Can Hinokitiol Kill Cancer Cells? Alternative Therapeutic Anticancer Agent via Autophagy and Apoptosis

Health Benefits and Pharmacological Properties of Hinokitiol

Hinokitiol is a natural bioactive compound found in several aromatic and medicinal plants. It is a terpenoid synthetized and secreted by different species as secondary metabolites. This volatile compound was tested and explored for its different biological properties. In this review, we report the pharmacological properties of hinokitiol by focusing mainly on its anticancer mechanisms. Indeed, it can block cell transformation at different levels by its action on the cell cycle, apoptosis, autophagy via inhibiting gene expression and dysregulating cellular signaling pathways. Moreover, hinokitiol also exhibits other pharmacological properties, including antidiabetic, anti-inflammatory, and antimicrobial effects. It showed multiple and several effects through its inhibition, interaction and/or activation of the main cellular targets inducing these pathologies.

New Broth Macrodilution Volatilization Method for Antibacterial Susceptibility Testing of Volatile Agents and Evaluation of Their Toxicity Using Modified MTT Assay In Vitro

In this study, a new broth macrodilution volatilization method for the simple and rapid determination of the antibacterial effect of volatile agents simultaneously in the liquid and vapor phase was designed with the aim to assess their therapeutic potential for the development of new inhalation preparations. The antibacterial activity of plant volatiles (β-thujaplicin, thymohydroquinone, thymoquinone) was evaluated against bacteria associated with respiratory infections (Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes) and their cytotoxicity was determined using a modified thiazolyl blue tetrazolium bromide assay against normal lung fibroblasts. Thymohydroquinone and thymoquinone possessed the highest antibacterial activity against H. influenzae, with minimum inhibitory concentrations of 4 and 8 µg/mL in the liquid and vapor phases, respectively. Although all compounds exhibited cytotoxic effects on lung cells, therapeutic indices (TIs) suggested their potential use in the treatment of respiratory infections, which was especially evident for thymohydroquinone (TI > 34.13). The results demonstrate the applicability of the broth macrodilution volatilization assay, which combines the principles of broth microdilution volatilization and standard broth macrodilution methods. This assay enables rapid, simple, cost- and labor-effective screening of volatile compounds and overcomes the limitations of assays currently used for screening of antimicrobial activity in the vapor phase.

Transcription factor EB agonists from natural products for treating human diseases with impaired autophagy-lysosome pathway

Autophagy is a highly conserved degradation process for long-lived intracellular proteins and organelles mediated by lysosomes. Deficits in the autophagy-lysosome pathway (ALP) have been linked to a variety of human diseases, including neurodegenerative diseases, lysosomal storage disorders, and cancers. Transcription factor EB (TFEB) has been identified as a major regulator of autophagy and lysosomal biogenesis. Increasing evidence has demonstrated that TFEB activation can promote the clearance of toxic protein aggregates and regulate cellular metabolism. Traditional Chinese medicine (TCM)-derived natural products as important sources for drug discovery have been widely used for the treatment of various diseases associated with ALP dysfunction. Herein, we review (1) the regulation of TFEB and ALP; (2) TFEB and ALP dysregulation in human diseases; (3) TFEB activators from natural products and their potential uses.