Antifungal, antioxidant activity, and preservation effect of caffeic acid quaternary ammonium salt-modified chitosan.

Abstract. Andriani D, Revianti S, Prananingrum W. 2020. Identification of compounds isolated from a methanolic extract of Acanthus ilicifolius leaves and evaluation of their antifungal and antioxidant activity. Biodiversitas 21: 2521-2525. Acanthus ilicifolius L. (Acanthaceae) is commonly found in mangroves along the east coast of Surabaya. It can be used as an indicator of environmental pollution and damage in mangrove ecosystems. Studies have reported that A. ilicifolius has antimicrobial, antifungal, antiviral, anti-inflammatory, analgesic, antioxidant, anticancer, antileishmanial, and hepatoprotective activity due to the chemical compounds in the plant. This study aimed to determine the phytochemical compounds in methanolic extracts of A. ilicifolius and their antifungal and antioxidant activity. The study involved laboratory experiments with a post-test only control group design. Antifungal activity against Candida albicans biofilm was determined using microtiter plates. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Phytochemical screening used colorimetric methods. Methanolic extracts of A. ilicifolius at 16% and 20% concentration had the same inhibitory effect as nystatin against C. albicans (about 70% inhibition of biofilm). Chemical compounds identified in the extract included flavonoids, alkaloids, glycosides, polyphenols, tannins, and steroids. Methanolic extracts of A. ilicifolius have strong antioxidant and antifungal activity, and the plant’s phytochemical compounds are potential candidates for antifungal therapy.

Solanum dolichosepalum is a plant with anti-infective effects. It is a healing agent and has ethnopharmacological uses. In this study, the antifungal activity of extracts and fractions of this species on C. albicans and F. oxysporum was evaluated. The antioxidant activity was measured using the ABTS and DPPH methods, and by determining the total content of phenolic compounds. An HPLC-DAD qualitative analysis was carried out to identify phenolic compounds and alkaloids. Pearson’s correlation coefficients were calculated. Inhibitory effects were found in all the extracts and fractions on the analyzed microorganisms. F. oxysporum was the microorganism most sensitive to the action of S. dolichosepalum extracts. All extracts and fractions showed antioxidant activity, with the acetone extract and the acetone fraction being those that generated the best results. The content of total phenolic compounds showed that acetone has a greater affinity with the phenolic compounds present in S. dolichosepalum. In this plant, p-Hydroxybenzoic, vanillic, ferulic, trans-cinnamic, caffeic, p-coumaric, and rosmarinic acids were found, as well as theobromine, quercetin, and luteolin. The content of total phenolic compounds was determined to be directly proportional to the inhibition of the ABTS and DPPH radicals, and the inhibition of the analyzed microorganisms. It was determined that the extracts and fractions obtained from S. dolichosepalum show antioxidant and antifungal activity.

Sustainable hydrocolloid-based films containing natural antioxidants, caffeic and p-coumaric acids at different concentrations of 0.5%, 1%, 5%, and 10% w/w of polymers, were designed for packing fatty foods. Antioxidant activities and kinetics for all film formulations were assessed using radical scavenging activity (DPPH), reducing power, and iron chelating ability. Release kinetics of the antioxidants from the films into a food simulant (96% ethanol) were analyzed. The intermolecular interactions between antioxidants and polymers chains were assessed by Fourier transform infrared attenuated total reflectance (FTIR-ATR) and related to the film properties. Antioxidant activity of pure compounds (powder), showed that caffeic acid (IC50 = 4 μg/mL) had higher activity than p-coumaric acid (IC50 = 33 μg/mL). Films containing caffeic acid exhibited higher antioxidant activity, reducing power, and iron chelating ability than p-coumaric acid films. The antioxidant activity is concentration dependent. However, the percentage of release (PR) in ethanol (96%) is not influenced by the initial concentration. PR is 88% ± 9% and 82% ± 5%, respectively, for caffeic and p-coumaric acids. Determination of the partition ( Kp) and the apparent diffusion ( D) coefficients allowed better characterization of the release kinetic mechanisms. The partition coefficients of caffeic acid ( Kp = 454) and p-coumaric acid ( Kp = 480) are not influenced by the initial concentration. The diffusion coefficients ( D) of caffeic and p-coumaric acids were of same order, but they slightly increased with the antioxidant concentration and probably related to antioxidant activity. FTIR displayed that amide B and amide-III are involved in the interactions occurring between polymer chains and antioxidants. However, interactions are of only low energy and unable to significantly affect the structure of films and consequently the release kinetics.

