Browsing by Author "Haynes, Richard K."
Now showing items 1-20 of 27
-
Absorption of the novel artemisinin derivatives artemisone and artemiside: potential application of Pheroid™ technology
Steyn, J. Dewald; Du Plessis, Lissinda H.; Grobler, Anne F.; Kotzé, Awie F.; Haynes, Richard K. (Elsevier, 2011)Artemisinins have low aqueous solubility that results in poor and erratic absorption upon oral administration. The poor solubility and erratic absorption usually translate to low bioavailability. Artemisinin-based monotherapy ... -
Absorptive and secretory transport of selected artemisinin derivatives across Caco-2 cell monolayers
Heyns, Jaco; Willers, Clarissa; Haynes, Richard K.; Wong, Ho N.; Hamman, Josias; Gouws, Chrisna (Bentham Science, 2018)Background: Malaria continues to be a major health concern and affects more than 200 million people a year. Drugs currently used for treatment of malaria are increasingly rendered ineffectual by the ongoing emergence of ... -
Accessible and distinct decoquinate derivatives active against Mycobacterium tuberculosis and apicomplexan parasites
Beteck, Richard M.; Smit, Frans J.; N'Da, David D.; Haynes, Richard K.; Seldon, Ronnett (Nature, 2018)The quinolone decoquinate is coadministered with feed for treatment of parasites which cause coccidiosis in poultry. However, from a drug-development perspective, the biological activity is often not adequately exploited ... -
Accumulation of TB-active compounds in murine organs relevant to infection by mycobacterium tuberculosis
Tanner, Lloyd; Haynes, Richard K.; Wiesner, Lubbe (Frontiers Media, 2020)Tuberculosis (TB), the leading cause of death due to an infectious agent, requires prolonged and costly drug treatments. With the rise in incidence of MDR and XDR TB, newer more efficacious treatments which are better ... -
Activities of 11-azaartemisinin and N-sulfonyl derivatives against asexual and transmissible malaria parasites
Harmse, Rozanne; Wong, Ho Ning; Smit, Frans J.; Haynes, Richard K.; N'Da, David D. (Wiley, 2017)Dihydroartemisinin (DHA), either used in its own right or as the active drug generated in vivo from the other artemisinins in current clinical use—artemether and artesunate—induces quiescence in ring-stage parasites of ... -
Activities of 11-azaartemisinin and N-sulfonyl derivatives against Neospora caninum and comparative cytotoxicities
Harmse, Rozanne; Wong, Ho Ning; Smit, Frans J.; N'Da, David D.; Haynes, Richard K. (Wiley, 2017)Neosporosis caused by the apicomplexan parasite Neospora caninum is an economically important disease that induces abortion in dairy and beef cattle. There are no vaccines or drugs available on the market for control or ... -
Anti-melanoma activities of artemisone and prenylated amino-artemisinins in combination with known anticancer drugs
Wong, Ho Ning; Lewies, Angélique; Haigh, Michaela; Viljoen, Joe M.; Wentzel, Johannes F.; Haynes, Richard K.; Du Plessis, Lissinda H. (Frontiers Media, 2020)The most frequently occurring cancers are those of the skin, with melanoma being the leading cause of death due to skin cancer. Breakthroughs in chemotherapy have been achieved in certain cases, though only marginal advances ... -
Anti-mycobacterial peroxides: a new class of agents for development against tuberculosis
Van der Westhuyzen, Christiaan W.; Haynes, Richard K.; Panayides, Jenny-Lee; Wiid, Ian; Parkinson, Christopher J. (Bentham Science, 2020)Background: With few exceptions, existing tuberculosis drugs were developed many years ago and resistance profiles have emerged. This has created a need for new drugs with discrete modes of action. There is evidence that ... -
Anticancer properties of distinct antimalarial drug classes
Hooft van Huijsduijnen, Rob; Haynes, Richard K.; Chibale, Kelly; Peitz, Ingmar; Kelter, Gerhard (PLoS, 2013)We have tested five distinct classes of established and experimental antimalarial drugs for their anticancer potential, using a panel of 91 human cancer lines. Three classes of drugs: artemisinins, synthetic peroxides and ... -
Antimalarial N-1,N-3-dialkyldioxonaphthoimidazoliums: synthesis, biological activity, and structure-activity relationships
Ahenkorah, Stephen; Haynes, Richard K.; Coertzen, Dina; Tong, Jie Xin; Fridianto, Kevin (ACS, 2020)Here we report the nanomolar potencies of N1,N3-dialkyldioxonaphthoimidazoliums against asexual forms of sensitive and resistant Plasmodium falciparum. Activity was dependent on the presence of the fused quinone-imidazolium ... -
