Investigation into two Australian medicinal plants Viola odorata and Euphorbia peplus for anticancer agents

In the absence of a clear understanding of the aetiology of diseases and measurable parameters for the attributes of drugs described in the traditional systems of medicine, an approach encompassing a broad spectrum of biological activities on the whole body that may be ascribable to the attributes of the drugs and aetiology of a disease described in the traditional medical systems such as Ayurveda, taken to investigate putative anticancer plants, is presented. Extracts of the putative anticancer plants, Euphorbia peplus L. (petty spurge) and Viola odorata L. (sweet violet), which grow in Australia, were investigated for in vitro anticancer activity using DPPH free radical scavenging, Fe-(III)-TPTZ reducing (FRAP) and linoleic peroxidation inhibitory (TBARS and FTC) antioxidant activities; human complement inhibitory (CP and AP), anti-platelet aggregating (impedance method), COX-2 inhibitory immunomodulatory activities as well as the conventional in vitro anticancer activities using CEM (3H] thymidine uptake, MTS and US-NCI's sulforhodamine B assay using 60 cell line humour tumour screen. Results were compared with relevant standards. Isolation of active extracts and chemical studies were carried out using HPLC-PDA, UV-VIS, TLC, GC-MS, ESI-MS, and AAS. Although the two plants have failed in the NCI's conventional in vitro anticancer screen, our results showed that the extracts of both plants indicated a combination of biological activities. These results raise the possibility that broad-spectrum approach comprising a number of different biological systems may help to explain the purported in vivo anticancer activity of Euphorbia peplus L. and Viola odorata L. Preliminary chemical studies showed the presence of the flavonoid, quercetin among other compounds, in the antioxidant extracts of both plants. The ESI-MS and GC-MS profiles may be used to characterise the active extracts. Presented results may be used to design further in vivo studies towards utilising natural resources as anticancer agents.