Antihypertensive effects of the hydro-ethanol extract of Senecio serratuloides DC in rats.

BACKGROUND: Senecio serratuloides DC is used in folk medicine for treating hypertension, skin disorders, internal and external sores, rashes, burns and wounds. This study aimed at investigating the antihypertensive effects of the hydroethanol extract of S. serratuloides (HESS) in N-Nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. METHODS: Acute toxicity of HESS was first determined to provide guidance on doses to be used in this study. Lorke's method was used to determine safety of the extract in mice. Female Wistar rats were treated orally once daily with L-NAME (40 mg/kg) for 4 weeks and then concomitantly with L-NAME (20 mg/kg) and plant extract (150 and 300 mg/kg), captopril (20 mg/kg) or saline as per assigned group for 2 weeks followed by a 2-week period of assigned treatments only. Blood pressure was monitored weekly. Lipid profile, nitric oxide, renin and angiotensin II concentrations were determined in serum while mineralocorticoid receptor concentration was quantified in the kidney homogenate. Nitric oxide (NO) concentration was determined in serum and cardiac histology performed. RESULTS: HESS was found to be non-toxic, having a LD50 greater than 5000 mg/kg. Blood pressure increased progressively in all animals from the second week of L-NAME treatment. HESS treatment significantly and dose-dependently lowered systolic blood pressure (p < 0.001), diastolic blood pressure (p < 0.01), low density lipoprotein cholesterol (p < 0.01) and triglycerides (p < 0.01). It significantly prevented L-NAME induced decrease in serum angiotensin II (p < 0.01), high density lipoprotein cholesterol (p < 0.001) and serum nitric oxide concentrations (p < 0.001). HESS also significantly (p < 0.01) prevented collagen deposition in cardiac tissue. CONCLUSION: The hydro-ethanol extract of Senecio serratuloides showed antihypertensive, antihyperlipidemic and cardioprotective effects in rats thus confirming its usefulness in traditional antihypertensive therapy and potential for antihypertensive drug development.

Semi-synthesis of nitrogen derivatives of oleanolic acid and effect on breast carcinoma MCF-7 cells.

BACKGROUND: Oleanolic acid is a triterpenoid that has shown in vitro cytotoxic activity against human tumour cells and is known to be present in many higher plants. MATERIALS AND METHODS: Oleanolic acid is known to have some biological potential including anticancer property. Oleanolic acid was isolated from the ethyl acetate fraction of Syzygium aromaticum seed with an aim of dervitatising the functional group and evaluating the biological activities of the semi-synthesised compounds. Acylation of the alcohol functional group of the oleanolic acid afforded the opportunity of hydrazine reaction to give 3-acetoleanolic hydrazide. Further reaction of 3-acetoleanolic hydrazide with benzyladehyde, glacial acetic acid and methanol resulted in the synthesis of the corresponding 3-acetoxyoleanolic hydrazone. RESULTS: The semi-synthetic oleanolic acid derivatives did not exhibit enhanced cytotoxic activity over oleanolic acid itself. CONCLUSION: 3-acetoxyoleanolic hydrazide has a potent anticancer activity.

Identification of death receptors DR4 and DR5 in HTB-12 astrocytoma cell lines and determination of TRAIL sensitivity.

Astrocytomas are tumors which arise from astrocytes, cells that form the blood-brain barrier. There are very few drugs that successfully treat brain tumors. In this study, the cytotoxic effects on the HTB-12 astrocytoma cell line by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were studied. The presence of the TRAIL receptors, Death receptor 4 (DR4) and Death receptor 5 (DR5), were detected in HTB-12 cells by Enzyme-Linked Immunosorbent Assay (ELISA). Cytotoxicity assay by Trypan Blue Exclusion Method showed effective cell killing by TRAIL treatment. Thus, the presence of death receptors and TRAIL efficacy raises the therapeutic potential for this type of brain tumor.

Composition and biological potential of essential oil from Thelechitonia trilobata growing in South Africa.

Thelechitonia trilobata is regarded as a troublesome weed that grows to form a dense blanket over the soil preventing the growth of other crops in farmland. Although the plant is regarded as a notorious, invasive plant, its chemical composition and biological potential have not been reported. The essential oil was isolated from the fresh leaves of T. trilobata using hydrodistillation. alpha-Pinene (21.6%), alpha-phellendrene (21.0%), limonene (12.8%) and germacrene D (7.5%) were the major constituents of the oil. The essential oil was screened against agricultural pests. The anti-tick properties were tested on Ripicephalus e. ervertsi found on sheep, while repellency, fumigation, and contact toxicity tests were carried out with maize weevils. Except for the contact toxicity test, all other bioassays gave positive results.

Internalized racism is associated with elevated fasting glucose in a sample of adult women but not men in Zimbabwe.

OBJECTIVES: Internalized racism (INR) is associated with metabolic abnormalities among African Caribbean women. The current study was conducted to determine if similar associations exist among Black women living in Africa. METHODS: In 2003, a stratified random sample of Black adults ages > or =18 years was drawn from four high-density suburbs of the city of Bulawayo, Zimbabwe. A total of 318 persons (90% of those recruited) participated. Face-to-face interviews were used to gather information on demographic variables, health history, internalized racism, anthropometric measurements and blood pressure. Internalized racism, the extent to which individuals agree with racist stereotypes about their race, was measured with a standardized questionnaire. A fasting blood sugar level was also measured for each participant. Persons with diagnosed diabetes or incomplete data (n=44) were excluded from analyses. RESULTS: Women (n=188) and men (n=86) did not differ significantly by age, INR score, waist circumference or fasting glucose level. The mean body mass index of women (23.6 kg/m2) was higher (P<.05) than that of men (22.3 kg/m2). INR was significantly correlated with waist circumference, diastolic blood pressure and fasting glucose among women but not among men. In multiple logistic regression analyses using the data for women, a high INR remained independently associated with abnormal fasting glucose (odds ratio=2.74, P=.0085) after adjusting for potential confounders including adiposity. CONCLUSIONS: These findings show the consistency of the association of high INR with metabolic abnormalities among Black women in the Diaspora.

Composition and bioactivity of the leaf essential oil of Heteropyxis dehniae from Zimbabwe.

The leaf oil of Heteropyxis dehniae Suess. (Heteropyxidaceae) was obtained by hydrodistillation and analyzed by GC/MS. The most abundant essential oil components are linalool (58.3%), 4-terpineol (9.8%), alpha-terpineol (3.6%), and caryophyllene oxide (3.1%). The antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus niger, and the in vitro cytotoxicity of the oil on PC-3, MDA-MB-231, Hs 578T, MCF7, SK-MEL-28, and 5637 human tumor cells were also examined. Caryophyllene oxide shows notable cytotoxic activity with LC50 values of 147-351 microM.

Cytotoxic activity of Ozoroa insignis from Zimbabwe.

The crude methanol bark extract of the Zimbabwean medicinal plant, Ozoroa insignis, showed in-vitro cytotoxic activity against Hep-G2 (human hepatocellular carcinoma), MDA-MB-231 (human mammary adenocarcinoma), and 5637 (human primary bladder carcinoma). Bioactivity-directed chromatographic separation led to isolation of anacardic acid and ginkgoic acid as the cytotoxic components.