Novel nitric oxide-releasing derivatives of brusatol as anti-inflammatory agents: design, synthesis, biological evaluation, and nitric oxide release studies.

Brusatol, a biologically active natural product, was modified in four distinct positions through the covalent attachment of a furoxan moiety, which acts as a nitric oxide (NO) donor. Forty derivatives were synthesized and evaluated for their inhibitory effects on excess NO biosynthesis in activated macrophages. Among them, compound 75 demonstrated inhibition (IC50 = 0.067 µM) comparable to that of brusatol but were less cytotoxic. More importantly, even at very low doses (2 µmol/kg/day), compound 75 also showed substantial inhibitory efficacy against chronic obstructive pulmonary disease (COPD)-like inflammation in the mouse model induced by cigarette smoke (CS) and lipopolysaccharide (LPS). Particularly, this compound was over 100-fold less toxic (LD50 > 3852 µmol/kg) than brusatol and could be a promising lead for further studies. Notably, the improved properties of this derivative are associated with its NO-releasing capability.

Involvement of intrinsic mitochondrial pathway in neosergeolide-induced apoptosis of human HL-60 leukemia cells: the role of mitochondrial permeability transition pore and DNA damage.

CONTEXT: Quassinoids are biologically active secondary metabolites found exclusively in the Simaroubaceae family of plants. These compounds generally present important biological properties, including cytotoxic and antitumor properties. OBJECTIVE: In the present study, the cytotoxic effects of neosergeolide, a quassinoid isolated from Picrolemma sprucei Hook. f., were evaluated in human promyelocytic leukemia cells (HL-60). MATERIALS AND METHODS: Cytotoxicity and antiproliferative effects were evaluated by the MTT assay, May-Grünwald-Giemsa's staining, BrdU incorporation test, and flow cytometry procedures. The comet assay and micronuclei analysis were applied to determine the genotoxic and mutagenic potential of neosergeolide. RESULTS: After 24 h exposure, neosergeolide strongly inhibited cancer cell proliferation (IC50 0.1 µM), and its activity seemed to be selective to tumor cells because it had no antiproliferative effect on human peripheral blood mononuclear cells (PBMC) at tested concentrations. Apoptosis was induced at submicromolar concentrations (0.05, 0.1, and 0.2 µM) as evidenced by morphological changes, mitochondrial depolarization, phosphatidylserine externalization, caspases activation, and internucleosomal DNA fragmentation. Additionally, neosergeolide effects were prevented by cyclosporine A (CsA), an inhibitor of the mitochondrial permeability transition (MPT) pore, which reinforced the participation of intrinsic pathways in the apoptotic process induced by this natural quassinoid. Direct DNA damage was further confirmed by comet assay and cytokinesis-block micronucleus test. DISCUSSION AND CONCLUSION: The present study provided experimental evidence to support the underlying mechanism of action involved in the neosergeolide-mediated apoptosis. In addition, no antiproliferative effect or DNA damage effect of neosergeolide was evident in PBMC, highlighting its therapeutic potential.

In vivo anthelmintic activity of bruceine A and bruceine D from Brucea javanica against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus).

The present study was designated to ascertain the anthelmintic activity of the dried fruits of Brucea javanica and to isolate and characterise the active constituents. The methanol extract from the fruits of B. javanica showed significant anthelmintic activity against Dactylogyrus intermedius (EC(50) (median effective concentration) value=49.96 mg l(-1)). Based on this finding, the methanol extract was fractionated on silica gel column chromatography in a bioassay-guided fractionation affording two known quassinoids showing potent activity, bruceine A and bruceine D. Both bruceine A and D exhibited significant activity against D. intermedius with EC(50) values of 0.49 mg l(-1) and 0.57 mg l(-1), respectively, which were more effective than the positive control, mebendazole (EC(50) value=1.25 mg l(-1)). In addition, the 48-h median lethal concentration (LC(50)) for bruceine A and D against the host (Carassius auratus) was 10.6-fold and 9.7-fold higher than the EC(50) for D. intermedius. These results provide evidence that the isolated compounds might be potential sources of new anti-parasitic drugs for the control of Dactylogyrus. This is the first report on an in vivo anthelmintic investigation for B. javanica against D. intermedius.