H.S. Abdillahi

Anti-inflammatory, antioxidant, anti-tyrosinase and phenolic contents of four Podocarpus species used in traditional medicine in South Africa.

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 of four Podocarpus species, Podocarpus elongatus, Podocarpus falcatus, Podocarpus henkelii and Podocarpus latifolius, used in traditional medicine in South Africa. Phytochemical analysis to determine the phenolic contents was also carried out. MATERIALS AND METHODS DPPH, FRAP and β-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 the lowest EC(50) (0.84 μg/ml) inhibition against DPPH. The percentage antioxidant activity based on the bleaching rate of β-carotene ranged from 96% to 99%. High ferric reducing power was observed in all the extracts. For COX-1, the lowest EC(50) value was exhibited by stem extracts of Podocarpus elongatus (5.02 μg/ml) and leaf extract of Podocarpus latifolius showed the lowest EC(50) against COX-2 (5.13 μg/ml). All extracts inhibited tyrosinase activity in a dose-dependent manner with stem extract of Podocarpus elongatus being the most potent with an EC(50) value of 0.14 mg/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.

Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species

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 NI(50) 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 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.

South African plants and male reproductive healthcare: Conception and contraception

ETHNOPHARMACOLOGICAL RELEVANCE Traditional remedies from plants have been use to treat male reproductive related disorders for ages in South Africa. AIM This study reviewed the current status of medicinal plants used in male reproductive healthcare as well as their effectiveness as a mode of treatment. METHODOLOGY A detailed literature search was done by consulting books, peer-reviewed papers, scientific databases such as Scopus, Science direct and PubMed, and Google scholars. Keywords such as aphrodisiacs, conception, erectile dysfunction, fertility, infertility and sterility in relation to medicinal plants were used during the search. Plant species were selected based on their traditional use in different aspects of male reproductive healthcare. RESULTS A total of 61 plants species were found to be used in treating male impotency or as aphrodisiacs. However, only six species have been evaluated scientifically and these plants showed significant activities either in promoting conception by improving fertility and promoting erection or in contraception by decreasing sperm motility, virility and membrane integrity. CONCLUSION The importance of herbal products in the treatment of male infertility and related sexual disorders is undeniable. Scientific evaluations of the six species have proved the empirical use of these plants in the improvement of male sexual disorders as well as validating their traditional uses.

Antimicrobial activity of South African Podocarpus species.

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 1mg/ml. Inhibition against Gram-positive bacteria was stronger with an MIC value of 98 microg/ml while for Gram-negative bacteria, the highest inhibition was against Klebsiella pneumoniae with an MIC value of 0.33 mg/ml. All species exhibited strong antifungal activity with the best MIC being 30 microg/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.

Application of medicinal plants in maternal healthcare and infertility: a South African perspective.

Plants have played significant roles as medicine during pregnancy, birth, and postpartum care in many rural areas of the world. In addition to this, plants have been used for centuries to treat infertility and related reproduction problems. The aim of this paper was to review the current status of plant species used in maternal healthcare, including infertility, in South Africa, in terms of scientific evaluation for efficacy and safety. In addition to this, the role of medicinal plants as a tool in achieving the MDG5 of reducing maternal mortality by 2015 was evaluated. A search was done with the aid of Google Scholar, PubMed, Science Direct, peer-reviewed papers, and books, using keywords such as child birth, labour pain, maternal health, maternal mortality, menstrual pains, and postpartum. The plants listed in the different research articles were classified according to their use and the target effect of a plant extract or compound on reproductive function. Eighty-four plant species were found to be used to treat infertility and related problems. Twenty plant species are used during pregnancy, while 26 plant species are used to ease childbirth. For postpartum healing and any problems after childbirth, nine plant species were recorded. Unhealthy pregnancy and birth complications are among the factors that contribute to the loss of cognitive potential in the developing worlds children, condemning them to impoverished lives. The best way to keep a country poor is to rob its children of their full developmental potential. In this respect, medicinal plants play a significant role in reducing maternal mortality and ensuring the birth of healthy children.

A new sesquiterpenoid from the rhizomes of Homalomena sagittifolia

A new sesquiterpenoid, 1α,4β,7β-eudesmanetriol (1), was isolated together with the known compounds 1β,4β,7β-eudesmanetriol (2) and oplopanone (3) from the rhizomes of Homalomena sagittifolia. The structures of these compounds were determined by extensive spectral analyses. The compounds 1 and 2 inhibited growth of Pseudomonas stutzeri with a MIC value of 117 µM when evaluated for antibacterial activity using the minimum concentration assay. Both these compounds showed remarkable activities against acetylcholinesterase enzyme with IC50 values ranging between 25 and 26 µM. The isolation of these sesquiterpenoids and their biological activities observed in this study support the reported traditional uses of H. sagittifolia for the treatment of microbial related diseases and central nervous system disorders.