In vitro promoting activity of human interferon β production by extracts of marine algae from Japan

Towards a better understanding of medicinal uses of the brown seaweed Sargassum in Traditional Chinese Medicine: a phytochemical and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

For nearly 2000 years Sargassum spp., a brown seaweed, has been used in Traditional Chinese Medicine (TCM) to treat a variety of diseases including thyroid disease (e.g. goitre).

AIMS OF THE REVIEW

To assess the scientific evidence for therapeutic claims made for Sargassum spp. in TCM and to identify future research needs.

BACKGROUND AND METHODS

A systematic search for the use of Sargassum in classical TCM books was conducted and linked to a search for modern phytochemical and pharmacological data on Sargassum spp. retrieved from PubMed, Web of Knowledge, SciFinder Scholar and CNKI (in Chinese).

RESULTS AND DISCUSSION

The therapeutic effects of Sargassum spp. are scientifically plausible and may be explained partially by key in vivo and in vitro pharmacological activities of Sargassum, such as anticancer, anti-inflammatory, antibacterial and antiviral activities. Although the mechanism of actions is still not clear, the pharmacological activities could be mainly attributed to the major biologically active metabolites, meroterpenoids, phlorotanins and fucoidans. The contribution of iodine in Sargassum for treating thyroid related diseases seem to have been over estimated.

CONCLUSIONS

The bioactive compounds in Sargassum spp. appear to play a role as immunomodulators and could be useful in the treatment of thyroid related diseases such as Hashimoto's thyroiditis. Further research is required to determine both the preventative and therapeutic role of Sargassum spp. in thyroid health.

Inhibition of Lipopolysaccharide (LPS)-induced inflammatory responses by Sargassum hemiphyllum sulfated polysaccharide extract in RAW 264.7 macrophage cells

Sargassum hemiphyllum , a kind of brown seaweed generally found along coastlines in East Asia, has long served as a traditional Chinese medicine. S. hemiphyllum has shown an anti-inflammatory effect; however, its mechanism has not been elucidated clearly. This study explored S. hemiphyllum for its biomedical effects. S. hemiphyllum sulfated polysaccharide extract (SHSP) was first prepared; the mouse macrophage cell line (RAW 264.7) activated by lipopolysaccharide (LPS) was used as a model system. The secretion profiles of pro-inflammatory cytokines, including IL-1β, IL-6, TNF-α, and NO, were found significantly to be reduced in 1-5 mg/mL dose ranges of SHSP treatments. RT-PCR analysis suggested SHSP inhibits the LPS-induced mRNA expressions of IL-β, iNOS, and COX-2 in a dose-dependent manner. At protein levels, Western blot analysis demonstrated a similar result for NF-κB (p65) in cytosol/nuclear. Taken together, the anti-inflammatory properties of SHSP may be attributed to the down-regulation of NF-κB in nucleus.

The novel anti-Propionibacterium acnes compound, Sargafuran, found in the marine brown alga Sargassum macrocarpum

We screened extracts of 342 species of marine algae collected from Japanese coastlines for antibacterial activity against Propionibacterium acnes, and found a novel antibacterial compound, which we named Sargafuran, from the MeOH extract of the marine brown alga, Sargassum macrocarpum. Sargafuran has low cytotoxicity, and the MIC against P. acnes was 15 microg ml(-1), showing a broad antibacterial activity against Gram-positive bacteria. A time-kill study showed that Sargafuran was bactericidal and completely killed P. acnes at 4 x MIC by lysing bacterial cells. These results suggest that Sargafuran might be useful as a lead compound to develop new types of anti-P. acnes substances and new skin care cosmetics to prevent or improve acne.

A chlorophyll c2 analogue from the marine brown alga Eisenia bicyclis inactivates the infectious hematopoietic necrosis virus, a fish rhabdovirus

We screened in vitro antiviral activity against a salmonid pathogenic virus, infectious hematopoietic necrosis virus (IHNV), from the extracts of a total of 342 species of marine algae collected from the Japanese coastline. The anti-IHNV activity was found primarily in MeOH extracts, and the extract from one marine brown alga in particular, Eisenia bicyclis, showed high anti-IHNV activity. The anti-IHNV compound was isolated and purified as MC15 from the E. bicyclis extract, and the chemical structure was determined by several spectrometric analyses. The antiviral compound was proved to be a chlorophyll c2 derivative lacking the metal ion Mg(2+). MC15 showed similar antiviral activity against other salmonid enveloped viruses such as Paralichthys olivaceus virus and Oncorhynchus masou virus, and stability against any pH and temperatures up to 100 degrees C. No cytotoxicity was observed at up to 5 microg/ml. The antiviral mechanism of MC15 appears to be direct inactivation of the viral particles. A time course study showed that the inactivation of IHNV was completed within 40 min when 200 PFU of IHNV was reacted with MC15 at 800 ng/ml.

Inhibitory action of marine algae extracts on the Trypanosoma cruzi dihydroorotate dehydrogenase activity and on the protozoan growth in mammalian cells

Trypanosoma cruzi, the causative agent of Chagas' disease, replicates in mammalian cells and relies on the de novo pyrimidine biosynthetic pathway that supplies essential precursors for nucleic acid synthesis. The protozoan dihydroorotate dehydrogenase (DHOD), the fourth enzyme of the pathway catalyzing production of orotate from dihydroorotate, markedly differs from the human enzyme. This study was thus aimed to search for potent inhibitors against T. cruzi DHOD activity, and a number of methanol extracts prepared from green, brown, and red algae were assayed. The extracts from two brown algae, Fucus evanescens and Pelvetia babingtonii, yielded 59 and 58% decrease in the recombinant DHOD activity, respectively, at the concentration of 50 microg/ml. Inhibition by these extracts was noncompetitive with respect to dihydroorotate, with apparent Ki values of 35.3+/-5.9 and 10.3+/-4.4 microg/ml, respectively. Further, in an in vitro T. cruzi-HeLa cell infection system, ethanol-reconstituted F. evanescens and P. babingtonii extracts at the concentration of 1 microg/ml, respectively, decreased significantly the infection rate of host cells and the average parasite number per infected cell. These results imply that F. evanescens and P. babingtonii contain inhibitor(s) against the T. cruzi DHOD activity and against the protozoan infection and proliferation in mammalian cells. Identification of inhibitor(s) in these two brown algae and further screening of other marine algae may facilitate the discovery of new, anti-trypanosomal lead compounds.