Drug Discovery 2

Much pharmacognosy is focused on cancer, as with over 10 million new cases in the year 2000 alone there is huge demand for new treatments. For example, the US’s National Cooperative Drug Discovery Group (NCDDG) is working on “Novel Strategies for Plant-derived Anticancer Agents” alongside several leading universities and pharmaceutical companies. 

They collected 5886 plant accessions from 2582 species with collections primarily carried out in tropical forests due to their capacity to support a very diverse range of taxa and species. 

Chloroform-soluble extracts were then prepared and screened by a variety of in vitro bioassays. Active extracts were then subject to ‘dereplication’ to determine of they contained previously isolated cytotoxic compounds. Treating cells with cytotoxic compounds can result in cells undergoing apoptosis (programmed cell death), necrosis (where cells lose membrane integrity and die via cell lysis) or stopping growing and dividing. Potential extracts are isolated by fractionation and further follow up studies are carried out on compounds of interest (Balunas, M et al.  2005).

Following from this initial collection and subsequent testing, 3 main chemicals are still undergoing further study. One chemical of interest includes Pervilleine A, found in extracts from the roots of the Madagascan plant Erythroxylum pervillei. This chemical acts to restore sensitivity of certain multi drug resistant cells, as the development of multi-drug resistant tumour cells is a serious problem associated with chemotherapy (Mi, Q et al. 2001).  

Further developments in cancer treatment drawing on plant resources have occurred in Australia. EBC-46 developed by the QIMR Berghofer Medical Research Institute is thought to destroy cancerous tumours by cutting of blood supply and is produced from the berry of  Fontainea picrosperma (Boyle, G et al. 2014).

It is clear then, considering global plant biodiversity and the extent of plant collection and subsequent testing required, preserving tropical forests and maintaining maximum biodiversity for future drug potential is a priority.   

Sources:

Balunas, M et al. 2005. Drug Discovery from Medicinal Plants. Life Sciences. 78(5). pp 431-441. 

Boyle, G et al. 2014. Intra-Lesional Injection of the Novel PKC Activator EBC-46 Rapidly Ablates Tumors in Mouse Models. Plos:One. [online]. Available at: http://www.plosone.org/article/authors/info%3Adoi%2F10.1371%2Fjournal.pone.0108887.[Accesssed: 19 November 2014] 

Mi, Q et al. 2001. Pervilleine A, a novel tropane alkaloid that reverses the multidrug-resistance phenotype. Cancer Research. 61(10). pp 4030- 4037.