Anti-Cancer and Anti-Angiogenesis Activities of Zerumbone Isolated from Zingiber Zerumbet - A Systematic Review

Biosynthesis of Zinc Oxide-Zerumbone (ZnO-Zer) Nanoflakes Towards Evaluating Its Antibacterial and Reactive Oxygen Species (ROS)-Dependent Cytotoxic Activity

Being the second most prevalent metal oxide, zinc oxide (ZnO) nanomaterials have been widely studied and found to exhibit promising applications in various domains of biomedicine and agriculture. Considering the enhanced bioactivities displayed by secondary metabolite (SM) derived ZnO nanomaterials, present study was undertaken to evaluate the efficacy of ZnO nanoflake (NF) derived from Zerumbone (Zer), a sesquiterpenoid from Zingiber zerumbet rhizome with diverse pharmacological properties. ZnO NF prepared by homogeneous precipitation method using ZnSO4.7H2O (0.1 M) and NaOH (0.2 M) as precursors with and without the addition of Zer (0.38 mM) were characterized by powder UV-visible spectroscopy, X-ray diffraction (XRD), FT-IR spectroscopy and Field emission scanning electron microscope (FESEM) analysis. Optical and physical properties of ZnO-Zer NF were found to match with the typical ZnO nanomaterial properties. XRD analysis revealed reduction in size (15 nm) of the green synthesized ZnO-Zer NF compared to ZnO NF (21 nm). ZnO-Zer NF displayed linear correlation between concentration and antimicrobial activity to Salmonella typhi, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Determination of cytotoxic potential of the synthesized ZnO-Zer NF in cervical cancer cells (HeLa) showed higher cytotoxicity of ZnO-Zer NF (39.32 ± 3.01%) compared to Zer alone (27.02 ± 1.22%). Present study revealing improvement in bioactivity of Zer following conjugation with ZnO NF signifies potential of NF formation in improving therapeutic application of Zer that otherwise displays low solubility limiting its bioavailability.

Tumor-Inhibitory Effects of Zerumbone Against HT-29 Human Colorectal Cancer Cells

Colorectal cancer (CRC) is the second cause of cancer-associated death globally. Recently, herbal medicinal products and, in particular, zerumbone have been widely studied and used for cancer treatment as they induce significant anti-cancer effects. However, there is limited information about the anti-cancer effects of zerumbone in CRC. Therefore, we aimed to investigate the in vitro anti-cancer effects of the zerumbone in CRC, focusing on cell apoptosis and migration. Anti-proliferative and anti-migratory effects of zerumbone on HT-29 cells were evaluated using MTT and scratch wound healing assay, respectively. Quantitative real-time PCR (qRT-PCR) was performed to determine the mRNA expression levels of migration and apoptosis-related genes. Apoptosis and cell cycle distribution were evaluated by flow cytometry. The intracellular level of reactive oxygen species (ROS) was measured using a ROS assay kit. Additionally, matrix metalloproteinase-2/-9 (MMP-2/-9) activity was determined using gelatin zymography. Zerumbone suppressed the viability of the HT-29 cells dose-dependently while having less cytotoxicity on normal NIH/3T3 cells. Zerumbone induced apoptosis in HT-29 cells and arrested the cell cycle in the G2/M phase. These effects were associated with alteration in the expression of apoptosis-related genes (up-regulation of Bax and down-regulation of Bcl-2 genes). Zerumbone also enhanced the generation of ROS in HT-29 cells. Furthermore, zerumbone significantly inhibited the migration of HT-29 cells and decreased MMP-2/-9 mRNA expression and activity. Our findings provide a potential use for zerumbone to induce apoptosis and suppress metastasis in HT-29 cells; thus, it could be developed as a promising natural agent for future CRC therapy.