J.F. Finnie

Anti-inflammatory, anticholinesterase, antioxidant and phytochemical properties of medicinal plants used for pain-related ailments in South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE Extracts of seven South African medicinal plants used traditionally for the treatment of pain-related ailments were evaluated. AIMS OF THE STUDY The study was aimed at evaluating medicinal and therapeutic potentials of the investigated traditional medicinal plants. Plant extracts were evaluated for anti-inflammatory activity and other pharmacological properties such as anticholinesterase and antioxidant activities. Phytochemical analysis of total phenolic contents, condensed tannins, gallotannins and flavonoids in the aqueous methanol extracts of the medicinal plants were also carried out. MATERIALS AND METHODS The evaluation of anti-inflammatory activity of 50% methanol (50% MeOH), petroleum ether (PE), dichloromethane (DCM) and ethanol (EtOH) plant extracts was done against cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. 50% MeOH, PE, DCM and EtOH extracts were tested for acetylcholinesterase (AChE) inhibition, while 50% MeOH extracts were tested for 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and ferric-reducing power in the antioxidant assays. Total phenolic compounds, condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. RESULTS At the screening assay concentration (0.25 microg/microl), 13 extracts showed good COX-1 inhibitory activity (>50%), while good activity was observed in 15 extracts against COX-2 enzyme. All the extracts of Crinum moorei (bulbs) showed good inhibition against both COX-1 and COX-2 enzymes. Though not significantly different (P=0.05), the highest COX-1 percentage inhibition (100%) was shown by Aloe ferox leaf PE and Colocasia antiquorum tuber DCM extracts, while Colocasia antiquorum tuber PE extract exhibited the highest (92.7%) percentage inhibition against COX-2. Crinum moorei bulb DCM extract showed the lowest EC(50) value (2.9 microg/ml) in the AChE assay. In addition, good to moderate bioactivities were observed in some extracts of Aloe ferox (leaves), Crinum moorei (bulbs) and Pycnostachys reticulata (leaves) in all the assays. The presence and/or amounts of phenolic compounds varied with plant species. CONCLUSION The results obtained in this study validate the use of the investigated medicinal plants in South African traditional medicine for pain-related ailments.

Effect of Seaweed Concentrate and Applied Hormones on In Vitro Cultured Tomato Roots

Summary Seaweed concentrate prepared from Ecklonia maxima stimulated the growth of in vitro cultured tomato roots. Both root extension and root elongation were significantly improved. This effect could be mimicked by low concentrations of zeatin. At concentrations of 10 -6 M or above, all aspects of root growth were inhibited. IAA, ABA, and GA 3 had no stimulatory effect on root growth. Autoclaving did not result in a loss of the stimulatory effect of seaweed concentrate. With ashing this effect was however, eliminated. Chromatographic separation of the seaweed concentrate indicated the presence of more than one stimulatory compound each of which may affect different aspects of root growth differently.

Antimicrobial properties and phenolic contents of medicinal plants used by the Venda people for conditions related to venereal diseases.

ETHNOPHARMACOLOGY RELEVANCE Many people are infected by venereal diseases and the human immunodeficiency virus (HIV) in rural areas. Sexual transmitted diseases are considered a disgrace in the community because of the stigmas attached to them. Indigenous people tend to use several medicinal plants to treat these infectious diseases rather than western medicines. AIM OF THE STUDY This study was aimed to evaluate the antibacterial, antifungal, antigonococcal, HIV-type 1 reverse transcriptase (RT) and to determine phenolic content of twelve medicinal plants used by the Venda people to treat venereal diseases. MATERIALS AND METHODS The dried plant materials of twelve medicinal plants were extracted with petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water. The extracts were evaluated for their antimicrobial properties against two Gram-positive (Bacillus subtilis and Staphylococcus aureus), three Gram-negative (Neisseria gonorrhoeae, Escherichia coli and Klebsiella pneumoniae) bacteria and a fungus Candida albicans. The phenolic contents including total phenolics, flavonoids, gallotannins and condensed tannins of the methanolic extracts of the same plants were also determined. RESULTS DCM and EtOH extracts of Bolusanthus speciosus bark and stems exhibited good activity (<0.1mg/ml) against Escherichia coli and Staphylococcus aureus with MIC values ranging from 0.098 to 0.012 mg/ml. The DCM extracts of Bolusanthus speciosus bark showed the best activity against Candida albicans with MIC and MFC values of 0.012 mg/ml. Water and 50% methanol extracts of Acacia karroo bark, Bolusanthus speciosus stems and Ximenia caffra roots and leaves showed good RT inhibition percentages (>70%) at 1mg/ml. All tested extracts exhibited dose dependent IC(50) values ranging from (0.1 to 0.6 mg/ml). Almost all plant species investigated contained phenolic compounds, which were greater than 5mg/g with the exception of Adansonia digitata bark and Aloe chabaudii roots. The highest level of flavonoids (11.9 μg/g) were detected in Ximenia caffra leaves. Whereas the highest amount of gallotannins were detected in Ekebergia capensis bark (69 μg/g). Condensed tannins were higher in Ekebergia capensis bark and Ximenia caffra roots (0.47 and 0.48% respectively). Adansonia digitata bark and Aloe chabaudii roots exhibited low levels of phenolic compounds as well as antimicrobial activities. CONCLUSION The presented results offer supporting evidence for effective use of selected plant extracts. More in vitro confirmatory tests using other assays and/or in vivo tests are required. Toxicity studies are urgently needed to support the safe usage of these plants.

