Establishment and antifungal potential of in vitro biomass of Salvia somalensis

Carnosic acid, a well-known abietane diterpenoid produced by several Salvia spp., including S. somalensis , has shown potential as an agrochemical for the treatment of several phytopathogenic fungi [ 1 ]. Aim of this project was to establish micropropagated plants from S. somalensis , to assess their production of carnosic acid and to investigate the antifungal activity against common plant pathogens. Explants placed in medium containing the growth regulators, 0.5 mg/L BA plus 0.1 mg/L NAA, produced an average of 7.43 shoots per explant. The methanolic extracts of the aerial parts and micropropagated plants (MP) of S. somalensis were characterized by LC-MS analysis. Both produced carnosic acid, as well as carnosol, 12-methylcarnosic acid, 20-deoxocarnosol, and other terpenoids. The antifungal activity of the two extracts was assessed against Rhizoctonia solani , Fusarium solani , Colletotrichum coccodes , Sclerotinia sclerotiorum , and Botrytis cinerea . The extract of the in vivo biomass was active against all the fungi tested. The activity at 1000 μg/mL against F. solani, B. cinerea , and C. coccodes (72%, 84%, and 86% inhibition of mycelial growth, respectively) was statistically comparable to the activity of the reference commercial fungicides Ortiva ®​ and Switch ®​ (Syngenta), applied at 1000 μg/mL. The extract of the MP at 1000 μg/mL was active against B. cinerea , R. solani , C. coccodes , and S. sclerotiorum (63%, 69%, 63% and 62% inhibition of mycelial growth, respectively). Although the antifungal activity of the MP was statistically lower than the in vivo biomass, the results confirmed the significance of MP as a source of bioactive compounds of agricultural interest. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany