Use Of Natural Extracts Research Articles

Eco-Friendly Photocatalytic Treatment of Dyes with Ag Nanoparticles Obtained through Sustainable Process Involving Spirulina platensis

The development of efficient photocatalysts is crucial in addressing water pollution concerns, specifically in the removal of organic dyes from wastewater. In this context, the use of silver nanoparticles (Ag NPs) might represent a method to achieve high dye degradation efficiencies. On the other hand, the classical Ag NP production process involves several reactants and operating conditions, which make it poorly sustainable. In the present work, Ag NPs were synthesized according to a new sustainable process involving the use of natural extracts of Spirulina platensis and milder operating conditions. The material was also calcined to determine the influence of organic content on the properties of Ag NPs. The X-ray diffraction (XRD) analysis displayed the AgCl and Ag phases with a crystalline size of 11.79 nm before calcination. After calcination, only the Ag phase was present with an increased crystalline size of 24.60 nm. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the capping role of the metabolites from the extract. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the spherical or quasi-spherical morphologies with agglomeration due to the calcination. Energy-dispersive X-ray spectroscopy (EDX) and Thermogravimetric (TGA) analyses further confirmed the involvement of metabolites in the synthesis of Ag NPs. The optical changes in the products were observed in a UV-Vis analysis. The Ag NPs were tested for their photocatalytic activity against the laboratory dye brilliant blue r in visible light in various conditions. The highest degradation efficiency of 81.9%, with a kapp value of 0.00595 min−1, was observed in alkaline medium after 90 min of light irradiation.

Natural extracts as a sustainable alternative for the control of Aedes aegypti: an updated review

Aedes aegypti is the primary vector of viruses that cause diseases such as dengue, yellow fever, Zika, and Chikungunya, leading to high rates of morbidity and mortality in humans and substantial healthcare costs. The most common method for mosquito control involves the use of synthetic insecticides; however, continuous use of these substances leads to species resistance and environmental contamination. In response to these challenges, natural extracts have emerged as a promising alternative for vector control as they contain components potentially toxic to mosquitoes. The aim of this review is to present the current state of the use of natural extracts as a strategy for controlling both larval and adult Ae. aegypti. By means of information retrieval from databases, considering original articles published from 2018 to 2023, we sought information related to the plant part used for extract obtainment, extraction methods, and solvents used. A total of 676 articles were found, of which 35 met the established criteria. In these publications, 38 families, 69 genera, and 87 species of plants were identified, with a particular emphasis on the Asteraceae, Anacardiaceae, Myrtaceae, and Lamiaceae families due to their higher number of species used in research. On the other hand, the most commonly used methods for obtaining extracts included maceration with subsequent filtration, as well as Soxhlet extraction. Meanwhile, the preferred solvents for extract obtainment were ethanol and water. In conclusion, there is widespread use of plant extracts as insecticides, with extraordinary potential to control vector populations such as Ae. aegypti and, in turn, contribute to the reduction of arbovirus transmission by this mosquito.

Comparison of Efficacy of Topical Carica papaya Leaf Extract and Hemocoagulase in Postoperative Wound Healing After Therapeutic Orthodontic Premolar Extractions: a Split Mouth Study.

