Chemical composition, antioxidant activities and antibacterial activities of essential oil from Erythrina caffra Thunb. growing in South Africa.

INTRODUCTION: Essential oils from plants are recognized as one of the most promising secondary metabolites for the development of cheap and safer drugs. While Erythrina caffra has been prominently used in folk medicine for the treatment of microbial infections, there is dearth of information on the pharmacological effectiveness and chemical composition of its essential oil. The study, therefore, aimed at identifying the chemical composition and biological activities of the essential oil of Erythrina caffra. METHODS: In this study, the essential oil was extracted with all-glass Clevenger. The antioxidant activities of the essential oil and antibacterial susceptibility assay by agar well diffusion techniques were assessed while GC-MS analysis was performed to identify the chemical constituents of the essential oil. RESULTS: The study showed that the radical scavenging activity of the essential oil increases as the concentration of the essential oil increases. All bacterial isolates were susceptible to essential oil with the exception of Salmonella typhimurium and Pseudomonas aeruginosa producing inhibition zones ranging between 22 ± 1.3 and 35 ± 2.1 mm in the susceptible isolates. The GC-MS chromatogram indicated there are 35 bioactive compounds in the essential oil and Caryophyllene oxide (53.54%), [1S-(1α,7α,8aß)]-1,2,3,5,6,7,8,8a-octa-1 - hydro-1,8a-dimethyl-7-(1-methylethenyl)-Naphthalene (7.81%), Kauran-18-al (6.49%), 10,10-Dimethyl-2,6-dimethylenebicy clo[7.2.0]undecan-5.beta.-ol (5.83%), 10s,11s-Himachala-3(12),4-diene (4.51%), Caryophyllene (3.65%) and 1- Hexanol (3.31%) were the most prominent compounds. CONCLUSION: Excessive production of free radicals or reactive oxygen species (ROS) causes oxidative stress and disease. Oxidative stress resulting from imbalance between excessive generation of free radicals and inadequate antioxidant defense system has been linked to pathogenesis of many diseases. The essential oil of E. caffra stem bark extract possess antimicrobial and good antioxidant activities and its rich level of phytochemicals can be used as either dietary or complementary agents.

Multifunctional activity of vitamin E in animal and animal products: A review.

Vitamin E is an essential nontoxic fat-soluble micronutrient whose effects on livestock performance and products can be attributed to its antioxidant and nonantioxidant properties. Although it is needed in small quantity in the diet, its roles in livestock production are indispensable as it is required in boosting performance, nutritional qualities, and yield of animal and animal products. The dietary or oral supplementation of vitamin E is essential in reducing lipid oxidation in muscle, egg, and dairy products as well as lowering cholesterol concentrations and improving antioxidant status of livestock. Evidence has shown that bioavailability of vitamin E-enriched animal products could serve as an invaluable nutritional benefit to consumers; especially those in regions of limited resources where vitamin E deficiencies pose a risk that may be detrimental to some cellular activities of the body and on human health. It is therefore important to redirect research on the impact of vitamin E supplementation as antioxidant on livestock performance and animal products.

Inhibition of HIV-1 Protease by Carpobrotus edulis (L.).

Carpobrotus edulis (L.) is a plant commonly found in the Eastern Cape Province of South Africa and is used for the general treatment of infections relating to the human immunodeficiency virus (HIV). HIV-1 protease plays an important role during HIV replication and maturation to its infectious form, and therefore inhibition of the enzyme is one of the main focus areas in drug development. The inhibitory effect of a water extract of C. edulis leaves against HIV-1 protease activity was determined using the SensoLyte® 520 HIV-1 protease assay fluorimetric kit and employing a HiLyte Fluor™488/QXL™520 fluorescence resonance energy transfer (FRET) peptide. Cytotoxicity of the extract towards HeLa Chang cell lines was determined using an in vitro MTT assay, and the phytochemical profile of the extract was determined with FT-IR and LC-MS. HIV-1 protease activity was inhibited 83.06% (IC50 1.6 mg/ml) (p < 0.0001) by the pepstatin A inhibitor control. Treatment with all C. edulis extract concentrations (16, 1.6, 0.16, and 0.016 mg/ml) inhibited HIV-1 protease activity significantly (p < 0.0001) in a typical dose response manner. With regards to cytotoxicity, the negative controls containing untreated HeLa Chang cells exhibited high formazan formation rates in contrast with the positive controls, containing curcumin, which reduced formazan formation significantly (p < 0.001), exhibiting cytotoxicity towards the cells. There was no significant (p > 0.05) difference in the formazan formation rates between the negative controls and 1, 0.5, 0.125, 0.065, 0.031, and 0.015 mg/ml plant extract, confirming no toxicity of C. edulis extracts towards HeLa Chang cells. Major functional phytochemical compounds identified included alcohols, phenols, alkanes, amines, carboxylic acids, and esters. LC-ESI-TOF/MS analysis revealed the putative identities of main compounds present in the aqueous leaves extract, including some that contribute to its anti-HIV-1 protease action.

