Zanthosimuline and Related Pyranoquinolines as Antifungal Agents for Postharvest Fruit Disease Control

Recent advances in cascade reactions and their mechanistic insights: a concise strategy to synthesize complex natural products and organic scaffolds

The beauty of cascade reactions to bestow us with cumbersome organic scaffolds has made them a cutting-edge area of research. Although the planning of cascades may require intuition, their results can be highly impactful. The development of cascades to provide specific targeted molecules of an appropriate structural and stereochemical framework poses a significant challenge but can serve as one of the most impressive tools in organic synthesis. This review shares a broad interest in compiling cascade transformations towards the construction of polycyclic frameworks, induction of chirality/asymmetry in the protocol, etc. to solve diverse challenges in organic synthesis pursuits, as cascades enable the rapid and efficient construction of complex architectures from simple molecules. The studies highlighted herein manifest the utilization of a range of cascade reactions under various classifications for generating natural product skeletons such as palau'amine, benzosimuline, arcutinine, and others from simple building blocks, with emphasis on breakthroughs and potential for asymmetric synthesis. The exquisite synthetic designs of recently completed total synthesis of natural products with a focus on strategic concerns are also highlighted in this review.

Effect of alginate coatings incorporated with chitinase from ʻBaozhuʼ pear on the preservation of cherry tomato during refrigerated storage

The effects of edible coatings based on sodium alginate with ʻBaozhuʼ pear chitinase on the quality of cherry tomatoes during refrigerated storage were evaluated. Cherry tomatoes inoculated with Fusarium oxysporum were coated and stored up to 21 days. All coatings with the chitinase significantly reduced F. oxysporum proliferation on cherry tomatoes during storage and extended the shelf life of cherry tomatoes effectively (p < .05). Results showed that alginate coatings with the chitinase could prevent weight loss, maintain firmness, and slow down the changes of titratable acidity and vitamin C (p < .05) in a dose‐dependent manner. However, no significant differences were observed between T3 (1% alginate/0.15% ʻBaozhuʼ pear chitinase/1% glycerin) and T4 (1% sodium alginate/0.3% ʻBaozhuʼ pear chitinase/1% glycerin) (p > .05). Overall, alginate coating with 0.15% ʻBaozhuʼ pear chitinase could be a promising method to maintain the quality of cherry tomatoes.

Intramolecular Diels-Alder Cycloaddition of Furan-Derived β-Enamino Diketones: An Entry to Diastereoselective Synthesis of Polycyclic Pyrano[3,2-c]quinolin-5-one Derivatives

A series of 1,3-cyclodiketone- and tetrahydroepoxyisoindole-fused β-enamino dicarbonyl heterocycles were synthesized via a 1,4-diazabicyclo[2.2.2]octane-catalyzed, CH₃NO₂-mediated three-component reaction of 1,3-cyclodiketone, furfural, and allylamine in toluene. The target compounds were generated via the formation of β-enamino diketone as a key intermediate, followed by intramolecular Diels-Alder cycloaddition. The prepared molecules bearing a quinoline-2,4-dione moiety could be further brominated with N-bromosuccinimide and diastereoselectively reduced by NaBH₄ to afford pyrano[3,2-c]quinolin-5-one-derived heterocycles with six vicinal stereogenic centers.

Botanical Control of Citrus Green Mold and Peach Brown Rot on Fruits Assays Using a Persicaria acuminata Phytochemically Characterized Extract

Persicaria acuminata (Polygonaceae) is a perennial herb that grows in the central area of Argentina and it is commonly used by native populations to heal infected wounds and other conditions related to fungal infections. In this article, we explored the in vitro antifungal activity of its ethyl acetate extract against a panel of three fruit phytopathogenic fungi including: Penicillium digitatum, P. italicum, and Monilinia fructicola. The sesquiterpenes isolated from the extract were also evaluated against these strains, demonstrating that the dialdehyde polygodial was the responsible for this activity. In order to encourage the use of the extract rather than the pure compound, we displayed ex vivo assays using fresh oranges and peaches inoculated with P. digitatum and M. fructicola, respectively, and subsequently treated by immersion with an extract solution of 250 and 62.5 µg/mL, respectively. There were no statistically significant differences between the treatments with commercial fungicides and the extract over the control of both fruit rots. The concentration of the active compound present in the extract used on fruit experiments was determined by Gas Chromatography-Mass Spectroscopy. Finally, cytotoxicity evaluation against Huh7 cells showed that P. acuminata extract was less cytotoxic than the commercial fungicides at the assayed concentrations. After these findings we could conclude that a chemically characterized extract of P. acuminata should be further developed to treat fungal diseases in fruits from an agro-ecological model.

In Vitro Antifungal Screening of Argentine Native or Naturalized Plants against the Phytopathogen Monilinia fructicola

BACKGROUND

One of the main problems that fruit health has gone through in recent years is the difficult eradication of their fungal pathogens during crops or the post-harvest stage. This concerns the whole world because it represents huge production losses, fruit export restrictions and consumer distrust. Consequently, new alternatives are sought to avoid the increasing use of fungicides that cause important damage to fruit consumers and to the environment. One of the alternatives to solve this problem could be the exploration of plants and their active compounds applied to the treatment of fruit health.

MATERIALS AND METHODS

This article describes peach production worldwide and particularly in Argentina, in addition to the main fungal rot that causes the greatest economic losses. Furthermore, experimental in-vitro studies of 69 extracts obtained from 18 plants growing in the central region of Argentina were displayed against the devastating fungus Monilinia fructicola, which greatly affects stone fruits. A simple and effective method developed in agar plate was applied to evaluate a large number of samples in a short time.

RESULTS

Results showed that approximately 36% of the samples tested were strongly active against this pathogen, 12% were moderately active and 52% demonstrated to be inactive.

CONCLUSION

These findings support the possible use of natural products for fruit health and the importance of deepening in this field of science.