Umma Staff Publications

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Subject: search.filters.subject.Podocarpus

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    Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species
    (Elsevier, 2011-12-06) Abdillahi, Halima S.; Verschaeve, Luc; Finnie, Jeffrey F.; Staden, Johannes Van
    Ethnopharmacological relevance: Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetylcholinesterase inhibitory and antioxidant activities. Aim of the study: To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species. Material and methods: The mutagenicity and cytotoxic effects of extracts from four species of Podocarpus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonella typhimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity testing. The relative cytotoxicity of the extracts was assessed by determining their NI50 values (50% inhibitionof NRU). Results: The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest–lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was 38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml. Conclusion: Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.
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    Antimicrobial activity of South African Podocarpus species
    (2008-06-28) Abdillahi, H.S.; Stafford, G.I.; Finnie, J.F.; Staden, J. Van
    Ethnopharmacological relevance: Several species of Podocarpus (Podocarpaceae) are utilized in treating ailments across the world. In Africa, four species are used traditionally in both animal and human health Aim of the study: To investigate the antimicrobial activity of Podocarpus species against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Candida albicans. Materials and methods: Six solvents of varying polarity were used for extraction. Antibacterial activity was assessed using the microdilution bioassay and for antifungal activity, the microdilution bioassay and (M27-P) broth dilution were used. Results: All species exhibited antimicrobial activity with MIC values of less than 1 mg/ml. Inhibition against Gram-positive bacteriawas stronger with an MIC value of 98 g/ml while for Gram-negative bacteria, the highest inhibitionwas against Klebsiella pneumoniae with an MIC value of 0.33 mg/ml. All species exhibited strong antifungal activity with the best MIC being 30 g/ml after 48 h. Conclusions: All four species exhibited strong inhibition against all tested microbials, based on Aligiannis et al. [Aligiannis, N., Kalpotzakis, E., Mitaku, S., Chinou, I.B., 2001. Composition and antimicrobial activity of the essential oils of two Origanum species. Journal of Agricultural and Food Chemistry 40, 4168–4170] classification they can be classified as strong inhibitors.
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    Anti-inflammatory, antioxidant,anti-tyrosinase and phenolic contents off our Podocarpus species used in traditional medicine in South Africa
    (Elsevier Ireland, 2010-07-06) Abdillahi, Halima Saado; Finnie, J.F.; Staden, J.Van
    Ethnopharmacological relevance: Species of Podocarpus are used traditionally in their native areas for the treatment of fevers,asthma,coughs,cholera,chest complaints,arthritis,rheumatism,venereal diseases and distemper in dogs. Aims of the study: To investigate the antioxidant,anti-inflammatory and anti-tyrosinase activities off our Podocarpus species, Podocarpus elongatus, Podocarpus falcatus, Podocarpus henkelii and Podocarpus lati-folius, used in traditional medicine in South Africa. Phytochemical analysis to determine the phenolic contents was also carried out. Materials and methods: DPPH, FRAPand -carotene-linoleic acid assays were used to determine the antioxidant/radical scavenging activities of these species. Anti-inflammatory activity of these species was assayed against two cyclooxygenase enzymes(COX-1 and COX-2).Tyrosinase inhibition activity was analysed using the modified dopachrome method with l-DOPA as the substrate. Phenolics were quantitatively determined using spectrophotometric methods. Results: Stems of Podocarpus latifolius exhibited thelowestEC50 (0.84 g/ml) inhibition against DPPH.The percentage antioxidant activity based on the bleaching rate of -carotene rangedfrom96%to99%.High ferric reducing power was observed in all the extracts.For COX-1,the lowest EC50 value was exhibited by stem extracts of Podocarpus elongatus (5.02 g/ml) and leaf extract of Podocarpus latifolius showed the lowest EC50 against COX-2(5.13 g/ml). All extracts inhibited tyrosinase activity in a dose-dependent manner with stem extract of Podocarpus elongatus being the most potent with an EC50 value of 0.14mg/ml. The total phenolic content ranged from 2.38 to 6.94 mg of GAE/g dry sample. Conclusion: The significant pharmacological activities observed support the use of these species in traditional medicine and may also be candidates in the search for modern pharmaceuticals in medicine, food and cosmetic industries.
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    Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species
    (Elsevier, 2011-12-01) Abdillahi, Halima Saado
    Ethnopharmacological relevance: Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetyl-cholinesterase inhibitory and antioxidant activities. Aim of the study: To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species. Material and methods: The mutagenicity and cytotoxic effects of extracts from four species of Podocar-pus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonellatyphimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity test- ing. The relative cytotoxicity of the extracts was assessed by determining their NI50 values (50% inhibition of NRU). Results: The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest–lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml. Conclusion: Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.