Isolation and characterisation of nematicidal compound, leolorin C, from Leonotis leonurus acetone leaf extract.

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.

Anthelmintic and antimycobacterial activity of fractions and compounds isolated from Cissampelos mucronata.

ETHNOPHARMACOLOGICAL RELEVANCE: Cissampelos mucronata A. Rich., a perennial climber belonging to the family Menispermaceae, has been used traditionally to treat parasites and tuberculosis-related symptoms. Co-infection of helminth parasites and tuberculosis-causing pathogens heightens the risk of developing active tuberculosis. AIM OF THE STUDY: The aim was to isolate and characterize antimycobacterial compounds from Cissampelos mucronata and to investigate their antibiofilm and anthelmintic efficacy as well as cytotoxicity. MATERIALS AND METHODS: The acetone extract of C. mucronata leaves and stems was fractionated by vacuum liquid chromatography using hexane, ethyl acetate, acetone and methanol:chloroform (3:7). Separation of the active ethyl acetate fraction by column and preparative thin layer chromatography led to the isolation and identification of five compounds using NMR and LC-MS, as well as GC-MS for non-polar compounds. The anthelmintic, antimycobacterial, antibiofilm, antioxidant and anti-inflammatory effects as well as cytotoxicity of the fractions and compounds were determined. RESULTS: The ethyl acetate fraction had the best antimycobacterial activity (MIC = 0.015-0.08 mg/ml). The fractions were relatively non-toxic to Vero cells (0.03-0.79 mg/ml) and had good anti-inflammatory and antibiofilm effects. Five compounds were identified as stigmasterol, hentriacontane, simiarenol, nonacosene and carbonic acid. Nonacosene had moderate anthelmintic effects but poor antimycobacterial activity (MIC = 0.375 mg/ml). Nonacosene and hentriacontane had good biofilm inhibitory effect (90-100%). CONCLUSIONS: This study reveals that C. mucronata is a potential source of promising compounds with a range of useful bioactivities that support its use in traditional medicine. Development of plant-based remedies may assist in reducing the impact of co-infections with helminth parasites and tuberculosis-causing mycobacteria.

In vitro anticancer screening of South African plants.

AIM OF THE STUDY: The purpose of the present study is to evaluate South African plants for their anticancer activity. MATERIALS AND METHODS: Plant species were collected throughout South Africa and voucher specimens were deposited and identified at the South African National Biodiversity Institute. Plant extracts were prepared and screened for in vitro anticancer activity against a panel of three human cell lines (breast MCF7, renal TK10 and melanoma UACC62) at the CSIR. Plant extracts that exhibited anticancer activity against these three human cell lines were screened by the NCI against sixty human cancer cell lines organized into sub-panels representing leukaemia, melanoma, cancer of the lung, colon, kidney, ovary, central nervous system, breast and prostate. RESULTS: A total of 7500 plant extracts were screened for in vitro anticancer activity against breast MCF7, renal TK10 and melanoma UACC62 human cell lines between the period 1999 and 2006. Hits were classified into four categories based on their total growth inhibition of the cell lines. A hit rate of 5.9% was obtained for extracts which showed moderate activity and these were screened by the NCI against a panel of sixty human cancer cell lines. The extracts of plant species with limited published information for their anticancer properties were subjected to bioassay-guided fractionation and the active constituents isolated and identified. The largest number of plant specimens in this study was from the family Asteraceae, which is rich in sesquiterpene lactones. CONCLUSIONS: Although the extracts of the plants were randomly selected, 68% of these plant species which were hits in the screening programme are reported to be used medicinally. Based on our data, it appears that unrelated medicinal use of the source plants may serve as an initial guide to selection of plants for anticancer screening.

[Variation of the position and inclination of incisors in the sagittal plane using 2 modes of retention]. / Variation de la position et de l'inclinaison des incisives dans le plan sagittal selon deux modes de contention.

The evolution of the incisor position and inclination during retention depends on many factors. It specifically depends on: the amount of movements realized during treatment, the position obtained at the end of treatment, the type of retention used, the facial type, patient sex and age.