A method for producing an active ingredient-containing medium from cultured plant cells, selected from the Hoodia genus, is provided. The method comprises the steps of: (i) incubating a mixture of cultured plant cells of the genus Hoodia and a liquid media in light (ii) separating the incubated mixture into a first portion and a second portion (iii) passing the first portion through a tangential flow filter to produce a filtrate containing only media and a retentate containing cultured plant cells (iv) passing the filtrate through a nano-filter to obtain a nano-retentate having a high concentration of steroidal glycosides (v) reintroducing some of the nano-retentate into the second portion and (vi) repeating steps (i) to (v) using the second portion. The medium may be either plant cells or a plant extract.