In vitro antimicrobial synergism within plant extract combinations from three South African medicinal bulbs

ETHNOPHARMACOLOGICAL RELEVANCE Tulbaghia violacea, Hypoxis hemerocallidea and Merwilla plumbea are used in South African traditional medicine for the treatment of some infectious diseases and other ailments. AIM OF THE STUDY The study aimed at investigating the antimicrobial efficacies of independent and various within-plant extract combinations of three medicinal bulbs to understand the possible pharmacological interactions. MATERIALS AND METHODS Bulb and leaf extracts of the three medicinal plants, independently and in combinations, were comparatively assessed for antimicrobial activity against two Gram-positive and two Gram-negative bacteria and Candida albicans using the microdilution method. The fractional inhibitory concentration indices (FIC) for two extract combinations were determined. RESULTS At least one extract combination in each plant sample demonstrated good antimicrobial activity against all the test organisms. The efficacies of the various extract combinations in each plant sample varied, with the strongest synergistic effect exhibited by the proportional extract yield combination of PE and DCM extracts in Merwilla plumbea bulb sample against Staphylococcus aureus (FIC index of 0.1). Most extract combinations demonstrated either a synergistic, additive or indifferent interaction effect against the test bacteria with only a few exhibiting antagonistic effects. CONCLUSION The observed antimicrobial efficacy and synergistic interactions indicate the beneficial aspects of combination chemotherapy of medicinal plant extracts in the treatment of infectious diseases.

Use of the temporary immersion bioreactor system (RITA®) for production of commercial Eucalyptus clones in Mondi Forests (SA)

In order to optimise tissue culture systems and to meet production targets, Mondi Forests’ biotechnology programme has in the last 2 years concentrated efforts on the use of the RITA® temporary immersion bioreactor system. Protocols have been established for six Eucalyptus clones. Results indicate a four- to six-fold increase in yield, in half the time, with the RITA® system when compared with axillary bud proliferation on semi-solid media. Furthermore, plants produced from the RITA® system are hardier and acclimatize better, giving higher yields of hardened-off plants. The establishment of aseptic axillary shoots into the RITA® system is from shoots in the semi-solid system. Highest multiplication was achieved using 30-second flushes of medium every 10 min, starting with 50 shoots per vessel. The multiplication cycles in RITA® are between 14 and 18 days, compared with 25–28 days in a semi-solid system. There is minimal callus evident on the leaves and bases of the stems of plants in the RITA® system and, in addition, cold-tolerant plants have a greater rooting competence when compared with plants coming from the semi-solid system. Ex vitro rooting of RITA® – derived plantlets is substantially better than the plants from the semi-solid media.

Anti-inflammatory and phytochemical properties of twelve medicinal plants used for treating gastro-intestinal ailments in South Africa

ETHNOPHARMACOLOGICAL RELEVANCE The investigated medicinal plants are commonly used for the treatment of pains and cramps related to gastro-intestinal tract infections in South African traditional medicine. AIMS OF THE STUDY This study aimed to evaluate the ability of the plant extracts to inhibit cyclooxygenase enzymes. Phytochemical analysis was also carried out in the quest to determine some plant metabolites that may be responsible for the observed anti-inflammatory activity. MATERIALS AND METHODS The cyclooxygenase assay was used to test for the anti-inflammatory activity of the plant extracts using cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. Total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. Qualitative tests for alkaloids and saponins were also carried out. RESULTS Most of the plant extracts evaluated showed dose dependent activity against COX-1 and/or COX-2 enzymes. Agapanthus campanulatus root dichloromethane extract showed the highest COX-2 inhibitory activity (83.7%) at 62.5 microg/ml. The presence and/or amounts of phenolics, condensed tannins, gallotannins, flavonoids, alkaloids and saponins varied with plant parts and species. CONCLUSION The results support the use of the investigated plant in treating pain and cramp related to gastro-intestinal tract infections. To some extent, the observed anti-inflammatory activity could be attributed to the various plant secondary metabolites detected in the plant materials.

