ETHNOPHARMACOLOGICAL RELEVANCE Leonotis leonurus (L.) R.Br. (Lamiaceae) is a perennial shrub nati... more ETHNOPHARMACOLOGICAL RELEVANCE Leonotis leonurus (L.) R.Br. (Lamiaceae) is a perennial shrub native to South Africa used to treat various diseases including digestive tract problems, intestinal worms and constipation. AIM OF THE STUDY The aim was to isolate and characterise nematicidal compounds from leaves of L. leonurus. MATERIALS AND METHODS Bioassay-guided fractionation was carried out using the free-living nematode Caenorhabditis elegans as a model organism. Structural elucidation of the purified compound was carried out using NMR spectroscopic analyses and UPLC-QTOF-MS. The fractions and the isolated compound were tested for nematicidal activity on motility of plant-parasitic Meloidogyne incognita juveniles (J2s) and J2 hatch inhibition. Further screening was done to determine the minimum inhibitory concentration (MIC) of the fractions against bacterial phytopathogens and cytotoxicity against Vero kidney cells. RESULTS Leoleorin C isolated from L. leonurus had moderate activity against C. elegans juveniles (34%) but was not active against J2 motility and J2 hatch of M. incognita. Thus, activity against the free-living C. elegans did not correspond with efficacy against plant-parasitic nematodes. Leoleorin C was not active against the tested bacterial phytopathogens, but some activity was observed in the bioautography assay against Clavibacter michiganensis subsp. michiganensis, the organism causing bacterial canker in tomatoes. The plant extract, fractions and leolorin C were relatively non-toxic to Vero cells with LC50 values greater than 0.01 mg/mL. CONCLUSION The crude extract of L. leonurus and fractions may be useful in developing complementary treatments for controlling nematodes and phytopathogens. This study does not support the use of free-living nematodes as a model to isolate anti-parasitic compounds from plants.
Plants can act as protective agents against the mutagenic effects of mycotoxins. Such plants or c... more Plants can act as protective agents against the mutagenic effects of mycotoxins. Such plants or compounds can be incorporated in food and feed as a chemo-preventive measure against the genotoxic properties of mycotoxins. This study was aimed at evaluating the potential mutagenic effects of dichloromethane extracts of the selected Protea species and their antimutagenic activity against aflatoxin B 1 . The Ames test using Salmonella typhimurium, TA98 tester strain was used for mutagenicity and antimutagenicity testing. Furthermore, the cytotoxicity of the extracts was determined using human hepatocellular carcinoma (C3A) cells in the neutral red uptake (NRU) assay. All seven Protea species were not mutagenic at all concentrations tested (5, 0.5 and 0.05 mg/ml). In the antimutagenicity tests, Protea susannae demonstrated strong antimutagenic activity of up to 66% against aflatoxin B 1 at concentrations 5 and 0.05 mg/ml while at 0.05 mg/ml it exhibited moderate antimutagenic activity. In the cytotoxicity assay, cell viability was ≥91% for all extracts in a concentration range from 0.8 to 100 μg/ml. The most toxic extract was Protea lanceolata with only 31% cell viability at 500 μg/ml. The results demonstrated that P. susannae inhibits the mutagenicity induced by the indirect-acting mutagen aflatoxin B 1 .
There has been burgeoning interest in plant-based feed additives following restrictions placed on... more There has been burgeoning interest in plant-based feed additives following restrictions placed on the use of antibiotic feed additives in many countries. Phytogenic feed additives are recommended to have a range of useful properties to support the growth and development of poultry to a similar level as that obtained by supplementing feed with antibiotics. The aim of this study was to evaluate the antibacterial, anti-lipoxygenase and antioxidant activity, and in vitro safety of fractions and isolated compounds from leaves of Senna singueana. Antibacterial activities of the fractions and isolated compounds were determined against a panel of bacteria using a two-fold serial microdilution assay and qualitative bioautography assays. Anti-lipoxygenase activity was evaluated using the ferrous oxidation-xylenol orange (FOX) method. Antioxidant activity was assessed qualitatively and quantitatively using radical scavenging assays. Dichloromethane and ethyl acetate fractions from solvent-solvent partitioning had the best antibacterial activity with MIC values ranging from 156 to 313 μg/ml. Fractions obtained from column chromatography had significant to weak antibacterial activity with MIC values ranging from 50 to 1,250 μg/ml. Bioautography showed clear bands of bacterial inhibition, indicating the presence of a number of active compounds in several fractions. The ethyl acetate fraction and all the tested column fractions had potent anti-lipoxygenase activity with IC50 values of ≤2.5 μg/ml which were lower than that of quercetin (positive control), indicating anti-inflammatory potential. The ethyl acetate fraction and several column fractions had powerful antioxidant activity with IC50 values of ≤5 μg/ml in the ABTS assay. Cytotoxicity values against Vero kidney cells ranged from LC50 = 40.0–989.3 μg/ml. Bioassay-guided fractionation led to the isolation and identification of a known bioactive compound, luteolin. S. singueana is a promising candidate for the development of poultry phytogenic feed additives.
