Optimisation of asarone removal from Piper sarmentosum Roxburgh leaves using supercritical carbon dioxide extraction: the Box-Behnken design

Abstract

Piper sarmentosum is a herbaceous shrub with numerous pharmacological benefits. However, the presence of two toxic phenylpropanoids (α-and β-asarone) limits the medicinal usage of the plant. In this study, the extraction of three asarone isomers, namely α-, β-, and ɣ-asarone was optimised using supercritical carbon dioxide extraction (SC-CO 2 ) combined with Box-Behnken experimental design. Comparison of asarone contents in different conventional solvent extracts of P. sarmentosum leaves prior to and after SC-CO 2 extraction was performed. The SC-CO 2 method successfully maximised the extraction of α-, β-, and ɣ-asarone at P = 81.16 bar, T = 50.11°C, and t = 80.90 min, yielding 13.91% α-asarone, 3.43% β-asarone, and 14.95% ɣ-asarone. The SC-CO 2 residue of the leaves re-extracted with conventional solvents showed a significant decrease of asarone ranging from 45% to 100% (p<0.001) compared to their counterparts without SC-CO 2 treatment. α-, β-, and ɣ-asarone were completely removed in the ethanol extract of the residue. These findings suggested that the optimised SC-CO 2 extraction parameters may serve as a quick treatment step for the selective removal of asarone from P. sarmentosum to develop safer extracts for the food and nutraceutical industries applications.

Phenolics-Enhancing Piper sarmentosum (Roxburgh) Extracts Pre-Treated with Supercritical Carbon Dioxide and its Correlation with Cytotoxicity and α-Glucosidase Inhibitory Activities

“…Vuong and Roach (2014) also reported that functional polyphenolics such as catechins were maintained and preserved in green tea after decaffeination using SC-CO 2 . Our previous study successfully produced an asarones-free (α-, β-and γ-asarones) ethanol extract using the two-step extraction technique (Hamil et al, 2022). The present study showed that SC-CO 2 pre-treatment could retain and enhance the quantity of other beneficial components in the sample material, such as polyphenols and flavonoids, apart from removing unwanted compounds.…”

“…Dried powdered leaves (50 g) were extracted using a 1-litre SC-CO 2 extractor (Separex, France). The experimental parameters were set according to the method established by Hamil et al (2022): pressure = 81.16 bar, temperature = 50.11°C and dynamic extraction time = 80.90 min. The flow rate was maintained at 30 g/min, and the static extraction time was fixed at 30 min.…”

“…SFE was proven to be beneficial in the removal of toxic and undesirable compounds such as aristolochic acid from Aristolochia plants (Liang et al, 2010), phthalate plasticiser residue in Ganoderma lucidum (Li et al, 2018), and many other undesirable substances from food and herbal-based supplement products (Kobori et al, 2013;Shinde & Mahadik, 2019). Previously, we established a condition to reduce potentially carcinogenic asarone isomers from Piper sarmentosum leaves by removing 80.42%-100% of α-asarone, 91.26%-100% of β-asarone, and 89.24%-100% of γ-asarone by using supercritical carbon dioxide (SC-CO 2 ) extraction while applying the Box-Behnken experimental design at optimised pressure (P) = 81.16 bar, temperature (T) = 50.11°C, and time (t) = 80.90 min (Hamil et al, 2022).…”