Antifungal Potential of Salvia somalensis Against Botrytis cinerea and Colletotrichum coccodes

Salvia somalensis Vatke is a source of specialized metabolites with potential biological and agrochemical applications. Previous studies on the dichloromethane plant surface extract demonstrated strong antifungal activity associated with abietane diterpenoids. Building on these findings, the present study aimed to characterize the methanolic extract of S. somalensis and evaluate its antifungal potential against major phytopathogenic fungi, with the broader goal of exploring the extract as a sustainable source of antifungal metabolites for crop protection. LC-MS analysis of the methanolic extract revealed a diverse phytochemical profile comprising phenolic acids, including caffeic acid, ferulic acid, and rosmarinic acid, as well as abietane-type diterpenoids such as carnosol, rosmanol, and carnosic acid. Quantitative analysis showed that carnosic acid was present only at low levels (0.09% w/w of fresh biomass). The extract exhibited antifungal activity against Botrytis cinerea, Colletotrichum coccodes, Fusarium oxysporum, Rhizoctonia solani, and Sclerotinia sclerotiorum. More than 80% inhibition of mycelial growth was observed against B. cinerea and C. coccodes at 1000 μg/mL. In addition, as in vitro cultivation of this species has not previously been explored, micropropagated plants and callus culture were established. Phytochemical profiling revealed distinct chemical compositions in the in vitro biomass. Extracts obtained from micropropagated plants inhibited mycelial growth of the tested phytopathogens by 60–70% at 1000 μg/mL, except for F. oxysporum, which showed 35.29% inhibition at the same concentration. Collectively, these findings highlight S. somalensis as a source of bioactive metabolites with antifungal potential.