Volatile organic composition of five Rubiaceae species: Insights into their phytochemical diversity

Natural volatile organic compounds (VOCs) obtained from five Rubiaceae plants native to south China, namely Damnacanthus indicus, Hamelia patens, Exallage chrysotricha, Psychotria serpens, and Spermacoce pusilla, were isolated and characterized in this study. The analysis revealed that each plant contained 71, 57, 80, 73, and 70 volatile organic chemical compounds, respectively. The main VOCs shared by five plants was palmitate (10.20%- 36.26%). Methyl salicylate, caryophyllene oxide, tetradecanoic acid, 6,10,14-trimethyl-2-pentadecanone, pentadecanoic acid, pentacosane, pentadecanal, nonanal, hexadecanoic acid methyl ester, phytol, linalool, and (E)- beta-ionone were shared by at least 4 Rubiaceae plants in this study. Besides, each of the five plants has its main components as follows: 12.81% ethyl linoleate and 6.13% (E)-13-octadecenoic acid for D. indicus; 35.17% methyl salicylate for H. patens; 9.50% (Z, Z)-9,12-octadecadienoic acid and 7.56% endo-borneol for E. chrysotricha; 13.93% methyl salicylate for P. serpens; 6.19% humulene and 6.08% humulene oxide II for S. pusilla. This research provides insights into the phytochemical diversity and classification of Rubiaceae plants, laying a solid foundation for future natural product development in the Rubiaceae family.