Determination of Caffeoylquinic Acids Content by UHPLC in Scolymus hispanicus Extracts Obtained through Ultrasound-Assisted Extraction.

Scolymus hispanicus L., also known as golden thistle, Spanish oyster thistle or, more commonly, as tagarnina is a plant that belongs to the Asteraceae family. It is collected from the wild for human consumption in Mediterranean countries. It is a relevant ingredient in Andalusian culinary culture, where the midribs of young plants are harvested for consumption. Scolymus hispanicus L. contains a wide variety of phenolic compounds such as caffeoylquinic acids (CQAs), among others. In the present work, the major phenolic compounds present in tagarnina have been identified, with 5-caffeoylquinic acid (5-CQA) and 3,5-dicaffeoylquinic acid (3,5-diCQA) being the main ones. A method based on ultrasound-assisted extraction (UAE) has been developed for the extraction of these compounds, with the percentage of methanol, sample-to-solvent ratio and the pH being the most influential factors. The developed method has been validated and employed to determine the concentration of 5-CQA and 3,5-diCQA in the midribs of Scolymus hispanicus, collected in six different places in the south of Spain. The antioxidant activity of the samples has also been determined, and a direct correlation with their caffeoylquinic compounds content has been established, showing an antioxidant effect.

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), 3ß,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.

Synthesis, Fungitoxic Activity against Botrytis cinerea and Phytotoxicity of Alkoxyclovanols and Alkoxyisocaryolanols.

Clovane and isocaryolane derivatives have been proven to show several levels of activity against the phytopathogenic fungus Botrytis cinerea. Both classes of sesquiterpenes are reminiscent of biosynthetic intermediates of botrydial, a virulence factor of B. cinerea. Further development of both classes of antifungal agent requires exploration of the structure-activity relationships for the antifungal effects on B. cinerea and phytotoxic effects on a model crop. In this paper, we report on the preparation of a series of alkoxy-clovane and -isocaryolane derivatives, some of them described here for the first time (2b, 2d, 2f-2h, and 4c-4e); the evaluation of their antifungal properties against B. cinerea, and their phytotoxic activites on the germination of seeds and the growth of radicles and shoots of Lactuca sativa (lettuce). Both classes of compound show a correlation of antifungal activity with the nature of side chains, with the best activity against B. cinerea for 2d, 2h, 4c and 4d. In general terms, while 2-alkoxyclovan-9-ols (2a-2e) exert a general phytotoxic effect, this is not the case for 2-arylalkoxyclovan-9-ols (2f-2i) and 8-alkoxyisocaryolan-9-ols (4a-4d), where stimulating effects would make them suitable candidates for application to plants.

Antifungal and Cytotoxic Assessment of Lapachol Derivatives Produced by Fungal Biotransformation.

In the screening for biological active compounds, the biotransformation processes catalyzed by filamentous fungi are useful because they can provide information about the possible appearance of toxic metabolites after oral administration and also generate new leads. In this paper, biotransformation of lapachol (1) by three fungal strains, Mucor circinelloides NRRL3631, Botrytis cinerea UCA992 and Botrytis cinerea 2100, has been investigated for the first time. Lapachol (1) was biotransformed into avicequinone-A (2) by M circinelloides, 3'-hydroxylapachol (3) by B. cinerea, and into dehydro-α-lapachone (4) by both fungi. All these compounds were evaluated for their cytotoxic activities. The metabolite 2 displayed non-selective cytotoxicity against tumor and normal cell lines, 3 did not show cytotoxicity against the same cells, while 4 showed higher cytotoxicity against cancer cell lines than lapachol (1). The transformation of 1 into harmless and reactive metabolites evidences the importance of the evaluation of drug metabolism in the drug discovery process. Antifungal potential of lapachol (1) and its metabolites 2 and 4 against B. cinerea has also been evaluated. Dehydro-α-lapachone (4) has been shown to be less toxic to fungal growth than lapachol (1), which indicates a detoxification mechanism of the phytopathogen.