In vivo antifungal effect of Combretum and Terminalia species extracts on cutaneous wound healing in immunosuppressed rats

Acetone leaf extracts of Combretaceae species Combretum imberbe Wawra, Combretum nelsonii Duemmer, Combretum albopunctatum Suesseng, and Terminalia sericea Burch ex DC and a mixture of asiatic acid and arjunolic acid isolated from C. nelsonii were tested for antifungal activity against Candida albicans, Cryptococcus neoformans, Microsporum canis, and Sporothrix schenckii on wounds of immunocompromised Wistar rats. The therapeutic agents were selected based on low MIC values ranging 0.02-2.5 mg/mL and low toxicity (LC50) ranging 75.7-168.6 microg/mL. Seven circular, full-thickness wounds were made on the back skin of 24 Wistar rats, under general anesthetic and using an aseptic technique. Rats were infected with different fungal pathogens in groups of six. The treatments were administered topically using 20% concentrations of each extract in aqueous cream. Amphotericin B was used as positive control. Erythema, exudate, crust formation, swelling, and ulceration were used to determine the wound healing process. Throughout the experiment, body temperature, measured using a subcutaneous probe, and weight of the rats were found to be within normal ranges. Epithelial closure in all rats occurred by 17 days. There was no significant difference in contraction of the lesion areas treated with different extracts. The variability in erythema at each lesion in rats infected with different fungal pathogens differed with treatments; the lesion without treatment took a longer time to heal in all cases. Exudate formation was observed until day 12 in rats infected with C. albicans and day 8 in rats infected with C. neoformans. In lesions infected with M. canis and S. schenckii, exudate formation was observed until day 10. The treated group presented a rigid, dark, and thick crust formation after day 3 until day 15. During histopathological evaluations, scant fungi were noted in all the wounds, indicating that infection had occurred but had generally cleared. The antifungal potential of crude extracts of selected plants and a mixture of asiatic acid and arjunolic acid on the wounds of immunocompromised rats was confirmed. The extracts of these plants may possibly be further developed into drugs for topical treatment of fungally infected wounds.

Evaluation of the antioxidant, antibacterial, and antiproliferative activities of the acetone extract of the roots of Senna italica (Fabaceae)

Senna italica, a member of the Fabaceae family (subfamily Caesalpinaceae), is widely used traditionally to treat a number of disease conditions, such as sexually transmitted diseases and some forms of intestinal complications. The roots of Senna italica were collected from Zebediela subregion, Limpopo province (S.A), powdered and extracted with acetone by cold/shaking extraction method. The phytochemical composition of the extract was determined by thin layer chromatography (TLC). The chromatograms were visualised with vanillin-sulphuric acid and p-anisaldehyde reagents. The total phenolic content of the extract was determined by Folin-Ciocalteu method and expressed as TAE/g dry weight. The extract was assayed for the in vitro anticancer activity using Jurkat T cells, antioxidant activity using DPPH assay and antibacterial activity by bioautographic method and the microtitre plate method. The acetone extract of the roots of Senna italica inhibited the growth of Jurkat T cells in a dose- and time-dependent manner. The extract also had free radical scavenging activity as well as reasonable antibacterial activity against Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus with MICs ranging from 0,08 to 0.16 mg/ml in the same order as ampicillin the positive control. The biological activities observed in the acetone extract validated the ethnomedicinal use of Senna italica.

Dichloromethane extract of Dicerocaryum senecioides leaves exhibits remarkable anti-inflammatory activity in human T-lymphocytes

The leaves of Dicerocaryum senecioides are used in South Africa as a traditional remedy for many ailments, including inflammatory disorders. The purpose of this study was therefore to evaluate the anti-inflammatory potential of a dichloromethane extract of D. senecioides leaves. Methanol extracts of the leaves were sub-fractionated with dichloromethane and the anti-inflammatory potential of this fraction investigated according to its effects on the mitogen-induced proliferative responses and cytokine profiles of isolated human blood mononuclear leucocytes (MNL). The cells were pre-treated with the extract (25-100 microg mL(-1)) followed by addition of the mitogen, phytohaemagglutinin (PHA, 5 microg mL(-1) final), and measurement of lymphocyte activation and proliferation, using flow cytometric detection of up-regulation of expression of CD25 and incorporation of radiolabelled thymidine into newly synthesised DNA, respectively. Cytokine production by unstimulated and PHA-activated cells was measured using multiplex suspension bead array technology. Treatment of cells with the Dicerocaryum extract resulted in dose-related inhibition of PHA-activated lymphocyte proliferation and expression of CD25, as well as decreased production of Th1 (IFN-gamma, TNF-alpha) and Th2 (IL-10) cytokines. These observations not only underscore the anti-inflammatory potential of components of Dicerocaryum leaves, but also provide a basis for future definitive studies.

