Biological activity and alkaloid compounds of Mahonia napaulensis DC. extracts

Mahonia napaulensis DC. has historically been used for traditional medicine in Vietnam. However, the biological mechanisms underlying its medicinal effects are not yet fully understood. In the present study, a crude extract derived from the M. napaulensis stem was fractionated with n-hexane, ethyl acetate (EtOAc), and water-saturated butanol (BuOH). The antioxidant activities of the crude extract and the fractionated samples were evaluated using a DPPH assay and a reducing power assay. Our results revealed that the EtOAc fraction showed the highest total phenolic content as well as the highest free radical scavenging activity and reducing power. The antiproliferative effects of M. napaulensis DC. extracts were detected using a MTT assay. The results showed a significant reduction in cell viability of over 70% in human colon carcinoma CoLo 205 cells at the highest concentration tested (200 & mu;g/ml). We also used quantitative reverse transcription-polymerase chain reaction (RT-PCR) to measure the expression of mRNA transcripts involved in the regulation of cell proliferation such as survivin, p53, caspase-3, and caspase-9 in CoLo 205 cells treated with the crude extract and fractions to better understand the changes induced by the BuOH fraction. Two alkaloid compounds that possess strong antiproliferative activities in colon cancer cells, berberine and palmatine, were isolated from the BuOH fraction. The results from this study indicate that M. napaulensis may be considered a medicinal plant due to its anti-oxidative and antiproliferative properties.