Multi-functional application of Moringa oleifera Lam. in nutrition and animal food products: A review.

Research on the use of various parts of the Moringa oleifera Lam. plant (M. oleifera) as a nutritional and neutraceutical resource for human and animal diets has increased in recent years, emanating from the widespread use of the plant in traditional cuisines and medicinal remedies in several regions of the world. Analytical studies have identified M. oleifera as an important source of essential nutrients; rich in protein, essential amino acids, minerals, and vitamins, with a relatively low amount of antinutrients. It is also a rich source of other bio active compounds including flavonoids and phenolic compounds; with several studies detailing demonstrated in vitro and in vivo functional properties, most substantially, antioxidant activities. Moringa oleifera consumption has been reported to improve the health status, feed conversion efficiency, growth performance and product quality of several livestock species, at dietary inclusion rates generally not exceeding 5% of total dry matter intake. Fortification of processed foods with M. oleifera has been reported to increase nutritional value, some organoleptic properties, oxidative stability and product shelf life; with a notable need for further analytical and consumer studies in the development of these products. There is a paucity of literature detailing clinical studies, nutrient bioavailability, toxicity and the mode of action of the bioactive compounds to which the health claims associated with M. oleifera consumption are attributed. Many of these are not yet fully understood; therefore more research in these areas is required in order to fully utilize the potential benefits of this plant in human and livestock nutrition.

Anti-mycobacterium tuberculosis activity of polyherbal medicines used for the treatment of tuberculosis in Eastern Cape, South Africa.

BACKGROUND: The emergence of drug-resistant strains of Mycobacterium tuberculosis has become a global public health problem. Polyherbal medicines offer great hope for developing alternative drugs for the treatment of tuberculosis. OBJECTIVE: To evaluate the anti-tubercular activity of polyherbal medicines used for the treatment of tuberculosis. METHODS: The remedies were screened against Mycobacterium tuberculosis H37Rv using Middlebrook 7H9 media and MGIT BACTEC 960 system. They were liquid preparations from King Williams Town site A (KWTa), King Williams Town site B (KWTb), King Williams Town site C (KWTc), Hogsback first site (HBfs), Hogsback second site (HBss), Hogsback third site (HBts), East London (EL), Alice (AL) and Fort Beaufort (FB). RESULTS: The susceptibility testing revealed that all the remedies contain anti-tubercular activity with KWTa, KWTb, KWTc, HBfs, HBts, AL and FB exhibiting more activity at a concentration below 25 µl/ml. Furthermore, MIC values exhibited inhibitory activity with the most active remedies from KWTa, HBfs and HBts at 1.562 µg/ml. However, isoniazid showed more inhibitory activity against M. tuberculosis at 0.05 µg/ml when compare to the polyherbal remedies. CONCLUSION: This study has indicated that these remedies could be potential sources of new anti-mycobacterial agents against M. tuberculosis. However, the activity of these preparations and their active principles still require in vivo study in order to assess their future as new anti-tuberculosis agents.

Effect of the aqueous extract of the aerial parts of Monsonia angustifolia E. Mey. Ex A. Rich., on the sexual behaviour of male Wistar rats.