Introduction Postoperative wound healing is the most important factor in the outcome of any surgical procedure. Wound healing is a dynamic process involving inflammation, neovascularization, granulation, fibroblast proliferation, re-epithelization, and remodeling. It repairs tissue integrity, restoring the body's natural defense barrier. A hastened wound healing will help in the quicker re-establishment of the body's homeostasis. Carica papaya includes vital nutrients and bioactive substances such as minerals, vitamins, and antioxidants. Its primary active ingredientpapaincauses the enzymatic debridement of wounds. Hemocoagulase is a thrombin-like serine protease that is mostly employed for its procoagulant and wound-healing characteristics. It is derived from the venom of Bothrops species of snakes. This study aims to compare the wound-healing properties of topical Carica papaya leaf extract and Hemocoagulase after dental extractions. Materials & Methods For 48 patients requiring bilateral therapeutic dental extraction for orthodontic intervention, Carica papaya leaf extract (Caripill 275mg/5ml) was topically applied to the extraction socket on one side, and Hemocoagulase 0.2 CU solution (Botroclot) was applied to the extraction socket on the other side. The bilateral premolars were extracted for orthodontic treatment under local anesthesia. Patients were asked to apply the solution topically twice daily for seven days and were called forreview on the seventh day. The assessment of the efficacy of both solutions in post-operative wound healing was the objective of the study. Healing was assessed by using a blinded single observer for all patients using Landry's healing index. Results A total of 48 subjects with 96 sites completed the study, with a mean age of 15.4 years. The study population consisted of 24 males and 24 females, which were evenly distributed among the two study groups. On comparison of wound healing index (WHI) scores between the two groups using the Wilcoxon signed rank test, Group A had a significantly higher mean rank than Group B with regards to the wound healing indexscore, and the results were statistically significant (p = 0.037). Conclusion It can be concluded from the study that Carica papaya leaf extract showed better wound healing in post-extraction sockets compared to Hemocoagulase. This study presents the promising useof natural extracts such as Carica papaya in wound healing because they are easily accessible to patients, more economical, and haveno adverse reactions. More studies that focus on natural extracts to promote wound healing are required in the future.

The past is the future: from natural acid-base indicators to natural reagents in sustainable analytical chemistry

Abstract This article reviews the use of natural resources in analytical chemistry throughout history. Plant extracts were employed as indicators in chemistry for identifying the acidity or alkalinity of liquids as early as the 1650s. Later, as the industrial revolution altered people’s lives, synthetic chemicals were used instead. Modern techniques of analysis have replaced conventional ones as a result of advancements in physics and technology. The industrial revolution was an era of excitement until the toxic pollutants released from industries severely damaged people and the environment. The concepts of green chemistry and green analytical chemistry were proposed as potential solutions to the problems. The use of natural extracts as chemical analysis reagents has been reconsidered recently as a sustainable alternative. While new technologies such as artificial intelligence (AI) will influence future trends in analytical chemistry development, the primary goal is to move toward sustainable analytical chemistry, which includes using natural reagents and reducing the amount of chemicals consumed and waste produced.

The use of natural extracts with photoprotective activity: a 2015-2023 patent prospection.

Synthetic sunscreen offers protection against excessive exposure to ultraviolet (UV) radiation from the sun, and protects the skin from possible damage. However, they have low efficacy against the formation of reactive oxygen species (ROS), which are highly reactive molecules that can be generated in the skin when it is exposed to UV radiation, and are known to play a role in oxidative stress, which can contribute to skin aging and damage. Thus, there is an ongoing search for sunscreens that do not have these negative effects. One promising source for these is natural products. Therefore, the current patent review summarizes topical formulations made from natural compounds that have antioxidant properties and can be used as photoprotective or anti-aging agents, either using a single natural extract or a combination of extracts. The review reports basic patent information (applicant country, type of applicant, and year of filing) and gives details about the invention, including its chemical composition, and the in vitro and in vivo tests performed. These patents describe natural products that can be used to protect the skin and validate their efficacy, and safety, in addition to standardizing their formulations. The compositions described illustrate the consistent innovation in the use of natural products to protect against UV damage and photoaging disorders, a promising field which is receiving growing global recognition.

Utilización de extracto natural del Muicle (Justicia spicigera) en la elaboración de chocolate a partir de dos variedades de cacao (Theobroma bicolor Humb. & Bonpl. y Theobroma cacao L.)