Antibiotic resistance poses a serious threat to public health, raising the number of diseases in the community. Recent research has shown that plant-derived phenolic compounds have strong antimicrobial, antifungal, and cytotoxic properties against a variety of microorganisms and work as great antioxidants in such treatments. The goal of the current work is to evaluate the anticancerous, antibacterial, antifungal, antioxidant, and cytotoxicity activities in the extracts of the different plant parts (leaves, stems, and roots) of S. carvifolia (L.) L. This is a medicinally important plant and has been used for different kinds of diseases and ailments such as hysteria and seizures. The phenolic compounds from the different plant parts were analyzed using HPLC and the following were found to be present: chlorogenic acid, gallic acid, rutin, syringic acid, vanillic acid, cinnamic acid, caffeic acid, and protocatechuic acid. Gallic acid was found to have the highest concentration (13.93 mg/g), while chlorogenic acid (0.25 mg/g) had the lowest. The maximum TPC value, which ranged from 33.79 to 57.95 mg GAE/g dry extract weight, was found in the stem. Root extract with 9.4 mg RE/g had the greatest TFC level. In the leaf and stem extracts, the RSC ranged from 0.747 mg/mL to 0.734 mg/1 mL GE/g dry extract weight, respectively. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to measure in vitro antioxidant activity. In a concentration-dependent way, promising antioxidant activity was reported. Moreover, 3,5-dinitrosalicylic acid (DNSA) and the Folin-Ciocalteu phenol reagent technique were used to determine reducing sugar content and total phenolic content, respectively. Antibacterial activity against eight strains (MIC: 250-1,000 μg/mL) was analyzed, and the stem extract exhibited maximum activity. Antifungal activity was also assessed, and potent activity was reported especially in the extract obtained from the stem. Cytotoxicity was evaluated using an MTT assay in the A549 cell line, where different doses (0.0625, 0.125, 0.25, 0.5, and 1 mg/mL) of leaf, root, and stem extracts were used. Treatment with these extracts reduced the cell viability, indicating that S. carvifolia may possess anticancer potential, which can be of great therapeutic value.

Artemisia herba-alba Asso is an endemic plant from North-East Morocco offering a diverse range of pharmacological, cosmetic, and agro-ecological uses. However, Artemisia herba-alba has not been well exploited in the field of plant protection (post-harvest diseases). This is why the main objective of the present study is to evaluate the antifungal and antioxidant activities of extracts or the essential oil of this plant. Antifungal activity was assessed against Botrytis cinerea, Penicillium expansum, and Penicillium digitatum using the agar dilution method for the aqueous extracts and fumigation for the essential oil. Antioxidant activity was assessed using the DPPH scavenging test and the FRAP ferric ion reduction capacity. The chemical composition of the extracts was determined by HPLC and that of the essential oil by GC-MS/MS. In addition, the polyphenol, flavonoid, and tannin content was determined using colorimetric methods. The results of this study showed that the total content of polyphenols (217.60 mg GAE/g E), flavonoids (43.59 mg QE/g E), and tannins (32.58 mg GAE/g E) was significantly higher (p ≤ 0.05) in the ethanolic extract than in the aqueous and hexanoic extracts. Moreover, the HPLC analysis of the aqueous extract revealed the presence of six compounds, namely, catechin, gallic acid, hydroxybenzoic acid, syringic acid, caffeic acid, and rutin. In addition, the ethanolic extract was found to contain seven phenolic compounds. On the one hand, 35 compounds were identified in the essential oil of Artemisia herba-alba, representing 99.7% of the total. According to this study, the dominant compounds in the essential oil of Artemisia herba-alba Asso are camphor (46.57%), endo-borneol (5.65%), eucalyptol (5.64%), and thymol (3.85%). Furthermore, the biological evaluation showed that the extracts and essential oil of Artemisia herba-alba have significant antioxidant and antibacterial activities. The findings show that Artemisia herba-alba is a plant that can be used as a source of antifungal chemicals to prevent putrefaction of foodstuffs and, more specifically, postharvest diseases.