BACKGROUND: Monsonia angustifolia (Geraniaceae) is a medicinal plant traditionally used in South Africa to increase libido and to treat erectile dysfunction. METHODS: In-vivo aphrodisiac activities of the crude extracts of the plant prepared in water at 3, 30 and 300 mg/kg body weight were evaluated for 7 days using sildenafil citrate (Viagra) and 1% ethanol in distilled water as positive and negative controls respectively. Male rats were selected and monitored in each group for sexual behaviour by exposing them to sexually receptive females on days 1, 3 and 7 for 60 minutes each between 7:00 pm and 3:00 am. The following male sexual parameters were observed: Mount Frequency (MF), Intromission Frequency (IF), Mount Latency (ML), Intromission Latency (IL), Ejaculation Frequency (EF), Ejaculatory Latency (EL) and Post-Ejaculatory Interval (PEI). RESULTS: The administration of the extract resulted in significant increase (p < 0.05) in mount frequency, intromission frequency, ejaculation frequency, ejaculation latency and serum hormone concentrations. The computed indices of sexual behaviour such as erection, quick flips, long flips and total penile reflexes were also increased. However, the mount latency, intromission latency and post ejaculation interval were significantly decreased throughout the experimental period. The administration of 300 mg/kg body weight of the aqueous extract produced the best effects in all the parameters. CONCLUSION: Generally, the extract of Monsonia angustifolia produced pro-sexual stimulatory effects in the male rats especially when administered at 300 mg/kg body weight. The results validate the use of the plant by the indigenous people to increase libido and treat premature ejaculation and erectile dysfunction in males.

Tetracarpidium conophorum (Mull.Arg) Hutch & Dalziel inhibits FeSO4-induced lipid peroxidation in rat's genitals.

BACKGROUND: To search for new sources of safe and inexpensive antioxidant agents which can be used to treat various oxidative stress-related diseases, the phenolic contents of leaf of Tetracarpidium conophorum were characterized and its effect on pro-oxidant induced oxidative stress in rat's genitals for the first time was investigated. METHODS: The aqueous extract of the plant was prepared, the antioxidant activities of the extract were then evaluated using spectrophotometric method. RESULTS: The result revealed that the introduction of aqueous extract of the plant caused significant concentration-dependent decrease (P < 0.05) in the MDA content of the Fe(2+)-stressed testes and penis homogenates. The least MDA production occurred at the highest concentration of the extract (0.625 mg/mL). However, characterization of the extract with HPLC revealed that its major constituents were gallic acid, catechin, chlorogenic acid, caffeic acid, coumarin, rutin, quercitrin, quercetin, kaempferol and luteolin. Also, the result revealed that the ABTS* scavenging ability of the extract was 4.60 mmol/100 g while its vitamin C content was 23.49 mg/g which indicated that the plant is very rich in vitamin C. Furthermore, the extract scavenged DPPH, NO, OH* radicals and chelated Fe(2+) in a dose-dependent manner. CONCLUSION: The inhibitory effect of Tetracarpidium conophorum leaves could be attributed to the high levels of quercitrin, quercetin and luteolin and the mechanism through which these compounds possibly do this, could be by their radical scavenging abilities.

Ultrastructure and elemental analysis of Hypoxis hemerocallidea: a multipurpose medicinal plant.

BACKGROUND: Herbal medicine is a popular means of medical management in some parts of the world especially in Africa. Hypoxis hemerocallidea Fisch.C.A.Mey. & Avé-Lall, also known as African potato of the Hypoxidaecae family, is one of the medicinal plants that have enjoyed long usage as an herbal medicine in South Africa. In this study, the morphology and elemental constituents of H. hemerocallidea leaf was investigated to correlate the functional role of the ultrastructure in the production of therapeutic compounds. MATERIALS AND METHODS: Fresh leaves of H. hemerocallidea were prepared for analysis using standard methods. The ultrastructure and crystal deposits of the plant were assessed using scanning electron microscopy (SEM), and energy dispersive x-ray (EDX). RESULTS: It was observed that the leaves were characterised by multicelullar glandular and non glandular trichomes which are sparsely distributed over the entire surfaces. The glandular trichomes (GTs) in H. hemerocallidea leaf have boulbous heads which are probably filled with secretions, while the non glandular trichomes were long, fibrous and sparse. EDX-SEM of Hypoxis hemerocallidea leaf revealed that carbon, oxygen, nitrogen and silicon are the major components of the deposits, while other elements such as iron, sulphur, sodium, calcium, magnesium, potassium, manganese, iodine, chromium and iodine were present in small but variable amounts. CONCLUSION: The presence of these elements which are crucial to maintaining good health, in addition to other bioactive constituents might be accountable for the multipurpose therapeutic uses of Hypoxis hemerocallidea in the treatment of cancers, HIV/AIDS related diseases, urinary tract infections, cardiovascular disorders, diabetes and other chronic ailments of humans.

