Evaluation of the anti-Fusarium oxysporum f. sp cicer and anti-Alternaria porri effects of some essential oils

Antileishmanial and Antifungal Activities of Volatile Oils from Cinnamomum Cassia Bark and Schinus Molle Leaves

This study reports on the chemical composition and antileishmanial and anticandidal activities of volatile oils (VOs) of Schinus molle dried leaves (SM), Cinnamomum cassia branch bark (CC) and their blends. Major constituents of SM were spathulenol (26.93 %), β-caryophyllene (19.90 %), and caryophyllene oxide (12.69 %), whereas (E)-cinnamaldehyde (60.11 %), cinnamyl acetate (20.90 %) and cis-2-methoxycinnamic acid (10.37 %) were predominant in CC. SM (IC50=21.45 μg/mL) and CC (IC50=23.27 μg/mL) displayed good activity against L. amazonensis promastigotes, besides having good or moderate activity against nine Candida strains, with Minimum Inhibitory Concentration (MIC) values ranging from 31.25 to 250 μg/mL. While the three SM and CC blends were not more active than the VOs tested individually, they exhibited remarkably high antileishmanial activity, with IC50 values ranging between 3.12 and 7.04 μg/mL, which is very similar to the IC50 of amphotericin B (positive control).

Chemical Composition, Antioxidant and Antimicrobial Effects of Essential Oils Extracted from Two New Ocimum basilicum L. Varieties

Recent agricultural research aims to identify novel applications for plant extracts as efficient defenses against weeds, insects, or phytopathogenic agents. The main goal of the present study was to evaluate two new varieties of basil (Ocimum basilicum L., fam. Lamiaceae), Yellow basil, “Aromat de Buzau” variety and Red-violet basil, “Serafim” variety. The basil varieties were studied under different aspects regarding biochemical characterization using GC-MS, antioxidant activity evaluated under three methods (DPPH, ABTS, FRAP), and antimicrobial properties (for three G-bacteria: Perctobacterium carotovorum, Pseudomonas marginalis, Pseudomonas syringae and three phytopathogenic fungi: Rhizoctonia solani, Fusarium oxysporum, Botrytis cinerea). The results showed that linalool (39.28%; 55.51%), estragole (31.48%; 9.78%), and eugenol (5.42%; 7.63%) are the main compounds identified in the extracts, validating the high antioxidant activity of the studied essential oils and floral waters. When applied in high concentrations, essential oils have shown a potential bactericidal effect on P. carotovorum as well as a potential fungicidal effect on R. solani and B. cinerea.

Sage Species Case Study on a Spontaneous Mediterranean Plant to Control Phytopathogenic Fungi and Bacteria

Sage species belong to the family of Labiatae/Lamiaceae and are diffused worldwide. More than 900 species of sage have been identified, and many of them are used for different purposes, i.e., culinary uses, traditional medicines and natural remedies and cosmetic applications. Another use of sage is the application of non-distilled sage extracts and essential oils to control phytopathogenic bacteria and fungi, for a sustainable, environmentally friendly agriculture. Biocidal propriety of non-distilled extracts and essential oils of sage are w documented. Antimicrobial effects of these sage extracts/essential oils depend on both sage species and bacteria and fungi species to control. In general, it is possible to choose some specific extracts/essential oils to control specific phytopathogenic bacteria or fungi. In this context, the use of nanotechnology techniques applied to essential oil from salvia could represent a future direction for improving the performance of eco-compatible and sustainable plant defence and represents a great challenge for the future.

Essential Oil of Achillea ligustica (Asteraceae) as an Antifungal Agent against Phytopathogenic Fungi

The essential oil from the inflorescences of Ligurian yarrow ( Achillea ligustica All., Asteraceae) naturalized in Central Italy was investigated in order to evaluate the antifungal activity against five phytopathogenic fungi. The composition of the essential oil characterized by GC-FID and GC-MS, revealed linalool (24.8%), viridiflorol (9.6%), β-pinene (6.4%), 1,8-cineole (5.8%) and terpinen-4-ol (5.3%) as the major constituents. The antifungal activity was evaluated by the in vitro disc agar diffusion test and Agar vapor assay on 5 microbial strains. The essential oil showed a good antifungal activity against all fungal strains, being a valid candidate in the fight against plant pathogens that harm many traditional crops. The possible incorporation of this essential oil into antifungal preparations with a low environmental impact is hypothesized.

Antifungal activities of selected essential oils against Fusarium oxysporum f. sp. lycopersici 1322, with emphasis on Syzygium aromaticum essential oil

The antifungal effects of four essential oils viz., clove (Syzygium aromaticum), lemongrass (Cymbopogon citratus), mint (Mentha × piperita) and eucalyptus (Eucalyptus globulus) were evaluated against wilt causing fungus, Fusarium oxysporum f. sp. lycopersici 1322. The inhibitory effect of oils showed dose-dependent activity on the tested fungus. Most active being the clove oil, exhibiting complete inhibition of mycelial growth and spore germination at 125 ppm with IC₅₀ value of 18.2 and 0.3 ppm, respectively. Essential oils of lemongrass, mint and eucalyptus were inhibitory at relatively higher concentrations. The Minimum inhibitory concentration (MIC) of clove oil was 31.25 ppm by broth microdilution method. Thirty one different compounds of clove oil, constituting approximately ≥99% of the oil, were identified by gas chromatography-mass spectroscopy analysis. The major components were eugenol (75.41%), E-caryophyllene (15.11%), α-humulene (3.78%) and caryophyllene oxide (1.13%). Effect of clove oil on surface morphology of F. oxysporum f. sp. lycopersici 1322 was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM observation revealed shrivelled hyphae while AFM observation showed shrunken and disrupted spores in clove oil treated samples. In pots, 5% aqueous emulsion of clove oil controlled F. oxysporum f. sp. lycopersici 1322 infection on tomato plants. This study demonstrated clove oil as potent antifungal agent that could be used as biofungicide for the control of F. oxysporum f. sp. lycopersici in both preventive and therapeutic manner.

Identification of geranic acid, a tyrosinase inhibitor in lemongrass (Cymbopogon citratus)

Lemongrass is a popular Asian herb having a lemon-like flavor. Very recently, potent tyrosinase inhibitory activity has been found in lemongrass in addition to various biological activities reported in the literature. The aim of the present study is to identify the active compounds in the lemongrass. An assay-guided purification revealed that one of the active substances was geranic acid. Geranic acid has two stereoisomers, which are responsible for the trans and cis geometry on the conjugated double bond. Both isomers are present in the active ethyl acetate-soluble extract of the lemongrass, and their IC50 values were calculated to be 0.14 and 2.3 mM, respectively. The structure requirement of geranic acid for the potent tyrosinase inhibitory activity was investigated using geranic acid-related compounds.