Extraction, Purification, Quantification, and Stability of Bioactive Spilanthol from Acmella oleracea

Acmella oleracea is an ethnobotanically significant plant with a relatiwely high content of spilanthol. Due to its broad spectrum of activity, including anti-inflammatory, antioxidant, analgesic, antifungal, and bacteriostatic properties, it is considered a valuable bioactive natural product. In addition, spilanthol as its main bioactive component inhibits facial muscle contractions, making it an attractive ingredient in anti-wrinkle and anti-aging cosmetics. Due to its muscle paralyzing effects, it is called herbal botox. The commercial interest in spilanthol encourages the development of effective methods of isolating it from plant material. The methodology used in this paper allows for the obtaining of extracts from Acmella oleracea with a relatively high content of spilanthol. An effective method of spilanthol extraction from all aerial parts of Acmella oleracea as well as methods of enriching spilanthol concentration in extracts achieved by removing polar and acidic substances from crude extracts was developed. To quantify the concentration of spilanthol, a simple, fast and economically feasible quantification protocol that uses nuclear magnetic resonance (HNMR) was developed. In addition, it has been proven, that oxidation of spilanthol by air gives (2E,7Z)-6,9-endoperoxy-N-(2-methylpropyl)-2,7-decadienamide. The studies on spilanthol solutions stability were carried out and the conditions for the long-time storage of spilanthol solutions have also been developed. Additionally, for confirmation of obtained results a sensitive (LOQ=1 ng/mL), precise (RSD lower than 7%) and accurate (RE lower than 7.5%), new HPLC-MS/MS method was applied.