Klebsiella pneumoniae, Enterococcus faecium, Acinetobacter baumannii, Pseudomonas aeruginosa, Ent... more Klebsiella pneumoniae, Enterococcus faecium, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter cloacae, and Enterobacter aerogenes (ESKAPE) bacterial group is well noted for drug resistance. These strains cause various diseases and in doing so, utilize various ways to resist a broad range of antibiotics. Susceptibility to antibiotics amongst ESKAPE bacteria is rapidly declining, and therefore, there is a need to explore alternative ways to deal with ESKAPE-related conditions by utilizing bacterial compounds. The compounds used in this study were derived from secondary metabolites of Staphylococci stains (S saprophyticus [ATCC 35552], S. aureus [isolated from milk of mastitic cows], and S. epidermidis [ATCC 51625]. These compounds were screened, identi ed and evaluated for cytotoxicity beforehand. Such compounds included Veratramine, 1,2,6-Hexanetriol, Succinic acid, 4-Methyl-pentylamine; from S. saprophyticus, Fluoranthene, 3-Methyl-2-phenyl-1H-pyrrole, and Cyclo (L-Leu-L-Propyl) and from S. epidermidis, Oleamide and Methyl palmitate. However, Fluoranthene is excluded in this study as it previously exhibited cytotoxicity against Vero cells, therefore, is considered unsuitable as a prospective antimicrobial agent. Prior to exploring the antimicrobial properties of Staphylococci-derived compounds, the susceptibility of ESKAPE bacteria was tested against the antibiotic regimens as per South African guidelines. The investigations on antibiotics susceptibility were carried out to compare the susceptibility of ESKAPE bacteria to known antibiotics against Staphylococci-derived compounds. The antimicrobial properties of the compounds were evaluated both qualitatively and quantitatively by TLC bioautography and a broth microdilution method, respectively. In this study, we found that all the compounds did not exhibit any antimicrobial properties against the ESKAPE bacteria except for Succinic acid, which exhibited its e cacy against A. baumannii with a minimum inhibitory concentration (MIC) of 62.5 µg/mL. This research investigates if Staphylococci-derived compounds could be used as possible future antimicrobials against the ESKAPE bacterial group. It also responds to the request by the "Drugs for Neglected Diseases initiative" (DNDi) and the World Health Organisation (WHO) to prioritize research and development of new antibiotics to combat ESKAPE-related infections.
Journal of Medicinal Plants for Economic Development, 2022
Background: Guiera senegalensis (Ghibaish) is a medicinal plant extensively used in central and w... more Background: Guiera senegalensis (Ghibaish) is a medicinal plant extensively used in central and west Africa for the management of various diseases.Aim: This study aimed to determine the antioxidant activity of the ethanol leaf extract of the plant.Method: The ethanol leaf extract was sequentially sub-fractionated using liquid–liquid extraction, vacuum-liquid chromatography and preparative thin layer chromatography. Ultra-performance liquid chromatography with accurate mass spectrometry and nuclear magnetic resonance were employed to isolate and confirm the identity of the most abundant compound. The antioxidant activity of the fractions and isolated compound was assessed by bioautography analysis and the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging assay.Results: The dichloromethane subfraction contained the most promising antioxidant activity (IC50 = 3.18 µg/mL). Purification of this subfraction led to the isolation of a brown crystalline compound, which was iden...
Purification of dichloromethane extract from root barks and leaves of Synadenium glaucescens resp... more Purification of dichloromethane extract from root barks and leaves of Synadenium glaucescens respectively resulted into the isolation of two compounds namely Euphol and β-sitosterol. Chemical structures were established mainly by using 1H an d 13C NMR data and by comparing current NMR data with those reported in the literature. Both compounds are known and have been isolated from other plant species but are being reported from this plant species for the first time.
