Chemical characterisation and in vitro permeation of Siphonochilus aethiopicus extracts

Abstract

Studies have estimated that 80% of the people in southern Africa have an extensive history using plant materials for medicinal purposes. Siphonochilus aethiopicus (Schweinf.) B.L.Burtt (Zingiberaceae) is a critically endangered indigenous medicinal plant with a distinctive rhizome; the roots together with rhizomes are traditionally chewed for the relief of flu-like symptoms, as well as sinusitis, hysteria, dismennohria and other ailments. It is however known that for any biologically active compound to exert a pharmacological effect, a therapeutic concentration has to be reached first. The fresh rhizomes and roots of S. aethiopicus are traditionally chewed in no specific quantity; and very little is known concerning the active compounds present in S. aethiopicus as not all compounds have been isolated yet, characterised or studied. Several techniques were used in this study to investigate the chemical composition of S. aethiopicus, since no chemical fingerprint is available for this plant species. High performance thin layer chromatography (HPTLC) was therefore employed to develop a distinctive fingerprint. Ultra Performance Liquid Chromatography coupled to a Time of Flight mass analyser (UPLC-Q-TOF/MS) was used to establish a general profile of the chemical composition of S. aethiopicus. Chemical marker molecules were identified and fractionated; their structures were identified using Nuclear Magnetic Resonance (NMR) spectroscopy. For the first time, the volatiles from S. aethiopicus were explored using gas chromatography coupled to a time of flight mass spectrometer (GCxGC-TOF/MS). Finally, sufficient quality control protocols were designed for the future identification and authentication of S. aethiopicus. To establish if the isolated marker molecules of S. aethiopicus are indeed absorbed; at which site these molecules are absorbed; and to what extent absorption occurs; transport across porcine buccal and sublingual tissues as well as across Caco-2 cell monolayers were investigated. The results obtained indicated that poor absorption of the marker molecules across buccal and sublingual membranes transpires, whereas absorption of the marker molecules across Caco-2 cell monolayers indicated enhanced absorption. Additional studies investigating the chemical compounds absorbed and the gastro-intestinal tract as a site of absorption are therefore required.

Studies het beraam dat 80% van die mense in Suider-Afrika 'n uitgebreide geskiedenis aangaande die gebruik van plantmateriaal vir medisinale doeleindes het. Siphonochilus aethiopicus (Schweinf.) B.L.Burtt (Zingiberaceae) is 'n krities bedreigde, inheemse medisinale plant met 'n kenmerkende wortelstok; die wortels tesame met wortelstokke word tradisioneel gekou vir die verligting van griep-simptome, asook sinusitis, histerie, pyn tydens menstruasie en vele ander kwale. Dit is boonop bekend dat vir enige biologies aktiewe verbinding om 'n farmakologiese effek te lewer, 'n terapeutiese konsentrasie eers bereik moet word. Die vars wortelstokke en wortels van S. aethiopicus word tradisioneel gekou in geen spesifieke hoeveelheid nie; en baie min is bekend oor die aktiewe verbindings teenwoordig in hierdie plantspesie, aangesien alle verbindings nog nie geïsoleer, en geïdentifiseer is nie. Verskeie tegnieke is in hierdie studie gebruik om die chemiese samestelling van S. aethiopicus te ondersoek. Aangesien daar geen chemiese vingerafdruk beskikbaar is vir S. aethiopicus nie, is daar dus van hoë werkverrigting dunlaagchromatografie (HPTLC) gebruik gemaak om 'n eiesoortige vingerafdruk te ontwikkel. Ultra werkverrigting vloeistofchromatografie gekoppel aan 'n tyd van vlug massa ontleder (UPLC-Q-TOF/MS) is gebruik om ʼn algemene profiel van die chemiese samestelling van S. aethiopicus te vestig. Chemiese merker molekules is geïdentifiseer en gefraksioneer; hul strukture is geïdentifiseer met behulp van Kern Magnetiese Resonans (KMR) spektroskopie. Vir die eerste keer, is die vlugtige stowwe uit S. aethiopicus ondersoek met behulp van die gas chromatografie gekoppel aan n tyd van vlug massa analiseerder (GCxGC-TOF/MS). Voldoende gehaltebeheer protokolle is uiteindelik ontwerp vir die toekomstige identifikasie en verifikasie van S. aethiopicus. Om te bepaal of die geïsoleerde merker molekules van S. aethiopicus wel geabsorbeer word; waar die plek van absorpsie vir hierdie molekules is; en in watter mate absorpsie plaasvind; is transport oor vark bukale en sublinguale weefsel, sowel as oor Caco-2 sel enkel lae getoets. Die resultate dui daarop dat daar swak opname van die merker molekules oor die bukale en sublinguale membrane plaasvind, terwyl die absorpsie van die merker molekules oor die Caco-2 sel enkel lae verhoogde absorpsie getoon het. Verdere studies word aanbeveel om ondersoek in te stel na watter chemiese merkers geabsorbeer word en of daar wel absorpsie in die gastroïntestinale kanaal plaasvind.