Anticancer Potential of Sutherlandia frutescens and Xysmalobium undulatum in LS180 Colorectal Cancer Mini-Tumors

Colorectal cancer remains to be one of the leading causes of death worldwide, with millions of patients diagnosed each year. Although chemotherapeutic drugs are routinely used to treat cancer, these treatments have severe side effects. As a result, the use of herbal medicines has gained increasing popularity as a treatment for cancer. In this study, two South African medicinal plants widely used to treat various diseases, Sutherlandia frutescens and Xysmalobium undulatum, were evaluated for potential activity against colorectal cancer. This potential activity for the treatment of colorectal cancer was assessed relative to the known chemotherapeutic drug, paclitaxel. The cytotoxic activity was considered in an advanced three-dimensional (3D) sodium alginate encapsulated LS180 colorectal cancer functional spheroid model, cultured in clinostat-based rotating bioreactors. The LS180 cell mini-tumors were treated for 96 h with two concentrations of each of the crude aqueous extracts or paclitaxel. S. frutescens extract markedly decreased the soluble protein content, while decreasing ATP and AK per protein content to below detectable limits after only 24 h exposure. X. undulatum extract also decreased the soluble protein content, cell viability, and glucose consumption. The results suggested that the two phytomedicines have potential to become a source of new treatments against colorectal cancer.

Aqueous leaf extract of Sutherlandia frutescens attenuates ROS-induced apoptosis and loss of mitochondrial membrane potential in MPP+-treated SH-SY5Y cells

Purpose: To investigate the neuroprotective activity of the aqueous extract of Sutherlandia frutescens (SF) against 1-methyl-4-phenylpyridinium (MPP+)-induced toxicity in SH-SY5Y neuroblastoma cells. Methods: SH-SY5Y neuroblastoma cells were divided into different treatment groups: untreated cells, cells treated with MPP+ alone (2 mM), cells pretreated with SF (20 μg) prior to MPP+ (2 mM) treatment and cells treated with SF (20 μg) alone. Twenty-four hours after treatment with MPP+, cell viability was assessed by MTT assay, and changes in cell morphology, intracellular reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) as well as caspases 3/7 and 9 activities were determined. Results: Treatment of SH-SY5Y cells with MPP+ alone significantly altered cellular morphology, increased ROS production (p = 0.005), induced a significant loss of MMP (p = 0.0011) and caused significant apoptotic cell death, via the activation of caspases 3/7 and 9 (p ≤ 0.0359). These effects were however significantly (p ≤ 0.0359) attenuated in cells pre-treated with the aqueous leaf extract of SF, indicating the possible neuroprotective activity of the SF extract. Conclusion: The results of this study suggest that the aqueous leaf extract of SF may be neuroprotective against MPP+-induced toxicity via apoptotic cell death and inhibition of ROS production. Further mechanistic studies are required to validate the results of the present study using additional PD models, different extract preparations and active compounds derived from SF. Keywords: Parkinson’s disease, MPP+, Sutherlandia frutescens, Reactive oxygen species, Apoptosis, Neurodegeneration

The Implication of Chemotypic Variation on the Anti-Oxidant and Anti-Cancer Activities of Sutherlandia frutescens (L.) R.Br. (Fabaceae) from Different Geographic Locations

Extracts of Sutherlandia frutescens (cancer bush) exhibit considerable qualitative and quantitative chemical variability depending on their natural wild origins. The purpose of this study was thus to determine bioactivity of extracts from different regions using in vitro antioxidant and anti-cancer assays. Extracts of the species are complex and are predominantly composed of a species-specific set of triterpene saponins (cycloartanol glycosides), the sutherlandiosides, and flavonoids (quercetin and kaempferol glycosides), the sutherlandins. For the Folin-Ciocalteu phenolics test values of 93.311 to 125.330 mg GAE/g DE were obtained. The flavonoids ranged from 54.831 to 66.073 mg CE/g DE using the aluminum chloride assay. Extracts from different sites were also assayed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging method and ferric reducing anti-oxidant power (FRAP) methods. This was followed by an in vitro Cell Titer-Glo viability assay of various ecotypes using the DLD-1 colon cancer cell line. All test extracts displayed anti-oxidant activity through the DPPH• radical scavenging mechanism, with IC50 values ranging from 3.171 to 7.707 µg·mL−1. However, the degree of anti-oxidant effects differed on a chemotypic basis with coastal plants from Gansbaai and Pearly Beach (Western Cape) exhibiting superior activity whereas the Victoria West inland group from the Northern Cape, consistently showed the weakest anti-oxidant activity for both the DPPH• and FRAP methods. All extracts showed cytotoxicity on DLD-1 colon cancer cells at the test concentration of 200 µg·mL−1 but Sutherlandia plants from Colesburg (Northern Cape) exhibited the highest anti-cancer activity. These findings confirm that S. frutescens specimens display variability in their bioactive capacities based on their natural location, illustrating the importance of choosing relevant ecotypes for medicinal purposes.