Artemisone inhibits in vitro and in vivo propagation of Babesia bovis and B. bigemina parasites
Mazuz, Monica L.; Haynes, Richard K.; Golenser, Jacob; Fish, Leah; Wollkomirsky, Ricardo (Elsevier, 2013)Artemisone was evaluated, in in vitro and in vivo, for control of bovine babesiosis caused by Babesia bigemina and Babesia bovis parasites. In vitro, artemisone reduced parasitemia in a dose-dependent manner: the inhibitory ... -
Assessment of the induction of dormant ring stages in Plasmodium falciparum parasites by artemisone and artemisone entrapped in Pheroid vesicles in vitro
Grobler, Lizette; Haynes, Richard K.; Grobler, Anne F.; Chavchich, Marina; Edstein, Michael D. (American Society for Microbiology, 2014)The in vitro antimalarial activities of artemisone and artemisone entrapped in Pheroid vesicles were compared, as was their ability to induce dormancy in Plasmodium falciparum. There was no increase in the activity of ... -
The case for development of 11-aza-artemisinins for malaria
Harmse, Rozanne; Smit, Frans; Haynes, Richard K.; N'Da, David D.; Wong, Ho Ning (Bentham Science, 2015)The current treatment regimens for uncomplicated malaria comprise an artemisinin in combination with another drug (ACT). However, the recent emergence of resistance to ACTs in South East Asia dramatically emphasizes the ... -
Considerations on the mechanism of action of artemisinin antimalarials. Part 1. The 'carbon radical' and 'heme' hypotheses
Haynes, Richard K.; N'Da, David; Cheu, Kwan-Wing; Coghi, Paolo; Monti, Diego (Bentham Science, 2013)The isolation of artemisinin from the traditional medicinal herb qīng hāo (Artemisia annua), its characterization as a peroxide and preparation of the derivatives dihydroartemisinin, artemether and artesunate in the 1970s ... -
Development of pyridyl thiosemicarbazones as highly potent agents for the treatment of malaria after oral administration
Parkinson, Christopher J.; Haynes, Richard K.; Birrell, Geoffrey W.; Chavchich, Marina; Mackenzie, Donna (Oxford Univ Press, 2019)Objectives Drug resistance exists to all current and investigational antimalarial drug classes. Consequently, we have set out to develop chemically and mechanistically discrete antimalarials. Here we report on the development ... -
Elimination of Schistosoma mansoni in infected mice by slow release of artemisone
Gold, Daniel; Haynes, Richard K.; Wong, Ho Ning; Alian, Mohammed; Domb, Avraham (Elsevier, 2017)The current treatment of schistosomiasis is based on the anti-helminthic drug praziquantel (PZQ). PZQ affects only the adult stages of schistosomes. In addition, resistance to PZQ is emerging. We suggest a drug, which ... -
Facile preparation of N-glycosylated 10-piperazinyl artemisinin derivatives and evaluation of their antimalarial and cytotoxic activities
Wu, Yuet; Wong, Ho Ning; Haynes, Richard K.; Parapini, Silvia; Williams, Ian D. (MDPI, 2018)According to the precepts that C-10 amino-artemisinins display optimum biological activities for the artemisinin drug class, and that attachment of a sugar enhances specificity of drug delivery, polarity and solubility so ... -
Formulation of natural oil nano-emulsions for the topical delivery of clofazimine, artemisone and decoquinate
Burger, Cornel; Aucamp, Marique; Du Preez, Jan; Haynes, Richard K.; Du Plessis, Jeanetta; Gerber, Minja (Springer, 2018)Purpose The aim of this study was to formulate nano-emulsions comprising natural oils and the active pharmaceutical ingredients (APIs) clofazimine (CLF), artemisone (ATM) and decoquinate (DQ) in order to determine ... -
In vitro anti-cancer effects of artemisone nano-vesicular formulations on melanoma cells
Dwivedi, Anupma; Mazumder, Anisha; Du Plessis, Lissinda; Du Preez, Jan L.; Haynes, Richard K.; Du Plessis, Jeanetta (Elsevier, 2015)Artemisone is a 10-amino-artemisinin derivative that is markedly superior in vitro and in vivo to current artemisinins against malaria and also possesses antitumor activity. In seeking to capitalise on the last property, ... -
In vitro efficacies, ADME, and pharmacokinetic properties of phenoxazine derivatives active against Mycobacterium tuberculosis
Tanner, Lloyd; Haynes, Richard K.; Evans, Joanna C.; Seldon, Ronnett; Jordaan, Audrey (ASM, 2019)Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a leading infectious killer globally, demanding the urgent development of faster-acting drugs with novel mechanisms of action. Riminophenazines such ...