Chemical profile and antifungal activity of plant extracts on Colletotrichum spp. isolated from fruits of Pimenta dioica (L.) Merr

Genus Pimenta: An Updated Comprehensive Review on Botany, Distribution, Ethnopharmacology, Phytochemistry and Biological Approaches

Pimenta is a genus of flowering plants belonging to family Myrtaceae, native to the West Indies, Mexico, and South America. Numerous traditional uses were reported as anti-inflammatory, analgesic, antipyretic, sedative, diuretic, and sexual stimulant. This article aims to provide a comprehensive overview of the botany, traditional uses, phytochemical profile, and biological activities of genus Pimenta for future exploration of plant-based drugs and therapeutic approaches. The data were collected (up to date as of October 1, 2023) from several databases such as Web of Science, google scholar, science direct, Pubmed and Proquest. Pimenta species were reported to include various classes of phytochemicals like tannins, saponins, flavonoids, phenylpropanoids, monoterpenes, sesquiterpenes and essential oils. Quercetin glycosides and eugenol derivatives were the predominant compounds of this genus. Several biological activities have been reported such as antihypertensive, antioxidant, antimicrobial, antiviral, histidine decarboxylase inhibition, hypoglycemic, anticancer, anti-inflammatory, analgesic, antipyretic, acaricidal, anxiolytic, anti-depressant and anti-estrogenic. Several scientific reports have been published on various isolated phytochemicals and pharmacological properties of Pimenta species that confirm its ethnobotanical and traditional history. However, in vivo studies on different extracts and their phytoconstituents, alongside mechanistic analysis deserve more attention for drug researchers to provide better guidance to utilize Pimenta plants as medicinal resources for herbal formulations in different approaches.

Helichrysum stoechas (L.) Moench Inflorescence Extract for Tomato Disease Management

Helichrysum stoechas is a singular halophyte that has been shown to have anti-inflammatory, antioxidant, and allelopathic properties. In the work presented herein, we have characterized its inflorescences hydromethanolic extract and assessed its antifungal activity for the pre- and postharvest management of tomato crop diseases. Gas chromatography-mass spectrometry characterization of the extract showed that 4-ethenyl-1,3-benzenediol, 2,3-dihydro-benzofuran, quinic acid, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-1-benzopyran-4-one, 1,6-anhydro-β-D-glucopyranose, catechol, scopoletin, and maltol were the main constituents. The co-occurrence of pyranones, benzenediols, and quinic acids as phytoconstituents of H. stoechas extract resulted in promising in vitro minimum inhibitory concentrations of 500, 375, 500, 187.5, 187.5, and 375 μg·mL-1 against mycelia of Alternaria alternata, Colletotrichum coccodes, Fusarium oxysporum f. sp. lycopersici, Rhizoctonia solani, Sclerotinia sclerotiorum, and Verticillium dahliae, respectively. Further, to assess the potential of H. stoechas inflorescence extract for postharvest tomato crop protection, ex situ tests were conducted against C. coccodes, obtaining high protection at a dose of 750 μg·mL-1. Taking into consideration that the demonstrated activity is among the highest reported to date for plant extracts and comparable to that of the synthetic fungicides tested as positive controls, H. stoechas inflorescence extract may be put forward as a promising biorational and may deserve further testing in field-scale studies.

Microwave-Assisted Hydrodistillation of Essential Oil from Plectranthus amboinicus: Evaluation of Its Antifungal Effect and Chemical Composition

Fusarium wilt, a vascular syndrome in a wide range of plants, is caused by the pathogen Fusarium Oxysporum. The objective of this investigation was to evaluate the antifungal effect of four essential oils (EOs) (Plectranthus amboinicus, Syzygium aromaticum, Lippia alba, and Rosmarinus officinalis), which were obtained by using microwave-assisted hydrodistillation (MAH), against F. oxysporum. The yield obtained from P. amboinicus with the use of MAH was 0.2%, which was higher than that of a conventional extraction; its extraction time was also shorter. For concentrations of 100 and 300 μL/L, P. amboinicus caused an inhibition rate of 27.2 and 55.7%, respectively, while S. aromaticum caused an inhibition rate of 23.1 and 87.3%, respectively. It was observed that increasing the concentration also increased the % inhibition rate. The extracts of L. alba and R. officinalis caused an inhibition rate of 14.5 and 14.7% at 500 µL/L, respectively, at 10 days of incubation, while at this concentration, P. amboinicus and S. aromaticum achieved 100%. The major chemical compounds of P. amboinicus were carvacrol (41.20%), o-cymene (11.61%), caryophyllene (11.45%), α-bergamotene (7.71%), and caryophyllene oxide (4.62%), and these monoterpene hydrocarbons were responsible for the biological activity. The essential oil of P. amboinicus in appropriate concentrations is a potent antifungal agent that could be used for the control of F. oxysporum.

