Antifungal Activity of the Extract of a Macroalgae, Gracilariopsis persica, against Four Plant Pathogenic Fungi

Application of biomimetically synthesized silver nanoparticles as cathode catalyst, quorum-quencher, and anti-biofouling agent for the performance boosting of microbial fuel cell

A microbial fuel cell (MFC) is a cutting-edge bioelectrochemical technology, which demonstrates power and other valuables recovery while treating wastewater by cultivating electroactive microbes. However, rampant biofilm growth over the cathode surface of air cathode MFC exacerbates the oxidation-reduction reaction rate, triggering a dip in the overall performance of MFC. In this sense, biosynthesized silver nanoparticles (AgNPs) have garnered a plethora of potential applications as cathode catalysts as well as anti-biofouling agent for MFCs without harming nature. The MFC equipped with the mixture of aloe vera and algae (@5 mg/cm2) synthesized AgNPs on cathode generated a maximum power density of 66.5 mW/m2 and chemical oxygen demand removal efficiency of 85.2%, which was ca. 5.6 times and 1.2 times higher compared to control MFC operated without any catalyst on cathode. Thus, this investigation paves the way for using eco-amiable, low-cost bioderived organic compounds to assist MFC in achieving high power output and other valuables with minimal reliance on chemicals.

Chemical constituents and antifungal potential of Attalea geraensis Barb. Rodr. (Arecaceae) palm leaves, a species native to the Cerrado of Brazil

Fungal diseases, especially those that affect the root systems of plants, caused by Rhizoctonia and Macrophomina are limiting factors for achieving high crop yields. Alternatives to controlling fungi with chemical products drive the search for new options for bioactive compounds from plants. Attalea geraensis, a palm tree from the Brazilian Cerrado, is rich in flavonoids with antifungal actions. The objective of this work is to identify the chemical classes present in the ethanolic extract of green leaves of A. geraensis and determine the antifungal potential of the extract against isolates of Macrophomina phaseolina (Tassi) Goid. and Rhizoctonia solani JG Kühn. Phytochemical prospection, flavonoid dereplication, and antifungal activity were carried out of the ethanolic extract of the green leaves of A. geraensis harvested in the Cerrado area of Brazil. Steroids, triterpenes, saponins, and anthraquinones are described here for the first time for the leaves of A. geraensis. The flavonoids quercetin, isorhamnetin, 3,7-dimethylquercetin, quercetin 3-galactoside, 5,7-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-{[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-4H-chromen-4-one, rhamnazin 3-galactoside, keioside, and rhamnazin 3-rutinoside were identified. Of these, only quercetin and isorhamnetin had already been identified in the leaves of A. geraensis. The results show a fungistatic potential for the species. The diversity of flavonoids present in the leaves of A. geraensis may be the result of a synergistic action between fungus and plant or there could be an antagonistic effect between flavonoids and the other identified chemical classes.

Antifungal Activity of Water-Based Adhesives Derived from Pineapple Stem Flour with Apple Cider Vinegar as an Additive

As a byproduct of bromelain extraction procedures, pineapple stem flour is underutilized. Since water glues derived from gelatinization typically have poor mold resistance, this study aims to produce flour-based value-added products, such as mold-resistant water-based adhesives. To address this issue, this study explored the use of apple cider vinegar (ACV) as a low-cost, non-toxic, commercially available antifungal agent to improve the mold resistance of adhesives. Furthermore, laurate flour was produced via a transesterification of the flour and methyl laurate using a K2CO3 catalyst. Both the unmodified flour and the functionalized flour were employed to prepare water-based adhesives. For both flour systems, adding ACV at concentrations of at least 2.0% v/v enhanced the mold resistance of the adhesives and completely inhibited the development of A. niger mycelia for up to 90 days of storage. The adhesives made from the transesterified flour exhibited a higher shear strength for the paper bonding (ca. 8%) than the unmodified ones. Additionally, the ACV additive had no negative effects on the shear strengths of the water-based adhesives. All of the flour-based adhesives developed in this study had a higher shear strength for paper substrates than two locally available commercial water glues.

