Chemical profile, antiproliferative, antioxidant, and enzyme inhibition activities and docking studies of Cymbopogon schoenanthus (L.) Spreng. and Cymbopogon nervatus (Hochst.) Chiov. from Sudan.

Essential oils from the inflorescence of Cymbopogon schoenanthus and C. nervatus growing in Northern Sudan were examined for their chemical composition, antiproliferative activity against human breast carcinoma and human colon adenocarcinoma cell lines, antioxidant activity (phosphomolybdenum, antiradical, reducing power, and ferrous chelating), and enzyme inhibition activity against acetylcholinesterase butyrylcholinesterase, tyrosinase, α-glucosidase, and α-amylase. In silico study on the inhibition of tyrosinase and α-amylase was also performed. Piperitone (59.1%) and isomers of para-menthadienols (35.3%) were the main compounds in C. schoenanthus and C. nervatus oils, respectively. Oil from C. nervatus possessed higher antioxidant activity than that from C. schoenanthus except for its metal chelating ability. Both oils showed high antiproliferative activity. In silico study showed that trans-p-mentha-2,8-dien-1-ol and piperitone (both isomers) revealed the best docking scores for α-amylase and tyrosinase, respectively. In conclusion, oils from these two Cymbopogon species could be new natural agents with functional properties for food, cosmetics, and pharmaceutical industries. PRACTICAL APPLICATIONS: Recently, there is a growing tendency to replace synthetic oils by natural ones in the cosmetic, food, and pharmaceutical products. In this context, we investigated the chemical characterization and biological activities of two Cymbopogon species essential oils (C. schoenanthus (L.) Spreng. and C. nervatus). Antioxidant capacity, enzyme inhibition, and antiproliferative effects were tested for biological activities. Chemical characterization was identified by GC-MS. Based on our findings, the Cymbopogon species may be utilized as sources of natural bioactive agents in food industries.

Chemical composition, antiproliferative, antioxidant and antibacterial activities of essential oils from aromatic plants growing in Sudan.

OBJECTIVE: To explore the potential of essential oil, as therapeutic molecule source, from olibanum of Boswellia papyrifera (Burseraceae), leafy stems of Cymbopogon schoenanthus (Poaceae) and Croton zambesicus (Euphorbiaceae) and rhizome of Cyperus rotundus (Cyperaceae) found in Sudan. Respective essential oil was evaluated for anti-proliferative, antibacterial and antioxidant activity. METHODS: Essential oils were extracted by hydrodistillation and then analysed by gas chromatography coupled to mass spectrometry (GC-MS). Anti-proliferative activity was determined against human cell lines (MCF7 and MDA-MB231, HT29 and HCT116) by the thiazolyl blue tetrazolium bromide (MTT) procedure. Antioxidant activity was evaluated by diphenyl 2 pycril hydrazil (DPPH) assay. Antibacterial activity was determined against two Gram-positive and two Gram-negative bacteria by microdilution method. RESULTS: The essential oil from olibanum of Boswellia papyrifera contained mainly alcohol and ester derivatives (46.82%) while monoterpenes (69.84%) dominated in Corton zambesicus oil. Sesquiterpenes were the most highly represented classes of terpene derivatives in Cyperus schoenanthus (71.59%) and Cyperus rotundus (44.26%). Oil of Cymbopogon schoenanthus revealed the best anti-proliferative activity against HCT116 cell line with IC50 value at (19.1 ± 2.0) µg/mL. Oil of Croton zambesicus showed the best antioxidant activity [EC50 (4.20 ± 0.19) mg/mL]. All oils showed good antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus with minimum inhibitory concentration (MIC) value ranged from 16 to 250 µg/mL. CONCLUSIONS: The results suggest that the essential oils of these plants could be used as a source of natural anti-proliferative, antioxidant and antibacterial agents.

The Redox Cycler Plasmodione Is a Fast-Acting Antimalarial Lead Compound with Pronounced Activity against Sexual and Early Asexual Blood-Stage Parasites.

Previously, we presented the chemical design of a promising series of antimalarial agents, 3-[substituted-benzyl]-menadiones, with potent in vitro and in vivo activities. Ongoing studies on the mode of action of antimalarial 3-[substituted-benzyl]-menadiones revealed that these agents disturb the redox balance of the parasitized erythrocyte by acting as redox cyclers-a strategy that is broadly recognized for the development of new antimalarial agents. Here we report a detailed parasitological characterization of the in vitro activity profile of the lead compound 3-[4-(trifluoromethyl)benzyl]-menadione 1c (henceforth called plasmodione) against intraerythrocytic stages of the human malaria parasite Plasmodium falciparum We show that plasmodione acts rapidly against asexual blood stages, thereby disrupting the clinically relevant intraerythrocytic life cycle of the parasite, and furthermore has potent activity against early gametocytes. The lead's antiplasmodial activity was unaffected by the most common mechanisms of resistance to clinically used antimalarials. Moreover, plasmodione has a low potential to induce drug resistance and a high killing speed, as observed by culturing parasites under continuous drug pressure. Drug interactions with licensed antimalarial drugs were also established using the fixed-ratio isobologram method. Initial toxicological profiling suggests that plasmodione is a safe agent for possible human use. Our studies identify plasmodione as a promising antimalarial lead compound and strongly support the future development of redox-active benzylmenadiones as antimalarial agents.

