Abstract B73: Chemopreventive effect of Streblus asper, a bonsai plant, on osteosarcoma cells: A preliminary study

Abstract

Abstract Epidemiological studies have demonstrated a positive correlation between consumption of vegetables, fruits and beverages with reduced risk of cancer. It is estimated there are around 8,100 plant species in the Malaysian rain forests, with 10% of them reported to have some medicinal value. However, to date in Malaysia, not much investigation has been done on chemopreventive activities on cancer although Malaysian plants are an exclusive source of effective chemopreventive agents and therefore, this background leads to the premise that our local plants such as Streblus asper could have greater potential for the chemoprevention activities. Streblus asper is well known as an expensive bonsai plant which is indigenous to tropical countries such as Malaysia, Thailand, Sri Lanka and India. It is used traditionally in leprosy, piles, diarrhea, dysentery, elephantiasis and cancer. It finds place in Ayurvedic Pharmacopoeia of India and also been described in some monographs, but none have reported its activity as chemopreventive agents and the underlying mechanisms remain unclear. In the present study, we try to identify its biological properties and the cytotoxicity effect on normal liver and kidney cells. Using the osteosarcoma cells as our in vitro model, the IC50 of Streblus asper root extract was determined and observed its effect on the osteosarcoma cells morphology that changes within time, the anti-proliferative pattern and live-death analysis under confocal microscope analysis. The results showed that the root extracts did not contained any heavy metals compound such as mercury and cadmium and with less arsenic (0.02 ppm) and plumbum (0.07 ppm) and showing non-cytotoxic effect on vero cells (normal kidney cells) and WRL-68 cells (normal liver cells). Our HPLC profiling analysis also revealed antioxidants compounds exist in the Streblus asper root extracts such as caffeic acid which has been shown to act as a carcinogenic inhibitor. Although the low-level of anti-oxidants been found from the extracts but it still can inhibit the growth of the osteosarcoma cells which also exert apoptosis features like cell shrinkage (atrophy) and vocalization in time and dose-dependent manner. The plant extracts IC50 doses was at 0.05% of root extracts and it also demonstrated the anti-proliferative effect by suppressed the cells growth as early as 12 hours of treatment and marked cell death till day 6. On live-death analysis under confocal microscope using Calcein and Ethidium staining confirmed that Streblus asper root extract exert cell death to osteosarsoma cells. This study is just a preliminary study as to identify its pharmacological properties on carcinogenesis and further investigation is still on-going to develop it as the chemopreventive agent especially to determine the signaling pathway involved. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B73.