The influence of S. frutescens on adrenal cytochrome P450 11B-hydroxylase

Sergeant, Catherine Anne (2009-12)

Thesis (MSc (Biochemistry))--University of Stellenbosch, 2009.

Thesis

ENGLISH ABSTRACT: This study: 1. describes the preparation of a methanol extract of Sutherlandia frutescens and the HPLC fractionation of the methanol extract. 2. investigates the influence of S. frutescens on the binding properties of mitochondrial cytochrome 11 -hydroxylase (CYP11B1) to deoxycorticosterone (DOC) and deoxycortisol, demonstrating that methanol extracts of S. frutescens inhibit the Type I substrate-induced difference spectra. 3. investigates the influence of S. frutescens on the catalytic activity of CYP11B1 expressed in COS1 cells, demonstrating that the methanol extract of S. frutescens inhibits the conversion of DOC and deoxycortisol. 4. describes the sequential extraction of the methanol extract of S. frutescens using organic solvents and the inhibition of the conversion of DOC by CYP11B1 expressed in COS1 cells in the presence of these extracts. 5. describes the inhibition of the binding of DOC to CYP11B1 in ovine adrenal mitochondria, and the conversion of DOC by CYP11B1 expressed in COS1 cells by these fractions. 6. identifies the presence of the flavonoid compounds, orientin vitexin and rutin, in S. frutescens. 7. investigates the influence of the flavonoid compounds on the binding of DOC to CYP11B1 and on the catalytic activity of DOC by CYP11B1 expressed in COS1 cells. 8. identifies the presence of the triterpenoid, sutherlandioside A (SU1), in S. frutescens extracts and investigates its effect on the binding of DOC to CYP11B1.

AFRIKAANSE OPSOMMING: Hierdie studie beskryf: 1. die voorbereiding van ‘n metanol ekstraksie van Sutherlandia frutescens en die HPLC fraksionering van die metanol ekstrakte. 2. ‘n ondersoek na die invloed van S. frutescens op die bindingseienskappe van sitochroom P450 11 -hidroksilase (CYP11B1) in skaap bynier mitochondria en demonstreer dat S. frutescens metanol ekstrakte die vorming van steroïed-geinduseerde tipe I verskil spektra van deoksiekortisol en deoksikortikosteroon (DOC) inhibeer. 3. ‘n ondersoek na die invloed van S. frutescens op die katalitiese aktiwiteit van CYP11B1 in COS1 selle en demonstreer die inhibisie van DOC en deoksikortisol omsetting na hul produkte deur die methanol ekstrakte. 4. die opeenvolgende ekstraksie van methanol extrakte van S. frutescens met organiese oplosmiddels en beskryf die inhibisie van die CYP11B1 gekataliseerde omsetting van DOC in COS1selle in die teenwoordigheid van die ekstrakte. 5. die inhibeerende effek op die binding van DOC aan CYP11B1 in skaap bynier mitochondria en die inhibisie van die CYP11B1 gekataliseerde omsetting van DOC in COS1selle. 6. die identifisering van flavonoïed verbindings, orientin vitexin en rutin in S. frutescens. 7. ‘n ondersoek na die invloed van die flavonoïed verbindings op die binding van DOC aan CYP11B1 en op die katalitiese aktiwiteit van CYP11B1 in COS1 selle. 8. die indentifisering van die triterpenoïed, sutherlandiosied A (SU1), in S. frutescens en ondersoek die invloed van SU1 op die binding van DOC aan CYP11B1.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/2488
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