The medicinal potential of Helichrysum Aureonitens

Plants have been used successfully for centuries by herbalists all over the world and especially in Africa, Asia and Latin America for the treatment of various human diseases. It has been estimated that 80% of people living in developing countries are almost completely dependent on traditional medical practices for their primary health care needs (Farnsworth 1990; Nwosu and Okafor 1995). Higher plants are known to be the main source of drug therapy in traditional medicine. Out of the 250 000 species of higher plants known to exist on earth, only a relative handful have been thoroughly investigated for their therapeutic values. Yet, in terms of the quantity consumed, the plant kingdom has yielded more than 25 % of the drugs used in prescriptive medicines today (Farnsworth 1988; Balick 1990). On the basis of global survey data it has been discovered that about 119 plant-derived chemical compounds of known structure are currently used as drugs or as biodynamic agents that affect human health. Less than a dozen of these are produced- commercially by synthesis or by simple chemical modification of the extracted active compounds; the remainder are extracted and purified directly from plants. These 119 useful drugs are obtained from only about 90 species of plants (Farnsworth et al. 1985; Farnsworth 1990). Considering the current rate of deforestation and concurrent loss of biodiversity throughout the world, there is an urgent need to examine the rest of the plant kingdom for new pharmaceutical compounds.Thesis (PhD)--University of Pretoria, 1994.Plant SciencePhDUnrestricte

Antibacterial and antioxidant activities of hydroalcoholic stem bark extract of Schotia latifolia Jacq

AbstractObjectiveTo investigate the antibacterial and antioxidant activities of hydroalcoholic extract of Schotia latifolia (S. latifolia) bark commonly used in South Africa traditional medicine for the treatment of various ailments.MethodsThe antibacterial test and MIC was determined by using agar well diffusion and dilution methods respectively against eight strains of bacteria. The total phenol, proanthocyanidin and flavonoid contents of S. latifolia were assessed using standard methods. The antioxidant activity of the extract was evaluated using ferric reducing power and the free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS), nitric oxide (NO), hydrogen peroxide (H2O2) and lipid oxidation (LO).ResultsThe antibacterial activity demonstrated an appreciable effect against all the gram positive bacteria at MIC between 0.016 and 10 mg/mL while that of gram negative bacteria was above 10 mg/mL. The plant extract exhibited high concentration of proanthocyanidin [(300.00±0.10) mg CE/g], followed by flavonoid [(12.46±0.04 mg) TE/g] and phenol [(11.06±0.03) mg QE/g] contents. Similarly, the extract at 0.5 mg/mL scavenges DPPH, ABTS, H2O2, LO and NO by 87.55%, 89.47%, 77.15%, 86.48% and 77.75% of the radicals respectively. The reducing power was also found to be concentration dependent.ConclusionsOur data suggest that S. latifolia extract has antibacterial and antioxidants activity and thus could be used as alternative therapy against antibiotic resistance bacteria and to prevent many radical related diseases

Characteristics of pathogenic bacteria isolates associated with the gut and gill of molluscan shellfish, Eastern Cape, South Africa

Introduction: Infectious diseases attributable to the consumption of raw and lightly cooked molluscan shellfish are caused by bacterial agents that are associated either with human waste disposed into the ocean or those of marine origin. This has led to the increase in prevalence of bacterial diseases and microbial resistance to antibiotics. Method: Samples of P. perna were dissected and homogenized for bacterial isolation. Six bacteria were isolated, identified and evaluated for their antimicrobial susceptibility profiling. Results: The microbial counts obtained revealed significant differences in the pathogenic bacteria populations found in the gut and gill of Perna perna. The morphological characteristics of the isolates were found to be of different shapes. All the isolates were catalase and oxidase positive except Vibrio spp. which was negative to the latter. Chloramphenicol and ciprofloxacillin were the most effective antibiotics against all the isolates, each exhibiting 100% efficacy. The highest resistance to ampicilin was observed in Salmonella spp., Shigella spp., Listeria monocytogenes and Staphylococcus xylosus. Conclusions: The results revealed that marine habitats are reservoirs of bacterial pathogens and there is increased resistance to antibiotic therapy, thereby constituting risks to public health. Therefore, appropriate surveillance measures to safeguard the health of shellfish consumers’ should be established

Toxicity assessment of aqueous extract of Curtisia dentata (Burm.f) C.A. Sm: stem bark in male Wistar rats

