Antiproliferative effect of the Red Sea cone snail, Conus geographus

Purpose: To investigate the antiproliferative effect of the Red Sea cone snail, Conus geographus, against 4 MCF-7 (breast), MDA-MB-231 (epithelial human breast), HepG2 (hepatocellular) and SKOV-3 (ovarian) cancer cell lines. Methods: Extraction of Red Sea cone snail sample with a mixture of CH2Cl2 and CH3OH (1:1, v/v) yielded 0.55 g of a green viscous material. The cytotoxic effects of the organic extract against the cancer cell lines were determined using cell proliferation (MTT) assay, and the half-maximal concentration (IC50) values measured. The effect of the crude extract on the cell cycle of the HepG-2 was determined by flow cytometry. Results: The extract produced significant inhibitory effects against SKOV-3, MDA-MB-231, MCF-7 and HepG2, with IC50 values of 22.7 ± 2.2, 68.7 ± 6.2, 47 ± 4.2 and 19 ± 2.1 μg/mL, respectively. Cell cycle analysis revealed that the extract enhanced accumulation of HepG2 cells in the Go/G1 phase, at a level of 23.4 and 24.1 % at IC50 (19 μg/mL) and ½ IC50 (9.5 μg/mL), respectively, when compared to the untreated cells. Conclusion: These results indicate that C. geographus extract exhibits potent cytotoxic effect against HepG2 cells via a mechanism involving G0/G1 cell cycle arrest. Thus, C. geographus is a potential source of a new anti-cancer agent. Keywords: Conus geographus, Marine invertebrate, HepG2, Antiproliferatio

Green synthesis, antimicrobial and cytotoxic effects of silver nanoparticles mediated by Eucalyptus camaldulensis leaf extract

Objective: To investigate the environmental-friendly extracellular biosynthetic technique for the production of the silver nanoparticles (AgNPs) by using leaf extract of Eucalyptus camaldulensis (E. camaldulensis). Methods: The NP were characterized by colour changes and the UV-visible spectroscopy. The cytotoxic effects of prepared AgNPs was detected against four types of pathogenic bacteria, including two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli) and two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) by using agar well diffusion method. Results: A peak absorption value between 400-450 nm for the extract and the colour change to dark brown were corresponding to the plasmon absorbance of AgNPs. On the other hand, aqueous extract of E. camaldulensis leaves could be effective against tested microorganisms which showed inhibition zones of 9.0-14.0 mm. Furthermore, biologically synthesized AgNPs had higher ability to suppress the growth of the tested microorganisms (12.0-19.0 mm). Conclusions: Our findings indicated that extracellular synthesis of AgNPs mediated by E. camaldulensis leaf extract had an efficient bactericidal activity against the bacterial species tested. The exact mechanism of the extracellular biosynthesis of metal NP was not well understood. Further studies are needed to highlight the biosynthesis process of AgNPs and also to characterize the toxicity effect of these particles

ASSESSMENT OF IN-VITRO ANTI-FUNGAL POTENTIAL OF ETHANOLIC EXTRACT OF CALLIGONUM COMOSUM AGAINST TWO FUNGAL POSTHARVEST PATHOGENS OF FRUITS AND VEGETABLES IN SAUDI ARABIA

ABSTACT: The present investigation aimed to evaluate the antifungal activity of Calligonum comosum extracts, frequently used in traditional medicine against two phytopathogenic fungi using agar well diffusion technique. Calligonum comosum was selected as a model plant species for this investigation on the basis of its reported ethno-botanical uses. Ethanolic extracts of Calligonum comosum plant was screened in vitro for its antifungal activity against two fungal species (Alternaria spp and Rhizopus spp). Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of the extracts were determined. Three extracts were assayed from different parts of the plant (leaves, stem and roots). Generally, the results showed that all extracts inhibited the fungal growth. Regardless of the plant part assayed, the MIC and MFC values of the extracts were in the range between 3.13 and 12.50 mg ml-1 for both fungal species. Interestingly, the highest significant level of mycelia growth inhibition zone was observed in the stem tissues and the lowest level was detected in root tissues. In the current study, the fungal growth inhibition zone was slightly different among the two fungal genera with respect to the plant parts used. In the light of these findings it could be concluded that, the ethanolic extracts of Calligonum comosum exhibit powerful fungicidal properties indicating the presence of potential antifungal compounds effective in the treatment of plant diseases. Further work in no doubt required to identify the compounds in such extracts responsible for the antifungal activity in Calligonum comosum. Provision of detaile

Microsoft Word - 011-Afrah Eltayeb Mohammed _1_.doc

ABSTRACT: Light is the most important environmental factor that critically affects growth and development of algae through its immediate influence on photosynthesis. In such a process, the initial phase (light reactions) involves light absorption resulting in the formation of intermediate energy compounds (ATP and NADPH), which would later be utilized for driving the second phase of photosynthesis (carbon fixation) in the Calvin cycle. In the current investigation the principal objective was to evaluate the effect of different light conditions on the physiological and growth behaviour of the Cyanobacterium, Phormidium fragile. To realize that goal carbohydrates content as well as dry mass production were analyzed and determined. Phormidium fragile tissues were propagated in sterilized flasks containing an appropriate algal culture and subjected to four different light conditions: sun light, laboratory light, white lamb light (control) and darkness. Analysis of carbohydrates content showed that the algal growth under both laboratory and darkness conditions exhibited significantly higher values (106 mg and 81 mg, respectively) relative to control (38 mg). On the other hand, the dry matter content was significantly lower in darkness and laboratory conditions (30 and 35 mg, respectively) compared to that of the control (75 mg). Based on these findings our present study provided additional supporting evidence for the significance of light energy as a determinant factor in the photosynthetic activity of algae in relation to dry mass accumulation and carbohydrate metabolism. Further studies need to be carried out in order to validate our conclusions