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A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL−1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy. [ABSTRACT FROM AUTHOR]

There is extensive ethnobotanical information on Ocimum campechianum as it is widely used by the natives of Central and South America and the Amazon. Although many of its traditional uses have been confirmed, studies are still scarce and scattered. Therefore, the main focus of this review is to provide a comprehensive and critical analysis of the state of the art about ethnobotanical, phytochemical, pharmacological, and toxicological knowledge of O. campechianum. This overview offers a starting point for further studies of possible health applications that meet modern needs for human well-being. Future challenges should be focused on research based on new approaches for the understanding of its global benefits. It is suggested to promote studies on multiple herbal remedies, and the antiproliferative and cytotoxic activities of the compounds, as well as new strategies that relate phytochemistry with bioactivity, toxicological evaluations on acute and long-term toxicity, mechanisms of action, pharmacodynamic, and pharmacokinetic studies. Finally, a focus on the possible application of O. campechianum as a biopesticide for the sustainable protection crop of crops and suggests the need to explore new uses of its essential oil for the treatment of foodborne pathogens. [ABSTRACT FROM AUTHOR]

Alpha-phellandrene is a very common cyclic monoterpene found in several EOs, which shows extensive biological activities. Therefore, the main focus of the present systematic review was to provide a comprehensive and critical analysis of the state of the art regarding its biological activities and pharmaceutical and food applications. In addition, the study identified essential oils rich in alpha-phellandrene and summarized their main biological activities as a preliminary screening to encourage subsequent studies on their single components. With this review, we selected and critically analyzed 99 papers, using the following bibliographic databases: PubMed, SciELO, Wiley and WOS, on 8 July 2022. Data were independently extracted by four authors of this work, selecting those studies which reported the keyword "alpha-phellandrene" in the title and/or the abstract, and avoiding those in which there was not a clear correlation between the molecule and its biological activities and/or a specific concentration from its source. Duplication data were removed in the final article. Many essential oils have significant amounts of alpha-phellandrene, and the species Anethum graveolens and Foeniculum vulgare are frequently cited. Some studies on the above-mentioned species show high alpha-phellandrene amounts up to 82.1%. There were 12 studies on alpha-phellandrene as a pure molecule showed promising biological functions, including antitumoral, antinociceptive, larvicidal and insecticidal activities. There were 87 research works on EOs rich in alpha-phellandrene, which were summarized with a focus on additional data concerning potential biological activities. We believe this data is a useful starting point to start new research on the pure molecule, and, in particular, to distinguish between the synergistic effects of the different components of the OEs and those due to alpha-phellandrene itself. Toxicological data are still lacking, requiring further investigation on the threshold values to distinguish the boundary between beneficial and toxic effects, i.e., mutagenic, carcinogenic and allergenic. All these findings offer inspiration for potential applications of alpha-phellandrene as a new biopesticide, antimicrobial and antitumoral agent. In particular, we believe our work is of interest as a starting point for further studies on the food application of alpha-phellandrene. [ABSTRACT FROM AUTHOR]

This study is extended in many years, from 2010 in which is investigated the herbal drug biological activity. The evolution of antibiotic-resistant bacteria has been developed very rapidly lately over the world. In this point, there is an urgent need to develop alternative strategies to address this issue. Herbal drugs are a very promising group since they are used since ancients time for their antimicrobial, antifungal and antinflammatory properties. The essential oils obtained from medicinal and aromatic plants by Albanian origin, such as Satureja montana, Thymus vulgaris, Origanum vulgare, Myrtus communis, Rosmarinus officinalis, Thymus capitatus and Salvia officinalis are studied for antibacterial and antifungal properties in this study. Essential oils are obtained by hydrodistillation in a Clevenger type apparatus and the chemical composition of isolated essential oils is determined by gas GC/MS and GC/FID methods. Complexes of β-cyclodextrine and essential oils are prepared by cold co-precipitation method with the four ratios oil: β-cyclodextrine as follows 5:95, 10:90, 15:85 and 20:80 (w/w) in order to determine the effect of the ratio on the inclusion efficiency of β-cyclodextrin for encapsulating oil. On the other hand, current topical applications of these volatile compounds turn out to be complicated because of their problems of stability, evaporation and controlled release, which are major problems for their therapeutic uses; Therefore, is studied their microencapsulation in polymers such as β-cyclodextrine which could be the solution to their chemical and physical problems. The essential oils were tested for antimicrobial and antifungal activity before and after microencapsulation. The antimicrobial test is done by the disc diffusion method using suspension of P. vulgaris, E. coli, S. aureus, C. albicans and dermatophytes such as M. gypseum, M. canis, A. cajetani, T. violaceum, T. mentagrophytes, E. floccosum, T. rubrum, T. tonsurans, B. cinerea and P. oryzae. Positive controls of antibiotics and antifungals were used for comparison. Essential oils showed high inhibition zones against selected bacterias, and encapsulated ones were found to be more efficient. In conclusion these essential oils can be applied in many formulations due to their low risk of skin sensitizing and high antibacterial and antifungal activity they demonstrated before and after encapsulation. Further investigation is going on with systemic formulation with complexed essential oils which can be a very useful solution in many patient. [ABSTRACT FROM AUTHOR]

