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In recent years, there has been great development in the search for new natural compounds for food preservation aimed at a partial or total replacement of currently popular antimicrobial chemicals. Carob (Ceratonia siliqua) offers a natural promising alternative for food safety and bioconservation. In this work, the methanolic extract of carob leaves (MECL) was tested for the ability to inhibit the growth of a range of microorganisms. MECL inhibited the growth of Listeria monocytogenes at 28.12 μg/mL by the broth microdilution method. The effect of this bacteriostatic concentration on the growth of this bacterium revealed a pattern of inhibition characterized by (a) a resumed growth phase, which showed a lower rate of growth if compared with controls; and (b) first a lag and then a stationary phase at a lower bacterium concentration. The study of the chemical composition of MECL by high-performance liquid chromatography and liquid chromatography/mass spectrometry showed the presence of gallic acid, (-)-epigallocatechin-3-gallate, myricitrin, isoquercitin, catechin, chlorogenic acid, and malic acid. L. monocytogenes growth inhibition was recorded for myricitrin and gallic acid at 450 μg/mL and for (-)-epigallocatechin-3-gallate and isoquercitin, respectively, at 225 and 112.5 μg/mL. Taking into account that proline is a ligand of proline dehydrogenase (PDH), the use of this compound leads us to hypothesize the mode of action of MECL constituents.

Pome trees, apple, pear, and quince, are classified into the subfamily Pomoideae, belonging to the Rosaceae family. Their autumnal fruits are consumed worldwide in different forms, that is, fresh or transformed into jams, jelly, juices, etc. Their well-established beneficial properties to human health were found mainly related to their phenolic content. Pulp and peel aqueous acetone extracts obtained from Tunisian fruits at commercial maturity were comparatively evaluated for their phenolic profiles and antioxidant and antimicrobial potentials. The phenolic compounds present in the extracts were identified and quantified using RP-HPLC-DAD and ESI-MS techniques. Significant differences in the chromatographic profiles among these fruits, as well as between pulp and peel extracts of each fruit, were observed. Quince, followed by 'Red Delicious', peel extracts showed the highest phenolic content (160.33 and 110.90 mg/100 g of fresh weight). The stronger inhibitory effect on DPPH radicals corresponded to those obtained from peel materials. A comparative analysis of the antimicrobial potential against a range of microorganism strains was also carried out. Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus were the most sensitive to the active extracts. Among the examined phenolic extracts, 'Red Delicious' and quince peels showed the highest effects for inhibiting bacteria growth. Minimum inhibitory and bactericide concentrations ranged from 10(2) to 10(4) microg of polyphenol/mL. Red skin apple and quince peels could be of great interest as important antioxidant and antimicrobial polyphenol sources.

Essential oils from the stems/leaves (L) and flowers (F) of Lavandula stoechas L. ssp. stoechas growing wild in southern Sardinia (Italy) were extracted by hydrodistillation and analyzed by gas chromatography coupled with flame ionization detector and ion trap mass spectrometry. The major compound was fenchone, accounting for, on average, 52.60% in L and 66.20% in F, followed by camphor (13.13% versus 27.08%, in L and F, respectively). F essential oil yields (volume per dry weight) decreased from the beginning to the end of the flowering stage, whereas L yields remained constant during the year. The nine main compounds derived from two different subpathways, A and B. The compounds that belong to the same subpathway showed a similar behavior during the year. The essential oils were tested for their antifungal activity using the paper disk diffusion method. The essential oils tested were effective on the inactivation of Rhizoctonia solani and Fusarium oxysporum and less effective against Aspergillus flavus. Among the single compounds tested, fenchone, limonene, and myrtenal appeared to be the more effective on the inhibition of R. solani growth.

The chemical composition of the essential oil from flowering tops of Achillea ligustica All. was studied. Samples were collected in different localities of Sardinia (Italy) and hydrodistilled both with Clevenger-type and with simultaneous distillation-extraction apparatus. The yields ranged between 0.88 +/- 0.06 and 0.43 +/- 0.02% (vol/dry wt). The essential oils were analyzed by GC-MS, and a total of 96 components were detected. From a qualitative point of view, irrelevant differences between samples were observed. Strong chemical variability depending on the origin of the samples was observed. The major compounds found were santolina alcohol (6.7-21.8%, for the first time detected in A. ligustica), borneol (3.4-20.8%), sabinol (2.1-15.5%), trans-sabinyl acetate (0.9-17.6%), alpha-thujone (0.4-25.8%), and, among sesquiterpenes, viridiflorol (0.7-3.6%). No significant differences were detected between essential oils extracted by hydrodistillation and simultaneous distillation-extraction with CH2Cl2 and n-hexane. Antioxidant activity as DPPH radical scavenging activity was expressed in TEAC and ranged between 0.40 and 0.88 mmol/L. The antimicrobial and antifungal activities were investigated on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Penicillium commune, Fusarium oxysporum, Rizoctonia solani, and Aspergillus flavus, showing low activity.

The composition of the essential oil from ripe and unripe berries and leaves of Juniperus oxycedrus L. ssp. oxycedrus, Juniperus phoenicea ssp. turbinata and Juniperus communis ssp. communis was analyzed by GC-MS, and microbiological assays were carried out. Samples were collected in different localities (Sardinia, Italy) and hydro distilled. The yields ranged between 2.54% +/- 0.21 (v\w dried weight) and 0.04% +/- 0.00. A total of 36 components were identified. The major compounds in the essential oils were alpha-pinene, beta-pinene, delta-3-carene, sabinene, myrcene, beta-phellandrene, limonene, and D-germacrene. Both qualitative and quantitative differences between species and between different parts of the plant were observed. The essential oils and their major compounds were tested against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the minimum inhibitory concentration and minimum bactericidal concentration were determined. The results obtained led to a nonsignificant inhibitory effect, although all the essential oils from Juniperus phoenicea ssp. turbinata and the essential oil from leaves of Juniperus oxycedrus ssp. oxycedrus exhibited rather good or weak activity against Candida albicans and Staphylococcus aureus.