Mahmoud H. Abdelkader

Synthesis and tautomeric structure of novel 3,7-bis(arylazo)-2,6-diphenyl-1H-imidazo-[1,2-b]pyrazoles in ground and excited states

Abstract Two series of novel 3,7-bis(arylazo)-2,6-diphenyl-1 H -imidazo[1,2- b ]pyrazoles were prepared starting from N -aryl 2-oxo-2-phenylethanehydrazonoyl bromides. The acid dissociation constants in both the ground and excited states, p K and p K ∗ , respectively, were determined for both series and were correlated by the Hammett equation. The results of such correlations together with spectral data indicated that the title compounds exist predominantly in the 1 H -bis-(arylazo) form in both ground and excited states.

Chlorophyll derivative mediated PDT versus methotrexate: An in vitro study using MCF-7 cells

BACKGROUND Breast cancer is the most common cause of cancer deaths among women worldwide. Although chemotherapy is a standard method for the treatment of breast cancer, the photodynamic therapy (PDT) is a recent promising modality for cancer diagnosis and treatment. Its major advantages over chemotherapy are better selectivity of tumour tissue destruction and lack of severe local and systemic complications. This work is directed towards evaluation of the efficacy of Photodynamic therapy using chlorophyll derivative (CHL) as a photosensitizer in treatment of breast cancer. It also aims at investigation of the genetic safety of chlorophyll mediated PDT in comparison to the conventional chemotherapy. METHODS Both methotrexate (MTX) and light activated chlorophyll derivative were used to target MCF-7 breast cancer cell line. Standard karyotyping and alkaline single cell microgel electrophoresis assay (Comet assay) were applied on normal human peripheral blood lymphocytes (HPL) in order to investigate the respective possible mutagenic and genotoxic side effects that might result from application of each therapeutic modality. RESULTS Results obtained from this study showed that 50% of MCF-7 tumour cell death (LC(50)) was reached by using a concentration of chlorophyll derivative that is 138 times lower than MTX. Moreover, chlorophyll derivative exerted no genetic side effects as compared to MTX that resulted into several types of chromosomal breakages. CONCLUSIONS Compared to MTX, light activated chlorophyll derivative proved to be a better candidate for breast cancer cell toxicity, referring to its higher efficacy at tumour cells killing, safety to normal cells and simple method of extraction.

Functional characterization of Fospeg, and its impact on cell cycle upon PDT of Huh7 hepatocellular carcinoma cell model

BACKGROUND Although several treatment options are available for hepatocellular carcinoma (HCC), their application is mostly restricted to early diagnosed cases or includes liver transplantation, which is rarely available due to donor scarcity. The attractiveness of PDT as a cancer treatment does not only come from its minimal invasiveness, but also from the high selectivity due to tumor localization that can be applied. Precise focusing of light on tumor lesions will result in tumor-specific PDT activation. Novel photosensitizers can be applied in such low concentrations that cells not subjected to irradiation remain healthy. The lethal effect and mechanism of death induction of the photosensitizer Fospeg has never been studied on hepatocellular carcinoma. The aim of the present study is to functionally analyze the impact of PDT on Huh-7 HCC cell line, as well as to analyze its impact on cell cycle protein expression. METHODS Cellular viability, and proliferation assays were conducted via MTT and BrdU assay, respectively. Transfected cell models of Huh7 with different constructs harboring cell cycle genes and downstream reporter luciferase gene were generated. RESULTS Our results show a statistically significant decrease in both viability and proliferation of Huh-7 cells following PDT, while maintaining Fospeg and laser concentrations far below toxic levels. Proliferative cell cycle genes show a tendency of inhibition, while p53 levels show a significant increase following PDT. CONCLUSION Fospeg-mediated PDT is a promising strategy for treatment of hepatocellular carcinoma and needs to be further explored in vivo.