A comprehensive study on essential oil samples extracted from Ridolfia segetum Moris (Apiaceae) collected in Tarquinia (Italy) is reported. In this study, a 30-hour, fractionated, steam distillation procedure for essential oil preparation was applied. The gas chromatographic-mass spectrometry analysis showed monoterpene o-cymene and phenylpropanoid dill-apiol as the major essential oil's constituents revealing a new chemotype dependent on extraction duration. Great impact of the duration of the distillation process on chemical profile of essential oil was observed; prolonged distillation gives chemically more diverse essential oil samples. Preliminary microbiological evaluations of the essential oils samples revealed some activity, although not high, against Candida albicans. [ABSTRACT FROM AUTHOR]

A comprehensive study on essential oil samples of Foeniculum vulgare Miller from Tarquinia (Italy) is reported. A 24-h systematic steam distillation was performed on different harvested samples applying different extraction times. The GC-MS analysis of the residue outcome showed o-cymene, α-phellandrene, α-pinene and estragole as the major constituents. The predominance and continued presence of o-cymene makes this fennel oil a rather unique chemotype. An evident correlation between the antifungal activity and phenological stage is demonstrated. The most active fractions were particularly rich in estragole, as well as a significant amount of fenchone that possibly exerts some additive effect in the expression of overall antifungal potency. Pre-fruiting material produced oil particularly rich in o-cymene. With reference to the duration of the extraction, the maximum amount of oil was released within the first 3 h, whereas the reproductive phase material needed at least 6 h for the extraction. [ABSTRACT FROM AUTHOR]

A study on essential oil fractions of the Western Balkan endemic Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood collected in Montenegro is reported. The 24-h systematic steam distillation extraction procedure was performed. The gas chromatographic/mass spectrometric (GC/MS) analysis of the fractions showed γ-elemene and spathulenol as two main constituents, revealing a new chemotype of this plant species. Although varying in the content of these two main compounds, which makes the fractions quite different between each other, evaluation of the anti-Candida activity showed the lack of any significant efficacy. [ABSTRACT FROM AUTHOR]

A comprehensive study on essential oils extracted from different Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) Ball samples from Tarquinia (Italy) is reported. In this study, the 24-h steam distillation procedure for essential oil preparation, in terms of different harvesting and extraction times, was applied. The Gas chromatography-mass spectrometry (GC/MS) analysis showed that C. nepeta (L.) Savi subsp. glandulosa (Req.) Ball essential oils from Tarquinia belong to the pulegone-rich chemotype. The analysis of 44 samples revealed that along with pulegone, some other chemicals may participate in exerting the related antifungal activity. The results indicated that for higher activity, the essential oils should be produced with at least a 6-h steam distillation process. Even though it is not so dependent on the period of harvesting, it could be recommended not to harvest the plant in the fruiting stage, since no significant antifungal effect was shown. The maximum essential oil yield was obtained in August, with the highest pulegone percentage. To obtain the oil with a higher content of menthone, September and October should be considered as the optimal periods. Regarding the extraction duration, vegetative stage material gives the oil in the first 3 h, while material from the reproductive phase should be extracted at least at 6 or even 12 h. [ABSTRACT FROM AUTHOR]

Scientific investigation on essential oils composition and the related biological profile are continuously growing. Nevertheless, only a few studies have been performed on the relationships between chemical composition and biological data. Herein, the investigation of 61 assayed essential oils is reported focusing on their inhibition activity against Microsporum spp. including development of machine learning models with the aim of highlining the possible chemical components mainly related to the inhibitory potency. The application of machine learning and deep learning techniques for predictive and descriptive purposes have been applied successfully to many fields. Quantitative composition–activity relationships machine learning-based models were developed for the 61 essential oils tested as Microsporum spp. growth modulators. The models were built with in-house python scripts implementing data augmentation with the purpose of having a smoother flow between essential oils' chemical compositions and biological data. High statistical coefficient values (Accuracy, Matthews correlation coefficient and F1 score) were obtained and model inspection permitted to detect possible specific roles related to some components of essential oils' constituents. Robust machine learning models are far more useful tools to reveal data augmentation in comparison with raw data derived models. To the best of the authors knowledge this is the first report using data augmentation to highlight the role of complex mixture components, in particular a first application of these data will be for the development of ingredients in the dermo-cosmetic field investigating microbial species considering the urge for the use of natural preserving and acting antimicrobial agents. [ABSTRACT FROM AUTHOR]

