oligosaccharides (NA-COS) of two different molecular weight ranges (below 1 and 1-3 kDa) were examined for their capabilities against lipopolysaccharide-induced inflammatory responses in BV-2 murine microglia. It was found that NA-COS reduced the level of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production by suppressing the expression of NO synthase (iNOS) and cyclooxygenase (COX)-2 without significant cytotoxicity. Furthermore, the inhibitory effects of NA-COS on generation of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α were determined. Notably, NA-COS exerted anti-inflammatory activities via blocking degradation of inhibitor of kappaB-alpha (IκB-α), translocation of nuclear factor (NF)-κB, and phosphorylation of mitogen-activated protein kinases (MAPKs) in a dose-dependent manner. These findings provide mechanistic insights into the anti-inflammatory and neuroprotective actions of NA-COS in BV-2 microglia.

Potential beneficial effects of marine algal sterols on human health.

The importance of bioactive derivatives as functional ingredients has been well recognized due to their valuable health beneficial effects. Therefore, isolation and characterization of novel functional ingredients with biological activities from marine algae have gained much attention. Sterols are important structural component of cell membranes. It has been reported that plant sterols exhibit various beneficial biological activities such as hypercholesterolemic, antioxidant, anticancer, antidiabetic, antihypertensive, anti-inflammatory, antifungal, and antibacterial activities. Marine algae with a great diversity can be a very interesting natural resource of sterols. This chapter focuses on biological activities of marine algae derived sterols with potential health beneficial applications in functional foods and pharmaceuticals.

Bioactive sterols from marine resources and their potential benefits for human health.

Bioactive agents from marine resources have shown their valuable health beneficial effects. Therefore, increase knowledge on novel functional ingredients with biological activities from marine animal and microbe has gained much attention. Sterols are recognized as potential in development functional food ingredients and pharmaceutical agents. Marine resources, with a great diversity, can be a very interesting natural resource of sterols. This chapter focuses on biological activities of marine animal and microbe sterols with potential health beneficial applications in functional foods and pharmaceuticals.