Ahmed A. Hussein

Activity against Mycobacterium smegmatis and M. tuberculosis by extract of South African medicinal plants

Seven ethnobotanically selected medicinal plants were screened for their antimycobacterial activity. The minimum inhibitory concentration (MIC) of four plants namely Artemisia afra, Dodonea angustifolia, Drosera capensis and Galenia africana ranged from 0.781 to 6.25 mg/mL against Mycobacterium smegmatis. G. africana showed the best activity exhibiting an MIC of 0.78 mg/mL and a minimum bactericidal concentration (MBC) of 1.56 mg/mL. The MICs of ethanol extracts of D. angustifolia and G. africana against M. tuberculosis were found to be 5.0 and 1.2 mg/mL respectively. The mammalian cytotoxicity IC50 value of the most active antimycobacterial extract, from G. africana, was found to be 101.3 µg/mL against monkey kidney Vero cells. Since the ethanol G. africana displayed the best antimycobacterial activity, it was subjected to fractionation which led to the isolation of a flavone, 5,7,2′‐trihydroxyflavone. The MIC of this compound was found to be 0.031 mg/mL against M. smegmatis and 0.10 mg/mL against M. tuberculosis. This study gives some scientific basis to the traditional use of these plants for TB‐related symptoms. Copyright

Antioxidant activity and cytotoxicity effect of flavonoids isolated from Athrixia phylicoides

Bioassay-guided fractionation of an ethanolic extract from aerial parts of Athrixia phylicoides using silica and sephadex column chromatography led to the isolation of three flavonoids. The compounds were identified as: 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol (1), 3-0-demethyldigicitrin (2), and Quecertin (3). Isolated compounds together with ethanol crude extract were tested for antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH)-spectrophotometric assay, while cytotoxicity effect was determined using XTT colorimetric assay. The crude extract showed a concentration-dependent radical scavenging activity with EC 50 value of 10.64 ± 0.08 µg/ml. Compound 3 was the most potent radical scavenger, exhibiting EC 50 value of 1.27 ± 0.25 µg/ml, followed by compound 1 and 2 showing 2.74 ± 0.10 and 3.41 ± 0.09 µg/ml respectively. The crude extract showed no or little toxicity on Vero cells at lower concentrations tested exhibiting the IC 50 value of 107.8 ± 0.13 µg/ml. Compound 3 showed minimal toxicity effect by exhibiting IC 50 value of 81.38 ± 0.33 µg/ml as compared to compound 2 (IC 50 , 28.92 ± 0.12 µg/ml) and compound 1 (IC 50 , 27.91 ± 0.18 µg/ml). The results obtained from this study provide a clear rationale for the medicinal uses of A. phylicoides .

Inhibition of HIV-1 enzymes, antioxidant and anti-inflammatory activities of Plectranthus barbatus

ETHNOPHARMACOLOGICAL RELEVANCE Plectranthus barbatus is widely used in African countries as an herbal remedy to manage HIV/AIDS and related conditions. AIM OF THE STUDY To investigate the HIV-1 inhibitory, anti-inflammatory and antioxidant properties of P. barbatus and thereby provide empirical evidence for the apparent anecdotal success of the extracts. MATERIALS AND METHODS Ethanolic extract of P. barbatuss leaves was screened against two HIV-1 enzymes: protease (PR) and reverse transcriptase (RT). Cytotoxicity of the extract was determined through measuring tetrazolium dye uptake of peripheral blood mononuclear cells (PBMCs) and the TZM-bl cell line. Confirmatory assays for cytotoxicity were performed using flow cytometry and real-time cell electronic sensing (RT-CES). The free radical scavenging activity of the extract was investigated with 2,2-diphenyl-1-picrylhydrazyl while the anti-inflammatory properties of the plant extract were investigated using a Th1/Th2/Th17 cytometric bead array technique. RESULTS P. barbatus extract inhibited HIV-1PR and the 50% inhibitory concentration (IC50) was 62.0 µg/ml. The extract demonstrated poor inhibition of HIV-1 RT. Cytotoxicity testing presented CC50 values of 83.7 and 50.4 µg/ml in PBMCs and TZM-bl respectively. In addition, the extract stimulated proliferation in HIV negative and positive PBMCs treated. RT-CES also registered substantial TZM-bl proliferation after extract treatment. The extract exhibited strong antioxidant activity with an IC50 of 16 µg/ml and reduced the production of pro-inflammatory cytokines indicating anti-inflammatory potential. CONCLUSION This is the first demonstration of the in vitro anti HIV-1 potential of P. barbatus including direct activity as well as through the stimulation of protective immune and inflammation responses. The low cytotoxicity of the extract is also in agreement with the vast anecdotal use of this plant in treating various ailments with no reported side-effects.

