Extraction of phytocompounds from the medicinal plant Clinacanthus nutans Lindau by microwave-assisted extraction and supercritical carbon dioxide extraction

The composition and bioactivity of natural plant extracts strongly depends on the extraction technique employed. Clinacanthus nutans Lindau (C. nutans) is a well-known medicinal plant in South-East Asia that has been traditionally used for treatment of hepatitis, skin-rashes and snake venom poisoning, and recently has attracted attention for its applications for treatment and prevention of cancer diseases. In previous studies, the extraction of bioactive compounds from C. nutans by conventional Soxhlet solvent extraction has been described, but this method shows limitations in terms of selectivity, extraction yield and toxicity of the solvents employed. In this study, phytochemical compounds were extracted from leaves and stems of C. nutans by microwave-assisted extraction (MAE), pressurized microwave-assisted extraction (PMAE), supercritical carbon dioxide extraction (SFE) and Soxhlet method to investigate the best technique in terms of yield, extraction time and recovery of bioactive compounds: phenols, flavonoids, phytosterols and beta-sitosterol. The extracted phytocompounds and phenolics were characterized by gas chromatography mass spectrometry (GC/MS) and ultra performance liquid chromatography (UPLC). The results showed that MAE was the best technique to achieve a high yield and a maximal total polyphenol content (11.30 +/- 0.39 mg GAE/g DM) and flavonoids content (and 4.66 +/- 0.20 mg GAE/g DM), whereas SFE was the best method for phytosterols and beta-Sitosterol extraction. P-MAE merely enhanced the polyphenol and flavonoids yield to 14.56 +/- 0.77 mg GAE/g DM and 5.29 +/- 0.30 mg QE/g DM respectively, without significant variations on the type of compounds obtained. MAE appears as the most efficient technique for the extraction of phytochemical compounds from C nutans in a short time with a reasonable yield and a good selectivity toward bioactive nutraceutical compounds, with high concentrations of antioxidants, anti-inflammatory and antimicrobial compounds. (C) 2015 Elsevier B.V. All rights reserved.