A survey of plants responsible for causing irritant contact dermatitis in the Amathole district, Eastern Cape, South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Potentially harmful plants grow almost everywhere, hence, it is not practical to eradicate them all. However, a basic understanding of adverse cutaneous reactions and the common plants that cause each type can enable vulnerable individuals to discover the source of their dermatitis and thus prevent re-exposure. The aim of this study therefore, was to document the plants responsible for irritant contact dermatitis (ICD) in the Eastern Cape, along with their respective irritants and clinical presentations. MATERIALS AND METHODS: Study participants (161) in 12 locations were selected by convenient sampling with particular focus on local people who regularly interact with plants or plant products. Interview questions were focused on the local names of plants that contain irritating chemicals and physical characteristics that cause ICD. RESULTS: Forty four plant species distributed in 24 families and 34 genera were reported as causative agents of irritant contact dermatitis. Herbs constituted 67.35%, trees 24.49% and shrubs 8.16%. Mechanical ICD was reported to be caused by 23 species, closely followed by chemical ICD (20 species) and mechanico-chemical ICD (6 species). Species with the highest frequency of citations were Allium cepa, Acacia karroo, Capsicum annuum, Citrus limon and Zea mays. The most representative families were Euphorbiaceae (for chemical ICD), Urticaceae (for mechanico-chemical ICD), Fabaceae and Rutaceae for mechanical ICD. Most of the classes of chemical compounds identified as being responsible for chemical ICD were restricted to plants of specific genera such as the diterpenes in Euphorbia spp., disulphides in Allium spp., terpenes in Citrus spp. and isothiocyanates in Brassica spp. Thorns and hairs were reported for causing Mechanical ICD in 6 plant species each, including widely cultivated plants such as Acacia karoo and Citrus reticulata. CONCLUSION: Irritant contact dermatitis is a common cutaneous disorder in individuals exposed to plants in the Eastern Cape, especially among workers of the food and flower industries. Health practitioners should therefore consider the possible work-related causes of dermatitis, especially in cases associated with a clear history of symptoms.

Selected spices and their combination modulate hypercholesterolemia-induced oxidative stress in experimental rats.

BACKGROUND: Effect of aqueous extracts of Allium sativum (garlic), Zingiber officinale (ginger), Capsicum fructensces (cayenne pepper) and their mixture on oxidative stress in rats fed high Cholesterol/high fat diet was investigated. Rats were randomly distributed into six groups (n=6) and given different dietary/spice treatments. Group 1 standard rat chow (control), group 2, hypercholesterolemic diet plus water, and groups 3, 4, 5, 6, hypercholesterolemic diet with 0.5 ml 200 mg · kg-1 aqueous extracts of garlic, ginger, cayenne pepper or their mixture respectively daily for 4 weeks. RESULTS: Pronounced oxidative stress in the hypercholesterolemic rats evidenced by significant (p<0.05) increase in MDA levels, and suppression of the antioxidant enzymes system in rat's liver, kidney, heart and brain tissues was observed. Extracts of spices singly or combined administered at 200 mg.kg-1 body weight significantly (p<0.05) reduced MDA levels and restored activities of antioxidant enzymes. CONCLUSIONS: It is concluded that consumption of garlic, ginger, pepper, or their mixture may help to modulate oxidative stress caused by hypercholesterolemia in rats.

The inhibitory effect of Mesembryanthemum edule (L.) bolus essential oil on some pathogenic fungal isolates.