Suppression of retrovirus-induced immunodeficiency disease (murine AIDS) by trimidox and didox: novel ribonucleotide reductase inhibitors with less bone marrow toxicity than hydroxyurea

Recently, the use of the ribonucleotide reductase (RR) inhibitor hydroxyurea (HU) in combination with nucleoside analogs has gained attention as a potential strategy for anti-HIV-1 therapy. However, appeal for the long-term use of HU in HIV-1 infection may be limited by its propensity to induce hematopoietic toxicity. We report a comparison of the efficacy and bone marrow toxicity of HU (400 and 200 mg/kg/day) with the novel RR inhibitors and free radical-scavenging compounds didox (DX; 3,4-dihydroxybenzohydroxamic acid; 350 mg/kg/day) and trimidox (TX; 3,4,5-trihydroxybenzamidoxime; 175 mg/kg/day) in the murine AIDS (LPBM5 MuLV) model of retrovirus infection. Infected mice received daily drug treatment for 8 weeks. Efficacy was determined by measuring drug effects on retroviral-induced disease progression (i.e. development of splenomegaly and hypergammaglobulinemia) and by evaluating splenic levels of proviral DNA. Bone marrow toxicity was evaluated by measuring peripheral blood indices (WBC, hematocrit and reticulocyte counts), femoral cellularity and by determining the numbers of hematopoietic progenitor cells (CFU-GM, BFU-E) per femur and spleen. Compared to infected controls receiving no drug treatment, disease progression was significantly suppressed by TX, DX and HU. However, HU was associated with mortality and induced significant hematopoietic toxicity in a time- and dose-dependent manner. Conversely, TX and DX effectively inhibited retrovirus-induced disease but did not induce hematopoietic toxicity. These results suggest that due to their reduced hematopoietic toxicity and ability to inhibit disease progression in murine AIDS, TX and DX may offer effective alternatives to HU therapy in HIV-1 infection.

Analysis of events associated with serum deprivation-induced apoptosis in C3H/Sol8 muscle satellite cells

Satellite cells are the source of new muscle fibers in postnatal skeletal muscle growth and regeneration. Regulation of satellite cell survival is of fundamental importance in maintaining normal muscle function. Here we describe and characterize a tissue culture model of satellite cell apoptosis. Kinetic studies indicate that serum deprivation triggers a set of sequential events: early cell death, transient cell cycle traverse, and delayed cell death. The satellite cell death occurs by apoptosis based on the internucleosomal DNA laddering, in situ DNA end-labeling, and the requirements for de novo protein synthesis and extracellular calcium influx. The transient period of cell cycle progression (7-11 h after serum withdrawal) is accompanied by temporal induction of members of the immediate early gene family, such as c-myc, c-fos, and SRF, and appears to precede the delayed phase of cell death. Satellite cell apoptosis can be suppressed by several growth factors and by blocking the activity of calpain, a calcium-regulated protease. The late phase of apoptosis is marked by selective activation of ubiquitin-mediated protein conjugation and degradation. This study defines several control points where satellite cell apoptosis may be genetically or pharmacologically intervened.

Induction of apoptosis in HL-60 cells by lithium

It has been established that lithium, a preferred drug for the treatment of manic depression, affects the growth of HL-60 cells. Concentrations of lithium above 10 mM were shown to be cytotoxic to these cells. However, the mechanism by which lithium induces its cytotoxicity is still obscure. In this study, we examined whether programmed cell death was involved in lithium cytotoxicity. Our findings show that lithium induced apoptosis in a time- and concentration-dependent manner. Morphological features and DNA fragmentation revealed that with 10 mM lithium, apoptosis was maximal at 72 hours of treatment. Interestingly, other monovalent ions were unable to elicit DNA fragmentation, suggesting that this phenomenon is specific for lithium. Cell cycle studies revealed that lithium arrested the cells at the G2/M phase.