Cytotoxicity of naturally occurring phenolics and terpenoids from Kenyan flora towards human carcinoma cells

ABSTRACT

Background: Cancer constitutes a major hurdle worldwide and its treatment mainly relies onchemotherapy.Objectives: The present study was designed to evaluate the cytotoxicity of eleven naturally occurringcompounds including six phenolics amongst them were 4 chalcones and 2 flavanones as well as 5 terpenoids (3 clerodane and 2 trachylobane diterpenoids) against 6 human carcinoma cell lines and normalCRL2120 fibroblasts.Materials and methods: The neutral red uptake (NR) assay was used to evaluate the cytotoxicity of thecompounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle and mitochondrialmembrane potential (MMP) were all analyzed via flow cytometry meanwhile levels of reactive oxygenspecies (ROS) was measured by spectrophotometry.Results: Chalcones 20,40-dihydroxy-60-methoxychalcone (1); 40,60-dihydroxy-20,50-dimethoxychalcone(2); 20,40,60-trihydroxy-50-methoxychalcone (3); 20,60-diacetate-40-methoxychalcone (4), trachylobanediterpenoids 2,6,19-trachylobanetriol; (ent-2a,6a)-form (10) and 2,18,19-trachylobanetriol; (ent-2a)-form (11) as well as doxorubicin displayed IC50 values below 110 mM in the six tested cancer cell lines. TheIC50 values of the most active compounds were between 6.30 mM and 46.23 mM for compound 1respectively towards breast adenocarcinoma MCF-7 cells and small lung cancer A549 cells and between0.07 mM and 1.01 mM for doxorubicin respectively against SPC212 cells and A549 cells. Compounds 1induced apoptosis in MCF-7 cells mediated by increasing ROS production and MMP loss.Conclusion: Chalcones 1e3 are potential cytotoxic phytochemicals that deserve more investigations todevelop novel anticancer drugs against human carcinoma.© 2018 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services byElsevier B.V. This is an open access article under the CC BY-NC-ND license (http//creativecommons.org/licenses/by-nc-nd/4.0/).