Se propuso fomentar la incorporación del extracto natural del Muicle (Justicia spicigera) en la producción de chocolate, utilizando dos variedades de cacao: Theobroma bicolor Humb. & Bonpl y Theobroma cacao L. Para evaluar los efectos, se implementó un diseño estadístico completamente al azar con arreglo bifactorial, compuesto por 6 tratamientos y 3 repeticiones. Como factor A se evaluó dos tipos de Theobromas y factor B las concentraciones del extracto de Justicia Spicigera (0%, 3% y 6%). Se realizó la toma de las variables morfológicas para la comparación entre variedades, Theobroma bicolor Humb. & Bonpl presentó un peso de mazorca promedio de 969, mientras que Theobroma cacao L. tubo un promedio de 787 g. Durante la fermentación se tomó la temperatura inicial que fue de 21 - 48°C, pH inicial de 3,88 - 5,46 y °Brix 21- 6°Brix. La capacidad antioxidante se determinó mediante los métodos ABTS y DPPH, con valores de 239,83 y 176,49 µmol. Se requirió de 25 catadores semientrenados, se evaluó el aroma, intensidad, color y sabor. La adición del extracto de Justicia Spicigera mejoró significativamente las notas sensoriales y la aceptabilidad del chocolate.

Catalytical Degradation of Industrial Dyes using Biosynthesized Nanoparticles - Review

The rapid growth of the textile industry has led to a surge in the release of industrial dyes, posing a severe environmental threat. An attempt was made in this review paper to explore the catalytical degradation of industrial dyes using biosynthesized nanoparticles as a promising avenue for sustainable remediation and to provide a thorough understanding of the advancements, challenges and potential applications of this innovative approach. The synthesis methods of biosynthesized nanoparticles were explained, highlighting the use of natural extracts and their inherent catalytic properties. A critical analysis of the catalytic degradation process was presented, examining the diverse range of industrial dyes targeted by biosynthesized nanoparticles. The factors influencing degradation efficiency, such as nanoparticle size, composition and the nature of the dye pollutants were investigated and the kinetics and mechanisms governing catalytic degradation were explored, shedding light on the intricacies of the reaction pathways. The environmental impact and sustainability of biosynthesized nanoparticles for dye degradation were thoroughly evaluated. Comparisons with conventional remediation methods were made, emphasizing the eco-friendly nature and potential scalability of this innovative approach. Moreover, challenges and future directions in this field were outlined to guide further research efforts.

Emulsifying properties of biopolymer extracts from Opuntia ficus indica cladodes

The use of natural extracts in the field of cosmetics and pharmaceuticals is increasing due to the growing demand for sustainable and safe products, together with their potential therapeutic benefits. Bioextracts from the parenchyma of Opuntia ficus indica cladodes were characterized and evaluated as emulsifying agents. They contain pectin together with variable amounts of arabinogalactan-protein complex (AGP), as in many polysaccharides of natural origin. Their protein content varies according to the purification steps: 11.4 wt% for the raw mucilage (Mofi), 4.7 wt% for the pectin fraction (Pofi) and less than 0.5 wt% for the filtrated pectin fraction (FPofi). Part of the AGP contained in the Mofi and Pofi extracts precipitates as particles with a ∼5 µm diameter. Mofi at 1.5 wt% concentration is an efficient emulsifier of oil-in-water emulsions of medium-chain triglycerides or sunflower oil with stability against coalescence for more than three months. Pofi is less efficient and FPofi does not allow the stabilization of emulsions. The performance of emulsifiers is directly related to the protein content of the extracts and the role of the insoluble particles is essential. The insoluble particles of AGP are responsible for the stabilization through a Pickering effect. The emulsions have the characteristic properties of Pickering emulsions.

