Hong Ngoc Thuy Pham
Nha Trang University, Australia
Title: Maximizing saponin yield and antioxidant capacity of Catharanthus roseus (L.) G. Don (Patricia White cultivar) stem by ultrasound-assisted extraction
Biography
Biography: Hong Ngoc Thuy Pham
Abstract
Catharanthus roseus (L.) G Don (C. roseus) is traditionally known as a medicinal plant; however only its leaf has been investigated for its bioactive compounds. Other plant components, such as the stem and the root have not been studied. Our previous study conducted on the stem revealed a high level of saponins, which have been linked with various biological activities such as antimicrobial, ant herbivore and/or cytotoxic activities. Ultrasound-assisted extraction (UAE) is known as an advanced extraction method because of its eff ectiveness, simplicity and up-scale capability, thus UAE shows potential for the eff ective extraction of saponins from the stem of C. roseus. Response surface methodology (RSM) has been commonly applied to optimize extraction conditions as it can show the interactive eff ects between the tested parameters. Th is study aimed to optimize UAE conditions including temperature, time and power in combination with ratio of sample-to-solvent for the effi cient extraction of saponins from stem of C. roseus using RSM with Box-Behnken design. Th e results indicated that either ultrasonic temperature or sample-to-solvent ratio had a signifi cant infl uence on saponin yield, DPPH and ABTS radical scavenging activities (p<0.05). With the exception of ultrasonic power, the other three parameters (UAE temperature, sampleto- solvent ratio and time) statistically aff ected ferric reducing antioxidant power (FRAP) and cupric ion reducing antioxidant capacity (CUPRAC). A maximized saponin yield (138.21 mg ESE/g) and high levels of antioxidant activity (8.34, 12.06, 10.53 and 19.15 mg TE/g ABTS, DPPH scavenging capacity, FRAP and CUPRAC respectively) could be obtained under the optimal extraction conditions (ultrasonic temperature of 55°C, ultrasonic time of 35 min, sample-to-solvent ratio of 1/100 (g/mL) and ultrasonic power of 150W). Th e saponin-enriched extract from C. roseus stem can be potentially used for further investigation and application in the nutraceutical and pharmaceutical industries.