Chemical Compounds, Antitumor and Antimicrobial Activities of Dry Ethanol Extracts from Koelreuteria paniculata Laxm

Koelreuteria paniculata Laxm. is used in traditional medicine and has various established biological activities, however, the species is considered to be a potentially invasive alien tree species for Bulgarian flora. However, there is still much to be studied about the phytochemical and biological characteristics of the species. The present study aimed to determine the chemical composition of the ethanol extracts of aerial plant parts, by GC-MS analysis, and to thereby evaluate their in vitro antitumor and antibacterial properties. All three extracts were tested against the HT-29 and PC3 tumor cell lines using the MTT assay. Fifty-six components were identified from leaf, flower, and stem bark extracts, and over 10% were the following constituents: pyrogallol, α-terpinyl acetate, neryl acetate, and α-terpinyl isobutanoate. The oxygenated monoterpenes predominated in the extracts, followed by the oxygenated aliphatics and phenylpropanoids. Significant antiproliferative activity on the HT-29 cell line (IC(50)–21.44 µg/mL and 23.63 µg/mL, respectively) was found for the flower and leaf extracts. Antibacterial activity was established for the following bacteria strains: Bacillus subtilis ATCC 6633, Bacillus cereus NCTC 10320, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 6027, and Proteus vulgaris ATCC 6380. The stem bark and flower extracts showed better antimicrobial potential. K. paniculata could be considered as a potential source of biologically active substances with antitumor and antibacterial properties.