Determination of anti-microbial and anti-viral efficacy of the mixture of extracted piper betle linn leaves and cynodon dactylon with curd and calcium oxide against shingles disease

The prevalence of shingles disease has become a significant concern in the healthcare industry, and the search for effective treatment options has intensified. In this research paper, we investigate the anti-microbial and anti-viral efficacy of a mixture of extracted Piper Betle Linn leaves and Cynodon Dactylon with curd and calcium oxide against shingles disease. The study employed a randomized controlled trial design, with participants divided into four groups. The first group was administered the mixture of extracted Piper Betle Linn leaves and Cynodon Dactylon, the second group received the same mixture with curd, the third group was given the mixture with calcium oxide, while the fourth group served as the control and received a placebo. Results from the study revealed that the mixture of extracted Piper Betle Linn leaves and Cynodon Dactylon with curd and calcium oxide demonstrated potent anti-microbial and anti-viral efficacy against shingles disease, as evidenced by a significant reduction in the severity and duration of symptoms. The mixture was also found to be safe and well-tolerated by participants, with no adverse effects reported.The findings of this research paper have significant implications for the treatment of shingles disease, as the mixture of extracted Piper Betle Linn leaves and Cynodon Dactylon with curd and calcium oxide presents a promising alternative to conventional treatment options. The use of natural extracts and compounds in the mixture also provides a safer and more sustainable approach to treating the disease. In conclusion, the results of this study demonstrate the effectiveness of the mixture of extracted Piper Betle Linn leaves and Cynodon Dactylon with curd and calcium oxide in treating shingles disease. Further research is needed to fully explore the potential of this mixture in combating other viral and microbial infections.

Sweet Cherry Extract as Permeation Enhancer of Tyrosine Kinase Inhibitors: A Promising Prospective for Future Oral Anticancer Therapies.

Although patients would rather oral therapies to injections, the gastrointestinal tract's low permeability makes this method limiting for most compounds, including anticancer drugs. Due to their low bioavailability, oral antitumor therapies suffer from significant variability in pharmacokinetics and efficacy. The improvement of their pharmacokinetic profiles can be achieved by a new approach: the use of natural extracts enriched with polyphenolic compounds that act as intestinal permeability enhancers. Here, we propose a safe sweet cherry extract capable of enhancing oral absorption. The extract was characterized by the HPLC-UV/MS method, evaluated for in vitro antioxidant activity, safety on the Caco-2 cell line, and as a potential permeation enhancer. The sweet cherry extract showed a high antioxidant capacity (ABTS and DPPH assays were 211.74 and 48.65 µmol of Trolox equivalent/g dried extract, respectively), high content of polyphenols (8.44 mg of gallic acid per gram of dry extract), and anthocyanins (1.80 mg of cyanidin-3-glucoside equivalent per g of dry extract), reassuring safety profile (cell viability never lower than 98%), and a significant and fully reversible ability to alter the integrity of the Caco-2 monolayer (+81.5% of Lucifer yellow permeability after 2 h). Furthermore, the ability of the sweet cherry extract to improve the permeability (Papp) and modify the efflux ratio (ER) of reference compounds (atenolol, propranolol, and dasatinib) and selected pyrazolo[3,4-d]pyrimidine derivatives was investigated. The obtained results show a significant increase in apparent permeability across the Caco-2 monolayer (tripled and quadrupled in most cases), and an interesting decrease in efflux ratio when compounds were co-incubated with sweet cherry extract.

Plant-Mediated Inorganic Nanoparticles for Anti-Tumor Therapy in Colorectal Cancer: A Systematic Review

Colon cancer is the third most frequent neoplasm and the second most lethal worldwide. Despite progress in its treatment, new therapies are still needed to improve the prognosis of this type of tumor and, in this context, the use of plant compounds with anti-tumor properties has been increasing in recent years. The aim of this systematic review was to analyze the potential benefits of encapsulation of compounds derived from plant extracts in nanoparticles and their cytotoxic effect under in vitro conditions. Once the search strategy was defined based on the selected MESH terms, 147 publications published since 2012 were identified from three different databases (PubMed, SCOPUS and WOS). After eliminating duplicates and applying the inclusion and exclusion criteria, 17 studies were finally included. The results showed that the use of natural extracts encapsulated in nanoparticles offered significant cytotoxic activity against colon neoplastic cells by increasing the therapeutic effect of free plant extracts through their encapsulation and without producing toxicity on healthy cells. In addition, most studies (14) involved metal-derived nanoparticles (zinc, iron and gold). Despite the possible efficacy of these nanodrugs, more in vivo studies are needed to elucidate their potential future therapeutic application and their biocompatibility.

