Antileukemic activity of Viva-Natural, a dietary seaweed extract, on Rauscher murine leukemia in comparison with anti-HIV agents, azidothymidine, dextran sulfate and pentosan polysulfate

Antiviral Portrait Series: 4. Polysuifates as Inhibitors of HIV and Other Enveloped Viruses

Polysulfates are highly potent and selective inhibitors of the in vitro replication of HIV and other enveloped viruses. They not only inhibit the cytopathic effect of HIV, but also prevent HIV-induced syncytium (giant cell) formation. They also act synergistically with other anti-HIV drugs. The anti-HIV activity of polysulfates is a result of their shielding of the positively charged sites in the V3 loop of the viral envelope glycoprotein gp120. When polysulfates were administered intravenously to rabbits, their half-life was approximately 2h. Although they are very poorly absorbed following oral administration, they can be made orally bioavailable with the appropriate chemical modifications. Also, polysulfates may lose (much of) their anticoagulant activity upon chemical modification without giving up their anti-HIV activity. Their efficacy in the therapy and/or prophylaxis of retroviral infections remains to be demonstrated both in animal models and in humans.

Anticancer drugs from marine flora: an overview

Marine floras, such as bacteria, actinobacteria, cyanobacteria, fungi, microalgae, seaweeds, mangroves, and other halophytes are extremely important oceanic resources, constituting over 90% of the oceanic biomass. They are taxonomically diverse, largely productive, biologically active, and chemically unique offering a great scope for discovery of new anticancer drugs. The marine floras are rich in medicinally potent chemicals predominantly belonging to polyphenols and sulphated polysaccharides. The chemicals have displayed an array of pharmacological properties especially antioxidant, immunostimulatory, and antitumour activities. The phytochemicals possibly activate macrophages, induce apoptosis, and prevent oxidative damage of DNA, thereby controlling carcinogenesis. In spite of vast resources enriched with chemicals, the marine floras are largely unexplored for anticancer lead compounds. Hence, this paper reviews the works so far conducted on this aspect with a view to provide a baseline information for promoting the marine flora-based anticancer research in the present context of increasing cancer incidence, deprived of the cheaper, safer, and potent medicines to challenge the dreadful human disease.

A combined Phase I and II open-label study on the immunomodulatory effects of seaweed extract nutrient complex

Background:

Isolated fucoidans from brown marine algae have been shown to have a range of immune-modulating effects. This exploratory study aimed to determine whether a seaweed nutrient complex containing a blend of extracts from three different species of brown algae plus nutrients is safe to administer and has biological potential as an immune modulator. The study was undertaken as an open-label combined Phase I and II study.

Methods:

Participants (n = 10) were randomized to receive the study medication at either a 100 mg (n = 5) or 1000 mg (n = 5) dose over 4 weeks. The primary outcome measurement was in vivo changes in lymphocyte subsets. The secondary outcome measures were ex vivo changes in T-lymphocyte (CD4 and CD8) activation, phagocytosis of granulocytes and monocytes, T helper 1/T helper 2 cytokines, and serum oxygen radical absorbance capacity.

Results:

The preparation was found to be safe over the 4 weeks at both doses tested. There were no clinically relevant changes to blood measurements of hemopoietic, hepatic, or renal function. Immunomodulatory measurements showed no dose response between the two doses. The combined results from the two doses demonstrated a significant increase in cytotoxic T cell numbers and phagocytic capacity in monocytes, and a significant decrease in levels of the inflammatory cytokine interleukin 6. A separate analysis of the 100 mg dose (n = 5) alone showed a significant linear component over time (P < 0.05) for phagocytosis by both granulocytes and monocytes.

Conclusion:

The seaweed nutrient complex was safe to use when taken orally over 4 weeks. The preparation was demonstrated to have potential as an immune modulator, and this bioactivity deserves further exploration.

