Five xanthone derivatives and one flavanol were isolated from the dichloromethane extract of Garcinia mangostana. Dichloromethane, ethyl acetate extract and the major xanthone (α-mangostin) were evaluated in vitro against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. The major constituent α-mangostin was also checked for antimicrobial potential against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Bacillius subtilis, Staphylococcus aureus, Mycobacterium smegmatis, M. cheleneoi, M. xenopi and M. intracellulare. Activity against P. falciparum (IC50 2.7 μg/mL) and T. brucei (IC50 0.5 μg/mL) were observed for the dichloromethane extract, however, with only moderate selectivity was seen based on a parallel cytotoxicity evaluation on MRC-5 cells (IC50 9.4 μg/mL). The ethyl acetate extract was inactive (IC50 > 30 μg/mL). The major constituent α-mangostin showed rather high cytotoxicity (IC50 7.5 μM) and a broad but non-selective antiprotozoal and antimicrobial activity profile. This in vitro study endorses that the antiprotozoal and antimicrobial potential of prenylated xanthones is non-conclusive in view of the low level of selectivity.

Selective cytotoxic effect toward tumor cells but not the normal tissues represent a major challenge in cancer drug discovery. Herein, we describe the synthesis and selective antitumor activity of some HHT. All the synthesized compounds showed a good antitumor activity against leukemia K562 cells. In regard to cytotoxicity in normal cells, compounds (1-11) showed no cytotoxic effect within 200 μM range, however compounds 12-16 showed non-selective cytotoxic effect.

Selective cytotoxic effect toward tumor cells but not the normal tissues represent a major challenge in cancer drug discovery. Herein, we describe the synthesis and selective antitumor activity of some HHT. All the synthesized compounds showed a good antitumor activity against leukemia K562 cells. In regard to cytotoxicity in normal cells, compounds (1-11) showed no cytotoxic effect within 200 μM range, however compounds 12-16 showed non-selective cytotoxic effect.

Selective cytotoxic effect toward tumor cells but not the normal tissues represent a major challenge in cancer drug discovery. Herein, we describe the synthesis and selective antitumor activity of some HHT. All the synthesized compounds showed a good antitumor activity against leukemia K562 cells. In regard to cytotoxicity in normal cells, compounds (1-11) showed no cytotoxic effect within 200 μM range, however compounds 12-16 showed non-selective cytotoxic effect.

In the course of our screening program for new bioactive compounds from our natural product library, a number of ‘talented’ strains were discovered based on their bioactivity spectrum or novel peaks on liquid chromatography-diode array detection-mass spectrometry (LC-DAD-MS) analysis. A Streptomyces sp. LS1924 strain was found to have the ability to produce bioactive metabolites and was selected to be studied further leading to the discovery of LS1924A (1), a new analog of emycins, together with three known compounds of angucyclinone family. In this paper, we report the fermentation, isolation, chemical characterization of these compounds and the bioactivity of the new compound.

Seventeen daucane sesquiterpenoid esters, including a new one (4), were isolated from the root of Ferula hermonis Boiss. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidence and correlated with known compounds. The relative stereochemistry of the new compound was determined using 2D NOESY and the most stable and the lowest energy conformation was determined using molecular modelling. The antimicrobial activity was evaluated by determination of MIC using the broth microdilution method against six bacterial strains and one fungal strain (Pseudomonas aeruginosa PAO1, Escherichia coli, Bacillus subtilis ATCC6633, Mycobacterium bovis BCG Pasteur, Mycobacterium tuberculosis H37Rv, Staphylococcus aureus ATCC6538 and Candida albicans SC5314). There was a significant indication that compounds 15, 16, 17 demonstrated potent activity against Gram +ve (S. aureus, B. subtilis), as well as Mycobacterium strains M. bovis BCG and M. tuberculosis H37Rv. None of the isolated compounds exhibited a significant antifungal activity. In the antioxidant study using the DPPH assay method, the highest radical scavenging activity was observed for compounds 15, 16, 17.

