Effect of crude sulphated polysaccharide from brown algae against acetaminophen-induced toxicity in rats

Mechanism of drug-induced liver injury and hepatoprotective effects of natural drugs

Drug-induced liver injury (DILI) is a common adverse drug reaction (ADR) and a serious threat to health that affects disease treatments. At present, no targeted clinical drugs are available for DILI. Traditional natural medicines have been widely used as health products. Some natural medicines exert specific hepatoprotective effects, with few side effects and significant clinical efficacy. Thus, natural medicines may be a promising direction for DILI treatment. In this review, we summarize the current knowledge, common drugs and mechanisms of DILI, as well as the clinical trials of natural drugs and their bioactive components in anticipation of the future development of potential hepatoprotective drugs.

Hepatoprotective activity against acetaminophen-induced liver dysfunction and GC-MS profiling of a brown algae Sargassum ilicifolium

Background

Drug-induced hepatotoxicity is one of the most important causes of liver dysfunction. Acetaminophen (paracetamol) an analgesic-antipyretic drug is generally considered safe but its overdose may cause liver toxicity. Marine macro-algae (seaweeds) especially brown seaweeds possess unique biological activities including hepatoprotective potential. The current study focused on the hepatoprotective effect of different solvent fractions of Sargassum ilicifolium and characterization of its n-hexane soluble fraction.

Methods

The ethanol extract (20 g) of S. ilicifolium was mixed with solvents of increasing polarity, starting with n-hexane followed by chloroform and methanol. All three (n-hexane, chloroform and methanol) soluble fractions were administered to the rats at dose of 150 mg/kg, b.w. Intraperitoneal administration of acetaminophen (600 mg/kg b.w.) to rats was used to cause liver injury. The hepatic damage was evaluated by liver markers enzymes; aspartate aminotransferases (AST), alanine aminotransferases (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), bilirubin along with other metabolites i.e., triglycerides, cholesterol, urea, glucose and creatinine. Lipid peroxidation and glutathione and were estimated in liver tissue. n-Hexane fraction was subjected to GC-MS analysis in order to identify potent compounds.

Results

The oral administration of n-hexane and methanol soluble fractions reduced the acetaminophen-augmented liver marker enzymes ALT, AST, ALP, LDH, along with bilirubin, urea, creatinine, glucose and triglycerides. The n-hexane and methanol soluble fractions also improved hepatic antioxidant level via enhancing hepatic glutathione and reversing lipid peroxidation. GC-MS spectroscopy of n-hexane fraction of S. ilicifolium revealed the presence of some new compounds. Among them, fatty acids were found to be in highest concentration followed by halogenated hydrocarbons, benzene derivatives, and sterols. Fatty acid in seaweed may be one of the factors for hepatoprotection from drug-induced hepatotoxicity.

Conclusion

From the results, it is evident that n-hexane and methanol soluble fractions of S. ilicifolium have the ability to protect the liver against toxicity, which is comparable with silymarin used as a standard drug. Sargassum ilicifolium contains bioactive compounds with pharmaceutical importance.

Comparative study of components and anti-oxidative effects between sulfated polysaccharide and its iron complex

Sulfated polysaccharide (SP) extracted from sea algae has been used to chelate with ferric to yield polysaccharide iron complex (SPIC). The main active components and groups, monosaccharide composition, molecular weight and anti-oxidative capability were studied comparatively. Results showed that both have good stability and no free ferric ions in SPIC, and no significant difference in total polysaccharide content while sulfate and protein contents lowering and iron content increasing. Fourier-transform infrared (FTIR) spectra indicated further that iron was chelated in polysaccharide chain. Gas chromatograph (GC) showed that the major monosaccharides were fucose, mucose and glucose with molecular ratio of 10:3.8:3.5 in SPIC and 10:8.4:7.5 in SP. MW of SP and SPIC varied no more at 231,3 kD and 237.2 kD respectively using high-performance liquid chromatography (HPLC). Both had hydroxyl radicals scavenging effects in vitro while SPIC showed stronger effects. Comparing oxygen consumption with control PMA-differentiated cells, both took longer time to achieve higher platform and SPIC showed stronger effects than SP. Fluorescence extensity of intracellular ROS showed that SP could reduce the ROS generation while SPIC enhances the effect. The results revealed that the main active components and antioxidant activity exhibit differentiation after SP chelating with ferric.

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.