Antioxidant Activity, Inhibition of Intestinal Cancer Cell Growth and Polyphenolic Compounds of the Seagrass Posidonia oceanica's Extracts from Living Plants and Beach Casts.

The aim of the present study was to investigate the use of Posidonia oceanica for making products beneficial for human health. Firstly, we demonstrated that the antioxidant defense (i.e., SOD and APX activity) of P. oceanica's living leaves (LP) has low efficacy, as they partly neutralize the produced H2O2. However, high H2O2 levels led LP to produce, as a response to oxidative stress, high phenolic content, including chicoric acid, p-coumaric acid, caftaric acid, trans-cinnamic and rutin hydrate, as shown by UHPLC-DAD analysis. In addition, LP extracts inhibited intestinal cancer cell proliferation. Moreover, P. oceanica's beach casts consisting of either Wet 'Necromass' (WNP) or Dry 'Necromass' (DNP) were used for preparing extracts. Both DNP and WNP exhibited antioxidant and antiproliferative activities, although lower as compared to those of LP extracts. Although both P. oceanica's meadows and beach casts are considered priority habitats in the Mediterranean Sea due to their high ecological value, legislation framework for beach casts forbidding their removal is still missing. Our results suggested that both LP and DNP could be utilized for the production of high-added value products promoting human health, provided that a sustainability management strategy would be applied for P. oceanica's meadows and beach casts.

Effects of fungal endophytes and arbuscular mycorrhizal fungi on growth of Echium vulgare and alkannin/shikonin and their derivatives production in roots.

Endophytic fungi as well as arbuscular mycorrhizal fungi (AMF) are known to stimulate plant growth and production of secondary metabolites in medicinal plants. Here, 10 endophytic fungi isolated from roots of wild Alkanna tinctoria plants and 5 AMF purchased from the Glomeromycota in vitro collection were evaluated, during two successive three-month greenhouse experiments, on the growth of Echium vulgare and alkannin/shikonin and their derivatives (A/Sd) production in the roots. Some of the endophytic fungi tested significantly increased plant growth parameters as compared to the control: Cladosporium allicinum, Cadophora sp., Clonostachys sp., Trichoderma hispanicum and Leptosphaeria ladina increased root volume, Plectosphaerella sp. And T. hispanicum root fresh weight and root water retention and T. hispanicum plant water retention. However, none of these fungi impacted A/Sd production. Conversely, none of the AMF strains tested impacted plant growth parameters, but those inoculated with Rhizophagus intraradices MUCL 49410 had a significantly higher concentration of alkannin/shikonin (A/S), acetyl-A/S, ß,ß- dimethylacryl-A/S, isovaleryl-A/S and total A/Sd, compared to the control plants. Further studies are needed to investigate the mechanisms involved in the production of A/Sd in plants associated to specific endophytic fungi/AMF and on the cultivation conditions required for optimal production of these compounds.

The Role of Cone Beam Computed Tomography in Periodontology: From 3D Models of Periodontal Defects to 3D-Printed Scaffolds.

The treatment of osseous defects around teeth is a fundamental concern within the field of periodontology. Over the years, the method of grafting has been employed to treat bone defects, underscoring the necessity for custom-designed scaffolds that precisely match the anatomical intricacies of the bone cavity to be filled, preventing the formation of gaps that could allow the regeneration of soft tissues. In order to create such a patient-specific scaffold (bone graft), it is imperative to have a highly detailed 3D representation of the bone defect, so that the resulting scaffold aligns with the ideal anatomical characteristics of the bone defect. In this context, this article implements a workflow for designing 3D models out of patient-specific tissue defects, fabricated as scaffolds with 3D-printing technology and bioabsorbable materials, for the personalized treatment of periodontitis. The workflow is based on 3D modeling of the hard tissues around the periodontal defect (alveolar bone and teeth), scanned from patients with periodontitis. Specifically, cone beam computed tomography (CBCT) data were acquired from patients and were used for the reconstruction of the 3D model of the periodontal defect. The final step encompasses the 3D printing of these scaffolds, employing Fused Deposition Modeling (FDM) technology and 3D-bioprinting, with the aim of verifying the design accuracy of the developed methodοlogy. Unlike most existing 3D-printed scaffolds reported in the literature, which are either pre-designed or have a standard structure, this method leads to the creation of highly detailed patient-specific grafts. Greater accuracy and resolution in the macroarchitecture of the scaffolds were achieved during FDM printing compared to bioprinting, with the standard FDM printing profile identified as more suitable in terms of both time and precision. It is easy to follow and has been successfully employed to create 3D models of periodontal defects and 3D-printed scaffolds for three cases of patients, proving its applicability and efficiency in designing and fabricating personalized 3D-printed bone grafts using CBCT data.

