Essential Oils of Rosmarinus officinalis L., Cymbopogon citratus (DC.) Stapf., and the phyto-compounds, delta-carene and alpha-pinene mediate cell cycle arrest at G2/M transition in budding yeast Saccharomyces cerevisiae

Abstract Ethnopharmacological relevance: Rosmarinus officinalis L. (Lamiaceae) is widely used in folk and traditional medicine for inflammation-related diseases due to its anti-oxidant and wound healing properties. Cymbopogon citratus (DC.) Stapf. is a widely distributed perennial herb belonging to the Poaceae family and has been extensively consumed for its traditional and ethnomedicinal, cosmetic, and nutritional effects for centuries. Aim of the study: Budding yeast is a valuable system to study cell-cycle regulation, which is the underlying defect in cancer cells. The aim of the present study was to characterize the antiproliferative effect of essential oil of Rosmarinus officinalis L. (rosemary) and Cymbopogon citratus (DC.) Stapf. (lemon grass) and their effect on cell cycle of Saccharomyces cerevisiae. Materials and methods: Rosmarinus officinalis L. and Cymbopogon citratus (DC.) Stapf. essential oil was extracted from leaves and characterized by GC–MS, TLC and FTIR. The antiproliferative activity of essential oils and their major compounds, delta-carene and α-pinene was studied by liquid growth assay. Microscopic examination of yeast cells was done to determine the budding index. Flowcytometry analysis of DNA content was analyzed to confirm the G2/M arrest of cell cycle of budding yeast. Results: Both the essential oils mediated a dose-dependent inhibition of yeast growth in liquid assays. Analysis of budding index and DNA content by flowcytometry revealed that R. officinalis L. and C. citratus (DC.) Stapf. essential oils mediate the arrest of yeast cells at G2/M phase of cell cycle. GC/MS analysis of R. officinalis oil revealed the presence of two major compounds, delta-carene (7.75%), and α-pinene (15.1%). Both delta-carene and α-pinene showed antiproliferative activity (92% and 95% of growth inhibition, respectively) and caused the arrest of yeast cell cycle at G2/M phase. Conclusions: The essential oils of R. officinalis and C. citratus, delta-carene and α-pinene can be validated in animal model for cell cycle inhibition and cancer therapeutics.