Dhaliwal, HarmandeepLi, YanYoo, Michelle2025-11-242025-11-242025-10-31Antioxidants, ISSN: 2076-3921 (Print); 2076-3921 (Online), MDPI AG, 14(11), 1319-1319. doi: 10.3390/antiox141113192076-39212076-3921http://hdl.handle.net/10292/20200Kunzea ericoides (kanuka), a native plant of New Zealand, has a significant role in traditional medicine due to the presence of essential oils. Apart from these oils, this plant also is a source of many bioactive compounds, majority of which are polyphenols. However, there is lack of sufficient data supporting the extraction of polyphenols from kanuka plant leaves and investigating its bioactivity and phytochemical properties. The study aims to extract polyphenols from kanuka plant leaves with a conventional solvent-based method and determine the phytochemical analysis as well as bioactive potential. Extraction was performed with methanol and acetone as solvents. Polyphenolic prolife was analyzed with LC-MS. Bioactive analysis of kanuka leaf extract was carried out to determine total phenolic content and antioxidant activity. We investigated the cytotoxic effect of kanuka leaf extract on two triple-negative breast cancer cells—MDA-MB-231 and BT-549. LC-MS analysis confirmed kanuka leaf extract is a source of many polyphenols, some giving very prominent signals on TIC scan. Ten polyphenolic compounds were confirmed to be present in kanuka leaf extract based on MRM analysis. FRAP-CUPRAC analysis indicated significant antioxidant activity in the kanuka leaf extract. Antiproliferative analysis has confirmed cytotoxicity of the kanuka leaf extract on the triple-negative breast cancer cell lines. This study indicates that Kunzea ericoides leaf extract, rich in polyphenols, shows promising antioxidant and antiproliferative potential, warranting further investigation for therapeutic applications.© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).3101 Biochemistry and Cell Biology32 Biomedical and Clinical Sciences31 Biological Sciences3205 Medical Biochemistry and Metabolomics3214 Pharmacology and Pharmaceutical SciencesMinority HealthBreast CancerComplementary and Integrative HealthWomen's HealthDietary SupplementsNutritionCancerkanukatotal phenolic contentantiproliferative activityantioxidant activitytriple-negative breast cancerLC-MSJournal ArticleOpenAccess10.3390/antiox14111319