Family Myrtaceae: The treasure hidden in the complex/diverse composition

Myrtaceae is one of the most important plants families, being regarded as the eighth largest flowering plant family. It includes many genera of utmost ecological and economical importance distributed all over the world. This review aimed to report the latest studies on this family focusing on certain widely used plants including Eucalyptus sp., Eugenia sp. (Eugenia uniflora, Eugenia sulcata), Syzygium sp. (Syzygium aromaticum and Syzygium cumini), Psidium sp., Pimenta dioica, Myrtus sp. (Myrtus communis), Myrciaria sp. and Melaleuca alternifolia. The extraction of bioactive compounds has been evolving through the optimization of conventional methods and the use of emerging technologies. Supercritical CO2 was applied for essential oils and ultrasound for polyphenols leading to extracts and essential oils rich in bioactive compounds. Advances in the field of encapsulation and delivery systems showed promising results in the production of stable essential oils nanoemulsions and liposomes and the production of plant extracts in the form of nanoparticles. Moreover, a significant increase in the number of patents was noticed especially the application of Myrtaceae extracts in the pharrmacuetucal field. The applications of ceratin plants (Pimenta dioica, Melaleuca alternifolia, Syzygium aromaticum essential oils or Myrciaria cauliflora peel extract) in food area (either as a free or encapsulated form) also showed interesting results in limiting microbial spoilage of fresh meat and fish, slowing oxidative degradation in meat products, and inhibiting aflatoxin production in maize. Despite the massive literature on Myrtaceae plants, advances are still necessary to optimize the extraction with environmentally friendly technologies and carry out risk assessment studies should be accomplished to harness the full potential in food, industrial and pharmaceutical applications.

A review of plant antipathogenic constituents: Source, activity and mechanism

Green prevention and control of plant pathogens is a development direction of sustainable and low-carbon agriculture given the limitation of traditional chemicals. Plant-derived antipathogenic constituents (PAPCs) exhibit the advantages of being environmental benign and a broad spectrum of target pathogens over traditional chemicals. Here, we review the research advances on plant sources, chemical compositions, activities of antipathogenic constituents in the past 20 years. Reported PAPCs are classified into categories of phenols, flavonoids, terpenoids, alkaloids and antimicrobial peptides. Angiosperms, gymnosperms and some lower plants are the main plant source of detected PAPCs. The PAPCs act on pathogens through multiple pathways including destroying cell structures, blocking key composition synthesis and inhibiting cell metabolism. The development trends of PAPCs are finally prospected. This review serves as a comprehensive review on the study of plant antipathogenic constituents and a key reference for forecasting the source, characteristic and activity of PAPC.

Identification of a Novel Therapeutic Target against XDR Salmonella Typhi H58 Using Genomics Driven Approach Followed Up by Natural Products Virtual Screening

Typhoid fever is caused by a pathogenic, rod-shaped, flagellated, and Gram-negative bacterium known as Salmonella Typhi. It features a polysaccharide capsule that acts as a virulence factor and deceives the host immune system by protecting phagocytosis. Typhoid fever remains a major health concern in low and middle-income countries, with an estimated death rate of ~200,000 per annum. However, the situation is exacerbated by the emergence of the extensively drug-resistant (XDR) strain designated as H58 of S. Typhi. The emergence of the XDR strain is alarming, and it poses serious threats to public health due to the failure of the current therapeutic regimen. A relatively newer computational method called subtractive genomics analyses has been widely applied to discover novel and new drug targets against pathogens, particularly drug-resistant ones. The method involves the gradual reduction of the complete proteome of the pathogen, leading to few potential and novel drug targets. Thus, in the current study, a subtractive genomics approach was applied against the Salmonella XDR strain to identify potential drug targets. The current study predicted four prioritized proteins (i.e., Colanic acid biosynthesis acetyltransferase wcaB, Shikimate dehydrogenase aroE, multidrug efflux RND transporter permease subunit MdtC, and pantothenate synthetase panC) as potential drug targets. Though few of the prioritized proteins are treated in the literature as the established drug targets against other pathogenic bacteria, these drug targets are identified here for the first time against S. Typhi (i.e., S. Typhi XDR). The current study aimed at drawing attention to new drug targets against S. Typhi that remain largely unexplored. One of the prioritized drug targets, i.e., Colanic acid biosynthesis acetyltransferase, was predicted as a unique, new drug target against S. Typhi XDR. Therefore, the Colanic acid was further explored using structure-based techniques. Additionally, ~1000 natural compounds were docked with Colanic acid biosynthesis acetyltransferase, resulting in the prediction of seven compounds as potential lead candidates against the S. Typhi XDR strain. The ADMET properties and binding energies via the docking program of these seven compounds characterized them as novel drug candidates. They may potentially be used for the development of future drugs in the treatment of Typhoid fever.