Chem. Pharm. Bull.(オピニオン)

Isolation and characterization of bioactive compounds from plant resources: the role of analysis in the ethnopharmacological approach.

A review on phytochemistry and therapeutic uses of Hibiscus sabdariffa L.

Effects of extraction solvents on total phenolic and flavonoid contents and biological activities of extracts from Sudanese medicinal plants

Apigenin is a common dietary flavonoid with considerable cytotoxic activity in vitro and in vivo. Despite many mechanistic studies, less is known about resistance factors hampering apigenin's activity. We investigated the ATP-binding cassette (ABC) transporters BCRP/ABCG2, P-glycoprotein/ABCB1 and its close relative ABCB5. Multidrug-resistant cells overexpressing these ABC transporters were not cross-resistant toward apigenin. Moreover, apigenin inhibited not only P-glycoprotein but also BCRP by increasing cellular uptake of doxorubicin and synergistic inhibition of cell viability in combination with doxorubicin or docetaxel in multidrug-resistant cells. To perform in silico molecular docking studies, we first generated homology models for human P-glycoprotein and ABCB5 based on the crystal structure of murine P-glycoprotein. Their nucleotide binding domains (NDBs) revealed the highest degrees of sequence homologies (89%-100%), indicating that ATP binding and cleavage is of crucial importance for ABC transporters. Molecular docking of apigenin bound to the NDBs of P-glycoprotein and ABCB5 in molecular docking studies. Hence, apigenin may compete with ATP for NDB-binding leading to energy depletion to fuel the transport of ABC transporter substrates. Furthermore, we performed COMPARE and hierarchical cluster analyses of transcriptome-wide mRNA expression profiles of the National Cancer Institute tumor cell line panel. Microarray-based mRNA expressions of genes of diverse biological functions (signal transduction, transcriptional regulation, ubiquitination, autophagy, metabolic activity, xenobiotic detoxification and microtubule formation) significantly predicted responsiveness of tumor cells to apigenin. In conclusion, apigenin's activity is not hampered by classical mechanisms of multidrug resistance and the inhibition of ABC transporters by apigenin indicates that apigenin may overcome multidrug resistance in otherwise refractory tumors.

Activity of the dietary flavonoid, apigenin, against multidrug-resistant tumor cells as determined by pharmacogenomics and molecular docking.

Sudanese folk medicine represents a unique blend of indigenous cultures with Islamic, Arabic and African traditions. In addition, Sudan encompasses different terrains and climatic zones, ranging from desert and semi-desert in the north to equatorial with a short rainy season (semi-aridand semi-humid) in the centre to equatorial with a long rainy season (arid-humid and equatorialhumid) in the south. This variation contributes to the immense diversity of vegetation in the region. The flora of Sudan consists of 3137 species of flowering plants belonging to 170 families and 1280 genera. It is estimated that 15% of these plants are endemic to Sudan. The intersection of diverse cultures and the unique geography holds great potential for Sudanese herbal medicine. Medicinal and aromatic plants and their derivatives represent an integral part of life in Sudan. Indigenous remedies are the only form of therapy available to the majority of poor people. It has been estimated that only 11% of the population has access to formal health care. Therefore, research on the desired pharmacological effects and possible unwanted side effects or toxicity is required to improve efficacy and safety of Sudanese herbal medicine. In the future, it would be preferable to promote the use of traditional herbal remedies by conversion of raw plant material into more sophisticated products instead of completely replacing the traditional remedies with synthetic products from industrialized countries. The present review gives an overview of traditional Sudanese medicinal and aromatic herbs and their habitats, traditional uses, and phytochemical constituents.

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Haider Abdelgadir

Papers

Gems from traditional north-African medicine: medicinal and aromatic plants from Sudan

Cytotoxicity of 35 medicinal plants from Sudan towards sensitive and multidrug-resistant cancer cells.