BACKGROUND: Mesembryanthemum edule is a medicinal plant which has been indicated by Xhosa traditional healers in the treatment HIV associated diseases such as tuberculosis, dysentery, diabetic mellitus, laryngitis, mouth infections, ringworm eczema and vaginal infections. The investigation of the essential oil of this plant could help to verify the rationale behind the use of the plant as a cure for these illnesses. METHODS: The essential oil from M. edule was analysed by GC/MS. Concentration ranging from 0.005-5 mg/ml of the hydro-distilled essential oil was tested against some fungal strains, using micro-dilution method. The plant minimum inhibitory activity on the fungal strains was determined. RESULT: GC/MS analysis of the essential oil resulted in the identification of 28 compounds representing 99.99% of the total essential oil. A total amount of 10.6 and 36.61% constituents were obtained as monoterpenes and oxygenated monoterpenes. The amount of sesquiterpene hydrocarbons (3.58%) was low compared to the oxygenated sesquiterpenes with pick area of 9.28%. Total oil content of diterpenes and oxygenated diterpenes detected from the essential oil were 1.43% and 19.24%. The fatty acids and their methyl esters content present in the essential oil extract were found to be 19.25%. Antifungal activity of the essential oil extract tested against the pathogenic fungal, inhibited C. albican, C. krusei, C. rugosa, C. glabrata and C. neoformans with MICs range of 0.02-0.31 mg/ml. the activity of the essential oil was found competing with nystatin and amphotericin B used as control. CONCLUSION: Having accounted the profile chemical constituent found in M. edule oil and its important antifungal properties, we consider that its essential oil might be useful in pharmaceutical and food industry as natural antibiotic and food preservative.

Ethnobotanical survey of medicinal plants used in the management of skin disorders among the Xhosa communities of the Amathole District, Eastern Cape, South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Skin diseases have been of major concern recently due to the association of skin opportunistic infections and HIV/AIDS, are usually the first sign of HIV infection and conversion to AIDS. More than 90% of HIV-infected individuals develop skin and mucosal complications at some stage during the disease. Although classical medicine is undoubtedly addressing these diseases, the people of the Eastern Cape, South Africa still depend, to a large extent on traditional herbal medicine for the treatment of various diseases. The current study was undertaken to investigate the local peoples characterisation of skin diseases/disorders and to document the medicinal plants used for various skin disorders among the Xhosa-speaking communities of the Amathole District, Eastern Cape. MATERIALS AND METHODS: Information was obtained by interviewing 54 respondents in 7 locations. Collection of the reported medicinal plants from the wild was assisted by the informants and identification of the collected plants specimens was done with the help of floristic works of South Africa. Quantitative methods including the use-value and the informant consensus factor (ICF) were computed for determining the relative importance of species known locally and the homogeneity of the informants׳ knowledge respectively. RESULTS: Twenty five skin disorders, classified under 5 categories are being treated with the listed medicinal plants in the study area. The highest ICF (0.45) was linked to bacteria-related skin disorders. This category comprised of 57 use citations, 3 skin disorders; with sore throat being the most frequently mentioned (4.2%). In this study, 106 plant species distributed in 61 families and 107 genera were identified as being used to treat one or more of the skin disorders. The species with the highest use-value was Aloe ferox Mill. (Xanthorrhoeaceae) known locally as Umhlaba. The most representative families were Solanaceae and Asteraceae with 6 species each, followed by Fabaceae, Poaceae and Rutaceae (5 species each). The leaves were the most frequently used plant part, followed by the bark (10%) and fruits (7%). Administration of the different plant parts was mostly topical (77%) on the affected area. CONCLUSION: A total of twenty five skin disorders/conditions, classified under 5 categories are being treated with the listed medicinal plants in the study area. 106 plant species distributed in 61 families and 107 genera were identified as being used to treat one or more of the skin disorders. The species with the highest use-value was Aloe ferox Mill. (Xanthorrhoeaceae) known locally as Umhlaba. The most representative families were Solanaceae, Asteraceae, Fabaceae, Poaceae, Rutaceae and Euphorbiaceae. Majority of the plant species were herbs and the leaves were the most frequently used, mostly applied topically as a paste, powder or sap on the affected skin area.