3D-Printed Antibacterial Scaffolds for the Regeneration of Alveolar Bone in Severe Periodontitis.

Current clinical treatment of periodontitis alleviates periodontal symptoms and helps to keep the disease under control for extended periods. Despite this, a significant destruction of the tooth's underlying bone tissue often takes place progressively. Herein, we present a two-way therapeutic approach for local delivery of antibacterial agents and bone tissue regeneration, incorporating ~1% w/w tetracycline hydrochloride (TCH) into a 3D-printed scaffold composed of poly(ε-caprolactone) (PCL). Samples were assessed for their morphological, physicochemical, pharmacokinetic, and antibacterial properties. Furthermore, osteoprecursor cells (MC3T3-E1) were employed to evaluate the osteoinductive potential of the drug-loaded scaffolds. Cell proliferation, viability, and differentiation were determined on all cell-seeded scaffolds. At the end of the culture, PCL-TCH scaffolds promoted abundant collagen organic matrix, demonstrating augmented alkaline phosphatase (ALP) activity and areas of accumulated mineralised bone tissue, despite their belayed cell proliferation. Based on the observed effectiveness of the PCL-TCH scaffolds to inhibit Staphylococcus aureus, these constructs could serve as an alternative bioactive implant that supports bacterial inhibition and favours a 3D microenvironment for bone tissue regeneration in severe periodontitis.

Occurrence of Luteolin in the Greek Flora, Isolation of Luteolin and Its Action for the Treatment of Periodontal Diseases.

Higher plants possess the ability to synthesize a great number of compounds with many different functions, known as secondary metabolites. Polyphenols, a class of flavonoids, are secondary metabolites that play a crucial role in plant adaptation to both biotic and abiotic environments, including UV radiation, high light intensity, low/high temperatures, and attacks from pathogens, among others. One of the compounds that has received great attention over the last few years is luteolin. The objective of the current paper is to review the extraction and detection methods of luteolin in plants of the Greek flora, as well as their luteolin content. Furthermore, plant species, crop management and environmental factors can affect luteolin content and/or its derivatives. Luteolin exhibits various biological activities, such as cytotoxic, anti-inflammatory, antioxidant and antibacterial ones. As a result, luteolin has been employed as a bioactive molecule in numerous applications within the food industry and the biomedical field. Among the different available options for managing periodontitis, dental care products containing herbal compounds have been in the spotlight owing to the beneficial pharmacological properties of the bioactive ingredients. In this context, luteolin's anti-inflammatory activity has been harnessed to combat periodontal disease and promote the restoration of damaged bone tissue.

Bacterial responses to plant antimicrobials: the case of alkannin and shikonin derivatives.

Alkannin, shikonin and their derivatives (A/S) are secondary metabolites produced in the roots of certain plants of the Boraginaceae family such as Lithospermum erythrorhizon Siebold & Zucc. and Alkanna tinctoria (L.) Tausch. These naphthoquinones express anti-cancer, wound healing, and antimicrobial activities. To study the interactions between endophytic bacteria isolated from A. tinctoria and the antimicrobials A/S, endophytic bacteria known to be resistant to the compounds were screened for their effect on A/S in liquid medium. Thereafter, the strain Pseudomonas sp. R-72008, was selected and tested for its ability to modify A/S in nutrient medium and minimal medium with A/S as sole carbon source. Bacterial growth was recorded, and high performance liquid chromatography-diode array and ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry analyses were performed to detect and quantify metabolites. In nutrient medium inoculated with R-72008, a decrease in the amount of A/S monomers initially present was observed and correlated with an increase of A/S oligomers. Moreover, a significant decrease of initial A/S monomers in minimal medium was correlated with bacterial growth, showing for the first time that a bacterial strain, Pseudomonas sp. R-72008, was able to use the naphthoquinones A/S as sole carbon source. This study opens new perspectives on the interactions between bacteria and plant antimicrobials.

