Experimental Animal Models of HIV/AIDS for Vaccine Trials

AIDS still persists as a relevant disease in public health and scientific research. There have been significant advances in HIV research, notably the development of an effective regimen in antiretroviral therapy. However, the emergence of drug resistance has facilitated continued research in administration of therapy and the development of new antiretroviral drugs. In spite of nearly three (3) decades of intensive research, there still is not an effective vaccine against HIV-1. Animal models have been a crucial tool in drug discovery process for invasive investigation of HIV disease mainly in preclinical evaluation of drugs and vaccines. This undoubtedly is an integral part of successes so far achieved in HIV/AIDS research. Advances in both non-human primate and murine model immunogenetics in response to recombinant viruses have greatly increased the options of animal models available for research. Understanding the pros and cons of these models is imperative for animal study design that could further the development of vaccines and antiretroviral therapies for HIV prevention and treatment of AIDS patients

In vitro antioxidant capacity and free radical scavenging evaluation of active metabolite constituents of Newbouldia laevis ethanolic leaf extract

BACKGROUND: The aim of the present study was to evaluate the in vitro antioxidant and free radical scavenging capacity of bioactive metabolites present in Newbouldia laevis leaf extract. RESULTS: Chromatographic and spectrophotometric methods were used in the study and modified where necessary in the study. Bioactivity of the extract was determined at 10 μg/ml, 50 μg/ml, 100 μg/ml, 200 μg/ml and 400 μg/ml concentrations expressed in % inhibition. The yield of the ethanolic leaf extract of N.laevis was 30.3 g (9.93%). Evaluation of bioactive metabolic constituents gave high levels of ascorbic acid (515.53 ± 12 IU/100 g [25.7 mg/100 g]), vitamin E (26.46 ± 1.08 IU/100 g), saponins (6.2 ± 0.10), alkaloids (2.20 ± 0.03), cardiac glycosides(1.48 ± 0.22), amino acids and steroids (8.01 ± 0.04) measured in mg/100 g dry weight; moderate levels of vitamin A (188.28 ± 6.19 IU/100 g), tannins (0.09 ± 0.30), terpenoids (3.42 ± 0.67); low level of flavonoids (1.01 ± 0.34 mg/100 g) and absence of cyanogenic glycosides, carboxylic acids and aldehydes/ketones. The extracts percentage inhibition of DPPH, hydroxyl radical (OH(.)), superoxide anion (O(2)(.-)), iron chelating, nitric oxide radical (NO), peroxynitrite (ONOO(−)), singlet oxygen ((1)O(2)), hypochlorous acid (HOCl), lipid peroxidation (LPO) and FRAP showed a concentration-dependent antioxidant activity with no significant difference with the controls. Though, IC(50) of the extract showed significant difference only in singlet oxygen ((1)O(2)) and iron chelating activity when compared with the controls. CONCLUSIONS: The extract is a potential source of antioxidants/free radical scavengers having important metabolites which maybe linked to its ethno-medicinal use