Seaweed Extracts to Control Postharvest Phytopathogenic Fungi in Rocha Pear

Fungal infections cause losses amounting to between 20 and 25% of the fruit industry's total outcome, with an escalating impact on agriculture in the last decades. As seaweeds have long demonstrated relevant antimicrobial properties against a wide variety of microorganisms, extracts from Asparagopsis armata, Codium sp., Fucus vesiculosus, and Sargassum muticum were used to find sustainable, ecofriendly, and safe solutions against Rocha pear postharvest fungal infections. Alternaria alternata, Botrytis cinerea, Fusarium oxysporum, and Penicillium expansum mycelial growth and spore germination inhibition activities were tested in vitro with five different extracts of each seaweed (n-hexane, ethyl acetate, aqueous, ethanolic, and hydroethanolic). An in vivo assay was then performed using the aqueous extracts against B. cinerea and F. oxysporum in Rocha pear. The n-hexane, ethyl acetate, and ethanolic extracts from A. armata showed the best in vitro inhibitory activity against B. cinerea, F. oxysporum, and P. expansum, and promising in vivo results against B. cinerea using S. muticum aqueous extract were also found. The present work highlights the contribution of seaweeds to tackle agricultural problems, namely postharvest phytopathogenic fungal diseases, contributing to a greener and more sustainable bioeconomy from the sea to the farm.

Advances in Alternative Measures in Plant Protection

Food production, along with the constant demand for higher yields, is an imperative of contemporary agricultural production [...].

Chemical Composition and Biological Activities of Lavandula coronopifolia Poir Extracts: A Comparison between Callus Culture and Native Plant

Nowadays, according to the development and high functions of in vitro cultivation, one of the questions that researchers are looking for is whether the characteristics and compositions of the obtained product meet the needs of the society or not. Therefore, this research was done aimed to compare the bioactive characteristics of callus and native plant aqueous extracts of Lavandula coronopifolia Poir. Thus, two different culture media were utilized for calluses’ growth. Extracts from these calluses and native plants were obtained using the sequential ultrasound-microwave assisted extraction (SUMAE) method. The extraction conditions were a constant temperature of 70°C ultrasound in 20 min at 250 W and 8 minutes at 800 W for microwave at 85°C. At first, results revealed that callus cultures were not able to produce any significant amounts of essential oil. Therefore, aqueous extracts obtained from calluses as well as the natural plant were examined in terms of antioxidant activity, total phenolic content, total flavonoid content, and antimicrobial activity. Moreover, their volatile components were detected with GC-MS. Both DPPH and FRAP techniques demonstrated that the callus on MS + Auxin had stronger antioxidant activity than the other callus and native plant. It also had the greatest total phenolic content. In terms of total flavonoid content, the native plant has the highest value. Generally, it can be concluded that the extract of callus on MS + Auxin has shown significant activity against the tested microorganisms than the other samples.

First Report of Clonostachys rosea as a Mycoparasite on Sclerotinia sclerotiorum Causing Head Rot of Cabbage in India

Clonostachys rosea, an ascomycetous, omnipresent, cellulose-decaying soil fungus, has been reported to be a well-known mycoparasitic biological control agent. In this study, we isolated C. rosea, a mycoparasitic fungus for the first time in India from sclerotia of the notorious plant pathogen Sclerotinia sclerotiorum, causing head rot disease in cabbage. A total of five mycoparasitic fungi were isolated from the sclerotial bodies of S. sclerotiorum (TNAU-CR 01, 02, 03, 04 and 05). All the isolates were tested under morpho-molecular characterization. Among them, TNAU-CR 02 showed the greatest mycelial inhibition of 79.63% over the control. Similarly, the SEM imaging of effective C. rosea isolates indicated the presence of numerous conidia destroying the outer cortex layers of sclerotia. Metabolite fingerprinting of C. rosea TNAU-CR 02 identified 18 chemical compounds using GC-MS analysis. The crude antibiotics of C. rosea TNAU-CR 02 were verified for their antifungal activity against S. sclerotiorum and the results revealed 97.17% mycelial inhibition compared with the control. Similarly, foliar application of TNAU-CR 02 at 5 mL/litre on 30, 45 and 60 days after transplanting showed the lowest disease incidence of 15.1 PDI compared to the control. This discovery expands our understanding of the biology and the dissemination of C. rosea, providing a way for the exploitation of C. rosea against cabbage head rot pathogens.