Purpose: To investigate the acute and sub-acute toxicity effects of aqueous stem bark extract in male Wistar rats.Methods: For the acute toxicity study, a single dose of 5000 mg/kg body weight of the extract was orally administered to the animals by oral gavage and the rats thereafter were observed for mortality and toxicity signs for 14 days. In the sub-acute toxicity test, the graded doses (50, 100, and 200 mg/kg body weight) of the aqueous extract of CD were given to the animals once daily for 28 days. In each of the experiment, the food and water intake, body weight changes, relative organ weights, hematological, clinical biochemistry and histopathological parameters were evaluated.Results: In both the acute and sub-acute toxicity studies, CD did not show any visible signs of toxicity. There were also no significant differences (p > 0.05) between the control and CD-treated rats for all the investigated parameters; no obvious gross pathological features in the kidney, heart and liver of all the experimental animals were observed.Conclusion: The findings indicate that the extract is not toxic when administered at the tested doses and within the exposure period. Thus, the aqueous stem bark extract of CD may be adjudged relatively safe and pharmacologically non-toxic in Wistar rats.Keywords: Curtisia dentata, Hematopoietic, Histopathology, Toxicit

Contributions to the Classification of Capsicum annuum L. and Capsicum frutescens L. in West Africa Using Morphological Traits

In West Africa, the genus Capsicum is represented by two cultivated species namely C. frutescens and C. annuum with different varieties. However, the taxonomic identity of these two species has been unresolved because they are morphologically related. There has been considerable debate on their status as two separate species or just varieties of one species. The  study  was  aimed  at  assessing  the   variability  and  relatedness  among  the four varieties of the two closely related  Capsicum species in West Africa. The varieties used in this study are C. annuum var. abbreviatum, C. annuum var. acuminatum, C. annuum var. grossum and C. frutescens var. baccatum. The varieties were morphologically characterized using 80 quantitative and qualitative standard descriptors from seedling emergence to plant maturity. Data collected were subjected to statistical analysis using SPSS statistical package, descriptive statistics and cluster analysis. The results revealed overlapping similarities in the morphology of the four varieties. Classification analysis based on data collected showed two distinct clusters by grouping varieties sharing close phenotypic similarities into distinct cluster. The differences observed among the varieties majorly in flower and fruit traits do not provide enough evidence to conceive that the collections are two separate species. Our results therefore support the inclusion of C. frutescens var. baccatum as a variety of C. annuum. Additional comparative molecular profiling is needed to fully understand the phylogenetic relationship among the cultivated Capsicum species in this part of the world

A Review of the Antidiabetic Activities of Ginger

Diabetes mellitus, a chronic metabolic disorder with major health care burden worldwide, is increasing, with 173 million adults being diabetic and over 8 million deaths recorded annually. Undesirable pathological conditions and high rates of secondary failure limit the use of current antidiabetic agents, thus, the need for more effective antidiabetic agents. Medicinal plants such as spices, rich in bioactive components that promote prevention and treatment of chronic conditions such as heart disease, cancer and Type-2 diabetes, are inexpensive with no side effects. The Zingiberaceae family, of which ginger is a member, consists of many species frequently cited for their antidiabetic and hypoglycemic properties. All important scientific literatures from 2000 to 2018 on the antidiabetic potentials of Zingiber officinale were evaluated. According to these studies, ginger exerts its antidiabetic effects through restorative effects on pancreatic β-cells, increasing insulin sensitivity, action and peripheral utilization of glucose. Other mechanisms include increased synthesis of hepatic glycogen through the enhancement of glycogen regulatory enzyme expression in the liver, inhibition of carbohydrate metabolizing enzymes, stimulation of pancreatic insulin release and inhibition of hepatic glucose production. Further studies, especially in humans are needed, more so, since ginger is one of the spices generally regarded as safe

Acute and Subacute Toxicological Evaluation of the Aerial Extract of Monsonia angustifolia

The acute and subacute toxicity profile of the aerial extract of Monsonia angustifolia in Wistar rats was evaluated. The Organization for Economic Cooperation and Development (OECD) 420 guideline was adopted in the acute toxicity testing with a single oral dose of 5000 mg/kg (b.w.). For the 28-day daily oral dosing, the extract was administered at 75, 150, and 300 mg/kg b.w.; 1% ethanol in sterile distilled water was used as control. Clinical toxicity signs were subsequently evaluated. At a single dose of 5000 mg/kg b.w. the extract elicited no treatment-related signs of toxicity in the animals during the 14 days of experimental period. In the subacute toxicity, there was no significant difference in hematological, renal, and liver function indices. However, dose-dependent significant increases were observed on the plasma concentrations of white blood cell and platelet counts of the treated animals compared to the control group. While cage observations revealed no treatment-facilitated signs of toxicity, histopathological examinations of the kidneys and liver also showed no obvious lesions and morphological changes. These results suggest that the extract may be labelled and classified as safe and practically nontoxic within the doses and period of investigation in this study