A Review of the Role of Natural Products as Treatment Approaches for Xerostomia.

Xerostomia, commonly known as dry mouth, is a widespread oral health malfunction characterized by decreased salivary flow. This condition results in discomfort, impaired speech and mastication, dysphagia, heightened susceptibility to oral infections, and ultimately, a diminished oral health-related quality of life. The etiology of xerostomia is multifaceted, with primary causes encompassing the use of xerostomic medications, radiation therapy to the head and neck, and systemic diseases such as Sjögren's syndrome. Consequently, there is a growing interest in devising management strategies to address this oral health issue, which presents significant challenges due to the intricate nature of saliva. Historically, natural products have served medicinal purposes, and in contemporary pharmaceutical research and development, they continue to play a crucial role, including the treatment of xerostomia. In this context, the present review aims to provide an overview of the current state of knowledge regarding natural compounds and extracts for xerostomia treatment, paving the way for developing novel therapeutic strategies for this common oral health issue.

Antioxidant Activity and Inhibition of Liver Cancer Cells' Growth of Extracts from 14 Marine Macroalgae Species of the Mediterranean Sea.

Macroalgae exhibit beneficial bioactivities for human health. Thus, the aim of the present study was to examine the antioxidant and anticancer potential of 14 macroalgae species' extracts, namely, Gigartina pistillata, Gigartina teedei, Gracilaria gracilis, Gracilaria sp., Gracilaria bursa pastoris, Colpomenia sinuosa, Cystoseira amentacea, Cystoseira barbata, Cystoseira compressa, Sargassum vulgare, Padina pavonica, Codium fragile, Ulva intestinalis, and Ulva rigida, from the Aegean Sea, Greece. The antioxidant activity was assessed using DPPH, ABTS•+, •OH, and O2•- radicals' scavenging assays, reducing power (RP), and protection from ROO•-induced DNA plasmid damage assays. Moreover, macroalgae extracts' total polyphenol contents (TPCs) were assessed. Extracts' inhibition against liver HepG2 cancer cell growth was assessed using the XTT assay. The results showed that G. teedei extract's IC50 was the lowest in DPPH (0.31 ± 0.006 mg/mL), ABTS•+ (0.02 ± 0.001 mg/mL), •OH (0.10 ± 0.007 mg/mL), O2•- (0.05 ± 0.003 mg/mL), and DNA plasmid breakage (0.038 ± 0.002 mg/mL) and exhibited the highest RP (RP0.5AU 0.24 ± 0.019 mg/mL) and TPC (12.53 ± 0.88 mg GAE/g dw). There was also a significant correlation between antioxidant activity and TPC. P. pavonica (IC50 0.93 ± 0.006 mg/mL) exhibited the highest inhibition against HepG2 cell growth. Conclusively, some of the tested extracts exhibited significant chemopreventive properties, and so they may be used for food products.

Optimizing the Distillation of Greek Oregano-Do Process Parameters Affect Bioactive Aroma Constituents and In Vitro Antioxidant Activity?