Endophytic fungi associated with Sudanese medicinal plants show cytotoxic and antibiotic potential.

In this study, we isolated 15 endophytic fungi from five Sudanese medicinal plants. Each fungal endophytic strain was identified by sequencing of internal transcribed spacer (ITS) regions of rDNA. Ethyl acetate extracts were prepared from each endophyte cultivated in vitro and tested for their respective antibacterial activities and antiproliferative activities against human cancer cells. Antibacterial screening was carried out against two bacterial strains: Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus, by the broth dilution method. Cell viability was evaluated by the MTT procedure after exposure of MCF7 breast cancer cells and HT29 or HCT116 human colon adenocarcinoma cells to each endophytic extract. Of interest, Byssochlamys spectabilis isolated from Euphorbia prostata showed cytotoxicity (IC50 = 1.51 ± 0.2 µg mL(-1)) against MCF7 cells, but had a low effect against HT29 or HCT116 cells (IC50 > 20 µg mL(-1)). Cladosporium cladosporioides 2, isolated from Vernonia amygdalina leaves, showed antiproliferative activities against MCF7 cells (IC50 = 10.5 ± 1.5 µg mL(-1)) only. On the other hand, B. spectabilis and Alternaria sp. extract had antibacterial activities against the S. aureus strain. The findings of this work revealed that endophytic fungi associated with medicinal plants from Sudan could be considered as an attractive source of new therapeutic compounds.

Synthesis and antioxidant potential of novel synthetic benzophenone analogues.

Considering that oxidative stress is strongly implicated in the toxicity of chemotherapy, much effort is focused on the research of diverse antioxidants as protective agents. An efficient synthesis of three novel benzophenones containing 1,3-thiazol moiety (6a-c) is described. Their antioxidant power was evaluated in vitro and in three cell lines (the cancerous MCF7 and the non-cancerous hTERT-HME1 mammary cells, and the H9c2 cardiomyoblastic cells). One analogue 5-(2,5-dihydroxybenzoyl)-2(3H)-benzothiazolone (6c), displayed an important antioxidant activity, a low cytotoxicity, and could decrease reactive oxygen species production generated by tert-butyl hydroperoxide (tBHP) in all three cell lines. Interestingly, 6c was able to protect the non-cancerous cells against tBHP-induced death. Further studies are underway to determine its relevance as an adjuvant in oxidative stress inducing chemotherapy.

Antineoplastic and anticlastogenic properties of curcumin.

Curcumin is the pigment of turmeric and has been reported as a signal transduction modulator and inhibitor of transcription factors, for example, NF-kappaB. In our article we found a concentration-dependent cytotoxic activity of curcumin in a panel of eight leukemic cell lines (SKW-3, CEM, U-937, HL-60, HL-60/Dox, K-562, LAMA-84, and AR-230). Additive to synergistic interactions was recorded for combinations with bendamustine and idarubicine in SKW-3 and LAMA-84 cells. Noteworthy, in multiple myeloma cells (RPMI-8226 and U-266) a potentiation of the efficacy of bendamustine by curcumin application was found. Moreover, curcumin increased the bendamustine cytotoxicity in cultures of cells isolated from the bone marrow of a patient with non-Hodgkin's lymphoma (NHL). The increased bendamustine efficacy could be explained by NF-kappaB inhibition, because this factor is activated in many cancers, especially leukemia and multiple myeloma. Curcumin is characterized by low toxicity and was described to have a chemoprotective activity. Therefore, the level of reduced glutathione (GSH) was measured and a concentration-dependent increase of GSH levels was recorded in AR-230 and SKW-3 cells (concentration range 5-25 muM). Experiments with mice showed significant protection against cisplatin-induced chromosomal aberrations (clastogenic effect) and inhibition of mitoses in bone marrow cells. Curcumin alone caused reduction of the mitotic index. In combination with cisplatin, however, this parameter was increased when compared to cisplatin alone. Our data indicate that curcumin has pleiotropic effects on signal transduction by inhibiting transcription thus exerting antitumor activity. In addition, curcumin has protective and anticlastogenic activity by enhancing the scavenging of free radicals.

Cytoprotective effects of 5 benzophenones and a xanthone from Hypericum annulatum in models of epirubicin-induced cytotoxicity: SAR-analysis and mechanistic investigations.