Seventeen daucane sesquiterpenoid esters, including a new one (4), were isolated from the root of Ferula hermonis Boiss. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidence and correlated with known compounds. The relative stereochemistry of the new compound was determined using 2D NOESY and the most stable and the lowest energy conformation was determined using molecular modelling. The antimicrobial activity was evaluated by determination of MIC using the broth microdilution method against six bacterial strains and one fungal strain (Pseudomonas aeruginosa PAO1, Escherichia coli, Bacillus subtilis ATCC6633, Mycobacterium bovis BCG Pasteur, Mycobacterium tuberculosis H37Rv, Staphylococcus aureus ATCC6538 and Candida albicans SC5314). There was a significant indication that compounds 15, 16, 17 demonstrated potent activity against Gram +ve (S. aureus, B. subtilis), as well as Mycobacterium strains M. bovis BCG and M. tuberculosis H37Rv. None of the isolated compounds exhibited a significant antifungal activity. In the antioxidant study using the DPPH assay method, the highest radical scavenging activity was observed for compounds 15, 16, 17.

In the course of our screening program for anti-Mycobacterium bovis bacillus Calmette-Guérin (BCG) and anti-Mycobacterium tuberculosis H37Rv (MTB H37Rv) agents from ourmarine natural product library, a newly isolated actinomycete strain, designated as MS449, was picked out for further investigation. The strain MS449, isolated from a sediment sample collected from South China Sea, produced actinomycin X2 and actinomycin D in substantial quantities, which showed strong inhibition of BCG and MTB H37Rv. The structures of actinomycins were elucidated by nuclear magnetic resonance and mass spectrometric analysis. The strain MS449 was taxonomically characterized on the basis of morphological and phenotypic characteristics, genotypic data, and phylogenetic analysis. The 16S rRNA gene sequence of the strain was determined and a database search indicated that the strain was closely associated with the type strain of Streptomyces avermitilis (99.7 % 16S rRNA gene similarity). S. avermitilis has not been previously reported to produce actinomycins. The marine-derived strain of Streptomyces sp. MS449 produced notably higher quantities of actinomycin X2 (1.92 mg/ml) and actinomycin D (1.77 mg/ml) than previously reported actinomycins producing strains. Thus, MS449 was considered of great potential as a new industrial producing strain of actinomycin X2 and actinomycin D.

Our investigations into the anti-TB properties of the South China Sea deep-sea Verrucosispora sp. (MS100128) led to the isolation, identification, and anti-TB evaluation of new (1–3) and known (4–6, 10) abyssomicins. Structures were assigned to 1–3 on the basis of detailed spectroscopic analysis, biosynthetic considerations, mechanistic studies, and semisynthesis from the co-metabolite 5. Detailed analytical studies into abyssomicin Michael addition chemistry informed our understanding of the chemical reactivity, stability, and anti-TB properties of this rare structure class. We established 8 as a far more potent Michael acceptor than 5, and used this to rationalize its superior antibacterial properties. We transformed 5 into the Michael adduct 1 and used both in vitro and cell-based analytical studies to demonstrate that 1 can act as a prodrug, thus responding to oxidative activation to selectively deliver the anti-TB antibiotic 8. Our studies make a contribution beyond the specifics of the abyssomicin pharmacophore by drawing attention to the possible utility of thioether Michael addition adducts as a means to stabilize highly reactive Michael acceptors, thereby enhancing bioavailability and improving therapeutic potential. The thioether Michael adduct prodrug concept, inspired by abyssomicins from the South China Sea, offers a promising new approach to “chemically package” bioactive Michael acceptors, thus improving their chances of being developed into clinically useful drugs.

Fenitrothion is being increasingly used as an insecticide under intensive cultivation to control vegetables and fruits pests. The bioconcentration of fenitrothion 2 different groups of freshwater fish (Oreochromis niloticus) was investigated after 28 days of exposure. One tenth of the determined 96 h-LC50 concentrations applied to fish. Fenitrothion concentration was 3.85 mg kg-1 and the Bioconcentration Factors (BCFs) after the experimental period 28 days 675.43 for whole fish body while the concentration was 1.51 mg kg-1 with respective BCFs was reached 264.91 for muscle tissue were 1.61 after daily exposure during the experimental time 28 days. Results concluded that the fenitrothion has ability to fenitrothion bioconcentration factor was high in whole fish compared to muscle tissue.