Anti-mutagenic potential of algal extracts on chromosomal aberrations in Allium cepa L.

In the present study, sodium azide (SA) toxicity and the anti-mutagenic effects of different algal extracts at 0.1% and 0.2% concentrations were studied on the mitotic index (MI), chromosomal and nuclear aberrations using Allium cepa L. root assay. Moreover, phytochemical screening of photosynthetic pigments, antioxidants compounds, total antioxidant, DPPH scavenging activity, polysaccharides, and phenolic contents were done for two red seaweeds (Laurencia obtusa (Hudson) Lamouroux and Polysiphonia morrowii Harvey) and for one brown seaweed (Dictyopteris delicatula Lamouroux). Treatment with 300 µg/ml sodium azide (SA) induced the highest number of aberrations in A. cepa root. A highly significant decrease in the MI appeared after treatment with SA, whereas its value increased following different algal extracts treatments. The highest anti-mutagenic inhibition activity of Dictyopteris delicatula added at 0.2% concentration was 72.96%, 69.84%, 56.89% and 43.59% with the algal polyphenol, polysaccharide, aqueous and methanol extract treatments, respectively. The different algal extracts minimized the genotoxicity and exhibited anti-mutagenic potential against SA in a dose-dependent manner. Phytochemical studies showed that Dictyopteris delicatula contained the highest total phenol, chlorophyll-a and carotenoid quantity. Moreover it exhibited the highest total antioxidant and DPPH scavenging activities. Total polysaccharides and the weight percentage of sulphated polysaccharides were relatively higher in Polysiphonia morrowii followed by Laurencia obtusa. Hydroquinone and bromophenol were detected only in the studied brown and red seaweeds, respectively. Polysiphonia morrowii and Laurencia obtusa contained the highest quantity of galactose, rhmnose and xylose, while Dictyopteris delicatula contained fucose and mannitol as main monosaccharide units. In conclusion, the studied seaweeds may be considered as rich sources of natural antioxidants. Meanwhile the investigated different algal extracts can minimize the genotoxicity in a dose-dependent manner and exhibit anti-mutagenic potential against the mutagenic substance sodium azide.

Schistosoma mansoni: Antiparasitic effects of orally administered Nigella sativa oil and/or Chroococcus turgidus extract.

Schistosoma mansoni is one of the parasites causing schistosomiasis, a disease which threatens millions of people all over the world. Traditional chemical drugs are not fully effective against schistosomaisis due to the evolving drug resistant worm strains, so exploring new remedies derived from natural products is a good way to fight schistosomiasis. In the present investigation two natural products, Nigella sativa oil and Chroococcus turgidus extract were used separately or in a combination to explore their effect on S. mansoni. The infected mice treated with Chroococcus turgidus extract or/and sativa seed oil showed a significant decrease in the total worm burden. The total number of deposited eggs by females of S. mansoni was significantly decreased in the liver of mice treated with Chroococcus turgidus extract or/and sativa seed oil. However, in the intestine, the number of eggs was significantly reduced in mice treated with algal extract and those treated with both algal extract and oil. Fecundity of female S. mansoni showed a significant decrease from mice treated with algal extract or/and sativa seed oil. According to SEM investigations the tegmental surface, oral and ventral suckers of worms also showed considerable changes; as the tubercles lost their spines, some are swollen and torn out. The suckers become edematous and enlarged while the tegmental surface is damaged due to the treatment with Chroococcus turgidus extract or/and sativa seed oil. In conclusion, the Nigella sativa oil and Chroococcus turgidus extract are promising natural compounds that can be used in fighting schistosomiasis.

Antiviral effect of edaphic cyanophytes on rabies and herpes-1 viruses.

Five cyanophyte species (Amorphonostoc punctiforme, Gloeocapsa turgidus, Sphaeronostoc coeruleum, Stratonostoc linckia f. spongiaeforme and Synechococcus cedrorum) were isolated and identified from sandy Egyptian soils. Polysaccharides extracted from these species showed a pronounced antiviral activity against Rabies and Herpes-1 viruses represented by the absence of the characteristic cytopathic effects of these viruses. It was found that 100 µg polysaccharide/ml induced 100% inhibition of the two viruses which, depending on the polysaccharide concentration. Both of Gloeocapsa turgidus and Synechococcus cedrorum showed higher antiviral activity against rabies virus than that against herpes-1 virus. Amorphonostoc punctiforme showed nil to weak antiviral activity against both viruses. It was suggested that polysaccharides of such species of cyanophyte react against human and animal viruses. So, it could be concluded that there is a need for further studies to explain the mode of action of these substances on the replication of different viral origins to know how one deals with cyanophyte polysaccharides as antiviral substances in the most suitable and effective manner.