The aim of the present work was to optimize the conditions of the distillation process at a pilot scale to maximize the yield of specific bioactive compounds of the essential oil of oregano cultivated in Greece, and subsequently to study the in vitro antioxidant activity of these oils. Steam distillation was conducted at an industrial distillery and a Face-Centered Composite (FCC) experimental design was applied by utilizing three distillation factors: time, steam pressure and temperature. Essential oil composition was determined by static headspace gas chromatography-mass spectrometry (HS-GC/MS). To obtain a comprehensive profile of the essential oils, instrumental parameters were optimized, including sample preparation, incubation conditions, sampling process, injection parameters, column thermal gradient and MS conditions. With the applied GC-MS method, more than 20 volatile compounds were identified in the headspace of the oregano essential oils and their relative percentages were recorded. Carvacrol was the most prominent constituent under all distillation conditions applied. Data processing revealed time as the main factor which most affected the yield. The Desired Space (DSc) was determined by conducting a three-dimensional response surface analysis of the independent and dependent variables, choosing yields of thymol and carvacrol as optimization criteria. The in vitro antioxidant activity of the essential oils of all samples was measured in terms of the interaction with the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) after 20 and 60 min. The most prominent essential oils at different distillation conditions were also tested as inhibitors of lipid peroxidation. Higher % values of carvacrol and thymol were correlated to higher antioxidant activity. Evaluating the impact of the distillation conditions on the in vitro results, it seems that lower pressure, less time and higher temperature are crucial for enhanced antioxidant activities.

µ-Raman Determination of Essential Oils' Constituents from Distillates and Leaf Glands of Origanum Plants.

A novel, inexpensive and simple experimental setup for collecting µ-Raman spectra of volatile liquids in very small quantities was developed. It takes advantage of capillary forces to detain minute volatile liquid volumes. Spectra of volatile and even scattering or absorbing media can be measured more effectively. The method is used to facilitate the collection of intensity-consistent Raman spectra from a series of reference compounds present in Origanum essential oils, in order to quantify their constituents by multiple linear regression. Wild grown Origanum plants, collected from five different regions in Greece and taxonomically identified as O. onites, O. vulgare subsp. hirtum and O. vulgare subsp. vulgare, were appropriately distilled to acquire their essential oils. Comparison of the Raman results with those from headspace gas chromatography-mass spectrometry (HS GC-MS) confirmed the successful relative quantification of the most abundant essential oil constituents, highlighting the similarities and differences of the three Origanum taxa examined. Finally, it is demonstrated that directly measuring the leaf peltate glandular hairs yields exploitable results to identify the main components of the essential oil they contain, underlining the potential of in situ (field or industry) measurements utilizing microscope-equipped portable Raman spectrometers.

Unravelling the Chemotaxonomic Identity of "White" and "Black" Oregano (Origanum vulgare) in Northern Greece.

The two types of oregano used by the inhabitants of the villages of Μount Belles (GR1260001), the "white" oregano with white flowers and "black" oregano with purple flowers, were studied. The two oregano types were collected from five localities along an altitudinal gradient from 217 m up to 1299 m. "White" oregano, was found in the three lowland regions (up to 752 m) where the Pannonian-Balkanic turkey oak-sessile oak forest habitat (code 91M0) dominates. The "black" oregano was collected from the two higher altitudes, at 1177 m and 1299 m, where the Asperulo-Fagetum beech forest habitat (9130) occurs. Measurements of the density and size of peltate glandular hairs (sessile glands) on calyces, bracts, and leaves suggest that "white" oregano is distinguished by its conspicuous - apparently larger - glands. These differences were reflected in the total essential oil content, with the "white" oregano being much richer (up to 4.3 mL/100 g dry weight) than the "black" (up to 0.6%). Striking differences have also been found in the volatile fraction of their essential oil composition. The "white" oregano oils were characterized by the high content of carvacrol (up to 92.6% of identified peaks, by Headspace GC-MS). On the other hand, the two "black" oregano oils have a different aromatic profile, first reported from Greece, with main components including the sesquiterpenes ß-caryophyllene, D-germacrene, δ-cadinene and ß-bisabolene. The results so far indicate that "white" and "black" oregano, Origanum vulgare subsp. hirtum and subsp. vulgare respectively, can be clearly distinguished either by their morphological (glandular) differences or by chemical (essential oil) composition.

Dynamics of alkannin/shikonin biosynthesis in response to jasmonate and salicylic acid in Lithospermum officinale.

