Chemical Composition and Antioxidant Capacities of Four Mediterranean Industrial Essential Oils and Their Resultant Distilled Solid By‐Products

Biological Activity of Extracts from Aromatic Plants as Control Agents against Spoilage Molds Isolated from Sheep Cheese

The aim of this work was to assess the antifungal and antioxidant activity of essential oils and ethanolic extracts from distilled solid by-products from aromatic plants (Artemisia dracunculus, Hyssopus officinalis, Lavandula stoechas, Origanum vulgare and Satureja montana) against 14 fungi strains isolated from sheep cheese and identified at species level using DNA barcoding based on β-tubulin sequence analysis. In addition, capacity of fungi to produce ochratoxin A, patulin, cyclopiazonic acid and sterigmatocystin was analyzed. Of the isolates, 85.7% belonged to Penicillium (P. commune/biforme, P. crustosum) and 14.3% to Aspergillus (A. puulaauensis and A. jensenii), the first time that these Aspergillus species have been found in sheep's cheese. All P. commune isolates were producers of cyclopiazonic acid, and the two Aspergillus strains produced sterigmatocystin, but the others did not produce any tested mycotoxin. Among the essential oils tested, oregano, savory and tarragon had a significant antifungal activity against all the isolated strains, but no ethanolic extract showed antifungal activity. By contrast, ethanolic extracts showed great potential as antioxidants. The identification of new molds in cheese will help the dairy industry to know more about those molds affecting the sector, and the use of aromatic plants in the control of fungal spoilage could be a suitable alternative to chemical preservatives used in the agri-food industry.

Valorization of Java citronella (Cymbopogon winterianus Jowitt) distillation waste as a potential source of phenolics/antioxidant: influence of extraction solvents

Solid residues obtained after essential oil extraction from Cymbopogon winterianus Jowitt (Java citronella) was explored as a potential source of phenolics/antioxidant. Both the non-distilled plant materials and their solid residues were extracted with Soxhlet extraction method using solvents of various polarity viz. petroleum ether, chloroform, ethyl acetate, acetone, ethanol, methanol, water and various combination of (50% and 75%) of methanol, ethanol, and acetone in water. Different antioxidant assays like 2,2-diphenyl-1- picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), superoxide anion (SO) radical scavenging assay, ferric-reducing antioxidant power (FRAP) and iron chelating ability along with total phenol (TPC) and flavonoid content (TFC) was measured to evaluate the extract. Compared to distilled materials, the non-distilled plant materials had significantly higher TPC/TFC content and also exhibited higher antioxidant activities. 50% aqueous methanol showed the highest extractive yield, whereas 75% aqueous methanol exhibited the highest TPC and TFC content. The 50% or 75% aqueous methanolic extract also exhibited the highest DPPH, ABTS and SO scavenging activity and ferric-reducing antioxidant power activity. However, ethyl acetate and 75% aqueous acetone extract of non-distilled and distilled plant materials, respectively showed the highest iron chelating activity. The half maximal effective concentration (IC₅₀ = µg/mL) for DPPH, ABTS, SO and metal chelating ability in non-distilled plant extract ranged from 64-387, 92-761, 285-870, and 164-924, respectively, and corresponding value of distilled materials ranged from 144-865, 239-792, 361-833 and 374-867, respectively. The EC₅₀ (µg/mL) for FRAP assay ranged from 118-840 and 151-952 for non-distilled and distilled materials, respectively. The findings of this study indicate the potential of these by-products as a natural antioxidants source.

Plant Secondary Metabolites: An Opportunity for Circular Economy

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement "greener" practices in the latter sector.

Reconsidering Hydrosols as Main Products of Aromatic Plants Manufactory: The Lavandin (Lavandula intermedia) Case Study in Tuscany

: The present work evaluates for the first time two Lavandin (Lavandula × intermedia Emeric ex Loisel.) aromatic waters obtained from different plant organs, the flowers and the stems. Both extracts were analysed by GC-MS, which indicates semi-quantitative differences between the major metabolites including linalool, 1,8-cineole, camphor, linalyl acetate and 4-terpineol. ¹H-NMR and LC-MS investigation confirmed the presence of these compounds. Moreover, behavioural tests with the food insect pest Tribolium confusum (Coleoptera Tenebrionidae) showed a good repellency for both hydrosols extracts with RD₅₀ values of 3.6 and 3.3 µL cm^-2 for the flowers and stems, respectively; at the higher concentrations, however, the hydrosol extract from the flowers is expected to be more effective than the one from the stems. The effect of the flowers and stems aromatic water of Lavandin on seed germination of Raphanus sativus was also evaluated. Results showed that seed germination was completely inhibited by flowers hydrolate, having a possible application as natural herbicide. The overall experience with these Lavandin extracts indicates the potential of improved hydrolates to become the main distillation products, rather than by-products, of the aromatic plants manufacturing; this stimulates further discussions about the potential positive impacts that such a shift could have in the context of ecopharmacognosy.