Response surface methodology (RSM) optimizes the ultrasonic-assisted extraction (UAE) of phenolic and antioxidant compounds from Ephedra foeminea Forssk

Most plants can be standardized by a single chemical marker, but Ephedra foeminea refuses to play by those rules—so scientists turned to a smarter, multi-target extraction strategy.

Ephedra foeminea, an East Mediterranean shrub with a long history in traditional medicine, is a biochemical treasure chest. But unlike its ephedrine-rich relatives, this species lacks a dominant alkaloid marker, making it impossible to standardize by monitoring a single compound. The solution? A multi-response extraction approach that optimizes several parameters at once.

Researchers used ultrasonic-assisted extraction (UAE) and a circumscribed central composite design to test how extraction volume, ethanol percentage, sonication time, and temperature interact. Response surface methodology (RSM) then modeled the data, producing robust quadratic models with non-significant lack-of-fit (p > 0.05). The optimized conditions delivered a yield of 11.93%, a total phenolic content of 3.06 mg GAE/g, and a radical scavenging activity of 90.63%.

Principal component analysis (PCA) revealed a strong positive link between phenolic content and antioxidant activity. HPLC-DAD validation confirmed the enrichment of key polyphenols, with gallic acid as the star compound at 0.82 mg/g.

This green, reproducible extraction framework not only valorizes Ephedra foeminea but also offers a blueprint for other phytochemically complex species. The findings open the door to deeper phytochemical exploration and sustainable use of this remarkable plant.

Key Points

• RSM optimized UAE for Ephedra foeminea
• Yield 11.93%, TPC 3.06 mg GAE/g, RSA 90.63%
• Gallic acid most abundant at 0.82 mg/g