Black pepper (Piper nigrum L.), one of the most popular Indonesian spices has been reported to possess various therapeutic effects. The aim of this study is to evaluate the cytotoxicity and antigenotoxicity of black pepper ethanolic extract (BPE) and its combination with doxorubicin (Dox) on CHO-K1 cells. Based on thin layer chromatographyanalysis, BPE contained piperine.Under MTT assay, BPE showed cytotoxic effect with the IC50 value of 68 μg/mL and performed synergism in combination with Dox. In vitro micronucleus test using Giemsa staining revealed that BPE did not cause morphological changes qualitatively on CHO-K1 cells at concentration of 8.5 μg/mL, whereas using flow cytometry analysis showed that BPE could decrease the number of micronucleus (MN) formation induced by doxorubicin. In addition, BPE reduced the ROS level on the CHO-K1 cells which observed by reactive oxygen species (ROS) intracellular assay. The decrease in ROS level indicated that the antioxidant activity of BPE contribute to the antigenotoxicity. Furthermore, molecular docking performed that piperine interacted with DNA Topoisomerase II with docking score of -80.68. Overall,BPE performed cytotoxic effect in single treatment, increased the cytotoxicity and reduced the genotoxicity of doxorubicin. Thus, BPE has potential to be developed further as co-chemotherapeutic and antigenotoxic agent.Keywords: Cytotoxic, genotoxic, Piper nigrum L., CHO-K1, micronucleus

One of the mechanisms of cancer cell resistance toward chemotherapy is through cancer stem cells (CSCs), which are characterized by excessive activation of regulator proteins such as human epidermal receptor 2 (HER2). Sappan wood (Caesalpinia sappan L.) contains brazilin and brazilein that exhibit cytotoxic effects on several cancer cell lines. We aimed to explore the potency of the ethanolic extract of sappan (EES) in CSCs through bioinformatic analyses and by using a three-dimensional (3D) breast cancer stem cells (BCSCs) for in vitro assay with two different models (i.e., BCSCs and HER2-BCSCs) in order to identify the potential therapeutic targets of genes (PTTGs). Bioinformatic analyses identified PTTGs, which were further analyzed by gene ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, protein-protein interaction (PPI) networks, and hub protein selection. Mammospheres were cultured under conditioned media. The cytotoxic effects of EES were then measured by direct counting and based on the mammosphere-forming potential (MFP). Bioinformatic analysis disclosed PIK3CA and TP53 as PTTGs in BCSCs and HER2-BCSCs, respectively. In addition, the KEGG pathway analyses also demonstrated that PTTGs could regulate the ERBB pathway. EES thus demonstrated cytotoxicity and inhibited the formation of mammospheres. Collectively, EES exhibited excellent potential for further development as an inhibitor of cancer stem cells in breast cancer.

DNA damage usually happens due to the several chemical materials that induce genotoxic effect in normal cells. Cinnamon essential oil (CEO), which contains cinnamaldehyde as its major compound, has been reported to possess antioxidant activity to prevent DNA damage. The aim of this study is to evaluate the genotoxic and cytotoxic effect of CEO on doxorubicin-induced Chinese Hamster Ovary (CHO-K1) cells. The cytotoxic effect of CEO was determined by MTT assay with the parameter of IC50 while the genotoxic effect was carried out by micronucleus (MN) assay by using acridine orange fluorescent staining with the parameter of MN/1000 cells reduction number. Based on MTT assay, CEO showed cytotoxic activity with the IC50 value of 30 μg/mL and for MN assay, 3 μg/mL ( 1 /10 IC50) of CEO decreased the percentage of micronucleus per 1000 cells up to 94.55%. Thus, the result can be summarized that CEO does not induce genotoxic and has the potency to prevent DNA damage caused by doxorubicin on CHO-K1 cells.