In South Africa it is estimated that at least 70% of South Africans consult one of the more than ... more In South Africa it is estimated that at least 70% of South Africans consult one of the more than 200,000 Traditional Healers in the country. Clearly traditional health practitioners in South Africa play a crucial role in providing primary health care to the majority of the population. This knowledge system together with South Africa's unique biodiversity provides valuable resources for scientists to undertake research in search of new pharmaceuticals, nutraceuticals and cosmeceuticals. Scientists often refer to this as "scientific validation of traditional medicines" which can be misleading to holders of the traditional knowledge since traditional health practitioners treat their patients holistically using traditional medicines consisting of one or more plant species. Four case studies i.e. appetite suppressant form Hoodia gordonii, monatin from Sclerochiton ilicifolius, mosquito repellent from Lippia javanica and the treatment of benign prostate hyperplasia (BPH) and male pattern baldness from Elephantorrhiza elephantina which were either commercialized or close to commercialization are described and in all cases these have followed the classical drug discovery or product development route. These case studies have led to the realization that the traditional use of the plants were not exactly the same as the commercialized use. Often the scientists select plants based on traditional use and through scientific intervention discover similar biological activities or different biological activities of the plant species or constituents thereof. The scientific discoveries are further developed and the route to commercialization requires huge investment, time and resources. Hence it could be concluded that the approach has not been to scientifically validate the traditional uses of plants or traditional medicines. As scientists we need to be responsible when utilizing traditional knowledge in our research approaches and it is important to share benefits with the owners of indigenous knowledge.
Diabetes mellitus is attributed as one of the major health problems globally. This study evaluate... more Diabetes mellitus is attributed as one of the major health problems globally. This study evaluated the antioxidative and antidiabetic potentials of P. prunelloides in an in-vitro model and also screened for the presence of phytochemicals in the extracts. The antioxidant activity of the extracts (water, ethanol, aqueous-ethanol and hexane) was determined by superoxide anion, hydroxyl, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays and iron chelation method while the antidiabetic potential was assessed by determining the inhibitory effects of the extracts on the activities of α-amylase, α-glucosidase, maltase and sucrase enzymes. The hexane extract displayed significantly higher (p < 0.05) inhibition of α-amylase (0.48 μg/mL) and α-glucosidase (18.08 μg/mL) respectively. Additionally, water extract demonstrated strong inhibition of sucrase (3.85 μg/mL), and aqueous-ethanol extract (26.03 μg/mL) on maltase activity when compared with other extracts and control. The Lineweaver Burke plot revealed the non-competitive inhibition of α-amylase and α-glucosidase by the ethanol extract. While hexane extract demonstrated significant (p < 0.05) scavenging activities against superoxide anion (0.33 μg/mL) and hydroxyl radical (0.51 μg/mL), water (75.42 μg/mL) and aqueous-ethanol (4.24 μg/mL) extracts exhibited the strongest DPPH activity and iron chelation effect respectively. The phytochemical analysis of the extract revealed the presence of tannins, terpenoids, alkaloids, saponins, flavonoids and cardiac glycosides while quantification of phytochemicals revealed total flavonoids with 15.40 mg quercetin equivalent (QE)/g from hexane extract, highest tannin content with 45.60 mg gallic acid equivalent (GAE)/g (aqueous-ethanol extract) and total phenol from water and aqueousextracts with 0.07 mg GAE/g while alkaloids and saponins contents were found to be low in the roots of P. prunelloides, at 0.6 and 13.9% respectively. It can therefore be concluded that P. prunelloides extracts possessed antioxidant and antidiabetic activities in vitro and could thus be suggested that its mechanism of antidiabetic action is through the inhibition of diabetes-related enzymes.
Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in ... more Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in vitro and, in the case of cynaropicrin, also reduce parasitemia in the murine model of trypanosomiasis. To explore their structure-antitrypanosomal activity relationships, a set of 34 natural and semi-synthetic STLs and amino-STLs was tested in vitro against T. b. rhodesiense (which causes East African sleeping sickness) and mammalian cancer cells (rat bone myoblast L6 cells). It was found that the α-methylene-γlactone moiety is necessary for both antitrypanosomal effects and cytotoxicity. Antitrypanosomal
ETHNOPHARMACOLOGICAL RELEVANCE Leonotis leonurus (L.) R.Br. (Lamiaceae) is a perennial shrub nati... more ETHNOPHARMACOLOGICAL RELEVANCE Leonotis leonurus (L.) R.Br. (Lamiaceae) is a perennial shrub native to South Africa used to treat various diseases including digestive tract problems, intestinal worms and constipation. AIM OF THE STUDY The aim was to isolate and characterise nematicidal compounds from leaves of L. leonurus. MATERIALS AND METHODS Bioassay-guided fractionation was carried out using the free-living nematode Caenorhabditis elegans as a model organism. Structural elucidation of the purified compound was carried out using NMR spectroscopic analyses and UPLC-QTOF-MS. The fractions and the isolated compound were tested for nematicidal activity on motility of plant-parasitic Meloidogyne incognita juveniles (J2s) and J2 hatch inhibition. Further screening was done to determine the minimum inhibitory concentration (MIC) of the fractions against bacterial phytopathogens and cytotoxicity against Vero kidney cells. RESULTS Leoleorin C isolated from L. leonurus had moderate activity against C. elegans juveniles (34%) but was not active against J2 motility and J2 hatch of M. incognita. Thus, activity against the free-living C. elegans did not correspond with efficacy against plant-parasitic nematodes. Leoleorin C was not active against the tested bacterial phytopathogens, but some activity was observed in the bioautography assay against Clavibacter michiganensis subsp. michiganensis, the organism causing bacterial canker in tomatoes. The plant extract, fractions and leolorin C were relatively non-toxic to Vero cells with LC50 values greater than 0.01 mg/mL. CONCLUSION The crude extract of L. leonurus and fractions may be useful in developing complementary treatments for controlling nematodes and phytopathogens. This study does not support the use of free-living nematodes as a model to isolate anti-parasitic compounds from plants.
Plants can act as protective agents against the mutagenic effects of mycotoxins. Such plants or c... more Plants can act as protective agents against the mutagenic effects of mycotoxins. Such plants or compounds can be incorporated in food and feed as a chemo-preventive measure against the genotoxic properties of mycotoxins. This study was aimed at evaluating the potential mutagenic effects of dichloromethane extracts of the selected Protea species and their antimutagenic activity against aflatoxin B 1 . The Ames test using Salmonella typhimurium, TA98 tester strain was used for mutagenicity and antimutagenicity testing. Furthermore, the cytotoxicity of the extracts was determined using human hepatocellular carcinoma (C3A) cells in the neutral red uptake (NRU) assay. All seven Protea species were not mutagenic at all concentrations tested (5, 0.5 and 0.05 mg/ml). In the antimutagenicity tests, Protea susannae demonstrated strong antimutagenic activity of up to 66% against aflatoxin B 1 at concentrations 5 and 0.05 mg/ml while at 0.05 mg/ml it exhibited moderate antimutagenic activity. In the cytotoxicity assay, cell viability was ≥91% for all extracts in a concentration range from 0.8 to 100 μg/ml. The most toxic extract was Protea lanceolata with only 31% cell viability at 500 μg/ml. The results demonstrated that P. susannae inhibits the mutagenicity induced by the indirect-acting mutagen aflatoxin B 1 .
There has been burgeoning interest in plant-based feed additives following restrictions placed on... more There has been burgeoning interest in plant-based feed additives following restrictions placed on the use of antibiotic feed additives in many countries. Phytogenic feed additives are recommended to have a range of useful properties to support the growth and development of poultry to a similar level as that obtained by supplementing feed with antibiotics. The aim of this study was to evaluate the antibacterial, anti-lipoxygenase and antioxidant activity, and in vitro safety of fractions and isolated compounds from leaves of Senna singueana. Antibacterial activities of the fractions and isolated compounds were determined against a panel of bacteria using a two-fold serial microdilution assay and qualitative bioautography assays. Anti-lipoxygenase activity was evaluated using the ferrous oxidation-xylenol orange (FOX) method. Antioxidant activity was assessed qualitatively and quantitatively using radical scavenging assays. Dichloromethane and ethyl acetate fractions from solvent-solvent partitioning had the best antibacterial activity with MIC values ranging from 156 to 313 μg/ml. Fractions obtained from column chromatography had significant to weak antibacterial activity with MIC values ranging from 50 to 1,250 μg/ml. Bioautography showed clear bands of bacterial inhibition, indicating the presence of a number of active compounds in several fractions. The ethyl acetate fraction and all the tested column fractions had potent anti-lipoxygenase activity with IC50 values of ≤2.5 μg/ml which were lower than that of quercetin (positive control), indicating anti-inflammatory potential. The ethyl acetate fraction and several column fractions had powerful antioxidant activity with IC50 values of ≤5 μg/ml in the ABTS assay. Cytotoxicity values against Vero kidney cells ranged from LC50 = 40.0–989.3 μg/ml. Bioassay-guided fractionation led to the isolation and identification of a known bioactive compound, luteolin. S. singueana is a promising candidate for the development of poultry phytogenic feed additives.
