Green Ultrasound-Assisted Extraction of Podophyllotoxin from Juniperus scopulorum Needles

Abstract

Background—Podophyllotoxin, a polyphenolic compound with major applications in cancer treatment, is in short supply, as its source is now an endangered plant species. It is therefore essential to find another available plant that produces high levels of podophyllotoxin. Some Juniperus species are known to contain podophyllotoxin, more exactly within their needles, but are still unused in this regard. Objective—The aim is to develop an efficient green ultrasound-assisted extraction protocol for podophyllotoxin from commercially available Juniperus scopulorum varieties. Methodology—To highlight optimal extraction conditions, a single-factor experiment was performed to identify the parameters (extraction duration, frequency, temperature extraction, preliminary grinding, and plant material concentration) influencing extraction. A multifactorial approach using the Box–Behnken design was then applied to determine the exact optimal extraction conditions. Results—The conditions for extracting the maximum amount of podophyllotoxin consist of 51.5 min of extraction time, in ethanol at 69.3%, and at 58.8 °C. This is the highest podophyllotoxin extraction yield ever obtained from Juniperus scopulorum needles. Compared with the reference protocol for the extracting of podophyllotoxin from Juniperus, ultrasonic extraction is an eco-friendly protocol, safe for humans, and the podophyllotoxin extracted by this method has much greater stability, allowing its purification. The analyses also indicate a variation in the podophyllotoxin content of Juniperus scopulorum needles, (from 7.02 to 10.34 mg/g DW) depending on the variety and year of purchase. Conclusion—Extraction in ethanol at 69.3% and at 58.8 °C for 51.5 min allows the extraction of up to 10.34 mg podophyllotoxin/g from freeze-dried Juniperus scopulorum needles.