The present study aimed to evaluate antioxidant and biological activities of Brazilian green propolis in order to elucidate its potential use as a food additive. The influence of seasonality over antioxidants compounds in green propolis was evaluated. Samples were collected during a year and, trough Response Surface Methodology (RSM), hydroalcoholic extracts were produced under optimize conditions. The variables evaluated on RSM were: degree of solvent hydration, temperature and extraction time. The responses observed were Total Phenolic Content and antioxidant activity determined by in vitro tests such as ORAC (Oxygen Radical Absorbance Capacity), ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), DPPH (2,2diphenyl-1-picrylhydrazyl) and FRAP (Ferric Reducing Antioxidant Power). The phenolic compounds identification and quantification were performed by chromatography techniques (UPLC-DAD e GC-MS), with antioxidants standards. The optimized essays made possible the production of green propolis extracts with higher antioxidant activities when prepared with 70% of solvent (ethanol: water, v/v), at 45C for 20 minutes. Chlorogenic acid, caffeic acid, p-coumaric acid, kaempferide, pinostrobin and artepillin C were identified in all samples, the greater amount was observed in winters 'sample. The influence of grinding over antioxidant and antifungal activities well as the antibacterial power were evaluated. Doses of green propolis extract were tested over Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Botrytis cinerea and Rhyzopus stolonifer. The results showed the inhibitory effect of green propolis extract on microorganisms tested. On model system evaluation in order to determine the antioxidant activity were used as raw material, emulsions prepared with flaxseed oil and water, added with different doses of green propolis extract (50, 100, 150 and 200 mg/kg) and submitted to accelerated oxidation test. To compare the results, synthetic antioxidants allowed by Brazilian legislation were also tested (TBHQ, BHA e BHT). The amount of hydroperoxides and specific absorbance on UV were monitored for 120 hours. The dose which presented higher protective effect was sensorially tested. The results of sensory analysis demonstrate that 100 mg/kg of extract was effective to retard the emulsions oxidation. According to sensory analysis's results, the green propolis aroma masked the rancid odor. Due to the presence of bioactive compounds, the use of green propolis based products as food additive is promising.

Hydroxycinnamates are among the most widely distributed plant phenylpropanoids present in the free, conjugated-soluble and insoluble-bound forms. This review will focus on the occurrence, in vitro and in vivo antioxidant activities of ferulic, coumaric, caffeic and sinapic acids and their derivatives. Hydroxycinnamates are found in almost all food groups though they are abundant in cereals, legumes, oilseeds, fruits, vegetables and beverages and render antioxidant activity by scavenging hydroxyl radical, superoxide radical anion, several organic radicals, peroxyl radical, peroxinitrite and singlet oxygen, among others. Further, their antioxidant activity as chain breaking antioxidants and reducing agents is also notable. Ferulic acid and its derivatives such as ferulic acid ethyl ester, ferulic acid dehydrodimers, feruloyl glycosides and curcumin have demonstrated potent antioxidant activity in both in vitro and in vivo systems. Similarly, caffeic acid and some of its derivatives such as caffeic acid phenethyl ester, rosmarinic acid, and chlorogenic acid exhibit antioxidant activity. The highest antioxidant activity was observed for caffeic acid whereas p-coumaric acid had the least effect among major hydroxycinnamic acids. The importance of structural effects on the potency of antioxidant activity of hydroxycinnamates is discussed. While this review also shows the existence of substantial body of evidences for in vitro antioxidant activity of hydroxycinnamates, there is a clear gap for in vivo information, particularly for sinapic and p-coumaric acids and their derivatives. The role of grains, fruits, vegetables and red wine in disease risk reduction and health promotion could partly be attributed to their constituent hydroxycinnamates.

