The majority of current infectious diseases are almost untreatable by conventional antibiotic therapy given the advent of multidrug-resistant bacteria. The degree of severity and the persistence of infections are worsened when microorganisms form biofilms. Therefore, efforts are being applied to develop new drugs not as vulnerable as the current ones to bacterial resistance mechanisms, and also able to target bacteria in biofilms. Natural products, especially those obtained from plants, have proven to be outstanding compounds with unique properties, making them perfect candidates for these much-needed therapeutics. This review presents the current knowledge on the potentialities of plant products as antibiotic adjuvants to restore the therapeutic activity of drugs. Further, the difficulties associated with the use of the existing antibiotics in the treatment of biofilm-related infections are described. To counteract the biofilm resistance problems, innovative strategies are suggested based on literature data. Among the proposed strategies, the use of phytochemicals to inhibit or eradicate biofilms is highlighted. An overview on the use of phytochemicals to interfere with bacterial quorum sensing (QS) signaling pathways and underlying phenotypes is provided. The use of phytochemicals as chelating agents and efflux pump inhibitors is also reviewed.

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The anamorphic genus Phoma was subdivided into nine sections based on morphological characters, and included teleomorphs in Didymella, Leptosphaeria, Pleospora and Mycosphaerella, suggesting the polyphyly of the genus. Recent molecular, phylogenetic studies led to the conclusion that Phoma should be restricted to Didymellaceae. The present study focuses on the taxonomy of excluded Phoma species, currently classified in Phoma sections Plenodomus, Heterospora and Pilosa. Species of Leptosphaeria and Phoma section Plenodomus are reclassified in Plenodomus, Subplenodomus gen. nov., Leptosphaeria and Paraleptosphaeria gen. nov., based on the phylogeny determined by analysis of sequence data of the large subunit 28S nrDNA (LSU) and Internal Transcribed Spacer regions 1 & 2 and 5.8S nrDNA (ITS). Phoma heteromorphospora, type species of Phoma section Heterospora, and its allied species Phoma dimorphospora, are transferred to the genus Heterospora stat. nov. The Phoma acuta complex (teleomorph Leptosphaeria doliolum), is revised based on a multilocus sequence analysis of the LSU, ITS, small subunit 18S nrDNA (SSU), β-tubulin (TUB), and chitin synthase 1 (CHS-1) regions. Species of Phoma section Pilosa and allied Ascochyta species were determined to belong to Pleosporaceae based on analysis of actin (ACT) sequence data. Anamorphs that are similar morphologically to Phoma and described in Ascochyta, Asteromella, Coniothyrium, Plectophomella, Pleurophoma and Pyrenochaeta are included in this study. Phoma-like species, which grouped outside the Pleosporineae based on a LSU sequence analysis, are transferred to the genera Aposphaeria, Paraconiothyrium and Westerdykella. The genera Medicopsis gen. nov. and Nigrograna gen. nov. are introduced to accommodate the medically important species formerly known as Pyrenochaeta romeroi and Pyrenochaeta mackinnonii, respectively. Taxonomic novelties New genera: Medicopsis Gruyter, Verkley & Crous, Nigrograna Gruyter, Verkley & Crous, Paraleptosphaeria Gruyter, Verkley & Crous, Subplenodomus Gruyter, Verkley & Crous. New species: Aposphaeria corallinolutea Gruyter, Aveskamp & Verkley, Paraconiothyrium maculicutis Verkley & Gruyter. New combinations: Coniothyrium carteri (Gruyter & Boerema) Verkley & Gruyter, C. dolichi (Mohanty) Verkley & Gruyter, C. glycines (R.B. Stewart) Verkley & Gruyter, C. multiporum (V.H. Pawar, P.N. Mathur & Thirum.) Verkley & Gruyter, C. telephii (Allesch.) Verkley & Gruyter, Heterospora (Boerema, Gruyter & Noordel.) Gruyter, Verkley & Crous, H. chenopodii (Westend.) Gruyter, Aveskamp & Verkley, H. dimorphospora (Speg.) Gruyter, Aveskamp & Verkley, Leptosphaeria errabunda (Desm.) Gruyter, Aveskamp & Verkley, L. etheridgei (L.J. Hutchison & Y. Hirats.) Gruyter, Aveskamp & Verkley, L. macrocapsa (Trail) Gruyter, Aveskamp & Verkley, L. pedicularis (Fuckel) Gruyter, Aveskamp & Verkley, L. rubefaciens (Togliani) Gruyter, Aveskamp & Verkley, L. sclerotioides (Sacc.) Gruyter, Aveskamp & Verkley, L. sydowii (Boerema, Kesteren & Loer.) Gruyter, Aveskamp & Verkley, L. veronicae (Hollós) Gruyter, Aveskamp & Verkley, Medicopsis romeroi (Borelli) Gruyter, Verkley & Crous, Nigrograna mackinnonii (Borelli) Gruyter, Verkley & Crous, Paraconiothyrium flavescens (Gruyter, Noordel. & Boerema) Verkley & Gruyter, Paracon. fuckelii (Sacc.) Verkley & Gruyter, Paracon. fusco-maculans (Sacc.) Verkley & Gruyter, Paracon. lini (Pass.) Verkley & Gruyter, Paracon. tiliae (F. Rudolphi) Verkley & Gruyter, Paraleptosphaeria dryadis (Johanson) Gruyter, Aveskamp & Verkley, Paralept. macrospora (Thüm.) Gruyter, Aveskamp & Verkley, Paralept. nitschkei (Rehm ex G. Winter) Gruyter, Aveskamp & Verkley, Paralept. orobanches (Schweinitz: Fr.) Gruyter, Aveskamp & Verkley, Paralept. praetermissa (P. Karst.) Gruyter, Aveskamp & Verkley, Plenodomus agnitus (Desm.) Gruyter, Aveskamp & Verkley, Plen. biglobosus (Shoemaker & H. Brun) Gruyter, Aveskamp & Verkley, Plen. chrysanthemi (Zachos, Constantinou & Panag.) Gruyter, Aveskamp & Verkley, Plen. collinsoniae (Dearn. & House) Gruyter, Aveskamp & Verkley, Plen. confertus (Niessl ex Sacc.) Gruyter, Aveskamp & Verkley, Plen. congestus (M.T. Lucas) Gruyter, Aveskamp & Verkley, Plen. enteroleucus (Sacc.) Gruyter, Aveskamp & Verkley, Plen. fallaciosus (Berl.) Gruyter, Aveskamp & Verkley, Plen. hendersoniae (Fuckel) Gruyter, Aveskamp & Verkley, Plen. influorescens (Boerema & Loer.) Gruyter, Aveskamp & Verkley, Plen. libanotidis (Fuckel) Gruyter, Aveskamp & Verkley, Plen. lindquistii (Frezzi) Gruyter, Aveskamp & Verkley, Plen. lupini (Ellis & Everh.) Gruyter, Aveskamp & Verkley, Plen. pimpinellae (Lowen & Sivan.) Gruyter, Aveskamp & Verkley, Plen. tracheiphilus (Petri) Gruyter, Aveskamp & Verkley, Plen. visci (Moesz) Gruyter, Aveskamp & Verkley, Pleospora fallens (Sacc.) Gruyter & Verkley, Pleo. flavigena (Constantinou & Aa) Gruyter & Verkley, Pleo. incompta (Sacc. & Martelli) Gruyter & Verkley, Pyrenochaetopsis pratorum (P.R. Johnst. & Boerema) Gruyter, Aveskamp & Verkley, Subplenodomus apiicola (Kleb.) Gruyter, Aveskamp & Verkley, Subplen. drobnjacensis (Bubák) Gruyter, Aveskamp & Verkley, Subplen. valerianae (Henn.) Gruyter, Aveskamp & Verkley, Subplen. violicola (P. Syd.) Gruyter, Aveskamp & Verkley, Westerdykella capitulum (V.H. Pawar, P.N. Mathur & Thirum.) de Gruyter, Aveskamp & Verkley, W. minutispora (P.N. Mathur ex Gruyter & Noordel.) Gruyter, Aveskamp & Verkley. New names: Pleospora angustis Gruyter & Verkley, Pleospora halimiones Gruyter & Verkley.