Comparative study of the chemical composition and antifungal activity of commercial brown seaweed extracts

INTRODUCTION

A sustainable agriculture and the great increase in consumers of organic products in the last years make the use of natural products one of the main challenges of modern agriculture. This is the reason that the use of products based on seaweed extracts has increased exponentially, specifically brown seaweeds, including Ascophyllum nodosum and Ecklonia maxima.

METHODS

In this study, the chemical composition of 20 commercial seaweed extract products used as biostimulants and their antifungal activity against two common postharvest pathogens (Botrytis cinerea and Penicillium digitatum) from fruits were evaluated. Data were processed using chemometric techniques based on linear and non-linear models.

RESULTS AND DISCUSSION

The results showed that the algae species and the percentage of seaweed had a significant effect on the final composition of the products. In addition, great disparity was observed between formulations with similar labeling and antifungal effect of most of the analyzed products against some of the tested pathogens. These findings indicate the need for further research.

Neuroprotective Effects of Quercetin on Ischemic Stroke: A Literature Review

Ischemic stroke (IS) is characterized by high recurrence and disability; however, its therapies are very limited. As one of the effective methods of treating acute attacks of IS, intravenous thrombolysis has a clear time window. Quercetin, a flavonoid widely found in vegetables and fruits, inhibits immune cells from secreting inflammatory cytokines, thereby reducing platelet aggregation and limiting inflammatory thrombosis. In pre-clinical studies, it has been shown to exhibit neuroprotective effects in patients with ischemic brain injury. However, its specific mechanism of action remains unknown. Therefore, this review aims to use published data to elucidate the potential value of quercetin in patients with ischemic brain injury. This article also reviews the plant sources, pharmacological effects, and metabolic processes of quercetin in vivo, thus focusing on its mechanism in inhibiting immune cell activation and inflammatory thrombosis as well as promoting neuroprotection against ischemic brain injury.

GC-MS analysis of cuticular waxes and evaluation of antioxidant and antimicrobial activity of Chaenomeles cathayensis and Ch. × californica fruits

Fruit extracts of the Chaenomeles species are a rich source of compounds having health-promoting properties, while their distribution between the species and cultivars varies significantly depending on both genotype and environmental threats. This study aimed at discovering antioxidant and antimicrobial potential of the secondary metabolites of fruit and waxes of fruit cuticular of introduced Ch. cathayensis and Ch. × californica plants. The sum of detected polyphenols in the isopropanolic fruit extracts varied slightly between the species, while significant excesses in indices were seen for both species peel extracts as compared to pulp extracts. Antimicrobial assays carried out by disc diffusion method showed notable activity of the fruit peel and pulp extracts of both species against all tested Gram-negative and Gram-positive bacterial strains, and two Candida strains as well. Pseudomonas aeruginosa strain was the most resistant to the action of both fruit extracts, especially peel extracts of Ch. cathayensis fruits. As identified by gas chromatography-mass spectrometry (GC-MS) assays, chloroformic extracts from the fruits of cuticular waxes of Ch. cathayensis and Ch. × californica contained six prevailing fractions: aldehydes, alkanes, alcohols, esters, fatty acids and various terpenoids. The predominant compounds were tetrapentacontane (21.8% of total amount) and heptacosanal (23.1% of total), respectively in the cuticular waxes of Ch. cathayensis and Ch. × californica. Cinnamaldehyde, cis-9-hexadecenal, hexadecanoic acid, oleic acid, olean-12-ene-3,28-diol (3. beta), lupeol, diisooctyl phthalate, 9-octadecenoic acid, 1,2,3-propanetriyl ester, 1,3,12-nonadecatriene-5,14-diol and some other identified compounds are well-known for their bioactivity, indicating the feasibility of studying the antimicrobial potential of plant fruits.