3-Keto-22-epi-28-nor-cathasterone, a brassinosteroid-related metabolite from Cystoseira myrica

Bioassay-guided purification of an ethanolic extract of Cystoseira myrica against HEPG-2 (liver) and HCT116 (colon) human cancer cell lines led to the isolation of 3-keto-22-epi-28-nor-cathasterone, 1 and cholest-4-ene-3,6-dione, 2. This finding allowed us to report for the first time that a brassinosteroid-related metabolite occurs in seaweed. These compounds showed activity in the range of 12.38-1.16 microM with selective activity of compound 2 to liver cancer cell lines.

Investigation of the possible biological activities of a poisonous South African plant; Hyaenanche globosa (Euphorbiaceae).

The present study was undertaken to explore the possible biochemical activities of Hyaenanche globosa Lamb. and its compounds. Two different extracts (ethanol and dichloromethane) of four different parts (leaves, root, stem, and fruits) of H. globosa were evaluated for their possible antibacterial, antityrosinase, and anticancer (cytotoxicity) properties. Two pure compounds were isolated using column chromatographic techniques. Active extracts and pure compounds were investigated for their antioxidant effect on cultured ‘Hela cells’. Antioxidant/oxidative properties of the ethanolic extract of the fruits of H. globosa and purified compounds were investigated using reactive oxygen species (ROS), ferric-reducing antioxidant power (FRAP), and lipid peroxidation thiobarbituric acid reactive substance (TBARS) assays. The ethanolic extract of the leaves and fruits of H. globosa showed the best activity, exhibiting a minimum inhibitory concentration (MIC) of 3.1 mg/ ml and a minimum bactericidal concentration (MBC) of 1.56 and 6.2 mg/ml, respectively, against M. smegmatis. The ethanolic extract of the fruits of H. globosa (F.E) showed the highest percentage of inhibitory activity of monophenolase (90.4% at 200 μg/ml). In addition, F.E exhibited 50% inhibitory concentration (IC50) of 37.7 μg/ml on the viability of ‘HeLa cells’ using cytotoxicity MTT assay. Subsequently, F.E was fractionated using phase-partitioning with n-hexane, ethyl acetate, and n-butanol. The cytotoxicity of these fractions were determined in vitro using different cancer cell lines. The n-hexane fraction exhibited the highest activity of toxicity. Therefore, this fraction was subjected to further separation by chromatographic methods. Two pure compounds known as: ‘Tutin’ and ‘hyenanchin’ were isolated and their structures were determined by NMR spectroscopic methods. Unpredictably, none of them showed significant (P < 0.01) inhibition on cell viability/proliferation at the concentrations that were used. F.E showed significant anti-tyrosinase, antibacterial, and cytotoxicity effects, therefore it can be considered as an effective inhibitor alone or in combination with other plant extracts.

Bioactive Diterpenes and Other Constituents of Croton steenkampianus

A new indanone derivative (1) and two new diterpenoids (2 and 3), together with three known flavonoids, have been isolated from an ethanol extract of the leaves of Croton steenkampianus. The structure of 2 was solved by single-crystal X-ray diffraction analysis, whereas those of 1 and 3 were established mainly by 1D and 2D NMR spectroscopic methods. The isolated compounds were tested for their antiplasmodial activity and cytotoxicity. Antiplasmodial assays against chloroquine-susceptible strains (D10 and D6) and the chloroquine-resistant strains (Dd2 and W2) of Plasmodium falciparum showed that compound 2 gave moderate activities at 9.1-15.8 μM, while none of the compounds were cytotoxic against Vero cells.

Antitubercular Activity of Compounds Isolated from Pelargonium sidoides.

Abstract The recent increase in the incidence of tuberculosis with the emergence of multidrug-resistant (MDR) cases has lead to the search for new drugs that are effective against MDR strains of Mycobacterium tuberculosis. and can augment the potential of existing drugs against tuberculosis. Pelargonium sidoides. DC (Geraniaceae) is highly valued by traditional healers for its curative properties and is well-known to treat coughs, diarrhea, and tuberculosis. The butanol root extract was found have bioactive inhibitory activity against M. tuberculosis. at a concentration of 2.5 × 103 µg/mL. Phytochemical analysis of the active fraction from the root of P. sidoides. led to the isolation and identification of six compounds: coumarins (umckalin, scopoletin, 6,8-dihydroxy-5.7-dimethoxy-2H.-benzopyran-2-one, and 6,8-dihydroxy-7-methoxy-2H.-benzopyran-2-one) and flavonoids (catechin and epigallocatechin, which is reported for the first time from P. sidoides.). The isolated compounds were evaluated for antitubercular activity with M. smegmatis. and M. tuberculosis.. Intracellular activity of these compounds was also investigated using THP-1 human macrophages infected with M. tuberculosis.. The isolated compounds did not show activity inhibitory against M. tuberculosis., intracellularly and extracellularly, at the highest concentration tested in the current study. Epigallocatechin and scopoletin showed good inhibitory activity against M. smegmatis., exhibiting a minimum inhibitory concentration (MIC) of 7.8 µg/mL. Catechin and umckalin exhibited MIC values of 31.25 and 62.5 µg/mL, respectively.