Phytophthora blight, caused by the oomycete pathogen, Phytophthora capsici, is a devastating disease on bell pepper and cucurbit crops in the United States and worldwide (29,40). P. capsici causes a root and crown rot, as well as an aerial blight of leaves, fruit, and stems, on bell pepper (Capsicum annuum), tomatoes, cucumber, watermelon, squash, and pumpkin (29,35, 40,57,73). The disease was first described on bell pepper in New Mexico in 1922 (40). In recent years, epidemics have been severe in areas of North Carolina, Florida, Georgia, Michigan, and New Jersey. Oospores are believed to provide the initial source of inoculum in the field, and the disease is polycyclic within seasons (1,7,59,60,67). In this article, we discuss the biology and epidemiology of Phytophthora blight on bell pepper and also describe management strategies that can be implemented based on existing knowledge of the ecology of this devastating pathogen. The objectives of ecologically based pest management (EBPM) are the safe, profitable, and durable management of pests that includes a total systems approach (25). EBPM relies primarily on biological input of knowledge concerning a pathogen life cycle, and secondarily, when necessary, on physical, chemical, and biological supplements for disease management. An understanding of the ecological processes that are suppressive to plant diseases is emphasized rather than secondary inputs (25). Fortunately, we have a considerable amount of information available on the biology and ecology of P. capsici, which can now be integrated to improve our ability to manage the disease using ecologically based approaches. Strategies recommended for management of Phytophthora blight involve integrated approaches that focus first on cultural practices that reduce high soil moisture conditions, but also include monitoring and reduction of propagules of P. capsici that persist in the soil, utilization of cultivars with resistance to the disease, and when necessary, judicious fungicide applications. Symptoms and Life Cycle P. capsici can infect virtually every part of the pepper plant. The pathogen causes a root and crown rot on pepper (Fig. 1) and also forms distinctive black lesions on the stem (Fig. 2). P. capsici can also infect the leaves and causes lesions that are circular, grayish brown, and water-soaked (Fig. 3). Leaf lesions and stem lesions are common when inoculum is splash dispersed from the soil to lower portions of the plant. The pathogen can also infect fruit and causes lesions that are typically covered with white sporangia, a sign of the pathogen (Fig. 4). P. capsici typically causes a fruit rot or stem rot on cucumbers and squash (Fig. 5). P. capsici reproduces by both sexual and asexual means (Fig. 6). The pathogen produces two mating types, known as the A1 and A2. These are actually compatibility types and do not correspond to dimorphic forms. Each mating type produces hormones that are responsible for gametangia differentiation in the opposite mating type. Both A1 and A2 mating types are common in fields in North Carolina and have also been identified within the same plant (59). P. capsici produces a male gametangium, called the antheridium, and a female gametangium, called the oogonium. The antheridium is amphigynous in this species. Meiosis occurs within the gametangia, and plasmogamy and karyogamy result

Caffeic acid (CFA) is one of the various natural antioxidants and chemoprotective agents occurring in the human diet. In addition, its metal complexes play fundamental roles in biological systems. Nevertheless, research on the properties of CFA with lanthanide metals is very scarce, and little to no chemical or biological information is known about these particular systems. Most of their properties, including their biological activity and environmental impact, strictly depend on their structure, stability, and solution behaviour. In this work, a multi-analytical-technique approach was used to study these relationships for the Eu(III)/CFA complex. The synthesized metal complex was studied by FT-IR, FT-Raman, elemental, and thermal (TGA) analysis. In order to examine the chemical speciation of the Eu(III)/CFA system in an aqueous solution, several independent potentiometric and spectrophotometric UV-Vis titrations were performed at different M:L (metal:ligand) and pH ratios. The general molecular formula of the synthesized metal complex in the solid state was [Eu(CFA)3(H2O)3]∙2H2O (M:L ratio 1:3), while in aqueous solution the 1:1 species were observed at the optimum pH of 6 ≤ pH ≤ 10, ([Eu(CFA)] and [Eu(CFA)(OH)]−). These results were confirmed by 1H-NMR experiments and electrospray-ionization mass spectrometry (ESI-MS). To evaluate the interaction of Eu(III)/CFA and CFA alone with cell membranes, electrophoretic mobility assays were used. Various antioxidant tests have shown that Eu(III)/CFA exhibits lower antioxidant activity than the free CFA ligand. In addition, the antimicrobial properties of Eu(III)/CFA and CFA against Escherichia coli, Bacillus subtilis and Candida albicans were investigated by evaluation of the minimum inhibitory concentration (MIC). Eu(III)/CFA shows higher antibacterial activity against bacteria compared to CFA, which can be explained by the highly probable increased lipophilicity of the Eu(III) complex.

