Isolation and Identification of Pennogenin Tetraglycoside from Cestrum nocturnum (Solanaceae) and Its Antifungal Activity against Fusarium kuroshium, Causal Agent of Fusarium Dieback

Abstract

Antifungal assay-guided fractionation of the methanolic crude extract of Cestrum nocturnum (Solanaceae), popular known as ‘lady of the night’, led the isolation and identification of the steroidal saponin named pennogenin tetraglycoside, which was identified for the first time in this plant species by spectroscopic means. The crude extract, fractions and pennogenin tetraglycoside exhibited mycelial growth inhibition of Fusarium solani and F. kuroshium. F. solani is a cosmopolitan fungal phytopathogen that affects several economically important crops. However, we highlight the antifungal activity displayed by pennogenin tetraglycoside against F. kuroshium, since it is the first plant natural product identified as active for this phytopathogen. This fungus along with its insect symbiont known as Kuroshio shot hole borer (Euwallacea kuroshio) are the causal agents of the plant disease Fusarium dieback that affects more than 300 plant species including avocado (Persea americana) among others of ecological relevance. Scanning electron microscopy showed morphological alterations of the fungal hyphae after exposure with the active fractions and 12 phenolic compounds were also identified by mass spectrometry dereplication as part of potential active molecules present in C. nocturnum leaves.

Antifungal and Insecticidal Activities of Selected Plant Species from Cloud Forest of Veracruz, Mexico: A Contribution to the Search of Novel Control Agents against Ambrosia Pest Complexes

“…So, we have proved that our ecological criterium of choosing plants from MCF ecosystems is valid and should be considered for incorporating these plants species in other bioprospecting programs such as drug discovery. In addition, active plant species here described represent opportunities for the isolation and identification of new antifungal compounds against Fusarium spp [36,37] . and bioassay‐guided fractionation approaches should be further considered leading the identification of the bioactive antifungal metabolites.…”

“…There are no previous reports about the antifungal activity of S. nudum and M. argyrophylla . Regarding C. nocturnum , we previously reported the antifungal activity of primary and secondary fractions against F. kuroshium and F. solani [36] . In addition, C. nocturnum methanolic extract obtained from the whole plant exhibited antifungal activity against Candida species and Microsporium canis with minimum inhibitory concentrations (MICs) ranging from 170 to 290 μg mL −1 [39] .…”

“…In addition, active plant species here described represent opportunities for the isolation and identification of new antifungal compounds against Fusarium spp. [36,37] and bioassay-guided fractionation approaches should be further considered leading the identification of the bioactive antifungal metabolites.…”

Identification of Antifungal Compounds from Avocado Rhizobacteria (Bacillus spp.) against Fusarium spp., by a Bioassay‐Guided Fractionation Approach

“…A mycelial disc (5 mm of diameter) taken from the border of mycelial growth was placed in the center of a Petri dish poured with 9 mL of PDA (40 to 45 °C), supplemented with 1 mL of the following treatments: 20 mg of bacterial extract dissolved in 1 mL of H 2 O‐MeOH (7 : 3; v/v), 20 mg of LB medium AcOEt or BuOH control extracts (acetate extract from culture medium (MC−Ac) and butanol extract from culture medium (MC−Bu)) dissolved in 1 mL of H 2 O−MeOH (7 : 3; v/v), 20 mg of thiabendazole, (Catalog number: T5535‐50G, Sigma‐Aldrich®) dissolved in 1 mL of sterilized distilled water (used as positive control, PC−T), 1 mL of H 2 O−MeOH (7 : 3; v/v), vehicle used as negative control (NC−V), and 1 mL of sterilized distilled water ( F. solani growth control (GC)). Thiabendazole was selected as a positive control due to its reported activity against fungal pathogens of the Fusarium genus [57,5,58] . Each treatment was tested in triplicate.…”

“…Thiabendazole was selected as a positive control due to its reported activity against fungal pathogens of the Fusarium genus. [57,5,58] Each treatment was tested in triplicate. Assays were incubated at 27 °C for seven days.…”