Selected spices and their combination modulate hypercholesterolemia-induced oxidative stress in experimental rats

BACKGROUND: Effect of aqueous extracts of Allium sativum (garlic), Zingiber officinale (ginger), Capsicum fructensces (cayenne pepper) and their mixture on oxidative stress in rats fed high Cholesterol/high fat diet was investigated. Rats were randomly distributed into six groups (n = 6) and given different dietary/spice treatments. Group 1 standard rat chow (control), group 2, hypercholesterolemic diet plus water, and groups 3, 4, 5, 6, hypercholesterolemic diet with 0.5 ml 200 mg · kg-1 aqueous extracts of garlic, ginger, cayenne pepper or their mixture respectively daily for 4 weeks. RESULTS: Pronounced oxidative stress in the hypercholesterolemic rats evidenced by significant (p < 0.05) increase in MDA levels, and suppression of the antioxidant enzymes system in rat's liver, kidney, heart and brain tissues was observed. Extracts of spices singly or combined administered at 200 mg.kg-1 body weight significantly (p < 0.05) reduced MDA levels and restored activities of antioxidant enzymes. CONCLUSIONS: It is concluded that consumption of garlic, ginger, pepper, or their mixture may help to modulate oxidative stress caused by hypercholesterolemia in rats.

Evaluation of Antidiabetic Activity and Associated Toxicity of Artemisia afra Aqueous Extract in Wistar Rats.

Artemisia afra Jacq. ex Willd. is a widely used medicinal plant in South Africa for the treatment of diabetes. This study aimed to evaluate the hypoglycemic activity and possible toxicity effect of aqueous leaf extract of the herb administered at different dosages for 15 days in streptozotocin-induced diabetic rats. Administration of the extract at 50, 100, and 200 mg/kg body weight significantly (P < 0.05) increased body weight, decreased blood glucose levels, increased glucose tolerance, and improved imbalance in lipid metabolism in diabetic rats. These are indications of antidiabetic property of A. afra with 200 mg/kg body weight of the extract showing the best hypoglycemic action by comparing favourably well with glibenclamide, a standard hypoglycemic drug. The extract at all dosages tested also restored liver function indices and haematological parameters to normal control levels in the diabetic rats, whereas the kidney function indices were only normalized in the diabetic animals administered with 50 mg/kg body weight of the extract. This investigation clearly showed that in addition to its hypoglycemic activity, A. afra may also protect the liver and blood against impairment due to diabetes. However, some kidney functions may be compromised at high dosages of the extract.

Protective effect of Tulbaghia violacea Harv. on aortic pathology, tissue antioxidant enzymes and liver damage in diet-induced atherosclerotic rats.

The protective effect Tulbaghia violacea rhizomes (TVR) against derangements in serum lipid profile, tissue antioxidant enzyme depletion, endothelium dysfunction and histopathological changes in the aorta and liver of rats fed with an atherosclerogenic (Ath) diet (4% cholesterol, 1% cholic acid and 0.5% thiouracil) was investigated in this study. Co-treatment with the TVR extracts (250 and 500 mg/kg body weight for two weeks significantly (p < 0.05) protected against elevated serum triglyceride (TG), total cholesterol (TC), LDL-cholesterol, VLDL-cholesterol and decreased HDL-cholesterol in a dose-dependent manner when compared with the atherogenic control. The extracts also reduced (p < 0.05) elevated thiobabutric reacting substance (TBARS) and reversed endothelial dysfunction parameters (fibrinogen and total NO levels) and tissue antioxidant enzyme activities to near normal. The protective ability of the extract was confirmed by the significant (p < 0.05) reduction in the activities of serum markers of liver (LDH, AST, ALT, ALP, bilirubin) and kidney damage (creatinine and bilirubin) in extract-treated groups compared with the atherogenic control group. Also, histopathology evaluations of aorta sections revealed that the extracts protected against the development of fatty streak plaques (aorta) and fatty changes in hepatocytes. The observed activities of the extracts compared favorably with standard drug atorvastatin. Our study thus showed that the methanolic extract of TVR could protect against the early onset of atherosclerosis.

