Biogenic synthesis of nanoparticles provides many advantages over synthetic nanoparticles including clean and non-toxic approaches. Nanoparticle-based application for the development of diagnostics and therapeutics is a promising field that requires further enrichment and investigation. The use of biological systems for the generation of gold nanoparticles (AuNPs) has been extensively studied. The search for a biocompatibility approach for the development of nanoparticles is of great interest since it can provide more targeting and less toxicity. Here, we reported a bio-reductive approach of gold to AuNPs using metabolites extracted from mammalian cells, which provided a simple and efficient way for the synthesis of nanomaterials. AuNPs were more efficiently synthesized by the metabolites extracted from breast cancer (MCF7) and normal fibroblasts (F180) cells when compared to metabolites extracted from cell-free supernatants. The metabolites involved in biogenic synthesis are mainly alcohols and acids. Spectroscopic characterization using UV-visible spectra, morphological characterization using electron microscopy and structural characterization using X-ray diffraction (XRD) confirmed the AuNPs synthesis from mammalian cells metabolites. AuNPs generated from MCF7 cells metabolites showed significant anticancer activities against MCF7 and low toxicity when compared to those generated from F180 cells metabolites. The results reflected the cytotoxic activities of the parent metabolites extracted from MCF7 versus those extracted from F180. Comparative metabolomics analysis indicated that MCF7-generated AuNPs harbored tetratetracontane, octacosane, and cyclotetradecane while those generated from F180 harbored a high percentage of stearic, palmitic, heptadecanoic acid. We related the variation in cytotoxic activities between cell types to the

Medicinal plants are valuable sources of different active constituents that are known to have important pharmacological activities including anticancer effects. Lupeol, a pentacyclic triterpenoid, present in many medicinal plants, has a wide range of biological activities. Although the anticancer activity of lupeol was reported, the published data are inconsistent and the clear mechanism of action has never been assigned. The current study aims at investigating the anticancer specificity and mechanism of lupeol isolated from Avicennia marina, which grows in the desert of the United Arab Emirates. The compound was purified by chromatography and identified by spectroscopy. Compared with a negative control, lupeol caused significant (p < .001) growth inhibitory activity on MCF‐7 and Hep3B parental and resistant cells by 45%, 46%, 72%, and 35%, respectively. The mechanism of action of lupeol was further explored by measuring its effect on key players in cancer development and progression, BCL‐2 anti‐apoptotic and BAX pro‐apoptotic proteins. Lupeol significantly (p < .01) downregulated BCL‐2 gene expression in parental and resistant Hep3B cells by 33 and 3.5 times, respectively, contributing to the induction of apoptosis in Hep3B cells, whereas it caused no effect on BAX. Furthermore, the immunoblotting analysis revealed that lupeol cleaved the executioner caspase‐3 into its active form. Interestingly, lupeol showed no significant effect on the proliferation of monocytes, whereas it caused an increase in the sub‐G1 population and a reduction in the apoptosis rates of monocytes at 48 and 72 h, indicative of no immuno‐inflammatory responses. Collectively, lupeol can be considered as promising effective and safe anticancer agent, particularly against Hep3B cancer cells.