The antiviral activity of extracts obtained from Ageratina havanensis (Kunth) R.M.King & H.Rob., Asteraceae, against rabbit vesivirus (RaV) (Caliciviridae) and human herpes simplex viruses type 1 and 2 (HSV-1, HSV-2) (Herpesviridae) were analyzed, and the main metabolites from the most active extract were isolated and characterized. The antiviral properties were investigated by measuring the inhibition of viral-induced cytopathic effect in Vero cells. The strongest inhibitory effects were found for ethyl acetate extract from leaves (SI=5 for RaV and SI=5.4 for HSV-1). The crude ethyl acetate extract was further fractionated by chromatographic methods and the structures of isolated compounds were established through comprehensive spectroscopic analyses, including IR, 2D NMR and MS. Four flavonoids were identified: 5,4'-dihydroxy-7-methoxyflavanone (sakuranetin), 3,5,4'-trihydroxy-7-methoxyflavanone (7-methoxyaromadendrin), 4'-O-β-D-glucosyl-5,3'-dihydroxy-7-methoxyflavanone (4'-O-β-D-glucosyl-7-methoxy-eriodictyol) and 4'-O-β-D-glucosyl-5-hydroxy-7-methoxyflavanone (4'-O-β-D-glucosylsakuranetin). This is the first report on antiviral activity for Ageratina havanensis.

Medium and high polarity extracts from Maytenus species are known to contain polyphenolic compounds such as proanthocyanidins. The high polarity and structural complexity of these compounds make very difficult their isolation even by modern chromatographic techniques. Maytenus cajalbanica (Borhidi & O. Muñiz) Borhidi & O. Muñiz is endemic from Cuba. So far, there are reports neither of phytochemical work nor of biological evaluation of extracts from this subspecies. The goal of this work is to determine the polyphenolic profile and the antioxidant capacity of the ethanolic extract from the barks of Maytenus cajalbanica. FIA/ESI/IT/MSⁿ analysis allowed the identification of 5 flavan-3-ol monomers, 33 proanthocyanidins, 2 free flavonoids and their respective glycosides as major compounds of the ethanolic extract, which showed a strong radical scavenging capacity and a significant ferric reduction power. FIA/ESI/IT/MSⁿ technique led the rapid, effective and sensitive determination of the polyphenolic profile of Maytenus cajalbanica without previous separation. GRAPHICAL ABSTRACT

Phaseolus vulgaris L. is one of the most important legumes for human consumption due to its contents of proteins, antioxidants, minerals, and bioactive compounds. In the last decade, there has been a growing research interest in increasing yields while reducing or replacing the use of chemical fertilizers. This has led to a focus on plant growth-promoting Rhizobacteria (PGPR) as biofertilizers in sustainable agricultural practices. The aim of this study was to determine the growth-promoting activity of a culture broth of the Gram-negative soil bacteria Rhizobium sp. (F7), which is conserved in the Collection of Beneficial Bacteria at the Institute of Fundamental Research in Tropical Agriculture (INIFAT), and to identify the main secondary metabolites present in the ethyl acetate crude extract using high-resolution liquid chromatography coupled with mass spectrometry (UHPLC-ESI-MS/MS). The growth-promoting activity of the culture broth on Phaseolus vulgaris L. seeds was evaluated. The ethyl acetate extract was obtained by liquid–liquid extraction with ethyl acetate from the culture broth, and UHPLC-ESI-MS/MS was used to identify secondary metabolites. The results indicated that the culture broth of Rhizobium sp. exhibited an in vitro growth-stimulating effect. Furthermore, ten secondary metabolites were identified in the ethyl acetate extract (p-coumaric acid, indole-3-lactic acid, naringenin, and siderophores B and C, among others). These findings highlight the bioactive metabolites produced by Rhizobium sp., a bacterial strain of the INIFAT collection, which have a positive effect as growth promoters in plants. They reveal the potential of Rhizobium sp. as a promising candidate for inclusion in agricultural management practices.

Plants belonging to the genus Maytenus are members of the Celastraceae family. They have been widely used by different peoples as treatment for curing many diseases. The aim of this study was to explore the anti-inflammatory and antioxidant properties of Maytenus elaeodendroides stem bark extracts, an endemic Cuban plant. The antioxidant activity of four extracts (EtOH, EtOAc, n-BuOH, and diethyl ether/petroleum ether 1:1) was determined using DPPH and FRAP methods. Meanwhile, anti-inflammatory effects by the edema method were induced by croton oil in the mouse ear. The investigated extracts showed radical reduction capacity and prevented ear inflammation at doses of 4 mg/ear. In addition, FIA/ESI/IT/MSⁿ was used to determine the qualitative chemical composition of the EtOAc extract and allowed the identification of five flavan-3-ol monomers, four dimers, and other proanthocyanidin oligomers. From this extract three flavan-3-ol compounds (elaeocyanidin and 4′-O-methylgallocatechin), one of them new (2′-hydroxy-4′-methoxy-epigallocatechin), and a proanthocyanidin dimer (afzelechin-($4\mathsf{\beta }\text{→}8$)-4′-O-methylepigallocatechin) were isolated and identified by the chromatographic method and spectroscopic techniques, mainly ESI-MS and NMR spectroscopic methods.