Defensive effects of a fucoidan from brown alga Undaria pinnatifida against herpes simplex virus infection

Fucoidan, a sulfated polysaccharide isolated from an edible brown alga Undaria pinnatifida, was previously shown to be a potent inhibitor of the in vitro replication of herpes simplex virus type 1 (HSV-1). HSV-1 is a member of herpes viruses that cause infections ranging from trivial mucosal ulcers to life-threatening disorders in immunocompromised hosts. In the in vivo conditions, the replication of HSV-1 is controlled under the immunoresponse coordinated by both the innate and adaptive immune systems. In the present study, the effects of the fucoidan were examined on in vivo viral replication and the host's immune defense system. Oral administration of the fucoidan protected mice from infection with HSV-1 as judged from the survival rate and lesion scores. Phagocytic activity of macrophages and B cell blastogenesis in vitro were significantly stimulated by the fucoidan, while no significant change in the release of NO(2)(-) by macrophages was observed. In in vivo studies, oral administration of the fucoidan produced the augmentation of NK activity in HSV-1-infected mice immunosuppressed by 5-fluorouracil treatment. CTL activity in HSV-1-infected mice was also enhanced by oral administration of the fucoidan. The production of neutralizing antibodies in the mice inoculated with HSV-1 was significantly promoted during the oral administration of the fucoidan for 3 weeks. These results suggested that oral intake of the fucoidan might take the protective effects through direct inhibition of viral replication and stimulation of both innate and adaptive immune defense functions.

Sulfated fucan as support for antibiotic immobilization

Xylofucoglucuronan from Spatoglossum schröederi algae was tested as a support for antibiotic immobilization. The polysaccharide (20 mg in 6 ml) was first activated using carbodiimide, 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide methiodide (20 mg in 2 ml), under stirring for 1 h at 25 masculine C and pH from 4.5 to 5.0. After adjusting the pH to 8.0, either gentamicin or amikacin (62.5 mg in 1.25 ml) was then immobilized on this chemically modified polysaccharide with shaking for 24 h in a cold room. Infrared spectra of the activated carbodiimide xylofucoglucuronan showed two bands to carbonyl (C=O at 1647.9 and 1700.7 cm(-1)) and to amide (C-NH2) groups (1662.8 and 1714.0 cm(-1)). Microbial characterization of the derivatives was carried out by the disk diffusion method using Staphylococcus aureus or Klebsiella pneumoniae incorporated in Müller Hinton medium. Inhibition halos of bacterial growth were observed for the antibiotics immobilized on this sulfated heteropolysaccharide before and after dialysis. However, the halos resulting from the samples after dialysis were much smaller, suggesting that dialysis removed either non-covalently bound antibiotic or other small molecules. In contrast, bacterial growth was not inhibited by either xylofucoglucuronan or its activated form or by gentamicin or amikacin after dialysis. An additional experiment was carried out which demonstrated that the sulfated heteropolysaccharide was hydrolyzed by the microorganism. Therefore, the antibiotic immobilized on xylofucoglucuronan can be proposed as a controlled drug delivery system. Furthermore, this sulfated heteropolysaccharide can be extracted easily from sea algae Spatoglossum schröederi.

Algae -- a poor man's HAART?

Drawing inferences from epidemiologic studies of HIV/AIDS and in vivo and in vitro HIV inhibition by algae, we propose algal consumption as one unifying characteristic of countries with anomalously low rates. HIV/AIDS incidence and prevalence in Eastern Asia ( approximately 1/10000 adults in Japan and Korea), compared to Africa ( approximately 1/10 adults), strongly suggest that differences in IV drug use and sexual behavior are insufficient to explain the 1000-fold variation. Even in Africa, AIDS/HIV rates vary. Chad has consistently reported low rates of HIV/AIDS (2-4/100). Possibly not coincidentally, most people in Japan and Korea eat seaweed daily and the Kanemba, one of the major tribal groups in Chad, eat a blue green alga (Spirulina) daily. Average daily algae consumption in Asia and Africa ranges between 1 and 2 tablespoons (3-13 g). Regular consumption of dietary algae might help prevent HIV infection and suppress viral load among those infected.