Year : 2011 | Volume
: 3 | Issue : 3 | Page : 149--150
Pharmacognosy Research - Indexed on PubMed Central
Director, Team Elucidate, Department of Chemistry, Cork Institute of Technology, Rossa Ave., Bishopstown, Cork, Ireland
Director, Team Elucidate, Department of Chemistry, Cork Institute of Technology, Rossa Ave., Bishopstown, Cork
|How to cite this article:|
Furey A. Pharmacognosy Research - Indexed on PubMed Central.Phcog Res 2011;3:149-150
|How to cite this URL:|
Furey A. Pharmacognosy Research - Indexed on PubMed Central. Phcog Res [serial online] 2011 [cited 2013 Dec 12 ];3:149-150
Available from: http://www.phcogres.com/text.asp?2011/3/3/149/84997
I am delighted to bring you the good news that our journal Pharmacognosy Research is now indexed on PubMed Central (PMC) and on the PubMed list. This is a wonderful achievement and a tribute to the hard work and dedication of all our editorial board members most especially the trojan work of our Managing Editor Prof. Muneen Ahmed KK.
PubMed is a free database that was first made available in 1996, which permits access to the invaluable MEDLINE database (maintained by the United States National Library of Medicine). There are over 5,000 biomedical journals indexed in MEDLINE and inclusion in the database is not automatic for new journals but based on the findings of an adjudication panel (the Literature Selection Technical Review Committee) who asses the quality and relevance of the journal, so this is a big step for our journal. The quality of the work submitted by our contributors in the past and present is of course what has made our inclusion possible, so I would very much like to extend my heartfelt thanks to them on behalf of everyone involved in the publication.
In this current issue, we have again a diverse and interesting array of articles, forming the foundation of many of these works is the selective extraction, the determination of the bioactivity and the identification of the active components. The most common modes of extraction used amongst researchers in the Pharmacognosy field would seem to be simple solvent (commonly simple alcohol), simple distillation and Soxhlet extraction of dried or pulverized plant material. This is expected as most of the research is conducted on the microscale. However, it is fair to say (and not in any way as a criticism to researchers) that since bioactives are usually present in plants at moderate to low concentrations, it is necessary and prudent to explore extraction techniques with enhanced selectivity and efficiencies. This is especially important where scale up follows on from fundamental research as plant materials are a limited resource and as more plant species face extinction and where environmental concerns restrict the usage of large volumes of solvent. To this end, a technology like super critical fluid extraction (SFE) comes into its own.
Many of the conventional methods of extraction involve significant losses of bioactives or simply lack the selectivity toward the more volatile plant components. For example, in heat-dependant extractions, many thermally fragile components are degraded, hydrolyzed, oxidized etc. leading to abysmal yields. Many conventional methods also require considerable quantities of plant materials (my team and I have worked with plant materials in the kg scale for simple solvent extraction protocols) whereas quantities of < 1 g can be extracted to 'completeness' for a wide range of polarities using SFE by progressive modification of the CO 2 fluid system (comprising only a few milliliters of solvent).
My personal experience of SFE has been mixed; early on I experienced restrictor clogging when extracting fresh plant material for volatiles and this was sorted out by adding anhydrous Na 2 SO 4 to the plant material. Miller et al., suggests that anhydrous Na 2 SO 4 helps by providing better contact between the supercritical fluid and the plant material and by helping to retain the moisture. Other approaches for improving the extraction of fresh plant material include the addition of silica gel  or the addition of acetals such as 2,2-dimethoxypropane (DMP).  I think it is a certainty especially with the rapid growth in the commercial herbal remedy industry and in the search for new drug targets that SFE techniques will expand and improve in the future and eventually supersede the traditional approaches.
|1||Miller KG, Poole CF, Chichila TM. Soxhlet and supercritical fluid extraction of pistacia seeds and determination of fatty acid content by GC-MS analysis. HRC CC J High Resolut Chromatogr Chromatogr Commun 1995;18:461.|
|2||Polesello S, Lovati F, Rizzolo A, Rovida C. Supercritical fluid extraction as a preparative tool for strawberry aroma analysis. HRC CC J High Resolut Chromatogr Chromatogr Commun 1993;16:555-9.|
|3||Weathers RM, Beckholt DA, Lavella AL, Danielson ND. Comparison of Acetals as in situ modifiers for the supercritical fluid extraction of b-Carotene from paprika with carbon dioxide. J Liq Chromatogr Relat Technol 1999;22:241.|