Publications by authors named "Sami Khalid"

In the search for new bioactive agents against the infectious pathogen responsible for the neglected tropical disease (NTD) mycetoma, we tested a collection of 27 essential oils (EOs) in vitro against , the primary pathogen responsible for the fungal form of mycetoma, termed eumycetoma. Among this series, the EO of (Santalaceae), i.e.

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Mycetoma is a devastating neglected tropical infection of the subcutaneous tissues. It is caused by fungal and bacterial pathogens recognized as eumycetoma and actinomycetoma, respectively. Mycetoma treatment involves diagnosing the causative microorganism as a prerequisite to prescribing a proper medication.

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The chemotherapy of tumors is frequently limited by the development of resistance and severe side effects. Phytochemicals may offer promising candidates to meet the urgent requirement for new anticancer drugs. We screened 69 phytochemicals, and focused on gedunin to analyze its molecular modes of action.

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Redox-active drugs are the mainstay of parasite chemotherapy. To assess their repurposing potential for eumycetoma, we have tested a set of nitroheterocycles and peroxides in vitro against two isolates of , the main causative agent of eumycetoma in Sudan. All the tested compounds were inactive except for niclosamide, which had minimal inhibitory concentrations of around 1 µg/mL.

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In a screening of Sudanese medicinal plants for antiprotozoal activity, the chloroform fractions obtained by liquid-liquid partitioning from ethanolic extracts of fruits of var. and stems of Roth ex Schult. exhibited activity against axenically grown amastigotes.

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Neglected tropical diseases are major health hazards in developing countries. Annually, up to 30 million people are affected by either Chagas disease, African trypansomiasis or leishmaniasis, and more than 200 million by malaria. Most of the currently available drugs have drawbacks in terms of toxicity, limited oral availability, development of resistance, or non-affordability.

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A screening of Sudanese medicinal plants for antiprotozoal activities revealed that the chloroform and water fractions of the ethanolic root extract of exhibited appreciable bioactivity against . The antileishmanial activity was tracked by HPLC-based activity profiling, and eight compounds were isolated from the chloroform fraction. These included lignans tetrahydrofuroguaiacin B (), nectandrin B (), furoguaiaoxidin (), and 3,3'-dimethoxy-4,4'-dihydroxylignan-9-ol (), and four cinnamoylphenethyl amides, namely dihydro-feruloyltyramine (), ()--feruloyltyramine (), ,'-diferuloylputrescine (), and 7'-ethoxy-feruloyltyramine ().

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Background: Oxidative processes might increase in patients with end-stage renal disease (ESRD) according to the current literature. Oxidative stress (OS) is a risk factor of atherosclerosis and cardiovascular complications, which are major causes of mortality among ESRD patients. Haemodialysis (HD) is life-saving procedure, nevertheless it is an active chronic inflammatory status that could augment cardiovascular disease and increase mortality.

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Background: Practices of biopiracy to use genetic resources and indigenous knowledge by Western companies without benefit-sharing of those, who generated the traditional knowledge, can be understood as form of neocolonialism.

Hypothesis: The One-World Medicine concept attempts to merge the best of traditional medicine from developing countries and conventional Western medicine for the sake of patients around the globe.

Study Design: Based on literature searches in several databases, a concept paper has been written.

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This paper describes an analysis of the diversity and chemical toxicity assessment of three chemical libraries of compounds from African flora (the p-ANAPL, AfroMalariaDb, and Afro-HIV), respectively containing compounds exhibiting activities against diverse diseases, malaria and HIV. The diversity of the three data sets was done by comparison of the three most important principal components computed from standard molecular descriptors. This was also done by a study of the most common substructures (MCSS keys).

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Background: Cerebral malaria is a rapidly developing encephalopathy caused by the apicomplexan parasite Plasmodium falciparum. Drugs currently in use are associated with poor outcome in an increasing number of cases and new drugs are urgently needed. The potential of the medicinal plant Azadirachta indica (Neem) for the treatment of experimental cerebral malaria was evaluated in mice.

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Ethnopharmacological Relevance: In agreement with ethnomedicinal reports, the dichloromethane extract of Ageratum conyzoides L. (Asteraceae) was recently shown to be of considerable activity against Trypanosoma brucei rhodesiense, the etiologic agent of East African Human Trypanosomiasis (East African Sleeping Sickness). Isolated compounds, namely, methoxylated flavonoids as well as the chromene derivative encecalol methyl ether, were less active than the crude extract.

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Background: Malaria is a major public health problem in the world, but treatment of malaria is becoming more difficult due to increasing drug resistance. Therefore, the need for alternative drugs is acute.

Aims: This study investigated the antiplasmodial and protective effect of an ethanolic extract of the leaves from a traditionally used medicinal plant, Azadirachta indica (Neem) in a mouse model of malaria.

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Aim Of The Study: The dichloromethane extract prepared from aerial parts of Ageratum conyzoides L. (Asteraceae), a plant commonly used in folk medicine for a number of illnesses including sleeping sickness, was recently found to exhibit a prominent activity (IC(50)=0.78 microg/mL) against bloodstream forms of Trypanosoma brucei rhodesiense, the etiologic agent of East African Human Trypanosomiasis (East African Sleeping Sickness).

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This review provides a panoramic view of Prof. Kurt Hostettmann's contribution to the study of African medicinal plants as documented in over 85 publications with collaborators from about a dozen African countries. Many novel bioactive secondary metabolites were isolated, their structures elucidated by hyphenated HPLC techniques and their biological activity determined.

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Prompted by results of our previous studies where we found high activity of some sesquiterpene lactones (STLs) against Trypanosoma brucei rhodesiense (which causes East African sleeping sickness), we have now conducted a structure-(in-vitro)-activity study on a set of 40 STLs against T. brucei rhodesiense, T. cruzi, Leishmania donovani and Plasmodium falciparum.

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In vitro screening of the dichloromethane extracts of 16 Asteraceae species native to Sudan for activity against major protozoan pathogens revealed that a Xanthium brasilicum Vell. [syn. X.

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The anti-trypanosomal activity of six sesquiterpene lactones (helenalin, mexicanin I, 11alpha,13-dihydrohelenalin acetate, chamissonolide, ivalin and isoalantolactone) against the African Trypanosoma brucei rhodesiense and American T. cruzi was investigated. All tested compounds were found active towards both parasites, the former being generally more sensitive.

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A new limonoid was isolated from the bark of Khaya senegalensis and identified as 2,6-dihydroxyfissinolide. The assignments of some signals in the (13)C NMR spectrum of fissinolide have been reversed and the signals of the (1)H NMR spectrum of methyl 3beta-acetoxy-6-hydroxy-1-oxomeliac-14-enoate have been assigned. The limonoids only showed moderate antiprotozoal activities.

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