A new benzophenone O-glucoside neoannulatophenonoside (1) together with the known pinocembrin-7-O-glucoside were isolated from the aerial parts of Hyperium annulatum Moris (Guttiferae). The former was identified as 3',5',6-trihydroxy-4-methoxybenzophenone-2-O-beta-D-glucopyranoside by means of chemical and physical evidence. The cytoprotective effects of the new compound together with the previously isolated from this species hypericophenonoside (2), annulatophenone (3), annulatophenonoside (4), acetylannulatophenonoside (5) and 1,3,7-trihydroxyxanthone (6) were evaluated in a model of epirubicin-induced cellular toxicity in K-562 cells. While the benzophenone O-glycosides 1, 2, 4 and 5 exerted substantial cytoprotective effects against the epirubicin cytotoxicity in K-562 cells the aglycones 3 and 6 lacked any significant cytoprotective activity. Biochemical investigations aimed at evaluating the free-radical scavenging activity of the tested compounds as well as their effects on the cellular glutathione stores were carried out as well, aiming at unravelling the mechanisms of cytoprotection. Finally, the ability of 1, 4 and 5 to ameliorate epirubicin-induced anticlonogenic effects on bone marrow cells colony forming units, in vitro were also evaluated. Taken together, the experimental data indicate that the benzophenone glycosides isolated from H. annulatum have a substantial cytoprotective potential against the toxic effects induced by epirubicin and necessitates further detailed pharmacological evaluation of these compounds as possible chemoprotective/radioprotective agents.

Synthesis, characterization, and cytotoxic activity of new lanthanum(III) complexes of bis-coumarins.

Complexes of lanthanum(III) with bis-coumarins: 3,3'-benzylidene-bis(4-hydroxy-2H-1-benzopyran-2-one) (H(2)L1) and bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-(1H-pyrazol-3-yl)-methane (H(2)L2) were synthesized by reaction of lanthanum(III) salt and the ligands, in amounts equal to metal : ligand molar ratio of 1 : 2. The complexes were prepared by adding an aqueous solution of lanthanum(III) salt to an aqueous solution of the ligand subsequently raising the pH of the mixture gradually to circa 5.0 by adding dilute solution of sodium hydroxide. The lanthanum(III) complexes with bis-coumarins were characterized by different physicochemical methods-elemental analysis, IR-, (1)H-, and (13)C-NMR-spectroscopies, and mass spectral data. The spectral data of lanthanum(III) complexes were interpreted on the basis of comparison with the spectra of the free ligands. This analysis showed that in the La(III) complexes, the ligands coordinated to the metal ion through both deprotonated hydroxyl groups. On the basis of the nu(C=O) red shift observed, participation of the carbonyl groups in the coordination with the metal ion was also suggested. In the present study, we performed a cytotoxic-effects screening of the lanthanum complexes with H(2)L1 and H(2)L2 in a panel of human tumor cell lines, using the standard MTT-dye reduction assay for cell viability. The panel consisted of the acute myeloid leukemia-derived HL-60 and the chronic myeloid leukemia-derived BV-173. Following a 24- hour treatment of BV-173 cells with lanthanum complex of H(2)L1 at 100 or 200 microM led to a DNA-laddering. The findings suggest that the observed cytotoxicity of the lanthanum complex of H(2)L1 on BV-173 is at least partly mediated through induction of programmed cell death.

Cytotoxic activity of new cerium (III) complexes of bis-coumarins.

Complexes of cerium (III) with bis-coumarins: 3,3'-benzylidene-bis(4-hydroxy-2H-1-benzopyran-2-one) and bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-(1H-pyrazol-3-yl)-methane were synthesized by reaction of cerium (III) salt and the ligands, in amounts equal to metal/ligand molar ratio of 1:2. The complexes were prepared by adding an aqueous solution of cerium (III) salt to an aqueous solution of the ligand subsequently raising the pH of the mixture gradually to ca. 5.0 by adding dilute solution of sodium hydroxide. The cerium (III) complexes with bis-coumarins were characterized by different physicochemical methods--elemental analysis, IR-, 1H- and 13C-NMR-spectroscopies and mass-spectral data. The spectral data of cerium (III) complexes were interpreted on the basis of comparison with the spectra of the free ligands. This analysis showed that in the Ce (III) complexes the ligands coordinated to the metal ion through both deprotonated hydroxyl groups. On the basis of the nu(C=O) red shift observed, participation of the carbonyl groups in the coordination to the metal ion was also suggested. Cytotoxic screening by MTT assay was carried out. In the present study we performed comparative evaluation of the cytotoxic effects of the two newly synthesized cerium complexes against the acute myeloid leukemia derived HL-60 and the chronic myeloid leukemia (CML)-derived BV-173. In addition the cytotoxic effects of Ce (III) complex with 3,3'-benzylidene-bis(4-hydroxy-2H-1-benzopyran-2-one) were evaluated on the CML-derived K-562 and LAMA-84 cells, characterized by relative low responsiveness to chemotherapy. The DNA isolated from the cytosolic fraction of BV-173 cells after 24 h treatment with the same complex (at 100 and 200 microM) demonstrated a laddering phenomenon that is indicative for apoptotic cell death.