Alkannin/shikonin and their derivatives are specialised metabolites of high pharmaceutical and ecological importance exclusively produced in the periderm of members of the plant family Boraginaceae. Previous studies have shown that their biosynthesis is induced in response to methyl jasmonate but not salicylic acid, two phytohormones that play important roles in plant defence. However, mechanistic understanding of induction and non-induction remains largely unknown. In the present study, we generated the first comprehensive transcriptomic dataset and metabolite profiles of Lithospermum officinale plants treated with methyl jasmonate and salicylic acid to shed light on the underlying mechanisms. Our results highlight the diverse biological processes activated by both phytohormones and reveal the important regulatory role of the mevalonate pathway in alkannin/shikonin biosynthesis in L. officinale. Furthermore, by modelling a coexpression network, we uncovered structural and novel regulatory candidate genes connected to alkannin/shikonin biosynthesis. Besides providing new mechanistic insights into alkannin/shikonin biosynthesis, the generated methyl jasmonate and salicylic acid elicited expression profiles together with the coexpression networks serve as important functional genomic resources for the scientific community aiming at deepening the understanding of alkannin/shikonin biosynthesis.

Transcriptional dynamics of Chitinophaga sp. strain R-73072-mediated alkannin/shikonin biosynthesis in Lithospermum officinale.

Plants are colonized by a wide range of bacteria, several of which are known to confer benefits to their hosts such as enhancing plant growth and the biosynthesis of secondary metabolites (SMs). Recently, it has been shown that Chitinophaga sp. strain R-73072 enhances the production of alkannin/shikonin, SMs of pharmaceutical and ecological importance. However, the mechanisms by which this bacterial strain increases these SMs in plants are not yet understood. To gain insight into these mechanisms, we analyzed the molecular responses of Lithospermum officinale, an alkannin/shikonin producing member of Boraginaceae, to inoculation with R-73072 in a gnotobiotic system using comparative transcriptomics and targeted metabolite profiling of root samples. We found that R-73072 modulated the expression of 1,328 genes, of which the majority appeared to be involved in plant defense and SMs biosynthesis including alkannin/shikonin derivatives. Importantly, bacterial inoculation induced the expression of genes that predominately participate in jasmonate and ethylene biosynthesis and signaling, suggesting an important role of these phytohormones in R-73072-mediated alkannin/shikonin biosynthesis. A detached leaf bioassay further showed that R-73072 confers systemic protection against Botrytis cinerea. Finally, R-73072-mediated coregulation of genes involved in plant defense and the enhanced production of alkannin/shikonin esters further suggest that these SMs could be important components of the plant defense machinery in alkannin/shikonin producing species.

Root-associated bacteria modulate the specialised metabolome of Lithospermum officinale L.

Bacteria influence plant growth and development and therefore are attractive resources for applications in agriculture. However, little is known about the impact of these microorganisms on secondary metabolite (SM) production by medicinal plants. Here we assessed, for the first time, the effects of bacteria on the modulation of SM production in the medicinal plant Lithospermum officinale (Boraginaceae family) with a focus on the naphthoquinones alkannin/shikonin and their derivatives (A/Sd). The study was conducted in an in vitro cultivation system developed for that purpose, as well as in a greenhouse. Targeted and non-targeted metabolomics were performed, and expression of the gene PGT encoding for a key enzyme in the A/S biosynthesis pathway was evaluated with qPCR. Three strains, Chitinophaga sp. R-73072, Xanthomonas sp. R-73098 and Pseudomonas sp. R-71838 induced a significant increase of A/Sd in L. officinale in both systems, demonstrating the strength of our approach for screening A/Sd-inducing bacteria. The bacterial treatments altered other plant metabolites derived from the shikimate pathway as well. Our results demonstrate that bacteria influence the biosynthesis of A/Sd and interact with different metabolic pathways. This work highlights the potential of bacteria to increase the production of SM in medicinal plants and reveals new patterns in the metabolome regulation of L. officinale.

Metabolite Production in Alkanna tinctoria Links Plant Development with the Recruitment of Individual Members of Microbiome Thriving at the Root-Soil Interface.

