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As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.

Organotin(IV) complexes represented as R2SnL2 (where R = Cl, CH3, C4H9, C6H5; L = N,N-diallyldithiocarbamate) have been synthesized and characterized by elemental analysis, 1H, 13C, 119Sn NMR and FTIR spectroscopic analyses. The structures of [(CH3)2SnL2] and [(C4H9)2SnL2] were further determined using single crystal X-ray crystallography. These complexes crystallized in a triclinic crystal system with P-1(2) space group. Two N,N-diallyldithiocarbamato ligands bond to the tin(IV) ion in an anisobidentate fashion resulting in a highly distorted six coordinate geometry, best described as skew trapezoidal-bipyramidal geometry. Results obtained for the antimicrobial study showed a varied activity against some Gram (+) and (−) bacterial and fungi species. This activity generally ranged from moderate to good in which complex [(C6H5)2SnL2] and [(C4H9)2SnL2] exhibited the best antimicrobial properties. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability and reducing power studies showed that complex [(CH3)SnL2] displayed the highest antioxidant activities compared to the other compounds but a little less than the standard, gallic acid. Furthermore, the cytotoxicity study against the human tumour cell line (HeLa) showed a varied activity due to lipophilicity and selectivity of the cell line towards the complexes. This observed activity compared favourably with the standard drug (5-FU) used in which complex [(C6H5)2SnL2] was found to show a better cytotoxic activity than the standard drug.

Objective: To investigate the protective effect of aqueous leaf extract of Acalypha (A.) wilkesiana Muell. Arg (Euphorbiaceae) against cyclophosphamide-induced toxicity in albino rats. Methods: Twenty male albino rats were randomly divided into five groups of four animals each. The control group (I) was fed with pellets and distilled water, while group II was orally administered with only 20 mg/kg cyclophosphamide. Groups III, IV and V were co- administered with 20 mg/kg body weight cyclophosphamide and 110, 220 and 440 mg/kg body weight A. wilkesiana leaf extract, respectively, for 7 d. After treatment, liver and kidney function biomarkers, haematological parameters, liver antioxidants, and mitochondrial membrane permeability transition pore opening were investigated. Results: A. wilkesiana leaf extract significantly reduced (P

This study was aimed at characterising the secondary metabolites responsible for antibacterial and antioxidant activities of Acalypha wilkesiana. Purification of the defatted methanol leaves extract was guided by the DPPH free radical scavenging assay as well as by evaluation of the antibacterial activity against four bacterial strains. As a result, geraniin, corilagin, quadrangularic acid M and shikimic acid were purified and isolated. Shikimic acid, reported for the first time from this plant, proved to be the major metabolite of the extract. All the four isolated compounds showed bactericidal activity against extended spectrum beta-lactamase-producing Klebsiella pneumoniae (700603), while corilagin was the single compound to exhibit antioxidant activity (IC50 53 μg/mL).

The antimicrobial activity of the leave of Acalypha wilkesiana methanolic extract and its four derivative fractions were determined on human pathogenic bacteria namely strains of Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis, Pseudomonas aeruginosa, Proteus vulgaris and Escherichia coli and fungi; Aspergillus niger, A. flavus, A. carbonerium, Trichophyton mentagrophytes and Candida albicans. Methanolic extract (200 mg/ml) and its fractions were tested on the bacteria and fungi using the disc diffusion method. In vitro antibacterial and antifungal activity were screened by using Mueller Hinton Agar (MHA) and Potato Dextrose Agar (PDA) respectively. The minimum inhibitory concentration for the bacteria and fungi were also determined. Results showed broad spectrum antimicrobial activity against the Gram-negative and Gram-positive bacteria but same cannot be said about its activity against the fungi. The ethyl acetate fraction inhibited the growth of more bacteria and fungi compared to the other fractions; however, Research Article European Journal of Medicinal Plants, 3(1): 52-64, 2013 53 the aqueous extract was more effective on the bacteria isolates as it showed the lowest MIC for more bacteria compared to the other fractions. The extract and its fractions were active against bacteria which some standard antibiotics were not able to inhibit. Methanolic extract of A. wilkesiana leaves and its fractions showed a better antibacterial activity than antifungal activity. The fact that the plant was active against both clinical and laboratory isolates is an indication that it can be a source of very potent antibiotic substances that can be used against drug resistant microorganisms. The search for new drugs to counter the challenges posed by resistant strains of bacteria and some fungi might have started yielding results as the investigation of this plant has demonstrated enormous therapeutic potential.