Antiproliferative and Apoptosis Induction Potential of the Methanolic Leaf Extract of Holarrhena floribunda (G. Don)

Natural plant products with potent growth inhibition and apoptosis induction properties are extensively being investigated for their cancer chemopreventive potential. Holarrhena floribunda (HF) is used in a wide range of traditional medicine practices. The present study investigated the antiproliferative and apoptosis induction potential of methanolic leaf extracts of HF against breast (MCF-7), colorectal (HT-29), and cervical (HeLa) cancer cells relative to normal KMST-6 fibroblasts. The MTT assay in conjunction with the trypan blue dye exclusion and clonogenic assays were used to determine the effects of the extracts on the cells. Caspase activities were assayed with Caspase-Glo 3/7 and Caspase-9 kits. Apoptosis induction was monitored by flow cytometry using the APOPercentage and Annexin V-FITC kits. Reactive oxygen species (ROS) was measured using the fluorogenic molecular probe 5-(and-6)-chloromethyl-2′,7′-dichlorofluorescein diacetate acetyl ester and cell cycle arrest was detected with propidium iodide. Dose-response analyses of the extract showed greater sensitivity in cancer cell lines than in fibroblast controls. Induction of apoptosis, ROS, and cell cycle arrest were time- and dose-dependent for the cancer cell lines studied. These findings provide a basis for further studies on the isolation, characterization, and mechanistic evaluation of the bioactive compounds responsible for the antiproliferative activity of the plant extract.

Is the outcome of caudal epidural injections affected by patient positioning

Study Design. A prospective, randomized controlled trial. Objective. To investigate the effect of the lateral decubitus position, after a caudal epidural injection, on outcome. Summary of Background Data. Caudal epidural injections are used widely in the treatment of low back pain and radicular leg pain. Various measures have been used to improve the efficacy of these injections in previous studies. Our aim was to investigate the effect of the lateral decubitus position, after administering a caudal epidural injection, on outcome. Methods. Fifty-seven patients undergoing caudal epidural injection for low back pain associated with radicular leg pain were randomly allocated into 2 groups. Group 1 (treatment group) had 28 patients who were placed in the lateral decubitus position after injection. Group 2 (control group) had 29 patients who were laid supine after injection. Patients were assessed before injection using the Verbal Pain Score (VPS) and the Oswestry Disability Index (ODI). They were reassessed after 6 weeks using the same outcome measures. Results. Both groups demonstrated improvement after injection. The degree of improvement in the VPS was significantly greater in group 1 compared with group 2 (P = 0.00007). The degree of improvement in the ODI was not statistically significant (P = 0.14). Conclusion. Laying a patient on the side of their leg pain after a caudal epidural injection has a beneficial effect on the degree of pain relief. We recommend that this simple and safe maneuver be introduced routinely after administering a caudal epidural injection, to aid in the eventual outcome of a potentially difficult clinical problem.

Cytotoxic, Cytostatic and HIV-1 PR Inhibitory Activities of the Soft Coral Litophyton arboreum

Bioassay-guided fractionation using different chromatographic and spectroscopic techniques in the analysis of the Red Sea soft coral Litophyton arboreum led to the isolation of nine compounds; sarcophytol M (1), alismol (2), 24-methylcholesta-5,24(28)-diene-3β-ol (3), 10-O-methyl alismoxide (4), alismoxide (5), (S)-chimyl alcohol (6), 7β-acetoxy-24-methylcholesta-5-24(28)-diene-3,19-diol (7), erythro-N-dodecanoyl-docosasphinga-(4E,8E)-dienine (8), and 24-methylcholesta-5,24(28)-diene-3β,7β,19-triol (9). Some of the isolated compounds demonstrated potent cytotoxic- and/or cytostatic activity against HeLa and U937 cancer cell lines and inhibitory activity against HIV-1 protease (PR). Compound 7 was strongly cytotoxic against HeLa cells (CC50 4.3 ± 0.75 µM), with selectivity index of SI 8.1, which was confirmed by real time cell electronic sensing (RT-CES). Compounds 2, 7, and 8 showed strong inhibitory activity against HIV-1 PR at IC50s of 7.20 ± 0.7, 4.85 ± 0.18, and 4.80 ± 0.92 µM respectively. In silico docking of most compounds presented comparable scores to that of acetyl pepstatin, a known HIV-1 PR inhibitor. Interestingly, compound 8 showed potent HIV-1 PR inhibitory activity in the absence of cytotoxicity against the cell lines used. In addition, compounds 2 and 5 demonstrated cytostatic action in HeLa cells, revealing potential use in virostatic cocktails. Taken together, data presented here suggest Litophyton arboreum to contain promising compounds for further investigation against the diseases mentioned.