Phytochemical Analysis of Volatile and Non-volatile Fractions, Antioxidant, and Anti-Cancer Activities of Dracocephalum polychaetum and Dracocephalum kotschyi

The present study was conducted to determine the volatile and non-volatile fractions and the antioxidant and anti-cancer activities of ethanolic extracts of Dracocephalum polychaetum and D. kotschyi. The volatile and non-volatile fractions were investigated by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The cytotoxicity effect of two ethanol extracts and the major phenolic components has been evaluated on breast and colon cancer cells by the MMT assay. GC-MS of the essential oils identified about 50 compounds, and perillylaldehyde and D-limonene were the main constituents in the essential oils of the two species. Moreover, high-performance liquid chromatography- Diode array detector analysis demonstrated that the ethanolic extract of  D. polychaetum and D. kotschyi were the source of phenolic compounds such as rosmarinic acid, protocatechuic acid, naringin, apigenin, syringic acid, epicatechin, chlorogenic acid, thymol, carvacrol, rutin, p-coumaric acid, gallic acid, benzoic acid, cinnamic acid, resorcinol, quercetin, salicylic acid, 4-hydroxybenzoic acid, and ferulic acid. Rosmarinic acid and thymol were the main predominant phenolic constituents in D. kotschyi and D. polychaetum ethanolic extracts. The cytotoxicity effect of D. kotschyi and D. polychaetum ethanol extracts and the major phenolic components including rosmarinic acid, thymol, apigenin, quercetin, and nariginin has been evaluated on breast and colon cancer cells by MMT assay and results indicated IC50 values in the range of 90 to 140 (µg.ml-1) after 48 hours of treatment with ethanol extracts. Among phenolic components, thymol caused the lowest cell viability and Narengin showed the lowest anti-proliferative activity. Both extracts also showed antioxidant activity using DPPH assay. The findings of this research suggest that the Dracocephalum have precious bioactive and natural compounds with significant antioxidant and in vitro anti-cancer activities.