Browsing by Author "Hussein, Ahmed"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Antibacterial and anti-inflammatory effects of Syzygium jambos L. (Alston) and isolated compounds on acne vulgaris
    (BioMed Central, 2013) Sharma, Richa; Kishore, Navneet; Hussein, Ahmed
    Acne vulgaris is a chronic skin disorder leading to inflammation as a result of the production of reactive oxygen species due to the active involvement of Propionibacterium acnes (P. acnes) in the infection site of the skin. The current study was designed to assess the potential of the leaf extract of Syzygium jambos L. (Alston) and its compounds for antibacterial and anti-inflammatory activity against the pathogenic P. acnes. The broth dilution method was used to assess the antibacterial activity. The cytotoxicity investigation on mouse melanocyte (B16-F10) and human leukemic monocyte lymphoma (U937) cells was done using sodium 3’-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitrobenzene sulfonic acid hydrate (XTT) reagent. The non-toxic concentrations of the samples was investigated for the suppression of cytokines interleukin 8 (IL 8) and tumour necrosis factor (TNF α) by testing the supernatants in the co-culture of the human U937 cells and heat killed P. acnes using enzyme immunoassay kits (ELISA). The statistical analysis was done using the Graph Pad Prism 4 program.
  • Thumbnail Image
    Item
    Green synthesis and characterization of gold nanoparticles from South African plants and their biological evaluations
    (University of the Western Cape, 2019) Elbagory, Abdulrahman Mohammed Mohammed Nagy; Meyer, Mervin; Hussein, Ahmed
    The field of nanotechnology continues to offer solutions for biotechnologists whose target is to improve the quality of life by finding new therapies to combat diseases. Gold nanoparticles (AuNPs) have been showing great potentials in many biomedical applications. The antibacterial activity of the AuNPs presents a therapeutic option for conditions caused by bacterial infections such as chronic wounds. Also, these versatile particles can offer solutions in the treatments of infectious diseases and can also be exploited as “smart” vehicles to carry drugs, such as antibiotics, for improved efficiency. Moreover, the anti-inflammatory activity of AuNPs makes them useful in the management of prolonged inflammation caused by bacterial infections. The synthesis of AuNPs can be achieved by variety of physical and chemical methods that have been successfully applied in labs and industry. Nonetheless, the drawbacks of these “conventional” methods in terms of high cost, adverse health side effects and incompatibility with the ecosystem cannot be overlooked. Thus, new safer and more cost-effective protocols have been reported for the synthesis of AuNPs. Plants have provided alternate synthesis methods in which the reducing capabilities of the phytochemicals, found in the aqueous plant extracts, can be used to chemically synthesize AuNPs from gold precursors. The biosynthesis and characterization of AuNPs from the phytochemicals of several South African plants is investigated in this study. The study also reports the optimization of the AuNPs biosynthesis by varying reaction conditions such as temperature and plant extracts’ concentrations. Furthermore, the study highlights the wound healing activity of the AuNPs synthesized from selected plants by investigating their antibacterial activity on bacterial strains known to cause chronic wounds. The ability of these AuNPs to carry ampicillin in order to enhance the antibacterial activity is also described herein. The cytotoxicity of the biosynthesized AuNPs was evaluated on human normal fibroblasts cells (KMST-6). Additionally, the immunomodulatory effect of the biosynthesized AuNPs on the cytokines production from macrophages and Natural Killer (NK) cells was examined. The study was successful to produce biocompatible and safe AuNPs synthesized from the tested aqueous plant extracts. The resulted AuNPs showed different physicochemical properties by varying the reaction conditions. The AuNPs exhibited antibacterial activity against several Gram-positive and Gram-negative bacteria. Also, ampicillin was successfully loaded on the biosynthesized AuNPs, which led to the formation of more antibacterial active conjugated AuNPs compared to the free AuNPs. The green synthesized AuNPs were also found to have anti-inflammatory responses as shown by the reduction of pro-inflammatory cytokines from immune cells. In vitro assays showed that the biogenic AuNPs were not toxic to KMST-6 cells. Overall, the data suggest that plant extracts produce biologically safe AuNPs with antibacterial and anti-inflammatory activities that can be exploited in the treatment of chronic wounds and in the management of chronic inflammation.
