Evaluation of the efficacy of Carpobrotus edulis (L.) bolus leaf as a traditional treatment for the management of HIV/AIDS
- Authors: Omoruyi, Beauty Etinosa
- Date: 2014
- Subjects: AIDS (Disease) -- Treatment -- South Africa -- Eastern Cape , Phytochemicals -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Carpobrotus
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: http://hdl.handle.net/10353/744 , vital:26493 , AIDS (Disease) -- Treatment -- South Africa -- Eastern Cape , Phytochemicals -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Carpobrotus
- Description: The human immunodeficiency virus (HIV) is one of the most common and dreaded diseases of the 21th century. Today, the disease is still spreading with increasing incidence. “Since the beginning of the epidemic, almost 75 million people have been infected with the HIV virus and about 36 million people have died of HIV. Globally, 35.3 million [32.2–38.8 million] people were living with HIV at the end of 2012” (http://www.who.int/gho/hiv/en/). Several studies have been conducted on herbs under a multitude of ethnobotanical grounds. The use of medicinal plants for the management of HIV has become a common practice especially, in the Eastern Cape Province of South Africa (Wilfred Otang Mbeng, 2013 PhD thesis, UFH). At the beginning of this programme, an ethnomedicinal survey of plants used for the management of HIV infection was carried out in targeted areas of the Province and information on the names of plants, the parts and the methods of preparation were collected. The survey revealed that 18 species representing 12 families were found to be commonly used for the management of HIV, as well as other opportunistic diseases such as tuberculosis, diabetes mellitus, sores, high blood pressure, etc. Carpobrotus edulis was selected for this research because it was the most frequently used in the Province. The foliar micro morphological contents of the plant, its phytochemical and antioxidant activity, in vitro antimicrobial activity, inhibitory effect against HIV-1 protease and reverse transcriptase, mechanisms of action and cytotoxicity were investigated. In terms of the foliar micro morphological contents in plants, an electron microscopy scanning (SEM) was completed. Investigation revealed that both glandular tricomes and calcium oxalate crystals (CaOX) were observed. Consequently, it is hypothesized that the bioactive therapeutic compounds secreted by C. edulis may be produced in the glandular trichomes. An investigation of phytochemical content of the plant extracts (C. edulis) was completed using four solvent extracts (hexane, acetone, ethanol and water). Results of the phytochemical analysis showed that proanthocyanidins (86.9 ± 0.005%) where highest in the aqueous extract with phenolics at 55.7 ± 0.404% in acetone extract, tannin at 48.9 ± 0.28% in ethanol extract, while the hexane extract had the highest levels of flavonoids (0.12 ± 0.05%) and flavonols (0.12 ± 0.05%). Antioxidant studies of the various extracts revealed that aqueous and ethanol extracts were found to be the best solvents for antioxidant activity in C. edulis leaves. GC-MS analysis of the essential oil from C. edulis leaves revealed that the essential oil contained at least 28 compounds. These included, in order of abundance: Oxygenated monoterpenes (36.61%); fatty acids esters (19.25%); oxygenated diterpenes (19.24%); monoterpenes (10.6%); sesquiterpenes (3.58%); and diterpenes (1.43%). Similarly, a GC-MS analysis of the crude hexane, acetone and ethanol extracts from C. edulis leaves identified a total of 59 compounds. Of the 59 compounds, 12 major phyto-metabolites that are active against infectious diseases were identified. To comfirm the potential use of C. edulis to treat infectious disease, antifungal activity of the crude essential oil extract and the four solvent extracts were tested against Candida albicans, Candida krusei, Candida glabrata, Candida rugosa and Cryptococcus neoformans strains. The essential oil extract was found to be the most active against all the fungal strains tested and performed better than the four extracts used various solvents used to extract (hexane, acetone, ethanol and water) the C. edulis leaves were tested for antibacterial and anti HIV-1 reverse transcriptase (RT) activity. The results indicated that both gram-positive and gram-negative isolates were inhibited by the extracts (hexane, acetone and ethanol) but antimicrobial activity was observed for the water extract. The lowest minimum inhibitory concentration values were obtained for the ethanol extract, followed by acetone and hexane extracts. No inhibition of HIV-1 reverse transcriptase was observed for any of the leaf extracts, even up to concentrations of 16 mg/ml. The potential inhibitory activities of the various solvent extracts against HIV-1 protease were evaluated at four different concentrations (16, 1.6, 0.16 and 0.016 mg/ml). Results indicated that the water extract showed almost 100% inhibition of HIV-1 protease activity, with an IC50 of 0.86 mg/ml leaf extract. Other solvent extracts (hexane, acetone and ethanol) however, did not show any inhibition activity above that observed for the DMSO control. The metabolic components in the water extract were subjected to LC-MS/MS analysis, which identified at least 91 compounds present in the water extract. Further studies involving the molecular modelling need to be carried out to confirm the inhibitory potential of these compounds. The cytotoxicity of the water extract of C. edulis leaves was also screened using human Chang liver cells at concentrations ranging bewteen 0.005 mg/ml and 1 mg/ml. Results indicated that the water extracts were not toxic. In conclusion the results from this study support the use of water extracts of C. edulis leaves by traditional healers to treat HIV infections and have identified possible mechanisms of action of the water extracts of C. edulis.