Organic compounds as corrosion inhibitors for reinforced concrete: a review

Abstract With the goal of preventing concrete deterioration by means of destructive corrosion processes, the use of single organic compounds or mixtures as organic corrosion inhibitors (OCIs) instead of inorganic chemicals is becoming a very attractive practice. As OCIs are more ecologically friendly in their production and environmental fate, they have several advantages over well-known inorganic additives such as metallic nitrites, chromates, or arsenates. In this article, the application of different single organic compounds (of either natural or synthetic origin) as well as mixtures that have been used to lengthen the lifespan of concrete structures is reviewed. After a small exemplification of the use of single organic compounds bearing amino, hydroxy, formyl, or carboxylic functionalities, the more often used OCIs are reviewed according to their principal functional group. Afterward, the application of compound mixtures of either synthetic or natural origin, the use of natural extracts, and biomass are surveyed. Finally, the effects of functional groups within the top 10 inhibitor molecules, the toxicity of OCIs, their effects on the physical-mechanical properties of concrete, and their long-term performance are discussed.

A new need, quality, and sustainability (NQS) index for evaluating chemical analysis procedures using natural reagents

The use of natural extracts as chemical reagents for flow analysis and downscaling techniques provides an alternative way to reduce risks to users and to the environment and is therefore considered a greener development in chemical analysis techniques according to the Green Analytical Chemistry (GAC) guidelines. The Green Analytical Procedure Index (GAPI) and the White Analytical Chemistry (WAC) have been used to evaluate some flow-based and downscaling procedures employing natural reagents in terms of environmental friendliness, analytical efficiency, and practicability. These flow-based and downscaling procedures are more environmentally friendly but less effective than the standard analytical ones. As recommended by Koel in 2016, these assessment aspects should be weighed against the need for applying the analysis. Furthermore, sustainable development has become an important issue worldwide. Thus, a new “Need, Quality, and Sustainability (NQS) index that assesses the analytical procedure in terms of ”Need“, the WAC as ”Quality“, and the Sustainable Development Goals (SDGs) as ”Sustainability“ is proposed. An approach for quantifying sustainability is also proposed. Application of this NQS index suggests that the use of natural reagents improves analytical procedures, especially in the need and sustainability aspects. The NQS index as an evaluation tool could assist in the development of analytical procedures addressing social needs, analytical performance, and global sustainability.

NATURAL EXTRACTS AS A PROMISING SOLUTION FOR GRAM-POSITIVE ANTIBIOTIC RESISTANCE: A COMPREHENSIVE REVIEW

Background: Antibiotic resistance is currently one of the biggest problems in public health. Infectious diseases are the second human death cause, and the emergence of antimicrobial-resistant bacteria increases mortality and morbidity rates. There is a growing clinical need for the development of new antibiotics. In this line, WHO issued an alert about 12 bacteria with an urgent need to develop new antibiotics. Aims: This review aims to analyze the current knowledge of their antibacterial activity against the gram-positive pathogens listed by WHO and their extraction techniques. Methods: We systematically reviewed the literature in PubMed, searching publications describing the use of natural extracts as antibiotics over bacteria. The exclusion criteria consisted of limiting papers on natural extracts tested over the bacteria culture related to eleven selected bacteria, according to an alert issued by WHO in 2017, and seven plant extracts. Results: All the gram-positive bacteria present in the WHO alert have been treated, with different degrees of advance, with some of the plant extracts and plant-based compounds reviewed. Currently, they are in the preclinical stage. Edible herbs are more often used, as well as artemisia and wine byproducts. Discussion: Natural products based on plants have shown to be efficient in inhibiting bacterial growth, even in antibiotic-resistant strains. The classical extraction methods are still in use and have been improved with the available technology to improve efficiency and yield. Conclusions: Ongoing evidence shows that plant extracts and plant-based compounds are effective as antibacterial, with minimal effects on the host cell, a promising antibiotic source. Furthermore, they are sustainable, environmentally friendly, and renewable.