In this study, the chemical profile of a crude methanol extract of Rauvolfia caffra Sond was determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Column chromatography and preparative thin layer chromatography were used to isolate three indole alkaloids (raucaffricine, N-methylsarpagine and spegatrine) and one triterpenoid (lupeol). The antiplasmodial activity was determined using the parasite lactate dehydrogenase (pLDH) assay. The UPLC-MS profile of the crude extract reveals that the major constituents of R. caffra are raucaffricine (m/z 513.2) and spegatrine (m/z 352.2). Fraction 3 displayed the highest antiplasmodial activity with an IC50 of 6.533 &mu, g/mL. However, raucaffricine, isolated from the active fraction did not display any activity. The study identifies the major constituents of R. caffra and also demonstrates that the major constituents do not contribute to the antiplasmodial activity of R. caffra.

The aim of this study was to determine the antioxidant activity of the extractable and non-extractable phenolics of Terminalia. Sericea Burch. Ex DC. Free, ester bound, ether or glycoside bound and insoluble phenolics were extracted from the fruit, leaves, stem, and root samples. Follin Ciocalteu was used to estimate the phenolic content while DPPH (2,2-diphenyl-1-picrylhydrazyl) assay was used to determine the antioxidant activity. The data obtained were subjected to multivariate analysis for relationships. The result indicated that the highest average total phenolic contents and antioxidant activities were found in the free (14.8 mgGAE/g, IC50 6.8 &mu, g/mL) and ester bound (15.1 mgGAE/g, IC50 6.4 &mu, g/mL) extractable phenolics. There was a strong negative correlation between TPC and DPPH (r = &minus, 0.828). Agglomerative hierarchical clustering revealed three clusters. Cluster one contained the insoluble and glycoside phenolics while cluster 2 contained only free phenolic acid of the root. The third cluster was predominantly free and ester bound phenolic extracts. The principal component analysis score plot indicated two major clusters with factor 1 (F1) explaining 61% of the variation. The nuclear magnetic resonance spectroscopy spectra indicated that gallic acid and resveratrol are the major phenolic compounds present in the root. This study has demonstrated that extractable phenolics contributed more to the antioxidant activities compared to the non-extractables.

Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function.

The Vhembe region of the Limpopo province has a rich tradition of medicinal plants use. Traditionally, boiled roots of Ziziphus mucronata are used in the treatment of boils, general swelling and other skin infections. A combination of leaf paste and root infusion treats measles, dysentery, chest complains, and gland swelling. Pterocarpus angolensis is famous for the treatment of menorrhagia, infertility in women, wounds and pain management. The purpose of the present study was to compare the cytotoxicity, anti-inflammatory potential and anti-microbial activities of Ziziphus mucronata and Pterocarpus angolensis from the Vhembe region. U937, MeWo, Vero and RAW 264.7 cells were treated to various concentrations (50, 100, or 125 or 250 μg/ml depending on assays) of Ziziphus mucronata and Pterocarpus angolensis. Cytotoxicity assay was done using MTT; Anti-inflammatory activity was assessed using NO production; Anti-bacterial activity was done using the Micro-Broth dilution method and Anti-mycobacteria activity was determined using the Alamar Blue Method while RT activity was measured by ELISA. Cytotoxicity results showed that Pterocarpus was more toxic than Ziziphus as observed in the Vero and MeWo cells; however both displayed toxicity towards a Human cancer cell line. Both extracts did not inhibit nitrate production but induced significant increase in macrophage activation. The plant extracts have shown anti-tuberculosis activity at concentrations >500 μg/ml and there was moderation inhibition of HIV replication. The results obtained indicated that the extracts have pro-inflammatory properties, and the observed toxicity on malignant cell lines must be investigated further for promising anti-cancer drug therapy.