Determination of the nutritional and phytochemical composition of monsonia burkeana (special tea) and its potential anti-proliferative effects on cancer cell lines

Abstract

Traditional medicinal plants have long been used to treat ailments in humans and animals. Africa is rich in such plants, many of which have been studied for bioactivities like anticancer, antimicrobial, and anti-inflammatory effects, though many remain uncharacterized. Monsonia burkeana (“special tea”) is widely consumed for its health benefits, usually as a decoction. Its antimicrobial properties are known; however, its phytotoxicity and antiproliferative activities remain underexplored. Elucidating these could benefit both traditional medicine and the pharmaceutical industry. This study aimed to investigate the effects of drying methods on the nutritional composition of special tea, identify bioactive compounds in its crude extract, and evaluate antiproliferative activities in cancer cell lines, offering insights for pharmaceutical development and commercial potential. The specific objectives included assessing nutritional composition, profiling bioactive compounds, and testing cytotoxicity against lung, colorectal, and liver cancer cell lines. Samples from Sekhukhune, Lanseria, Brits, and Rietondale were dried using shade, oven, and freeze-drying methods. Nutritional elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), phytochemicals profiled using nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS), and anticancer properties evaluated through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and caspase-3 activity assays. The results demonstrated a consistent elemental composition across all regions, with all 24 elements present in each sample and collection region. NMR analysis identified phenols, alkyls, esters, and ethers, while GC×GC/TOF-MS detected various bioactive compounds, including oxalic acid, β-caryophyllene, caryophyllene oxide, phytol, squalene, and vitamin E. LC-MS analysis confirmed the presence of additional key phytochemicals such as castalagin, vescalagin, acutissimin B, epicatechin, citroside, trifolin, 1,6-digalloyl-beta-D-glucopyranose, 5,7-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-{[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-4H-chromen-4-one, and puerarin 4',6''-diacetate. The MTT assay revealed significant cytotoxic activity against lung and liver cancer lines, however, activity against the colorectal cancer cell line was lower compared to that demonstrated against the other two cancerous cell lines. In conclusion, the combination of essential micro- and macronutrients, bioactive phytochemicals, and demonstrated cytotoxic effects against cancer cell lines highlights the medicinal value of M. burkeana plants. The study provides strong evidence that Monsonia burkeana is a promising alternative for cancer treatment. These findings not only validate its traditional use and benefits over the years but also highlight its potential for pharmaceutical applications.