In vitro anti-oxidative and carbohydrates digesting enzymes inhibitory effects of some medicinal plants used for the management of diabetes in the Mrewa district, Zimbabwe.

Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.Abstract available on PDF file

Comparative performance characteristics of the urine lipoarabinomannan strip test and sputum smear microscopy in hospitalized HIV-infected patients with suspected tuberculosis in Harare, Zimbabwe

BackgroundIn Zimbabwe, sputum smear microscopy (SSM) is the routinely used TB diagnostic tool in hospitalised HIV-infected patients. However, SSM has poor sensitivity in HIV-infected patients. We compared performance of urine lipoarabinomannan strip test (LAM) and SSM among hospitalized HIV-infected patients with suspected TB.MethodsHospitalized HIV-infected patients with suspected TB were randomized to LAM plus SSM or SSM alone groups as part of a larger multi-country parent study. Here we present a comparison of LAM versus SSM performance from the Zimbabwe study site. LAM analyses (grade 2 cut-off) were conducted using (i) a microbiological reference standard (MRS; culture positivity for M.tb and designated definite TB) and (ii) a composite reference standard (CRS; definite TB plus probable TB i.e. patients with clinical TB excluded from the culture negative group). CRS constituted the primary analysis.Results82/457 (18%) of the patients randomized to the LAM group were M.tuberculosis culture positive. Using CRS, sensitivity (%, 95 % CI) of LAM was significantly higher than SSM [49.2 (42.1-56.4) versus 29.4(23.2-36.3); p 100 cells/μL. The combined sensitivity of LAM and SSM was higher than SSM alone being highest at CD4 counts 97% in all the 3 CD4 strata.ConclusionAmong hospitalized HIV-infected patients with suspected TB, the sensitivity of LAM is significantly higher than that of SSM, especially at low CD4 counts. LAM and SSM are complimentary tests for diagnosis of TB in HIV-infected patients. We recommend a combination of LAM and SSM for TB diagnosis in HIV-infected patients with low CD4 counts in HIV/TB co-endemic countries, where alternative methods are unavailable

Anti-seizure activity of African medicinal plants: The identification of bioactive alkaloids from the stem bark of Rauvolfia caffra using an in vivo zebrafish model

peer reviewedEpilepsy is one of the major chronic diseases that does not have a cure to date. Adverse drug reactions have been reported from the use of available anti-epileptic drugs (AEDs) which are also effective in only two-thirds of the patients. Accordingly, the identification of scaffolds with promising anti-seizure activity remains an important first step towards the development of new anti-epileptic therapies, with improved efficacy and reduced adverse effects. Herbal medicines are widely used in developing countries, including in the treatment of epilepsy but with little scientific evidence to validate this use. In the search for new epilepsy treatment options, the zebrafish has emerged as a chemoconvulsant-based model for epilepsy, mainly because of the many advantages that zebrafish larvae offer making them highly suitable for high-throughput drug screening

Antibacterial and cytotoxic activities of new sphingolipids and other constituents isolated from Cissus incisa leaves

Cissus incisa is used in traditional Mexican medicine to treat certain ailments, infectious or cancerous diseases. Excepting for our previous research, this species had no scientific reports validating its traditional use. In this study, we evaluated the antibacterial and cytotoxic properties of the sphingolipids and others phytocompounds isolated from C. incisa leaves to increase the scientific knowledge of the Mexican flora. The antibacterial activity was evaluated against Gram-positive and Gram-negative bacteria by the Microdilution method. Meanwhile, the cytotoxic potential was determined on six human cancer cells: PC3, Hep3B, HepG2, MCF7, A549, and HeLa; using an aqueous solution cell proliferation assay kit. A cell line of immortalized human hepatocytes (IHH) was included as a control of non-cancerous cells. Selectivity index (SI) was determined only against the hepatocellular carcinoma cell lines. The phytochemical investigation of C. incisa leaves resulted in the isolation and characterization of five compounds: 2-(20-hydroxydecanoyl amino)-1,3,4-hexadecanotriol-8-ene (1), 2,3-dihydroxypropyl tetracosanoate (2), β-sitosterol-D-glucopyranoside (3), α-amyrin-3-O-β-D-glucopyranoside (4), and a mixture of cerebrosides (5). Until now, this is the first report of the sphingolipids (1), (5-IV) and (5-V). Only the compound (4) and cerebrosides (5) exhibited antibacterial activity reaching a MIC value of 100 μg/mL against Pseudomonas aeruginosa resistant to carbapenems. While, the acetylated derivate of (3), compound (3Ac) showed the best cytotoxic result against PC3 (IC50 ¼ 43 � 4 μg/mL) and Hep3B (IC50 ¼ 49.0 � 4 μg/mL) cancer cell lines. Likewise, (3Ac) achieved better SI values on HepG2 and Hep3B cell lines. This research reveals the importance of study medicinal plants, to identify bioactive molecules as sources of potential drugs. The presence of these compounds allows us to justify the use of this plant in traditional Mexican medicine