  • Thumbnail Image
    Item
    Investigation of anti-cancer potential of Pleiocarpa pycnantha leaves
    (University of the Western Cape, 2013) Omoyeni, Olubunmi Adenike; Green, Ivan Robert; Iwuoha, Emmanuel; Hussein, Ahmed
    The Apocynaceae family is well known for its potential anticancer activity. Pleiocarpamine isolated from the Apocynaceae family and a constituent of Pleiocarpa pycnantha has been reported for anti-cancer activity. Prompted by a general growing interest in the pharmacology of Apocynaceae species, most importantly their anticancer potential together with the fact that there is scanty literature on the pharmacology of P. pycnantha, we explored the anticancer potential of the ethanolic extract of P. pycnantha leaves and constituents. Three known triterpenoids, ursolic acid C1, 27-E and 27-Z p-coumaric esters of ursolic acid C2, C3 together with a new triterpene 2,3-seco-taraxer-14-en-2,3-lactone (pycanocarpine C5) were isolated from an ethanolic extract of P. pycnantha leaves. The structure of C5 was unambiguously assigned using NMR, HREIMS and X-ray crystallography. The cytotoxic activities of the compounds were evaluated against HeLa, MCF-7, KMST-6 and HT-29 cells using the WST-1 assay. Ursolic acid C1 displayed potent cytotoxic activity against HeLa, HT-29 and MCF-7 cells with IC50 values of 5.06, 5.12 and 9.51 μg/ml respectively. The new compound C5 and its hydrolysed open-chain derivative C6 were selectively cytotoxic to the breast cancer cell line, MCF-7 with IC50 values 10.99 and 5.46 μg/ml respectively. We further investigated the mechanism of action of the isolated compounds using specific markers of apoptosis. Exposure of C1-C6 (12.5 μg/ml) to HeLa cells showed a significant increase in reactive oxygen species (ROS) production with the exception of C5. On HT-29, C1, C4, C5 and C6 at 25 μg/ml increased ROS production while on MCF-7 using the same dose, only C5 and C6 caused a significant increase in ROS production compared with a control at P< 0.05. The result on caspase 3/7 activation showed that C1 and C2 (50 μg/ml) caused a marked increase in caspase 3/7 activity between 6-24 h on HeLa cells while only C1 (50 μg/ml) showed a significant increased caspase 3/7 activity on both HT-29 and MCF-7 cell lines when compared with the control, P< 0.05. Some selected compounds were further investigated for their dose-response on caspase 3/7 activity on HeLa and MCF-7 cells. Compounds C2 and C3 activated caspase 3/7 at 12.5 and 25 μg/ml respectively, while on MCF-7only C6 significantly increased caspase 3/7 activity within 24 h of treatment when compared with an untreated control. The result of time -dependent caspase 9 activity showed that C1, C2 and C3 caused an increased activity on HeLa cells between 6-12 h, while only C1 activated caspase 9 on HT-29 cells (3-24 h) and MCF-7 (6-24 h). The dose-response caspase 9 activity showed a significant increase in activation for C6 (12 and 25 μg/ml) on HeLa and C5 (25 μg/ml) on HT-29 cells. All isolated compounds inhibited Topoisomerase I when compared with Camptothecin. Compounds C1-C6 could induce apoptosis on cancer cell lines through an intrinsic pathway and topoisomerase 1 inhibition. This is the first report on the isolation of a 2,3-seco-taraxerene derivative from Apocynaceae family and the anticancer activity of Pleiocarpa pycnantha constituents.
  • Thumbnail Image
    Item
    The potential of leucosidea sericea against propionibacterium acnes
    (Elsevier, 2014) Sharma, Richa; Kishore, Navneet; Hussein, Ahmed
    The present study reports on the potential of Leucosidea sericea addressing acne vulgaris. Four known compounds namely phytol acetate, triacontanol, phytol and alpha kosin and one new compound namely, (E)-3,7,11,15-tetramethylheptadec-2-ene-1,17-diol have been isolated for the first time from this plant. The ethanol extract of leaves and one of the isolated compounds, alpha kosin exhibited significant minimum inhibitory concentration (with MIC values 15.7 μg/mL and 1.9 μg/mL, respectively) against acne inducing bacteria, Propionibacterium acnes. Moreover, the transmission electron micrographs showed the efflux of intracellular content of the cells of P. acnes caused by plant extract and alpha kosin. The ethanol extract of L. sericea exhibited significant anti-inflammatory activity by suppressing interleukin 8 (IL 8) and tumour necrosis factor (TNF α) in coculture of human U937 cells and heat killed P. acnes at concentrations of 25.0, 12.5 and 6.2 μg/mL.