Klebsiella pneumoniae, Enterococcus faecium, Acinetobacter baumannii, Pseudomonas aeruginosa, Ent... more Klebsiella pneumoniae, Enterococcus faecium, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter cloacae, and Enterobacter aerogenes (ESKAPE) bacterial group is well noted for drug resistance. These strains cause various diseases and in doing so, utilize various ways to resist a broad range of antibiotics. Susceptibility to antibiotics amongst ESKAPE bacteria is rapidly declining, and therefore, there is a need to explore alternative ways to deal with ESKAPE-related conditions by utilizing bacterial compounds. The compounds used in this study were derived from secondary metabolites of Staphylococci stains (S saprophyticus [ATCC 35552], S. aureus [isolated from milk of mastitic cows], and S. epidermidis [ATCC 51625]. These compounds were screened, identi ed and evaluated for cytotoxicity beforehand. Such compounds included Veratramine, 1,2,6-Hexanetriol, Succinic acid, 4-Methyl-pentylamine; from S. saprophyticus, Fluoranthene, 3-Methyl-2-phenyl-1H-pyrrole, and Cyclo (L-Leu-L-Propyl) and from S. epidermidis, Oleamide and Methyl palmitate. However, Fluoranthene is excluded in this study as it previously exhibited cytotoxicity against Vero cells, therefore, is considered unsuitable as a prospective antimicrobial agent. Prior to exploring the antimicrobial properties of Staphylococci-derived compounds, the susceptibility of ESKAPE bacteria was tested against the antibiotic regimens as per South African guidelines. The investigations on antibiotics susceptibility were carried out to compare the susceptibility of ESKAPE bacteria to known antibiotics against Staphylococci-derived compounds. The antimicrobial properties of the compounds were evaluated both qualitatively and quantitatively by TLC bioautography and a broth microdilution method, respectively. In this study, we found that all the compounds did not exhibit any antimicrobial properties against the ESKAPE bacteria except for Succinic acid, which exhibited its e cacy against A. baumannii with a minimum inhibitory concentration (MIC) of 62.5 µg/mL. This research investigates if Staphylococci-derived compounds could be used as possible future antimicrobials against the ESKAPE bacterial group. It also responds to the request by the "Drugs for Neglected Diseases initiative" (DNDi) and the World Health Organisation (WHO) to prioritize research and development of new antibiotics to combat ESKAPE-related infections.
Journal of Medicinal Plants for Economic Development, 2022
Background: Guiera senegalensis (Ghibaish) is a medicinal plant extensively used in central and w... more Background: Guiera senegalensis (Ghibaish) is a medicinal plant extensively used in central and west Africa for the management of various diseases.Aim: This study aimed to determine the antioxidant activity of the ethanol leaf extract of the plant.Method: The ethanol leaf extract was sequentially sub-fractionated using liquid–liquid extraction, vacuum-liquid chromatography and preparative thin layer chromatography. Ultra-performance liquid chromatography with accurate mass spectrometry and nuclear magnetic resonance were employed to isolate and confirm the identity of the most abundant compound. The antioxidant activity of the fractions and isolated compound was assessed by bioautography analysis and the 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging assay.Results: The dichloromethane subfraction contained the most promising antioxidant activity (IC50 = 3.18 µg/mL). Purification of this subfraction led to the isolation of a brown crystalline compound, which was iden...
Purification of dichloromethane extract from root barks and leaves of Synadenium glaucescens resp... more Purification of dichloromethane extract from root barks and leaves of Synadenium glaucescens respectively resulted into the isolation of two compounds namely Euphol and β-sitosterol. Chemical structures were established mainly by using 1H an d 13C NMR data and by comparing current NMR data with those reported in the literature. Both compounds are known and have been isolated from other plant species but are being reported from this plant species for the first time.
