Evaluation of selected biological capacities of Baeckea frutescens

Baeckea frutescens is a natural remedy recorded to be used in curing various health conditions. In Peninsular Malaysia, B. frutescens is found on the mountain tops, quartz ridge and sandy coasts. To our knowledge, there is only limited published literature on B. frutescens.

B. frutescens leaf crude methanol and its fractionated extracts (hexane, ethyl acetate and water) were prepared. Folin-Ciocalteau's method was used for the measurement of total phenolic content of the extracts. The antioxidant activity was measured by the scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, reducing power assay through the Prussian blue complex formation, the metal chelating assay as well as the β-Carotene-linoleic acid system assay. The cytotoxic activity of the extracts were evaluated against two lung carcinoma cell lines with varying molecular characteristics using the MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay. Lastly the toxicity of the crude methanol extract was evaluated using the acute oral toxicity experiment.

The methanolic extract with highest phenolic content showed the strongest β-carotene bleaching inhibition, whilst the water extract exhibited the highest activity in metal chelating and reducing power assays. The hexane extract displayed a mild cytotoxic effect on both A549 and NCI-H1299 human lung carcinoma cell lines. No mortalities and no adverse effects were observed in the acute oral toxicity investigation at the highest dose of 5000 mg/kg.

The findings in the present study suggest B. frutescens may be considered as a safe source of compounds with antioxidant and cytotoxic properties for therapeutic and functional food applications.