Microwave-assisted extraction of edible Cicerbita alpina shoots and its LC-MS phenolic profile.

BACKGROUND: Crude extracts obtained from the edible shoots of Cicerbita alpina using microwave-assisted extraction have been qualitatively profiled by liquid chromatography coupled with an ion trap mass spectrometry detector and an electrospray ionization interface (LC/ESI-MS(3) ) for their phenolic content. The main challenge of the present investigation was to create a working strategy designed to obtain a rich phenolic profile despite the limited amount of starting plant material and phytochemical data available. RESULTS: The best extraction conditions (temperature 90 °C; time 5 min; solvent methanol:water 50:50; sample weight 3 g) were achieved using a full factorial 2(4) experimental design. Fifteen compounds, including flavonoid conjugates and phenolic acid derivatives, were detected and tentatively identified. The total phenolic content varied from 93.58 mg g(-1) gallic acid equivalents (GAE), for the cultivated plant to 10.54 mg g(-1) GAE for the wild one, whereas the total flavonoid content varied from 145.00 mg g(-1) rutin for the cultivated plant to 25.22 mg g(-1) rutin for the wild one. CONCLUSION: A total of 11 compounds are herein reported, for the first time, as coming from this plant source.

UAE, MAE, SFE-CO2 and classical methods for the extraction of Mitragyna speciosa leaves.

Mitragyna speciosa, a tropical plant indigenous to Southeast Asia, is well known for its psychoactive properties. Its leaves are traditionally chewed by Thai and Malaysian farmers and manual labourers as it causes a numbing, stimulating effect. The present study aims to evaluate alkaloid yield and composition in the leaf extracts. For this purpose we have compared several non-conventional extraction techniques with classic procedures (room temperature or under heating). Dried M. speciosa leaves belonging to three batches of different origin (from Thailand, Malaysia and Indonesia) were extracted using ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and supercritical carbon dioxide extraction SFE-CO(2), using methanol, ethanol, water and binary mixtures. The extracts were compared using an HPLC/ESI-MS analysis of mitragynine and four other related alkaloids which were present in the alkaloid fraction. The extraction technique influences both the raw product yield and the relative alkaloid content of M. speciosa leaves. Of the several methods tested, MAE in a closed vessel at 110 °C (60 W, methanol/water 1:1) gave the highest alkaloid fraction amount, while UAE with an immersion horn at 25 °C (21.4 kHz, 50 W, methanol) showed the best yield for mitragynine. This work may prove to be a useful contribution to forensic, toxicological and pharmacognosy studies. Although the potential applications of M. speciosa alkaloids clearly need further investigation, these results may facilitate the scaling-up of their extraction.