The chemical composition and biological activity of essential oils isolated from the leaves of Siparuna aspera, Siparuna macrotepala, Piper leticianum, Piper augustum and the rhizome of Hedychium coronarium were evaluated. These species are used medicinally in different ways by the Amazonian communities that live near the Kutukú mountain range. Chemical studies revealed that the main components for the two Siparuna species were germacrene D, bicyclogermacrene, α-pinene, δ-cadinene, δ-elemene, α-copaene and β-caryophyllene; for the two Piper species β-caryophyllene, germacrene D, α-(E,E)-farnesene, β-elemene, bicyclogermacrene, δ-cadinene and for H. coronarium 1,8-cineole, β-pinene, α-pinene and α-terpineol. The antioxidant activity of all essential oils was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), photochemiluminescence (PCL) quantitative assays, and DPPH and ABTS bioautographic profiles, with different results for each of them. Antimicrobial activity studies were carried out on three yeasts, six Gram positive and four Gram negative bacteria, by means of the disc diffusion method. The essential oil of H. coronarium showed the most relevant results on L. grayi, K. oxytoca and S. mutans, P. augustum and P. leticianum on S. mutans. An antibacterial bioautographic test for H. coronarium was also carried out and highlighted the potential activity of terpinen-4-ol and 1,8-cineole. [ABSTRACT FROM AUTHOR]

Biofilm resistance to antimicrobials is a complex phenomenon, driven not only by genetic mutation induced resistance, but also by means of increased microbial cell density that supports horizontal gene transfer across cells. The prevention of biofilm formation and the treatment of existing biofilms is currently a difficult challenge; therefore, the discovery of new multi-targeted or combinatorial therapies is growing. The development of anti-biofilm agents is considered of major interest and represents a key strategy as non-biocidal molecules are highly valuable to avoid the rapid appearance of escape mutants. Among bacteria, staphylococci are predominant causes of biofilm-associated infections. Staphylococci, especially Staphylococcus aureus (S. aureus) is an extraordinarily versatile pathogen that can survive in hostile environmental conditions, colonize mucous membranes and skin, and can cause severe, non-purulent, toxin-mediated diseases or invasive pyogenic infections in humans. Staphylococcus epidermidis (S. epidermidis) has also emerged as an important opportunistic pathogen in infections associated with medical devices (such as urinary and intravascular catheters, orthopaedic implants, etc.), causing approximately from 30% to 43% of joint prosthesis infections. The scientific community is continuously looking for new agents endowed of anti-biofilm capabilities to fight S. aureus and S epidermidis infections. Interestingly, several reports indicated in vitro efficacy of non-biocidal essential oils (EOs) as promising treatment to reduce bacterial biofilm production and prevent the inducing of drug resistance. In this report were analyzed 89 EOs with the objective of investigating their ability to modulate bacterial biofilm production of different S. aureus and S. epidermidis strains. Results showed the assayed EOs to modulated the biofilm production with unpredictable results for each strain. In particular, many EOs acted mainly as biofilm inhibitors in the case of S. epidermidis strains, while for S. aureus strains, EOs induced either no effect or stimulate biofilm production. In order to elucidate the obtained experimental results, machine learning (ML) algorithms were applied to the EOs' chemical compositions and the determined associated anti-biofilm potencies. Statistically robust ML models were developed, and their analysis in term of feature importance and partial dependence plots led to indicating those chemical components mainly responsible for biofilm production, inhibition or stimulation for each studied strain, respectively. [ABSTRACT FROM AUTHOR]

A comprehensive study on essential oils extracted from different samples of Melissa officinalis L. subsp. altissima (Sibth. & Sm.) Arcang. (Lamiaceae) collected in Tarquinia (Italy) is reported. In this study, the 24-h steam distillation procedure for essential oil preparation, in terms of different harvesting periods and extraction times was applied. The GC/MS analysis showed cis -caryophyllene and its oxide as the major essential oil’s constituents. A great impact of phenological stage on chemical profile of essential oil was observed. Regarding the duration of the extraction process, prolonged distillation led to chemically more diverse oil samples. Preliminary microbiological evaluations of the essential oils samples revealed the lack of significant efficacy against Candida albicans . [ABSTRACT FROM AUTHOR]