<i>In vitro</i>α-amylase and α-glucosidase inhibitory effects and cytotoxic activity of<i>Albizia antunesiana</i>extracts

CONTEXT: Diabetes mellitus is a chronic disease, and its incidence is tremendously increasing globally. Decreasing postprandial hyperglycemia by retarding glucose absorption through inhibiting carbohydrates digesting enzymes (α-amylase and α-glucosidase) is one of many approaches used for the management of this disease. OBJECTIVES: The leaf and root aqueous and ethanol extracts of Albizia antunesiana were investigated for α-amylase and α-glucosidase inhibitory and cytotoxic activity in vitro. MATERIALS AND METHODS: The α-amylase and α-glucosidase activities were measured in the presence of aqueous and ethanol extracts of the plant parts using starch and p-nitrophenyl-D-glucopyranoside as substrates respectively. Furthermore, cytotoxic effects of the extracts were investigated on HEK (human embryonic kidney) 293 cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. RESULTS: The results showed that ethanolic root extract of A. antunesiana had mild α-amylase and strong α-glucosidase inhibitory activity with half-maximal inhibitory concentration values of 30.68 and 4.35 µg/mL, respectively. The aqueous root extract showed mild α-glucosidase but no α-amylase inhibitory activity. Cytotoxicity studies on the extracts using the MTT assay revealed that the ethanolic (leaf and root) extracts were relatively nontoxic at tested concentrations on the HEK 293 cell lines. However, the aqueous extracts (leaf and root) were cytotoxic at concentrations above 50 µg/mL. CONCLUSION: Data from this study suggest that the ethanolic root extract of A. antunesiana possess in vitro α-amylase and α-glucosidase inhibitory activities and are not cytotoxic at least in an in vitro condition

Higher serum 25-hydroxyvitamin D concentrations are associated with active pulmonary tuberculosis in hospitalised HIV infected patients in a low income tropical setting: a cross sectional study

Abstract Background The inherent risk of developing tuberculosis (TB) in HIV- infected individuals is further enhanced by hypovitaminosis D. Interventions that offset HIV-associated immune deterioration potentially arrest disease progression and incidence of opportunistic infections including TB. Despite conflicting reports on association between vitamin D deficiency (VDD) and risk of TB, vitamin D (VD) supplementation remains a promising intervention. Methods We conducted a comparative cross-sectional study on 145 HIV+/pulmonary TB+ (PTB) and 139 HIV+/PTB− hospitalised patients to investigate association of vitamin D status and risk of PTB. Stratified random sampling was used to select archived serum specimens from participants enrolled in a randomised controlled trial (RCT) conducted to investigate the impact of using a point-of-care urine lipoarabinomannan strip test for TB diagnosis. PTB status was confirmed using sputum smear microscopy, culture or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D [25(OH) D] concentrations were assayed by competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment. Effect of VD status on duration of hospital stay and patient outcomes on follow up at 8 weeks were also investigated. Median serum 25(OH) D concentrations were compared using Mann-Whitney test and covariates of serum VD status were assessed using logistic regression analysis. Results Overall VDD prevalence in the cohort was 40.9% (95% CI: 35.1–46.8). Median serum 25(OH)D concentrations were significantly higher in HIV+/PTB+ group (25.3 ng/ml, IQR:18.0–33.7) compared to the HIV+/PTB− group (20.4 ng/ml, IQR:14.6–26.9), p = 0.0003. Patients with serum 25(OH) D concentration ≥ 30 ng/ml were 1.9 times more likely to be PTB+ compared to those with serum 25(OH) D concentrations < 30 ng/ml (odds ratio (OR) 1.91; 95% CI 1.1–3.2). PTB-related death was associated with higher odds of having 25(OH) D levels≥30 ng/ml. Age, gender, CD4+ count, combination antiretroviral therapy (cART) status, efavirenz based cART regimen and length of hospital stay were not associated with vitamin D status. Conclusions The finding of an association between higher serum 25(OH) D concentrations and active PTB and TB-related mortality among hospitalised HIV-infected patients in the present study is at variance with the commonly reported association of hypovitaminosis and susceptibility to TB. Our findings though, are in concordance with a small pool of reports from other settings