Antioxidant and phytochemical properties of Carpobrotus edulis (L.) bolus leaf used for the management of common infections in HIV/AIDS patients in Eastern Cape Province.

BACKGROUND: Carpobrotus edulis (Mesembryanthemaceae), also known as igcukuma in Xhosa language is a medicinal plant used by the traditional healers to treat common infections in HIV/AIDS patients. Based on this information, we researched on the plant phytoconstituents, as well as its inhibitory effect using aqueous and three different organic solvent extracts in order to justify its therapeutic usage. METHODS: Antioxidant activity of the extracts were investigated spectrophotometrically against 1,1- diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) diammonium salt, hydrogen peroxide (H2O2), nitric oxide (NO), and ferric reducing power, Total phenols, flavonoids, flavonols, proanthocyanidins, tannins, alkaloids and saponins were also determined using the standard methods. RESULTS: Quantitative phytochemical analysis of the four solvent extracts revealed a high percentage of phenolics (55.7 ± 0.404%) in the acetone extract, with appreciable amount of proanthocyanidins (86.9 ± 0.005%) and alkaloids (4.5 ± 0.057%) in the aqueous extract, while tannin (48.9 ± 0.28%) and saponin (4.5 ± 0.262%) were major constituents of the ethanol extract. Flavonoids (0.12 ± 0.05%) and flavonols (0.12 ± 0.05%) were found at higher level in the hexane extract in comparison with the other extracts. The leaf extracts demonstrated strong hydrogen peroxide scavenging activity, with the exception of water and ethanol extracts. IC50 values of the aqueous and ethanolic extract against DPPH, ABTS, and NO were 0.018 and 0.016; 0.020 and 0.022; 0.05 and 0.023 mg/ml, respectively. The reducing power of the extract was found to be concentration dependent. CONCLUSION: The inhibitory effect of the extracts on free radicals may justify the traditional use of this plant in the management of common diseases in HIV/AIDs patients in Eastern Cape Province. Overall, both aqueous and ethanol were found to be the best solvents for antioxidant activity in C. edulis leaves.

Synergistic interactions of methanolic extract of Acacia mearnsii De Wild. with antibiotics against bacteria of clinical relevance.

With the emergence of multidrug-resistant organisms, combining medicinal plants with synthetic or orthodox medicines against resistant bacteria becomes necessary. In this study, interactions between methanolic extract of Acacia mearnsii and eight antibiotics were investigated by agar diffusion and checkerboard assays. The minimum inhibitory concentrations (MICs) of all the antibiotics ranged between 0.020 and 500 µg/mL while that of the crude extract varied between 0.156 and 1.25 mg/mL. The agar diffusion assay showed that extract-kanamycin combination had zones of inhibition ≥20 ± 1.0 mm in all the bacteria tested (100%), followed by extract-chloramphenicol (90%) > extract-ciprofloxacin = extract-tetracycline (70%) > extract-amoxicillin (60%) > extract-nalidixic acid (50%) > extract-erythromycin (40%) > extract-metronidazole (20%). The checkerboard showed synergistic interaction (61.25%), additivity/indifference (23.75%) and antagonistic (15%) effects. The synergistic interaction was most expressed by combining the extract with tetracycline, metronidazole, amoxicillin, ciprofloxacin, chloramphenicol and nalidixic acid against E. coli (ATCC 25922), erythromycin, metronidazole, amoxicillin, chloramphenicol and kanamycin against S. aureus (ATCC 6538), erythromycin, tetracycline, amoxicillin, nalidixic acid and chloramphenicol against B. subtilis KZN, erythromycin, metronidazole and amoxicillin against E. faecalis KZN, erythromycin, tetracycline, nalidixic acid and chloramphenicol against K. pneumoniae (ATCC 10031), erythromycin, tetracycline, metronidazole and chloramphenicol against P. vulgaris (ATCC 6830), erythromycin, tetracycline, amoxicillin and chloramphenicol against S. sonnei (ATCC 29930), metronidazole, amoxicillin and chloramphenicol against E. faecalis (ATCC 29212) and ciprofloxacin and chloramphenicol against Proteus vulgaris KZN. The synergistic interactions indicated that the bactericidal potentials of the antibacterial agents were improved and combining natural products with antibiotic could be potential sources for resistance-modifying agents useful against infectious multi-drug resistant bacteria.