Effect of binary solvents on the critical micelles concentration by using 1-methyl-4-[4′-aminostyryl]pyridinium iodide

Abstract The influence of preferential solvation of 1-methyl-4-[4′-aminostyryl]pyridinium iodide (M-NH 2 ) on critical micelles concentration (c.m.c) has been studied by using sodium dodecyl sulfate (SDS) in the binary aqueous mixtures of protic and aprotic co-solvents including glycerol, ethylene glycol, dimethyl sulfoxide (DMSO), and acetone. The results reveal that the c.m.c depends on the polarity, in addition to the dielectric constant of the co-solvents. The lower the polarity as well the dielectric constant ( e ), the more effective the breaking of the micelles. Acetone which has a low polarity ( Z ), low dielectric constant ( e ), and large hydrophobic surface is shown to be the strongest denaturant for micelles. On the other hand DMSO, which has relative hydrophobic effect with large ( e ), in addition with glycerol and ethylene glycol which has large ( e ) and small hydrophobic surface have the weakest effect.

Liposomal delivery of ferrous chlorophyllin: A novel third generation photosensitizer for in vitro PDT of melanoma

BACKGROUND Cutaneous melanoma (CM) has substantially increased among Caucasian populations in the past few decades. This increased the number of CM deaths throughout the world. Pigmentation of melanoma reduces the efficacy of photodynamic therapy (PDT). Third generation photosensitizers (PSs) are characterized by improved targeting to the diseased tissue and reduced systemic side effects. This study is directed towards synthesis and characterization of liposomes encapsulating sodium ferrous chlorophyllin (Fe-CHL) and assessing its efficacy as a PS in PDT of melanoma. METHODS Phenylthiourea (PTU) was used as a melanin synthesis inhibitor. PDT has been applied on de-pigmented melanoma cells using liposomes-encapsulated Fe-CHL. Cell death mechanisms after PDT were evaluated. RESULTS Treatment of melanoma cells with 200μM of PTU for 48h provided 49.9% melanin inhibition without significant cytotoxicity. Transmission electron microscope (TEM) results proved an increase in the cellular uptake of liposomes by increasing incubation period from 6 to 24h via endocytosis with preferential accumulation in the mitochondria and the nucleus. Following de-pigmentation, PDT was applied resulting in LC50 of 18.20 and 1.77μM after 24 and 48h incubation with liposomes-encapsulated Fe-CHL respectively and exposure to 56.2J/cm2 monochromatic red laser of wavelength of 652nm. Mechanism of cell death of Fe-CHL mediated PDT was found to be a combination of both apoptosis and necrosis. CONCLUSIONS Liposomes could be efficiently employed as a potential sustained release delivery system in the Fe-CHL-mediated PDT of de-pigmented melanoma.

History of Photodynamic Therapy

Photodynamic therapy (PDT) is a form of phototherapy that involves three key components: a photosensitizer, a light source, and tissue oxygen. When these components are combined together, they become toxic to the targeted cells.

Field implementation using chlorophyll derivatives with sunlight for malaria, filaria and dengue fever vectors control in infested Africa swamps

In this work, we present the successful field implementation of using Photodynamic modality to control Malaria, Filaria and Dengue Fever vectors in infested epidemic swamps in Uganda, Ethiopia and Sudan. As the Photodynamic technique has become a major approach for the control of human parasites and noxious insects. Field investigations were carried out based on laboratory and semi-field results. In these trials, chlorophyll derivatives were added to the infested swamps to be taken by the mosquito larvae and the accumulated photoactive compound (photosensitizer) inside the larvae body induces upon sunlight exposure an oxidation stress, that results in organism death. As example in Kasangati and Namanve cities of Wakiso a district in Uganda , chlorophyll derivatives , as sunlight active photosensitizers was applied to cover 250 000 square meter of infected swamps and sand pits (4 gm/ m2).The infected cities were mapped for this field study using Geographical Positioning System (GPS). All the biotic and a-biotic factors were measured before and after treatment. Confocal laser scanning microscopy measurements were used to monitor the concentration and the dynamic distribution of chlorophyll derivatives inside the larvae of Anopheles gambiae mosquito. The results reveal that from 85% to 100% mortality of larvae population are obtained at different concentrations of Chlorophyll derivatives (0.1 -100µM). Other biological beneficiary organisms, such as the dragon fly larvae and mosquito predator larvae, which were present in the same treated swamps were not affected (target selectivity). The field trials are the result of three years continuous and persistent work, which showed promising success in controlling Malaria, Filaria and Dengue Fever vectors by cutting the mosquito’s life cycle without new generation, formation, or reinfestation.

