###### Abstract  
The present study identifies the phytochemical profile of a hydroalcoholic extract derived from _Smilax aspera_ leaves and stems, estimates its antioxidant capacity and evaluates its cytotoxic activity against glioblastoma (A172 cell line) and rhabdomyosarcoma (TE671 cell line). Chemical analysis of leaves and stems was performed with liquid chromatography analysis combined with a quadrupole time-of-flight high-resolution mass spectrometry (LC/Q-TOF/HRMS). The antioxidant activity of the extract was evaluated with the 2,2-Diphenyl-I-picrylhydrazyl (DPPH) and the 2,2\({}^{\prime}\)-azinobis[3-ethylbenzhizazoline-6-acid]) (ABTS) assays. Cell viability was examined using the alamar blue assay. Most of the compounds tentatively identified belonged to the flavonoids family, with ruin being the most abundant, followed by luteolin. The extracted showed potent antioxidant activity which corresponded to 13.9 \(\pm\) 1.91 \(\mu\)g/mL (DPPH assay) and 6.27 \(\pm\) 1.7 \(\mu\)g/mL (ABTS assay), expressed as IC\({}_{50}\) values. The extract inhibited the proliferation of cancer cells. The lowest IC\({}_{50}\) value for A172 cells was observed 48 h after treatment and was calculated at 0.482 \(\pm\) 0.98 mg/mL while for the TE671 cell line the lowest IC\({}_{50}\) value was 0.629 \(\pm\) 1.31 mg/mL, calculated 72 h after treatment. Considering the high biological value of flavonoids as health defense promoters, _S. aspera_ leaves and stems can be an important natural source to consider as they may provide important health benefits. Smilax aspera; antioxidant; LC/Q-TOF/HRMS analysis; glioblastoma; rhabdomyosarcoma app1308784  
Academic Editor [PERSON]  
20 March 2023  
20 April 2023  
20 March 2023  
20 April 2023  
20 May 2023  
while a methanolic extract of _Smilax spinosa_ rhizomes exhibited antineoplastic activity against HL-60, MCF-7 and MDA231 cancer cell lines [7]. Gliomas are common neoplasms, stemming from glial cells of the central nervous system (CNS). The most common types of glioma are astrocytomas, with glioblastoma multiforme (grade IV astrocytoma) being the most devastating primary brain tumor, as it is a highly invasive and aggressive tumor. Despite advances in surgical techniques and adjuvant treatment, the average survival is only 1-2 years, which has not improved significantly during the last decades. Fewer than 5-10% of patients survive up to 5 years and only 25% of glioblastoma patients survive more than one year. Sarcomas develop in the connective tissue, e.g., bones, muscles, fat, ligaments, and blood vessels. Rhabdomyosarcoma (RMS) is a highly aggressive soft sarcoma, originating from the mesenchymal cells of skeletal muscles. It is a metastatic tumor with the most common sites of metastasis being the lungs and the lymph nodes [8; 9]. The prognosis of non-metastatic RMS is good and survival rates are high if treated early. Therapy and treatment include surgery, chemotherapy and radiotherapy. Nevertheless, recurrence cases are common and are accompanied by poor survival rates [10]. Phytochemicals are intensively studied against various chronic diseases including cancer. It is discussed that their efficacy is mainly due to their antioxidant activity. Though treatment with natural products is yet preliminary and much information is needed regarding their mechanism of action, data from many in vitro, in vivo and clinical trial studies evidence that these substances are of great therapeutic importance and may consist a new era of treatment [11; 12]. Secondary metabolites isolated from various plant materials are complex mixtures. Therefore, in order to understand their activity, the chemical characterization of these mixtures is necessary. Mass spectrometry is a powerful tool for the screening of various types of samples including plant-derived extracts [13; 14]. A common type of this analytical technique is quadrupole time of flight mass spectrometry. By coupling Q-TOF/MS with liquid chromatography, a challenging method that gains popularity is generated.