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Investigation of antidiabetic properties, mechanisms of action and toxicology of Strychnos Henningsii (GILG) bark
- Authors: Oyewole, Oyedemi Sunday
- Date: 2011
- Subjects: Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Diabetics -- Alternative treatment -- South Africa , Loganiaceae , Lamiaceae , Diabetes , Proteins
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11254 , http://hdl.handle.net/10353/d1001070 , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Diabetics -- Alternative treatment -- South Africa , Loganiaceae , Lamiaceae , Diabetes , Proteins
- Description: The apparent reversal of trend from modern drugs to herbal medicine is partly due to the fact that synthetic drugs have always shown adverse reactions and other undesirable side effects. Hence, the use of medicinal plants for the treatment of diseases such as diabetes is very common especially in the rural areas. Majority of these plants are used based on the experience and indigenous knowledge without identification of the therapeutic agents. There is enormous wealth of medicinal plants in the world yet many of them have not been discovered or studied scientifically to substantiate their ethno-medicinal usages. Ethnobotanical study has been the method often used to search for locally important plant species for the discovery of crude drugs with low side effects. An ethnobotanical survey was conducted on the medicinal plants commonly used for the management of diabetes mellitus in Nkonkobe Municipality, Eastern Cape of South Africa. Information was obtained through structured questionnaire administered to traditional healers and herbalists in the region. The study revealed 15 species of plants belonging to 13 families. Strychnos henningsii and Leonotis leonorus among others were repeatedly mentioned by the traditional healers as the two mostly used plants for the management of diabetes mellitus. The infusion and decoction of the roots, leaves and barks of these plants are the methods of preparation. The antioxidant potential of aqueous bark extract of S. henningsii was investigated both in vivo and in vitro using spectroscopic method. The antioxidant activity of the extract against hydrogen peroxide (H2O2), 2,2′-azinobis[3-ethylbenzothiazoline6-sulfonic acid] diammonium salt (ABTS), as well as reducing power was concentration dependent. The extract exhibited lower and average scavenging activities against 1,1diphenyl2picrylhydrazyl (DPPH) and nitric oxide (NO) radicals with IC50 value of 0.739 and 0.49 mg/ml respectively. The administration of the plant extract at 250, 500 and 1000 mg/kg significantly increased the activities of the antioxidant enzymes in the hepatotoxic rats induced with carbon tetrachloride. On the other hand, the stem bark extract had lower effect on lipid peroxidation level except at the dose of 250 mg/kg. The effect of oral administration of S. henningsii extract was evaluated in normal Wistar rats for 28 days. The observed result indicated non- toxic effect of sub-acute administration of plant extract to the animals except at certain doses. This is because, there was no apparent damage to some haematological and biochemical parameters used in assessing organ specific toxicity. However, the alterations observed on platelet, white blood cells and its differentials imply parameter and dose selective toxicity when repeatedly consumed on daily basis at the doses investigated. This study also investigated the antidiabetic activities of the extract at the doses of 125, 250 and 500 mg/kg body weight in diabetic rats induced with streptozotocin -nicotinamide for 15 days. The extract appreciably (P <0.05) reduced the blood glucose level, feed and water intake while the best result was obtained at 250 mg/kg. Similarly, the level of triacylglycerol at the three doses investigated was significantly decreased. In addition, the glucose tolerance was reduced to near normal level after 90 min at certain doses. The clinical significance of the extract on some biochemical and haematological parameters lessen both hepatic and renal damages. Anaemic condition in diabetic animals was also improved after plant extract administration. However, no significant effect was observed in white blood cells and some of its differentials. The extract demonstrated strong glucose utilization in 3T3-L1 cells with a response of 278.63 percent of the control at 12.5μg/ml while that of Chang liver cells was 103.54 percent. The cytotoxicity result revealed non toxic effects of the extract to both cell lines. Treatment of 3T3 L1 cells with the extract did not reduce lipid accumulation. The extract inhibited the activity of α- glucosidase and α- amylase in a concentration dependent manner with IC50 values of 38 μg/ml and 60.9 μg/ml respectively. The percentage protein antiglycation of S. henningsii was 18.4, 38.2 and 61.2 perceent for 0.25, 0.5 and 1 mg/ml respectively while aminoguanidine a known inhibitor of protein glycation was 87.2 percent at 1 mg/ml. The FRAP assay values of the extract was 357.05 μmol Fe (II)/g. The findings from this study support the folkloric usage of this plant for the management of diabetes mellitus in the region.
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