Biochemical Studies Of The Effect Of Two Laser Radiation Wavelengths On The Khapra Beetle Trogoderma Granarium Everts (Coleoptera : Dermestidae)

The present work was carried out to evaluate the actual effect of subleathal dosage of LD30 of two different lasers (Argon‐ion and CO2 lasers) on the main metabolites, phosphatases enzymes, transaminases, acetylcholinestrase and peroxidases in the one day adult stage of Trogoderma granarium treated as 2–3 days old pupae. Our results clearly indicated that two different wavelengths of laser radiation increased significantly the total proteins content, whereas no significant changes occurred in the total lipids for the two laser radiation wavelenghts. On the other hand the total carbohydrates were significantly decreased when irradiating using CO2 laser wavelength which is not the case for the Argon‐ion laser radiation. Significant changes of phosphatases occurred for both wavelengths. Inhibition of transaminases GOT (glutamic oxaloacetic transaminases) and insignificant changes of GPT (glutamic pyruvic oxaloacetic transaminases) was observed for both laser wavelengths. Significant inhibition of acetyl chol...

Dermal delivery of Fe-chlorophyllin via ultradeformable nanovesicles for photodynamic therapy in melanoma animal model

ABSTRACT Melanoma is resistant to chemotherapeutics with poor prognosis and high potential of metastasis. Photodynamic therapy (PDT) represents a localized therapeutic modality, as cytotoxicity occurs when light activates photosensitizer (PS) at the tumour site. The aim of this study is dermal delivery of a high molecular weight hydrophilic photosensitizer (PS), ferrous chlorophyllin (Fe‐CHL) via transethosomes for treatment of melanoma by PDT. Transethosomes were made of phosphatidyl choline, edge activator and 20%w/v Ethanol. They were evaluated for mean size, zeta potential, entrapment efficiency, ex‐vivo permeation, localization in skin layers by transmission electron microscope (TEM), and finally, evaluated in melanoma animal model. Transethosomes of different mean vesicle size were evaluated for their skin retention and permeation through mice skin. TE of ˜500nm (E3) being ultradeformable showed deep localization in skin confirmed by ex‐vivo and TEM micrographs without permeation of PS to recipient compartment due to its size. The proposed study offers successful treatment of resistant melanoma by PDT, where complete tumour regression of small tumours occurred after single PDT, while large tumours after double PDT without recurrence for 8months. This indicates the efficiency of nanovesicles in PS delivery and the efficiency of Fe‐CHL in production of reactive oxygen species.

In vivo suppression of solid Ehrlich cancer via chlorophyllin derivative mediated PDT: an albino mouse tumour model

In this study, copper chlorophyllin was used as a photosensitizer for photodynamic therapy (PDT) in Ehrlich tumour mouse model. Six groups of animals comprising 5 animals per group were subcutaneously transplanted with 1x106 Ehrlich tumour cells. A single dose of 200 μg/gm body weight chlorophylin derivative was administered by intravenous (IV) or intratumoral (IT) routes. Mice were exposed to monochromatic red laser of 630 nm for 1 h, and tumour regression was followed up for three consecutive months post treatment. Several Biochemical, histological and molecular tests were performed in order to evaluate the efficacy and safety of the applied treatment. An interest has been also directed towards investigating the molecular mechanisms underlying chlorophyllin derivative mediated PDT. PDT-treated animals via either the IV or IT routes showed significant decrease in tumour size 72 h post-treatment. Tumours at the IV-PDT group disappeared totally within a week with no recurrence over three months follow up. In the IT-PDT, the decrease in tumour size at the first week was interrupted by a slight increase; however never reached the original size. Histological examination of tumour tissues of the IV-PDT group at 24 h post treatment demonstrated restoring the normal muscle tissue architecture, and the biochemical assays indicated normal liver functions. The immunohistochemical analysis of caspase-3, and the quantitative PCR results of caspases-8 and 9 proved the presence of extrinsic apoptotic pathway after cholorphyllin derivative-mediated PDT. In conclusion IV-PDT strategy proved better cure rate than the IT-PDT, with no recurrence over three months of follow up.