ABSTRACT. Rumex abyssinicus showed strong cytotoxicity against HeLa cells (IC50 = 22.25 μg/mL) and weak cytotoxicity against PC3 and BJ cells with percent inhibition of 58.6, 25.8 and 29.7% at 30.0 μg/mL. It showed moderate antifungal activity against Aspergillus niger with a percent growth inhibition of 55.5% at 3000 µg/mL. It also strongly inhibited oxidative burst with IC50 value of 24.8 μg/mL. DCM (100%) and DCM: EtOAc (1:1) fractions showed strong cytotoxicity against HeLa cells, whilst pet ether: DCM (1:1) fraction showed strong cytotoxicity against PC3 cells with IC50 values of 29.3, 26.3 and 24.3 μg/mL, respectively. Moreover, the DCM: EtOAc (1:1) fraction inhibited ROS production with IC50 value of 18.8 μg/mL. Cytotoxic fractions afforded chrysophanol (1), physicon (2), emodin (3), citreorosein (4) and β-sitosterol (5). Among the isolated compounds, emodin (3) showed strong cytotoxicity against HeLa cells, whilst chrysphanol (1) and physicon (2) showed strong cytotoxicity against PC3 cells with IC50 values of 8.94, 22.5, and 28.5 µM, respectively. In addition, emodin (3) and citreorosein (4) showed strong inhibition against ROS production with an IC50 value of 16.2 and 38.2 μg/mL. The findings of this study suggest R. abyssinicus as a good candidate for cancer and inflammation management.     KEY WORDS: Polygonaceae, Rumex abyssinicu Jacq., Cytotoxic, Antifungal, Anti-Inflammatory, Reactive oxygen species   Bull. Chem. Soc. Ethiop. 2022, 36(4), 879-892.                                                               DOI: https://dx.doi.org/10.4314/bcse.v36i4.13

The current study has been carried out to assess the in vitro antioxidant and anti-inflammatory activities of the 80% ethanolic extracts of 22 traditionally used Ethiopian medicinal plants. Among the tested plants, Dodonaea angustifolia, Rumex nervosus, Carrisa spinarum, Pentas schimperiana, and Clerodendrum myricoides displayed good DPPH radical scavenging potential with IC50 values of 15.0, 26.9, 58.3, 62.5, and 78.8 µg/ml, respectively. Similarly, Dovyalis abyssinica, D. angustifolia, Rumex abyssinicus, and R. nervosus showed strong oxidative burst inhibitory potential with IC50 values of 10.2, 19.4, 24.8, 35.8 μg/ml, respectively. Furthermore, D. angustifolia and R. nervosus showed strong reactive oxygen species inhibitory activities.  The results of this study showed the potential use of herbal products as anti-inflammatory and antioxidant agents and provided scientific backing for utilizing these herbal preparations.

In vitro anticancer activity of the 80% ethanolic extracts of 23 traditionally used Ethiopian medicinal plants was studied using cervical (HeLa) and prostate (PC3) cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) colourimetric assay. Mouse embryonic fibroblast normal cells(3T3) were used for evaluation of safety of extracts. Among the tested plants, Dovyalis abyssinica, Scadoxus multiflorus, Rumex abyssinicus, and Euphorbia abyssinica exhibited significant anticancer activity against HeLa cells with IC50 values of 6.2, 14.6, 18.6, and 22.8 µg/ml, respectively. Similarly, S. multiflorus and D. abyssinica significantly inhibited PC3 cell growth with IC50 values of 9.8 and 17.4 µg/ml, respectively. Extracts of S. multiflorus, R. abyssinicus, and E. abyssinica demonstrated high selectivity index. D. abyssinica showed selective toxicity against HeLa (SI = 2.51) cancer cells, but not against PC3 (SI = 0.98) cancer cells. Evaluation for safety indicated that about 83.3% of the extracts under this study were nontoxic at 30 µg/ml. The findings of this study suggest that further bioactivity guided fractionation and phytochemical studies may lead to the discovery of novel anticancer compounds.