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Quorum sensing is a system of stimuli and responses in relation to bacterial cell population density that regulates gene expression, including virulence determinants. Consequently, quorum sensing has been an attractive target for the development of novel anti-infective measures that do not rely on the use of antibiotics. Anti-quorum sensing has been a promising strategy to combat bacterial infections as it is unlikely to develop multidrug resistant pathogens since it does not impose any selection pressure. A number of anti-quorum sensing approaches have been documented and plant-based natural products have been extensively studied in this context. Plant matter is one of the major sources of chemicals in use today in various industries, ranging from the pharmaceutical, cosmetic, and food biotechnology to the textile industries. Just like animals and humans, plants are constantly exposed to bacterial infections, it is therefore logical to expect that plants have developed sophisticated of chemical mechanisms to combat pathogens. In this review, we have surveyed the various types of plant-based natural products that exhibit anti-quorum sensing properties and their anti-quorum sensing mechanisms.

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Aim of study One-third of botanical remedies from southern Italy are used to treat skin and soft tissue infection (SSTI). Staphylococcus aureus, a common cause of SSTI, has generated increasing concern due to drug resistance. Many plants possess antimicrobial agents and provide effective remedies for SSTI. Our aim was to investigate plants from different ethnobotanical usage groups for inhibition of growth and biofilms in methicillin-resistant Staphylococcus aureus (MRSA). Materials and methods Three groups were assessed: plant remedies for SSTI, plant remedies not involving the skin, and plants with no ethnomedical application. We screened 168 extracts, representing 104 botanical species, for activity against MRSA (ATCC 33593). We employed broth dilution methods to determine the MIC after 18 h growth using an optical density (OD 600 nm) reading. Anti-biofilm effects were assessed by growing biofilms for 40 h, then fixing and staining with crystal violet. After washing, 10% Tween 80 was added and OD 570 nm readings were taken. Results Extracts from 10 plants exhibited an IC50 Conclusion This study has demonstrated that the anti-biofilm activity of medicinal plants used for SSTI is significantly greater than plants without any ethnomedical applications.

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An ethnopharmacobotanical survey of the medicinal plants and food medicines of the northern part of Lucca Province, north-west Tuscany, central Italy, was carried out. The geographical isolation of this area has permitted the survival of a rich folk phytotherapy involving medicinal herbs and also vegetable resources used by locals as food medicine. Among these are the uncommon use of Ballota nigra leaves as a trophic protective; the use of Lilium candidum bulbs as an antiviral to treat shingles (Herpes zoster); Parmelia sp. as a cholagogue; Crocus napolitanus flowers as antiseptic; Prunus laurocerasus drupes as a hypotensive; and the consumption of chestnut flour polenta cooked with new wine as bechic. Many wild gathered greens are eaten raw in salads, or in boiled mixtures, as 'blood cleansing' and 'intestine cleansing' agents. Of particular interest is the persistence of the archaic use of Bryonia dioica root against sciatica, and the use of ritual plant therapeuticals as good omens, or against the 'evil eye.' Over 120 species represent the heritage of the local folk pharmacopoeia in upper Garfagnana. Anthropological and ethnopharmacological considerations of the collected data are also discussed.

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