Studies on the isolation of plumbagin from in vitro and in vivo grown Drosera species.

The rapid clonal multiplication of two species of South African Drosera is described. Levels of plumbagin, (5-hydroxy-2-methyl-1,4-naphthoquinone) from in vivo and in vitro grown plants are compared to those present in Plumbago roots. P. auriculata Lam. roots contained more than twice as much plumbagin as in vivo grown D. capensis L. plants which in turn contained more than twice as much as comparable plants of D. natalensis Diels. It is concluded that the extraction of plumbagin from Drosera plants is not commercially feasible.

Isolation and Culture of Lichen Photobionts and Mycobionts

Lichens are dual organisms formed from a symbiotic association of a fungus, the mycobiont, and an alga and/or cyanobacterium, the photobiont, in which numerous photosynthetic cells are intertwined in a matrix of fungal hyphae. Such definitions raise the question as to whether lichens are technically individual organisms. Many aspects of lichen biology are concerned with the interactions of these different organisms. The separation, isolation and culture of the symbionts offers the scientist a fascinating opportunity to study the components and contribute to the understanding of the nature of the symbiosis in lichens. The culture of mycobionts, photobionts and lichen thalli is central for the establishment of experimental systems for lichens, needed to solve questions associated with symbiosis biology. In addition, they are essential to solving the many fundamental problems of lichen physiology, morphogenesis and molecular biology.

In vitro pharmacological effects of manufactured herbal concoctions used in KwaZulu-Natal South Africa

ETHNOPHARMACOLOGY RELEVANCE Manufactured and packaged herbal mixtures, known locally as muthi concoctions, have become a new feature of traditional medicine in South Africa. These herbal concoctions are often claimed to cure several diseases ranging from minor illness to life threatening conditions. AIM OF THE STUDY To document the prevalence, variety and evaluate the efficacy of selected herbal concoctions sold in KwaZulu-Natal. MATERIALS AND METHODS Nine herbal concoctions were evaluated for their effects as antibacterial and antifungal agents as well as their ability to inhibit the cyclooxygenase (COX-1 and COX-2) enzymes using standard in vitro methods. RESULTS Imbiza ephuzwato and Ibhubezi, both multipurpose mixtures showed high abilities to inhibit bacterial and fungal growth as well as inhibit the COX-1 and COX-2 enzymes. Umzimba omubi and Umuthi wekukhwehlela ne zilonda, both remedies for wounds, boils and chest infections were not active against the two Gram-positive and two Gram-negative bacterial strains tested. Vusa umzimba and Supreme one hundred were active against Candida albicans. CONCLUSIONS Four of the herbal concoctions showed no activity in all of the assays tested while only two showed good activity. Activity cannot be ruled out as there are many mechanisms upon which natural products can act.

A comparative study of the antimicrobial and phytochemical properties between outdoor grown and micropropagated Tulbaghia violacea Harv. plants

AIM OF THE STUDY The study aimed to compare the antimicrobial and phytochemical properties of in vitro cultured and outdoor grown Tulbaghia violacea plants in the quest to validate the use of micropropagated plants as alternatives to outdoor grown plants in traditional medicine. Tulbaghia violacea is used extensively in South African traditional medicine for HIV/AIDS patients and in the treatment of gastrointestinal ailments, asthma, fever and tuberculosis. MATERIALS AND METHODS Extracts of micropropagated and outdoor grown Tulbaghia violacea plants were evaluated for their antibacterial and antifungal activities against Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and a fungus Candida albicans using microdilution methods. Saponins and phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. A qualitative test for saponins was also carried out. RESULTS The petroleum ether (PE) extracts of micropropagated plants and dichloromethane (DCM) extracts of outdoor grown plants showed good antibacterial activity, each against two bacterial test strains. PE extracts of micropropagated plants showed the best antibacterial activity with a minimum inhibitory concentration (MIC) of 0.39 mg/ml against Bacillus subtilis. Good MIC (<1mg/ml) and minimum fungicidal concentration (MFC) values of 0.78 mg/ml were only obtained in DCM extracts of outdoor grown plants. MIC and MFC values for water and ethanol extracts of both micropropagated and outdoor grown plants were similar and in the range 3.125-12.5mg/ml. Total phenolics, gallotannins, flavonoids and saponins were significantly higher in micropropagated plants than in outdoor grown ones. In all cases, the amounts of phytochemical compounds in micropropagated plants were more than twice that of outdoor grown plants except for condensed tannins. CONCLUSION The results form a good basis for the use of Tulbaghia violacea micropropagated plants as a complement to the outdoor grown plants in traditional medicine.