Variation in the chemical composition of essential oils from Artemisia afra (Jacq) ex-Wild leaf obtained by different methods and the effect of oil extracts on Artemia salina L

Purpose: To determine the essential oils extracted from fresh and dried leaves of Artemisia afra using hydrodistillation (HD) and solvent free microwave extraction (SFME) methods and investigate the effects of the oils on Artemia salina.Methods: The essential oils were obtained from fresh and dried leaves of Artemisia afra using hydrodistillation and solvent-free microwave extraction methods. The compounds present in the oils were analysed by gas chromatography-mass spectrometry (GC-MS). The oils were assayed for hatchability and lethality  activities on Artemia salina for 72 h. The lethal concentration (LC50) required to kill 50 % of the population of brine shrimp by each test oil was determined using a Probit regression analysis.Results: The most abundant compound was thujone (32.02 and 30.02 % in fresh leaf by HD and SFME methods, respectively) and in dried leaf (26.57 and 25.82 %, by HD and SFME methods, respectively). Mean hatchability success rate of all the oils was 70 % while lethality activity was 30 % after 72 h at the lowest  concentration of the test oils. Half-maximal lethal concentration (LC50) on Artemia salina was 206.97 and 406.48 μg/mL of the oil from fresh leaf obtained by HD and SFME, respectively, while for the dried leaf, it was 277.18 and 669.30 μg/mL for the oil produced by HD and SFME, respectively.Conclusion: The phytoconstituents in each oil varied based on the method of  extraction and the state of the leaf before and after extraction. Furthermore, the toxic activity of the oils against Artemia salina suggests that they may possess anticancer properties but this needs to be further investigated.Keywords: Artemia salina, Artemisia afra, Essential oils, hydrodistillation, Solvent-free microwave extraction, Hatchability, Lethalit

Comparative evaluation of essential oils from Lippia javanica L leaf obtained by two methods and their effect on Artemia salina L

Purpose: To compare the chemical constituents of essential oils extracted from fresh and dried leaves of Lippia javanica by hydrodistillation (HD) and solvent-free microwave extraction methods (SFME), and evaluate their effects on Artemia salina.Methods: Oil was extracted from the fresh and dried leaves of Lippia javanica by HD and SFME methods, and assayed for chemical constituents using gas chromatography-mass spectroscopy (GCMS). The oils were tested for hatchability and preliminary toxicity on Artemia salina for 72 h. The lethal concentration required to kill fifty percent of A. salina (LC50) was determined by Probit regression analysis.Results: Mesityl oxide was the most abundant compound in the essential oils. Mesityl oxide content of fresh and dried leaves extracted with HD was 25.33 and 29.83 %, respectively, while SFME method yielded 19.75 and 13.46 %, respectively. The average hatching success rate of the oil was 30 % success while lethality was 100 % after 72 h. Median lethal concentration (LC50) of fresh and dried leaves extracted by HD was 90.11 and 128.49 μg/mL, respectively, whereas SFME method resulted in LC50 of 96.52 and 101.13 μg/mL, respectively.Conclusion: The results show that the essential oil yield is not significantly affected by the extraction methods used. However, the hatchability and lethality of the oils varied with the extraction method usedKeywords: Artemia salina, Lippia javanica, Essential oil, Hydrodistillation, Solvent-free microwave extractio

Evaluation of important mineral nutrients and vitamins in polyherbal medicines used for the treatment of tuberculosis in the Eastern Cape Province, South Africa

Polyherbal medicines are widely used for the treatment of various diseases in the developing countries. In order to validate their ability in boosting the immune system of tuberculosis patients, the mineral nutrients and vitamins present were determined. Their nutritive properties were analysed using an inductively coupled plasma optical emission spectrometer, while the vitamins were determined using standardized methods. The polyherbal preparations were found to be rich in mineral nutrients and vitamins. Calcium was the highest mineral nutrient detected, while the lowest nutrient was phosphorus. Quantitatively, calcium and magnesium contents in the remedies ranged from 973.30 to 6503.30 mg/100g and 80.00 to 406.00 mg/100g respectively. The amount of phosphorus and potassium was between 20.00 and 263.30 mg/100g; 160.00 and 2050.00 mg/100g respectively. Micro nutrients such as iron, manganese, zinc, aluminium and copper were also detected. Iron was the highest nutrient in the majority of the polyherbal preparations while the lowest value was recorded for copper. However, vitamin C was absent in the herbal preparations while vitamin A and E were detected. These findings indicate that these polyherbal formulations contain the essential mineral nutrients and vitamins that could probably be boosting the immune system of tuberculosis patients.