الفهرس 
Cyanobacterial bioactive compounds as an enhancer for the quality of some cosmetics.
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Abstract
The present study aimed to use bioactive cyanobacterial substances to improve the quality
of skin formulations cosmetics. This aim was accomplished through the following objectives:
Twelve isolates of cyanobacteria were identified according to 16S rRNA sequence. These
isolates were Nostoc sp. (3 isolates), Phormidium ambigum (2 isolates) and one isolate of each
Calothrix sp., Fischerella sp., Anagnostidinema amphibium, Desertifilum dzianense, Desertifilum
tharense, Laspinema thermale and Chlorella sp. which is classified as microalgae.
The methanolic extract and exopolysaccharides (EPS) extracted from isolated
cyanobacteria were characterized chemically using Fourier Transform Infrared Spectrometer, and
biologically through evaluating their antimicrobial and antioxidant activities. Only, Desertifiluim
tharense methanolic extract had antimicrobial activity against all tested microorganisms with
inhibition zone ranged from 7 mm against Candida albicans to 7.7 mm against Bacillus cereus.
Methanolic extract of Nostoc sp. (Am13) exhibited the highest scavenging activity of 20.8±0.2%.
Only, the exopolysaccharide extracted from Desertifilum tharense exhibited antimicrobial activity
against all tested microbes with inhibition zone ranged from 6 mm against B. cereus and MARSA
to 9 mm against Candida albicans. The highest scavenging activity of 77.7±0.5% was recorded
with EPS of Nostoc sp. (Am8). The FTIR spectrum demonstrated that EPS was a type of
polyanionic polysaccharide that contained carboxyl and carbonyl groups.
The isolates had superior activity to synthesize silver nanoparticles (Ag-NPs)
extracellularly under light conditions. Comparing the results of ultraviolet-visible (UV–Vis)
spectroscopic analysis indicated that, the Ag-NPs synthesized by non-heterocystous cyanobacteria
gave sharp SPR peaks at relatively short wave length. The other chemical and physical
characterization tests were conducted for Ag-NPs produced from Desertifilum tharense and
Phormidium ambiguum (Am6). The TEM micrographs showed spherical shape of Ag-NPs
produced by Desertifilum tharense and Phormidium ambiguum with particle size in a range of 6.24
– 11.7 nm and 6.46 – 12.2 nm, correspondingly. The FTIR spectrum exhibited the presence of OH stretching vibration of polysaccharides, and N-H stretching vibration of proteins.
The antimicrobial and antioxidant efficiency of Ag-NPs (1 mM) synthesized
extracellularly under light conditions by non-heterocystous cyanobacteria were assessed. All tested
Ag-NPs had effective antimicrobial activity against all selected pathogenic microbes. The highest
value of antioxidant activity of 49.6±0.5 was recorded with Ag-NPs of Phormidium ambiguum.
In this study, the anticancer effect of Ag-NPs synthesized by Desertifilum tharense was
evaluated in vivo against Ehrlich Cell Carcinoma (ECC) in mice through different determinations
of hematological parameters and histopathology analysis of tumor tissues. The treatment applying
Ag-NPs with EPS was considered as a good therapy response as a marked necrosis was observed
in malignant growth.
Finally, the cyanobacterial products including Ag-NPs, EPS and methanolic extract were
tested in skin cream. There were no signs of edema in all prepared formulations.