The anticancer potential of Artemisia afra

Artemisia afra Jacq. is one of the oldest, most well known and widely used traditional medicinal plants in South Africa. It is used to treat many different medical conditions, particularly respiratory and inflammatory ailments (Liu et al., 2009). There is no reported evidence of its use for the treatment of cancer but due to its reported cytotoxicity (Fouche et al., 2008; Mativandlela et al., 2008), we investigated the effect of A. afra extracts on 2 cancer cell lines. IC₅₀ values of 18.21µg/mL and 31.88µg/mL of ethanol extracts were determined against U937 and HeLa cancer cells, respectively. An IC₅₀ value of the aqueous extract was greater than 250µg/mL. Dose response assays were also performed using confluent HeLa cells, yielding an IC₅₀ value greater than 250µg/mL. The effect of the cytotoxic ethanolic A. afra extract (20µg/mL) on U937 cells and their progression through the cell cycle, apoptosis and mitochondrial membrane potential was investigated. Melphalan was used as a positive control. After 24 hours of treatment with melphalan using U937 cancer cells, an increase in sub G1 phase was evident. Treatment of cells with A. afra showed a delay in G2/M phase of the cell cycle. Apoptosis was confirmed using the TUNEL assay for DNA fragmentation, which was evident with the positive control and A. afra treatment at 24 and 48 hours. JC-1 staining showed a decrease in mitochondrial membrane potential at 24 hours. The results obtained suggest that A. afra potentially has medicinal anticancer properties.

Keywords: Artemisia afra, apoptosis, cytotoxicity

References: 1. Liu et al. (2009) S Afr J Bot 75: 185–195.

2. Fouche et al. (2008)J Ethnopharmacol 119: 455–461.

3. Mativandlela et al. (2008) Phytother Res 22: 841–845.