ARTICLE
Interview :
Andrew Whitfield-Cook speaks with Denis Stewart , Pioneer of Australian Herbal Medicine
Part 2 .
This is the second part of Andrew Whitfield-Cook ’ s podcast interview with Denis Stewart . The first part appeared in the previous issue of JATMS .
Andrew : You previously mentioned manufacturing herbs in their historical context . This must have changed dramatically over the decades that you ' ve practised . I mean , we ' ve now got cold percolation , and there ’ s a lot of contention over concentrations : one to two , or one to one , or whatever . I have misgivings over the idea that every herbal remedy should be made in the same way . Don ' t herbs have different actives , and even different attributes , requiring that they be cared for and prepared in differing ways - even down to the solvent used ? Or do you subscribe to using just one solvent ?
Denis : No , I don ' t . I think again here you need to recognise that the literature , the pharmacopeias , stipulate very frequently what solvents should be used in the extraction of particular herbal medications . Keep in mind that pharmacopeias were , and many of them still are , bristling with herbal preparations . Probably the best one is the 1934 edition of the British
Pharmacopeia . It ' s a remarkable text and a lot of its information is incorporated into the 1983 edition , which I hold in great esteem .
So what these pieces of literature do is indicate to the manufacturer what solvent has been traditionally used , whether it be a 25 %, a 45 %, or a 60 % solvent - sometimes even higher . And by that , I would infer that the literature is recognising traditional menstruums or solvents that have been used to give good results associated with the particular herbs that they ' ve been developed for . For instance , goldenseal , which is a melchelloidal remedy , I ’ m pretty sure has a 60 % solvent or menstruum associated with it . Now , that is called up in the pharmacopeias and indicates that history has shown that this solvent is particularly effective in extracting the representative alkaloids from goldenseal . And , of course , those alkaloids play a very fundamental role , and as we know with many of the alkaloids , if you use very aqueous solvents , you may not get the same extraction of the alkaloid that you would get when you ' re using a menstruum that is much more tailored to dragging it out of the herb .
So I subscribe to the idea that what is in the literature should be taken on board , that there ' s information there which in my opinion should govern the manufacture of liquid extracts and tinctures . And I feel that that should be pretty well seen as the yardstick for extracting many of the herbs which are the backbone of our profession : the solvents , the menstruum , are already called up in various monographs and , in my opinion should be used consequently in order to get the best extract from the herb .
Andrew : Do you ever use , say , one extraction concentration or amount of menstruum solvent ? Let ' s say I ' m going to use calendula here , a 40 % alcohol extract for an inflamed gut , where I don ' t want to use too much alcohol ,
JATMS | Spring 2021 | 147