Development of Cissus quadrangularis-Loaded POSS-Reinforced Chitosan-Based Bilayer Sponges for Wound Healing Applications: Drug Release and In Vitro Bioactivity.

Nowadays, antibiotic-loaded biomaterials have been widely used in wound healing applications. However, the use of natural extracts has come into prominence as an alternative to these antimicrobial agents in the recent period. Among natural sources, Cissus quadrangularis (CQ) herbal extract is used for treatment of bone and skin diseases in ayurvedic medicine due to its antibacterial and anti-inflammatory effects. In this study, chitosan-based bilayer wound dressings were fabricated with electrospinning and freeze-drying techniques. CQ extract-loaded chitosan nanofibers were coated on chitosan/POSS nanocomposite sponges using an electrospinning method. The bilayer sponge is designed to treat exudate wounds while mimicking the layered structure of skin tissue. Bilayer wound dressings were investigated with regard to the morphology and physical and mechanical properties. In addition, CQ release from bilayer wound dressings and in vitro bioactivity studies were performed to determine the effect of POSS nanoparticles and CQ extract loading on NIH/3T3 and HS2 cells. The morphology of nanofibers was investigated with SEM analysis. Physical characteristics of bilayer wound dressings were determined with FT-IR analysis, swelling study, open porosity determination, and mechanical test. The antimicrobial activity of CQ extract released from bilayer sponges was investigated with a disc diffusion method. Bilayer wound dressings' in vitro bioactivity was examined using cytotoxicity determination, wound healing assay, proliferation, and the secretion of biomarkers for skin tissue regeneration. The nanofiber layer diameter was obtained in the range of 77.9-97.4 nm. The water vapor permeability of the bilayer dressing was obtained as 4021 to 4609 g/m2day, as it is in the ideal range for wound repair. The release of the CQ extract over 4 days reached 78-80% cumulative release. The release media were found to be antibacterial against Gram-negative and Gram-positive bacteria. In vitro studies showed that both CQ extract and POSS incorporation induced cell proliferation as well as wound healing activity and collagen deposition. As a result, CQ-loaded bilayer CHI-POSS nanocomposites were found as a potential candidate for wound healing applications.

Biopolymer- and Lipid-Based Carriers for the Delivery of Plant-Based Ingredients

Natural ingredients are gaining increasing attention from manufacturers following consumers' concerns about the excessive use of synthetic ingredients. However, the use of natural extracts or molecules to achieve desirable qualities throughout the shelf life of foodstuff and, upon consumption, in the relevant biological environment is severely limited by their poor performance, especially with respect to solubility, stability against environmental conditions during product manufacturing, storage, and bioavailability upon consumption. Nanoencapsulation can be seen as an attractive approach with which to overcome these challenges. Among the different nanoencapsulation systems, lipids and biopolymer-based nanocarriers have emerged as the most effective ones because of their intrinsic low toxicity following their formulation with biocompatible and biodegradable materials. The present review aims to provide a survey of the recent advances in nanoscale carriers, formulated with biopolymers or lipids, for the encapsulation of natural compounds and plant extracts.

Maximising olive oil by‐products

Maximising olive oil by‐products

Effects of natural nitrite sources from arugula and barberry extract on quality characteristic of heat-treated fermented sausages

This study was designed to compare the effects of natural nitrite sources from the arugula leaves (arugula extract and pre-converted arugula extract) and the use of barberry extract (BE) in heat-treated fermented sausage formulations. Eight different sausages were manufactured as follows: pre-converted arugula extract (PA), arugula extract (A), pre-converted arugula extract + BE (PAB), arugula extract + BE (AB), nitrite +BE (POB), no nitrite+ BE (NEB), also positive and negative control groups were prepared with (POC) or without nitrite (NEC). The addition of arugula and barberry extracts reduced the residual nitrite content, in fact PAB had the lowest value with a reduction ratio of 47%. The addition of BE lowered the lipid oxidation compared to other counterparts. The use of arugula extract or pre-converted arugula extract resulted in a lower carbonylation than nitrite free samples. The use of natural extracts lowered the a* and b* values compared to control. At the end of the storage, no differences were observed on the overall acceptability of all samples. Combined use of barberry extract with arugula and pre-converted arugula extracts could be used as alternative novel curing agent in heat-treated fermented sausages.

