Bio-Guided Isolation of New Compounds from Baccharis spp. as Antifungal against Botrytis cinerea

Baccharis genus Asteraceae is widely used in traditional treatment against fever, headache, hepatobiliary disorders, skin ulcers, diabetes, and rheumatism, as well as an antispasmodic and diuretic. Its phytochemistry mainly shows the presence of flavonoids and terpenoids such as monoterpenes, sesquiterpenes, diterpenes, and triterpenes. Some of them have been evaluated for biological activities presenting allelopathic, antimicrobial, cytotoxic, and anti-inflammatory properties. In this paper, our research group reported the isolation, characterization, and antifungal evaluation of several molecules isolated from the dichloromethane extract from Baccharis prunifolia, Baccharis trinervis, and Baccharis zumbadorensis against the phytopathogen fungus Botrytis cinerea. The isolated compounds have not previously been tested against Botrytis, revealing an important source of antifungals in the genus Baccharis. Six known flavones were isolated from B. prunifolia. The dichloromethane extracts of B. trinervis and B. zumbadorensis were subjected to a bio-guided isolation, obtaining three known flavones, an α-hydroxidihydrochalcone mixture, one labdane, one triterpene, and two norbisabolenes from the most active fractions. The compounds 4′-methoxy-α-hydroxydihydrochalcone (7A), 3β,15-dihydroxylabdan-7-en-17-al (8), and 13-nor-11,12-dihydroxybisabol-2-enone (11) are novel. The most active compounds were the Salvigenin (5) and 1,2-dihydrosenedigital-2-one (10) with an IC50 of 13.5 and 3.1 μg/mL, respectively.