Plants are naturally associated with diverse microbial communities, which play significant roles in plant performance, such as growth promotion or fending off pathogens. The roots of Alkanna tinctoria L. are rich in naphthoquinones, particularly the medicinally used enantiomers alkannin and shikonin and their derivatives. Former studies already have shown that microorganisms may modulate plant metabolism. To further investigate the potential interaction between A. tinctoria and associated microorganisms, we performed a greenhouse experiment in which A. tinctoria plants were grown in the presence of three distinct soil microbiomes. At four defined plant developmental stages, we made an in-depth assessment of bacterial and fungal root-associated microbiomes as well as all extracted primary and secondary metabolite content of root material. Our results showed that the plant developmental stage was the most important driver influencing the plant metabolite content, revealing peak contents of alkannin/shikonin derivatives at the fruiting stage. Plant root microbial diversity was influenced both by bulk soil origin and to a small extent by the developmental stage. The performed correlation analyses and cooccurrence networks on the measured metabolite content and the abundance of individual bacterial and fungal taxa suggested a dynamic and at times positive or negative relationship between root-associated microorganisms and root metabolism. In particular, the bacterial genera Labrys and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium as well as four species of the fungal genus Penicillium were found to be positively correlated with higher content of alkannins. IMPORTANCE Previous studies have shown that individual, isolated microorganisms may influence secondary metabolism of plants and induce or stimulate the production of medicinally relevant secondary metabolism. Here, we analyzed the microbiome-metabolome linkage of the medicinal plant Alkanna tinctoria, which is known to produce valuable compounds, particularly the naphthoquinones alkannin and shikonin and their derivatives. A detailed bacterial and fungal microbiome and metabolome analysis of A. tinctoria roots revealed that the plant developmental stage influenced root metabolite production, whereas soil inoculants from three different geographical origins in which plants were grown shaped root-associated microbiota. Metabolomes of plant roots of the same developmental stage across different soils were highly similar, pinpointing to plant maturity as the primary driver of secondary metabolite production. Correlation and network analyses identified bacterial and fungal taxa showing a positive relationship between root-associated microorganisms and root metabolism. In particular, the bacterial genera Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Labrys as well as the fungal species of genus Penicillium were found to be positively correlated with higher content of alkannins.

Preparation and Evaluation of Siderol Amorphous Solid Dispersions: Selection of Suitable Matrix/Carrier.

The present study investigates the preparation of amorphous solid dispersions (ASD) for the ent-kaurane diterpenoid siderol (SDR). Initially, evaluation of the pure drug (isolated from Sideritis scardica) revealed that the API is a non-stable glass former, and hence the selection of a suitable ASD's matrix/carrier needs special attention. For this reason, four commonly used polymers and copolymers, namely poly(vinylpyrrolidone), copovidone, hydroxypropyl cellulose, and Soluplus® (SOL), were screened via film casting and crystal growth rate measurements. Amongst them, SOL showed the highest SDR's crystal growth rate reduction, and, since it was also miscible with the drug, it was selected for further testing. In this direction, SDR-SOL ASDs were successfully prepared via melt-quench cooling. These formulations showed full API amorphization, while good physical stability (i.e., a stable SDR amorphous dispersions) were obtained after storage for several months. Finally, evaluation of molecular interactions (with the aid of ATR-FTIR spectroscopy) showed strong H-bonds between SOL and SDR, while the use of molecular dynamics (MD) simulations unraveled the nature of these interactions. Therefore, based on the findings of the present work, SOL seems to be an appropriate matrix/carrier for the preparation of SDR ASDs, although further studies are needed in order to explore its full potentials.

Expanding the Biological Properties of Alkannins and Shikonins: Their Impact on Adipogenesis and Life Expectancy in Nematodes.

