Peter Masoko

Validation of antimycobacterial plants used by traditional healers in three districts of the limpopo province (South Africa).

The aim of the study was to scientifically evaluate the antimycobacterial activity of selected indigenous medicinal plants from the Limpopo Province used for the treatment of humans with symptoms of Mycobacterium tuberculosis. The leaves of five plant species (Apodytes dimidiata, Artemisia, Combretum hereroense, Lippia javanica, and Zanthoxylum capense) were collected from the Lowveld National Botanical Garden in Nelspruit, South Africa. The dried leaves were powdered and extracted using hexane, dichloromethane, acetone, and methanol. Antimycobacterial activity was evaluated using microdilution assay and bioautography and ρ-iodonitrotetrazolium violet (INT) as indicator. Antioxidant activities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH). Phytochemical content of extracts was further evaluated. The acetone extracts of L. javanica displayed antioxidant activity on BEA chromatogram. T Acetone extracts of A. afra had MIC value of 0.39 mg/mL against Mycobacterium smegmatis ATCC 1441. Acetone extracts of C. hereroense and L. javanica had MIC value of 0.47 mg/mL. Four bands that inhibited the growth of M. smegmatis were observed at R f values of 0.12, 0.63, and 0.87 on BEA and 0.73 on EMW. The plant species A. dimidiata, A. afra, C. hereroense, and L. javanica in this study demonstrated their potential as sources of anti-TB drug leads.

In Vitro Assessment of Cytotoxicity, Antioxidant, and Anti-Inflammatory Activities of Ricinus communis (Euphorbiaceae) Leaf Extracts.

Ricinus communis has been utilized traditionally as medicine to treat inflammatory related diseases including wounds, sores, and boils. The leaves of R. communis were sequentially extracted with n-hexane, dichloromethane, acetone, and methanol using serial exhaustive extraction method. Antioxidant activity of all crude extracts was quantitatively measured against 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) free radical molecules using ABTS+ assay. Cytotoxic effect and anti-inflammatory activity of R. communis leaves extracts were evaluated on Human Caucasian skin fibroblast and Raw 264.7 macrophage cell lines, respectively. Methanol extract had the highest percentage free radical (ABTS+) scavenging activity of 95% at 2.50 mg/mL, acetone 91%, dichloromethane 62%, and hexane the least (50%). Percentage scavenging activity of ABTS+ free radical molecules increases with increase in concentrations of the plant extracts. Hexane and dichloromethane extracts had more than 90% cell viability at 100 µg/mL after 24 and 48 hours of exposure. Methanol extract had LC50 of 784 µg/mL after 24-hour exposure, hexane had 629.3 µg/mL and dichloromethane 573.6 µg/mL, and 544.6 µg/mL was the lowest with acetone extract. The study present the first report on the scavenging activity of R. communis leaf extracts against ABTS+ radicals and cytotoxic effects on human Caucasian skin fibroblast cell lines.

Isolation and Chemical Structural Characterisation of a Compound with Antioxidant Activity from the Roots of Senna italica

Senna italica, a member of the Fabaceae family (subfamily Caesalpiniaceae), is widely used in South African traditional medicine to treat a number of disease conditions. Aqueous extracts of the plant are mainly used to treat sexually transmitted infections and intestinal complications. The roots of S. italica were ground to a fine powder and sequentially extracted with n-hexane, dichloromethane, acetone, and methanol using serial exhaustive extraction (SEE) method. Thin layer chromatography was used to analyse the phytochemical composition of the extracts and DPPH radical scavenging method to detect the presence of antioxidant compounds. The bioassay guided fractionation of the acetone fraction afforded an antioxidant compound with free radical scavenging activity. The isolated compound was subsequently identified as 3,4′,5-trihydroxystilbene (resveratrol). This study represents the first report of the stilbene resveratrol in S. italica.

The phytochemical, antibacterial and antioxidant activity of five medicinal plants against the wound infecting bacteria

Leaf extracts of Senna italica, Ricinus communis, Lantana camara, Lippia javanica and Ziziphus mucronata were screened for biological activity against bacteria which infect wounds. The leaves were extracted using different solvents of varying polarity (hexane, dichloromethane, acetone and methanol). Phytochemical analyses of the extracts were performed using thin layer chromatography (TLC). The extracts were loaded on TLC plates and developed in three solvent systems that is benzene/ethanol/ammonium solution (BEA), chloroform/ethyl acetate/formic acid (CEF) and ethyl acetate/methanol/water (EMW). Antibacterial activity of the plants was evaluated using micro-dilution and bioautography methods. The test organisms used were Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. Acetone extracts were chosen for antioxidant activity. Methanol was the best extractant, followed by acetone and dichloromethane (DCM). In the phytochemical analysis, more compounds were observed on BEA, followed by EMW and CEF plates. Lantana camara had no activity against any of the bacteria used. P. aeruginosa was the most resistant bacterium with only two plants active against it. E. faecalis and E. coli were sensitive to the extracts. More antibacterial compounds were observed on BEA plates against all the test bacteria in bioautographic method. The Rf values calculated from bioautography indicated that the selected plants have different active compounds. The most active compounds were from S. italica and Z. mucronata. BEA and EMW plates had good antioxidant activity. No antioxidant activity was observed on the CEF plate. Most extracts were active against wound pathogens; their application on the wound area may prevent infection. Further studies are required to identify the active compounds in the plant extracts which showed significant anti-bacterial activities.