Characterization of Polyphenol Oxidase (PPO) from Blackberry Thorny Wild Rubus Fruticosus and its Inhibition using Natural Extracts

The Polyphenol oxidase (PPO) leads to the enzymatic browning of fruits and vegetables and needs to be prevented in food browning and quality. The present study aimed to investigate the use of natural extracts and chemical inhibitors to prevent browning of the PPO of blackberries. Purification, characterization, and kinetics of PPO of blackberry parameters for five substrates, namely, pyrocatechol, 4-methylcatechol, Pyrogallol, Gallic acid, and tyrosine, were described. The results showed that the DEAE-Sepharose and Superdex G-200 purification methods, which achieved electrophoretic purity, increased PPO activity by 556 fold. Purification with Sephadex GE-200 and SDS-PAGE reveals two PPO isoenzymes with an apparent molecular weight of 22 kD and 70 kD. The optimum pH and temperature values indicated were 6.6 and 25°C, respectively. The PPO showed variable affinity towards o-dihydroxy phenolic substrates with catecholase activity but without any activity observed with phenol, a monohydroxy substrate, and it was very effective towards pyrocatechol, pyrogallol, and 4-methyl catechol. The results revealed that inhibition of the PPO using both synthetic inhibitors and natural extracts was the most effective method. Quercetin and ascorbic acid showed higher inhibition with the lowest Ki values. Fresh onion (Allium cepa) and wild Arbutus unedo extract were able to inhibit the blackberry PPO activity up to 50% and 60%, respectively. Therefore, the use of natural extracts from Arbutus unedo L as anti-browning agents on the blackberry PPO may provide new insight to overcome the enzymatic browning.

ADVANCES IN NATURAL EXTRACTS USED FOR ANTIBIOTIC-RESISTANT BACTERIA TREATMENT: THE GRAM-NEGATIVE CASES

Background: Infectious diseases are a global problem, the second human cause of death. Infectious diseases caused by pathogenic bacteria have been treated with a high degree of efficacy. However, even when the 20th century was considered the “golden age” of antibiotics, bacteria developed a different resistance mechanism to antibiotics. In 2017, the WHO issued an alert about 12 bacteria with an urgent need to develop new antibiotics. Aims: The aim of the present review is to analyze the current knowledge of the antibacterial activity of natural extract-based treatments against the pathogens listed by WHO. Methods: A systematic review of the literature in PubMed was performed to search for publications describing the use of natural extracts as antibiotics over bacteria. We focused on the Gram-Negative group. The exclusion criteria consisted of limiting papers on natural extracts tested over the bacteria culture related to eight selected bacteria, according to an alert issued by WHO in 2017, and seven plant extracts. Results: All the Gram-Negative bacteria listed in 2017 by WHO have been treated, with different degrees of advance, with some of the plant extracts and plant-based compounds reviewed. In general, the first approach is using inhibition disks applied over the bacterial biofilm in solid culture media. Discussion: While Salmonellae and P. aeruginosa have been extensively studied, over N. gonorrhoeae, A. baumannii have been tested with fewer natural extracts. Edible herbs are more often used, as well as artemisa and wine byproducts. In all cases, they are in the early stages of study, not being tested in patients at present. Conclusions: Plant extracts and plant-based compounds are effective as antibacterial, with minimal effects on the host cell. Furthermore, they are sustainable, environmentally friendly, and renewable.