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Hairy root cultures of Trigonella foenum-graecum L. were established with Agrobacterium rhizogenes strain A 4 . The hairy roots produce diosgenin, an important spirostanol for the semi-synthesis of steroid hormones. Fourteen different liquid media were investigated. The fastest growth was obtained in McCown's woody plant (WP) medium supplemented with 3% sucrose; the highest diosgenin content was observed in half-strength WP medium with 1% sucrose (0.040% dry weight), which represents almost twice the amount detected in the 8-month-old non-transformed roots (0.024%). A time-course study in WP liquid media supplemented with 3% sucrose was undertaken. In these conditions, 17 µg diosgenin/g fresh weight were produced. The influence of cholesterol, medium pH and chitosan on diosgenin production was tested. The addition of 40 mg/l chitosan elevated the diosgenin content to three times that found in non-elicited hairy roots.

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Sixteen withanolides isolated from Iochroma gesnerioides (Kunth) Miers (Solanaceae) have been assessed for their activities as ecdysteroid agonists and antagonists. None of the compounds showed any agonistic activity, but several showed significant antagonistic activity. With a 20‐hydroxyecdysone concentration of 5 times 10−8 M, the ED50 values for 2,3‐dihydro‐3ξ‐methoxywithaferin A, 2,3‐dihydro‐3ξ‐methoxywithacnistine, 2,3‐dihydro‐3ξ‐methoxyiochromolide and 2,3‐dihydro‐3ξ‐hydroxyξwithacnistine are 3.5 times 10−5 M, 1 times 10−5 M, 5 times 10−6 M and 2.5 times 10−6 M, respectively.