Adsorption of caffeic acid (CA) on chitosan (CH) powder from aqueous solution has been investigated to obtain insoluble CA–CH complex powders having different amount of CA. The pseudo-second kinetic model and the Langmuir, Freundlich and Dubinin–Radushkevich adsorption models were used to describe the kinetic and equilibrium adsorption of CA on CH. With the increase of adsorption temperature, the rate of adsorption increased while the amount of adsorbed CA decreased. The Langmuir adsorption model predicted that adsorption of CA takes place on the ionized amino groups of CH. However, with the increase of adsorption temperature the ion-exchange between carboxylic groups of CA and amino groups of CH became moderately difficult. The thermodynamic characteristics of adsorption have been evaluated. CA–CH complex formation was confirmed by FT-IR spectroscopy. With increasing amount of adsorbed CA the CA–CH powder was becoming more hydrophobic. 2,2′-Azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) assay confirmed that CA retained the antioxidant activity when immobilized on chitosan power.

Determination of the phenolic composition of sherry and table white wines by liquid chromatography and their relation with antioxidant activity

Chlorogenic acid is a major phenolic compound that forms a substantial part of plant foods and is an ester of caffeic acid and quinic acid. However, the effect of the structures of both chlorogenic and caffeic acids on their antioxidant and antidiabetic potentials have not been fully understood. Thus, this study sought to investigate and compare the interaction of caffeic acid and chlorogenic acid with α-amylase and α-glucosidase (key enzymes linked to type 2 diabetes) activities in vitro. The inhibitory effect of the phenolic acids on α-amylase and α-glucosidase activities was evaluated. Thereafter, their antioxidant activities as typified by their 1,1-diphenyl-2 picrylhydrazyl radical scavenging ability and ferric reducing antioxidant properties were determined. The results revealed that both phenolic acids inhibited α-amylase and α-glucosidase activities in a dose-dependent manner (2-8 μg/mL). However, caffeic acid had a significantly (p<0.05) higher inhibitory effect on α-amylase [IC50 (concentration of sample causing 50% enzyme inhibition)=3.68 μg/mL] and α-glucosidase (IC50=4.98 μg/mL) activities than chlorogenic acid (α-amylase IC50=9.10 μg/mL and α-glucosidase IC50=9.24 μg/mL). Furthermore, both phenolic acids exhibited high antioxidant properties, with caffeic acid showing higher effects. The esterification of caffeic acid with quinic acid, producing chlorogenic acid, reduces their ability to inhibit α-amylase and α-glucosidase activities. Thus, the inhibition of α-amylase and α-glucosidase activities by the phenolic acids could be part of the possible mechanism by which the phenolic acids exert their antidiabetic effects.

As a promising biological material, chitooligosaccharide (COS) has attracted increasing attention because of its unique biological activities. In this study, fourteen novel phenolic acid functional COS derivatives were successfully prepared using two facile methods. The structures of derivatives were characterized by FT-IR and 1H NMR spectra. The in vitro antioxidant activity experiment results demonstrated that the derivatives presented stronger 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), superoxide, hydroxyl radical scavenging activity and reducing power, especially the N,N,N-trimethylated chitooligosaccharide gallic acid salt (GLTMC), gallic acid esterified N,N,N-trimethylated chitooligosaccharide (GL-TMC) and caffeic acid N,N,N-trimethylated chitooligosaccharide (CFTMC) derivatives. Furthermore, the antifungal assay was carried out and the results indicated that the salicylic acid esterified N,N,N-trimethylated chitooligosaccharide (SY-TMC) had much better inhibitory activity against Botrytis cinerea and Fusarium graminearum. Additionally, the results of the bacteriostasis experiment showed that the caffeic acid esterified N,N,N-trimethylated chitooligosaccharide (CF-TMC) had the potential ability to inhibit Escherichia coli and Staphylococcus aureus bacteria. Altogether, this study may provide a neoteric method to produce COS derivatives with significantly increased biological activities, which have potential use in food, medicine, and health care products and other related industries.

Chapter 71 - Antifungal Inhibitory Activities of Caffeic and Quinic Acid Derivatives

The antioxidant and antifungal activity of chitosan derivatives bearing Schiff bases and quaternary ammonium salts