In Vitro Assessment of Selected Medicinal Plants Used by the Bapedi Community in South Africa for Treatment of Bacterial Infections

There is very little scientific information on indigenous plants used for medicinal purposes. Therefore, the aim of the study was to evaluate the antibacterial and antioxidant activities of the leaves of Commelina africana, Elephantorrhiza elephantina, Dombeya rotundifolia, and the whole plant excluding the roots of Schkuhria pinnata indigenous medicinal plants from the Limpopo Province, which may be used for the treatment in humans infected with bacterial pathogens. The screening of different phytoconstituents using standard methods revealed the presence of terpenoids, flavonoids, tannins, and saponins. The total phenolic, tannin, and flavonoid content were estimated using spectrophotometric methods. D rotundifolia had the highest amounts of phenol (259.00 ± 2.65 mg of gallic acid equivalent [GAE]/g), tannin (330.33 ± 15.63 mg of GAE/g), and flavonoid (19.90 ± 0.75 mg of quercetin equivalent [QE]/g) content, while S pinnata had the least. All the plants had antibacterial activity against Escherichia coli and Pseudomonas aeruginosa with the bioautography method. The microbroth dilution assay revealed antibacterial activity with minimum inhibitory concentration values raining from 0.02 to 2.50 mg/mL. D rotundifolia had the highest antioxidant activity in both the free radical scavenging and ferric reducing power methods. S pinnata and C africana extracts had high antibacterial activity, while D rotundifolia had high antioxidant activity, which made them potential plants for isolation of bioactive compounds and possible application in the pharmaceutical industry.

Evaluation of Herbal Concoctions Sold at Ga Maja (Limpopo Province) in South Africa and In Vitro Pharmacological Evaluation of Plants Used to Manufacture the Concoctions

The aim of the study was to evaluate the biological activities and safety of commercial herbal concoctions manufactured in Ga Maja (Limpopo province). Microbial contamination was evaluated by spread-plating the concoctions on agar plates. The VITEK 2 instrument was used for identification of the pure cultures. Nutritional content of the concoctions was determined. Thin layer chromatography was used to analyze the chemical constituents of the extracts. The microdilution assay and bioautography were used to evaluate antimicrobial activity against selected microorganisms. Sodium, potassium, and zinc were elements most abundant in the concoctions. Phytochemical screening revealed the presence of various phytoconstituents. Acetone extracts of Hypoxis hemerocallidea and Kirkia wilmsii extracts had antioxidant activity. The minimum inhibitory concentrations values against test bacteria ranged between 0.02 and 0.63 mg/mL. Further studies are required to isolate bioactive compounds and evaluate their cytotoxicity. Caution in the consumption of the herbal mixtures should be adhered to.

Antibacterial activity and in situ efficacy of Bidens pilosa Linn and Dichrostachys cinerea Wight et Arn extracts against common diarrhoea-causing waterborne bacteria

BackgroundBidens pilosa and Dichrostachys cinerea extracts were investigated for the antibacterial properties against waterborne diarrhoeagenic bacteria.MethodsThe plant materials were extracted using the direct and serial exhaustive methods using solvents of varying polarities, namely, hexane, dichloromethane, ethyl acetate, acetone and methanol. Qualitative phytochemical analysis and quantitative determination of total phenolic content of the leaf powders of the two plants were tested. The antioxidant activities of the plants were determined using the 2, 2-diphenyl-1-picrylhydrazyl method. The toxic effect of the extracts on C2C12 muscle cell line were assessed by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide method and the antibacterial activity was determined using the serial microbroth dilution.ResultsMethanol leaf extracts both plants had the highest yield in both direct and serial exhaustive extraction methods. Phytochemical profiling of the extracts displayed the presence of various secondary metabolites. The Benzene: ethanol: ammonia hydroxide solvent system showed a good resolution of chemical compounds in plant extracts from both plants. Most antioxidant compounds observed were developed in chloroform: ethyl acetate: formic acid and ethyl acetate: methanol: water solvent systems. All the bacterial species tested were sensitive to the effect of different extracts of both plant species, with E. coli being less sensitive to the effect of the extracts from D. cinerea. Following the simulated gastric fluid (SGF) treatment, a decrease in the antibacterial potency of the extracts was observed. No extract was toxic to the C2C12 muscle cell line.ConclusionThe presence of the secondary metabolites and nontoxic effect of the two plants tested may affirm the medicinal value of these leaf extracts. Our results suggest that B. pilosa and D. cinerea contain constituents with antioxidant and antimicrobial activities, which could be used in the treatment of diarrhoea in a case where untreated surface water is used.

Phytochemical Analysis, Antioxidant and Antibacterial Properties of Spilanthes mauritiana Used Traditionally in Limpopo Province, South Africa:

Spilanthes mauritiana belonging to the family Asteraceae, was screened for biological activity against bacterial pathogen. Antibacterial activity of the plant was investigated using microbroth dilution assay and bioautography. Total phenols and tannins of the extract were 52.47 ± 2.29 and 23.9 ± 1.18 as mg of gallic acid equivalents, respectively. Total flavonoid content was 25.1 ± 0.79 as mg of quercetin equivalents. Free radical scavenging activity of constituents in all the extract, against 2,2-diphenyl-1-picrylhydrazyl showed minimal activity. All extracts contained compounds with antibacterial activity against tested pathogens. Hexane extract had an average minimum inhibitory concentration value of 2.50 mg/mL, followed by methanol extract (1.72 mg/mL), acetone and dichloromethane extracts (1.96 mg/mL). The present study revealed the presence of compounds in S mauritiana with potent antibacterial activity against tested pathogens that are exhibiting the observed activity independent of other constituents contained in the extracts.