Pharmacological assessment of the medicinal potential of Acacia mearnsii De Wild.: antimicrobial and toxicity activities.

Acacia mearnsii De Wild. (Fabaceae) is a medicinal plant used in the treatment of microbial infections in South Africa without scientific validation of its bioactivity and toxicity. The antimicrobial activity of the crude acetone extract was evaluated by both agar diffusion and macrobroth dilution methods while its cytotoxicity effect was assessed with brine shrimp lethality assay. The study showed that both bacterial and fungal isolates were highly inhibited by the crude extract. The MIC values for the gram-positive bacteria (78.1-312.5) µg/mL, gram-negative bacteria (39.1-625) µg/mL and fungal isolates (625-5000) µg/mL differ significantly. The bacteria were more susceptible than the fungal strains tested. The antibiosis determination showed that the extract was more (75%) bactericidal than bacteriostatic (25%) and more fungicidal (66.67%) than fungistatic (33.33%). The cytotoxic activity of the extract was observed between 31.25 µg/mL and 500 µg/mL and the LC(50) value (112.36 µg/mL) indicates that the extract was nontoxic in the brine shrimp lethality assay (LC(50) > 100 µg/mL). These results support the use of A. mearnsii in traditional medicine for treatment of microbial infections. The extract exhibiting significant broad spectrum antimicrobial activity and nontoxic effects has potential to yield active antimicrobial compounds.

Assessment of allelopathic properties of Aloe ferox Mill. on turnip, beetroot and carrot.

Turnip (Brassica rapa var. rapa L.), beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are common vegetables in South Africa. The allelopathic potential of aqueous leaf and root extracts of Aloe ferox Mill.- a highly valued medicinal plant- was evaluated against seed germination and seedling growth of the three vegetables in Petri dish experiments. The extracts were tested at concentrations of 2, 4, 6, 8, and 10 mg/mL. Leaf extract concentrations above 4 mg/mL inhibited the germination of all the crops, while the root extract had no significant effect on germination irrespective of concentration. Interestingly, the lowest concentration of leaf extract stimulated root length elongation of beetroot by 31.71%. Other concentrations significantly inhibited both root and shoot growth of the vegetable crops except the turnip shoot. The most sensitive crop was carrot, with percentage inhibition ranging from 29.15 to 100% for root and shoot lengths. Lower percentage inhibition was observed for the root extract than the leaf extract against shoot growth of beetroot and carrot. The results from this study suggested the presence of allelochemicals mostly in the leaves of A. ferox that could inhibit the growth of the turnip, beetroot and carrot.

Assessment of allelopathic properties of Aloe ferox Mill. on turnip, beetroot and carrot

Turnip (Brassica rapa var. rapa L.), beetroot (Beta vulgaris L.) and carrot (Daucus carota L.) are common vegetables in South Africa. The allelopathic potential of aqueous leaf and root extracts of Aloe ferox Mill.- a highly valued medicinal plant- was evaluated against seed germination and seedling growth of the three vegetables in Petri dish experiments. The extracts were tested at concentrations of 2, 4, 6, 8, and 10 mg/mL. Leaf extract concentrations above 4 mg/mL inhibited the germination of all the crops, while the root extract had no significant effect on germination irrespective of concentration. Interestingly, the lowest concentration of leaf extract stimulated root length elongation of beetroot by 31.71%. Other concentrations significantly inhibited both root and shoot growth of the vegetable crops except the turnip shoot. The most sensitive crop was carrot, with percentage inhibition ranging from 29.15 to 100% for root and shoot lengths. Lower percentage inhibition was observed for the root extract than the leaf extract against shoot growth of beetroot and carrot. The results from this study suggested the presence of allelochemicals mostly in the leaves of A. ferox that could inhibit the growth of the turnip, beetroot and carrot.