In South Africa it is estimated that at least 70% of South Africans consult one of the more than ... more In South Africa it is estimated that at least 70% of South Africans consult one of the more than 200,000 Traditional Healers in the country. Clearly traditional health practitioners in South Africa play a crucial role in providing primary health care to the majority of the population. This knowledge system together with South Africa's unique biodiversity provides valuable resources for scientists to undertake research in search of new pharmaceuticals, nutraceuticals and cosmeceuticals. Scientists often refer to this as "scientific validation of traditional medicines" which can be misleading to holders of the traditional knowledge since traditional health practitioners treat their patients holistically using traditional medicines consisting of one or more plant species. Four case studies i.e. appetite suppressant form Hoodia gordonii, monatin from Sclerochiton ilicifolius, mosquito repellent from Lippia javanica and the treatment of benign prostate hyperplasia (BPH) and male pattern baldness from Elephantorrhiza elephantina which were either commercialized or close to commercialization are described and in all cases these have followed the classical drug discovery or product development route. These case studies have led to the realization that the traditional use of the plants were not exactly the same as the commercialized use. Often the scientists select plants based on traditional use and through scientific intervention discover similar biological activities or different biological activities of the plant species or constituents thereof. The scientific discoveries are further developed and the route to commercialization requires huge investment, time and resources. Hence it could be concluded that the approach has not been to scientifically validate the traditional uses of plants or traditional medicines. As scientists we need to be responsible when utilizing traditional knowledge in our research approaches and it is important to share benefits with the owners of indigenous knowledge.
Diabetes mellitus is attributed as one of the major health problems globally. This study evaluate... more Diabetes mellitus is attributed as one of the major health problems globally. This study evaluated the antioxidative and antidiabetic potentials of P. prunelloides in an in-vitro model and also screened for the presence of phytochemicals in the extracts. The antioxidant activity of the extracts (water, ethanol, aqueous-ethanol and hexane) was determined by superoxide anion, hydroxyl, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays and iron chelation method while the antidiabetic potential was assessed by determining the inhibitory effects of the extracts on the activities of α-amylase, α-glucosidase, maltase and sucrase enzymes. The hexane extract displayed significantly higher (p < 0.05) inhibition of α-amylase (0.48 μg/mL) and α-glucosidase (18.08 μg/mL) respectively. Additionally, water extract demonstrated strong inhibition of sucrase (3.85 μg/mL), and aqueous-ethanol extract (26.03 μg/mL) on maltase activity when compared with other extracts and control. The Lineweaver Burke plot revealed the non-competitive inhibition of α-amylase and α-glucosidase by the ethanol extract. While hexane extract demonstrated significant (p < 0.05) scavenging activities against superoxide anion (0.33 μg/mL) and hydroxyl radical (0.51 μg/mL), water (75.42 μg/mL) and aqueous-ethanol (4.24 μg/mL) extracts exhibited the strongest DPPH activity and iron chelation effect respectively. The phytochemical analysis of the extract revealed the presence of tannins, terpenoids, alkaloids, saponins, flavonoids and cardiac glycosides while quantification of phytochemicals revealed total flavonoids with 15.40 mg quercetin equivalent (QE)/g from hexane extract, highest tannin content with 45.60 mg gallic acid equivalent (GAE)/g (aqueous-ethanol extract) and total phenol from water and aqueousextracts with 0.07 mg GAE/g while alkaloids and saponins contents were found to be low in the roots of P. prunelloides, at 0.6 and 13.9% respectively. It can therefore be concluded that P. prunelloides extracts possessed antioxidant and antidiabetic activities in vitro and could thus be suggested that its mechanism of antidiabetic action is through the inhibition of diabetes-related enzymes.
Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in ... more Sesquiterpene lactones (STLs) are natural products that have potent antitrypanosomal activity in vitro and, in the case of cynaropicrin, also reduce parasitemia in the murine model of trypanosomiasis. To explore their structure-antitrypanosomal activity relationships, a set of 34 natural and semi-synthetic STLs and amino-STLs was tested in vitro against T. b. rhodesiense (which causes East African sleeping sickness) and mammalian cancer cells (rat bone myoblast L6 cells). It was found that the α-methylene-γlactone moiety is necessary for both antitrypanosomal effects and cytotoxicity. Antitrypanosomal
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