Alkannin, shikonin (A/S) and their derivatives are naturally occurring hydroxynaphthoquinones biosynthesized in some species of the Boraginaceae family. These natural compounds have been extensively investigated for their biological properties over the last 40 years, demonstrating a plethora of activities, such as wound healing, regenerative, anti-inflammatory, antitumor, antimicrobial and antioxidant. This study aims to extend the current knowledge by investigating the effects of various A/S compounds on two model systems, namely on 3T3-L1 pre-adipocytes and the nematode Caenorhabditis elegans. The former constitutes an established in vitro model for investigating anti-obesity and insulin-mimetic properties, while the latter has been widely used as a model organism for studying fat accumulation, lifespan and the anthelmintic potential. A set of chemically well-defined A/S derivatives were screened for their effect on pre-adipocytes to assess cell toxicity, cell morphology, and cell differentiation. The differentiation of pre-adipocytes into mature adipocytes was examined upon treatment with A/S compounds in the presence/absence of insulin, aiming to establish a structure-activity relationship. The majority of A/S compounds induced cell proliferation at sub-micromolar concentrations. The ester derivatives exhibited higher IC50 values, and thus, proved to be less toxic to 3T3-L1 cells. The parent molecules, A and S tested at 1 µM resulted in a truncated differentiation with a reduced number of forming lipids, whereas compounds lacking the side chain hydroxyl group projected higher populations of mature adipocytes. In C. elegans mutant strain SS104, A/S enriched extracts were not able to inhibit the fat accumulation but resulted in a drastic shortage of survival. Thus, the set of A/S compounds were tested at 15 and 60 µg/ml in the wild-type strain N2 for their nematocidal activity, which is of relevance for the discovery of anthelmintic drugs. The most pronounced nematocidal activity was observed for naphthazarin and ß,ß-dimethyl-acryl-shikonin, followed by isovaleryl-shikonin. The latter 2 A/S esters were identified as the most abundant constituents in the mixture of A/S derivatives isolated from Alkanna tinctoria (L.) Tausch. Taken together, the findings show that the structural variations in the moiety of A/S compounds significantly impact the modulation of their biological activities in both model systems investigated in this study.

A Review on Xerostomia and Its Various Management Strategies: The Role of Advanced Polymeric Materials in the Treatment Approaches.

The medical term xerostomia refers to the subjective sensation of oral dryness. The etiology seems to be multifactorial with the most frequently reported causes being the use of xerostomic medications, neck and head radiation, and systematic diseases (such as Sjögren's syndrome). Xerostomia is associated with an increased incidence of dental caries, oral fungal infections, and difficulties in speaking and chewing/swallowing, which ultimately affect the oral health-related quality of life. The development of successful management schemes is regarded as a highly challenging project due to the complexity of saliva. This is why, in spite of the fact that there are therapeutic options aiming to improve salivary function, most management approaches are alleviation-oriented. In any case, polymers are an integral part of the various formulations used in every current treatment approach, especially in the saliva substitutes, due to their function as thickening and lubricating agents or, in the case of mucoadhesive polymers, their ability to prolong the treatment effect. In this context, the present review aims to scrutinize the literature and presents an overview of the role of various polymers (or copolymers) on either already commercially available formulations or novel drug delivery systems currently under research and development.

Valorization of household food wastes to lactic acid production: A response surface methodology approach to optimize fermentation process.

Lactic acid is a valuable compound used in several industrial processes such as polymers, emulsifiers manufacturing, pharmaceutical, and cosmetic formulations. The present study aims to evaluate the potential use of food waste to produce lactic acid through fermentation, both by indigenous microbiota and by the bio-augmentation with two lactic acid bacteria, namely Lactobacillus plantarum BS17 and Lactobacillus casei BP2. Fermentation was studied both in batch and continuously fed anaerobic reactors at mesophilic conditions and a Response Surface Methodology approach was used to optimize the bioprocess performance and determine the environmental parameters (namely pH and time) that lead to the enhancement of lactic acid production during the batch fermentation by indigenous microorganisms. Results revealed an optimum set of conditions for lactic acid production at a pH value of 6.5 and a fermentation period of 3.5 days at 37 °C. Under these conditions lactic acid production reached a value of 23.07 g/L, which was very similar to the mathematically predicted ones, thus verifying the accuracy of the experimental design. This optimum set of conditions was further employed to examine the production of lactic acid under continuous fermentation operation. Furthermore, concentrations of volatile fatty acids and ethanol were monitored and found to be relatively low, with ethanol being the dominant by-product of fermentation, indicating the presence of heterofermentative bacteria in the food wastes. A final step of downstream process was performed resulting in the successful recovery of lactic acid with purity over 90%.