Abstract 2843: The effects of extracts of the indigenous South African plant, Tulbaghia violacea, on triple negative breast cancer cells
Authors: Dlamini Zodwa , Alouna Mohamed , Hull Rodney , Penny Clement 
Published: July 2021

Background: Up to 20% of all breast cancer cases can be defined as triple-negative breast cancers (TNBC). TNBC is defined by the absence of the expression of oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor 2 (HER2). TNBC is an aggressive cancer that in South Africa, primarily affects younger black females. Due to the lack of hormone receptors and current targeted therapies are ineffective. In South Africa, many people rely on traditional medicine to treat various ailments. However, the effectiveness of these treatments needs to be scientifically verified.

Aim: The aim of this study was to evaluate the in vitro responses of TNBC cancer cell lines to treatment with extracts from the indigenous South African medicinal plant, Tulbhaghia violacea.

Methods: To achieve this the TNBC cell line, MDA-MB-231, was treated with both water and methanol soluble extracts from the leaves. The IC50 values for the extract was determined using Real Time Cell Analysis in conjunction with alamarBlue cytotoxicity assay. The effect of the plant extract on cell migration was determined using the scratch assay. The chemical composition of the extract was determined using Fourier Transformer Infrared (FTIR) Spectrophotometry.

Results: Of the two extracts the water soluble T. violacea extract had the lowest IC50 value (314 μg/ml), while the methanol soluble extract showed much lower cytotoxic activity with a higher IC50 value (780 μg/ml). The T. violacea water extract strongly affected the migration of the TNBC cell line, with concentrations slightly lower than the IC50 value (300 μg/ml) preventing cell migration completely and lower concentrations delaying migration by up to 13 hours. This was similar to the effects observed when the cells were treated with the positive control (5-Fluorouracil). The FTIR spectrophotometry analysis of the T. violacea water extract revealed that this extract is a mixture of phytochemicals with various functional groups including alkyl, methyl, nitro, sulphur derivative and amine groups.

Discussion: The water soluble extract from T. violacea leaves showed cytotoxic effects against MDA-MB-231 TNBC cells and also inhibited the ability of these cells to migrate. Since migration is involved in invasion and metastasis this indicates that one or more of the chemical constituents found within the water soluble extract may serve as a lead compound for the development of new drugs to treat TNBC. The classes of chemical constituents we identified in the water soluble extract is consistent with compounds known to be present within T. violacea. Further characterization of this extract is under way and we are in the process of isolating individual active compounds from this extract and performing RNASeq experiments to ascertain aberrant molecular pathways including splicing events that this extract targets.

Citation Format: Zodwa Dlamini, Mohamed Alouna, Rodney Hull, Clement Penny. The effects of extracts of the indigenous South African plant, Tulbaghia violacea, on triple negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2843.