A review on endophytic bacteria of orchids: functional roles toward synthesis of bioactive metabolites for plant growth promotion and disease biocontrol.

MAIN CONCLUSION: In this review, we have discussed the untapped potential of orchid endophytic bacteria as a valuable reservoir of bioactive metabolites, offering significant contributions to plant growth promotion and disease protection in the context of sustainable agriculture. Orchidaceae is one of the broadest and most diverse flowering plant families on Earth. Although the relationship between orchids and fungi is well documented, bacterial endophytes have recently gained attention for their roles in host development, vigor, and as sources of novel bioactive compounds. These endophytes establish mutualistic relationships with orchids, influencing plant growth, mineral solubilization, nitrogen fixation, and protection from environmental stress and phytopathogens. Current research on orchid-associated bacterial endophytes is limited, presenting significant opportunities to discover new species or genetic variants that improve host fitness and stress tolerance. The potential for extracting bioactive compounds from these bacteria is considerable, and optimization strategies for their sustainable production could significantly enhance their commercial utility. This review discusses the methods used in isolating and identifying endophytic bacteria from orchids, their diversity and significance in promoting orchid growth, and the production of bioactive compounds, with an emphasis on their potential applications in sustainable agriculture and other sectors.

A review on endophytic fungi: a potent reservoir of bioactive metabolites with special emphasis on blight disease management.

Phytopathogenic microorganisms have caused blight diseases that present significant challenges to global agriculture. These diseases result in substantial crop losses and have a significant economic impact. Due to the limitations of conventional chemical treatments in effectively and sustainably managing these diseases, there is an increasing interest in exploring alternative and environmentally friendly approaches for disease control. Using endophytic fungi as biocontrol agents has become a promising strategy in recent years. Endophytic fungi live inside plant tissues, forming mutually beneficial relationships, and have been discovered to produce a wide range of bioactive metabolites. These metabolites demonstrate significant potential for fighting blight diseases and provide a plentiful source of new biopesticides. In this review, we delve into the potential of endophytic fungi as a means of biocontrol against blight diseases. We specifically highlight their significance as a source of biologically active compounds. The review explores different mechanisms used by endophytic fungi to suppress phytopathogens. These mechanisms include competing for nutrients, producing antifungal compounds, and triggering plant defense responses. Furthermore, this review discusses the challenges of using endophytic fungi as biocontrol agents in commercial applications. It emphasizes the importance of conducting thorough research to enhance their effectiveness and stability in real-world environments. Therefore, bioactive metabolites from endophytic fungi have considerable potential for sustainable and eco-friendly blight disease control. Additional research on endophytes and their metabolites will promote biotechnology solutions.

Unraveling the Red Sea soft coral Sarcophyton convolutum potentials against oxidative and inflammatory stresses in zebrafish.

The Red Sea is one of the world's hotspots for biodiversity, and for marine natural products (MNPs) as well. These MNPs attract special interest for their capabilities to combat inflammatory and oxidative stress-related diseases, being some of the most serious health problems worldwide nowadays. The current study aimed to identify the bioactive ingredients of the Red Sea soft coral Sarcophyton convolutum, and to assess its protective potentials against oxidative and inflammatory stresses. Coral extract (CE) was analyzed using GC-MS and HPLC. In a protection trial, adult zebrafish were intraperitoneally injected with two doses of crab extract, i.e. 50 and 500 µg/fish in 1 % DMSO as a vehicle, then challenged with 30 µg L-1 of CuSO4 for 48 h. All groups, but the negative control one, were challenged with 30 µg L-1 of CuSO4. Total antioxidant activity, as well as mRNA levels of proinflammatory markers and antioxidant enzyme genes were measured. The results showed richness of S. convolutum extract with various bioactive ingredients, including phenolic compounds, flavonoids, alkanes, fatty acids, sesquiterpenes, and pheromone-like substances. CuSO4 significantly induced the expected signals of inflammatory and oxidative stress, reducing both the antioxidant activity and increasing proinflammatory marker genes. However, CE, especially the low dose, showed significant capability to reduce proinflammatory markers and elevating the total antioxidant activity. Therefore, we concluded that S. convolutum can be a promising source for future efforts of drug discovery and a wide spectrum of pharmaceutical products.

Fungal endophytes Fusarium solani SGGF14 and Alternaria tenuissima SGGF21 enhance the glycyrrhizin production by modulating its key biosynthetic genes in licorice (Glycyrrhiza glabra L.).

AIMS: To identify promising fungal endophytes that are able to produce glycyrrhizin and enhance it in licorice and the mechanisms involved. METHODS AND RESULTS: Fifteen fungal endophytes were isolated from Glycyrrhiza glabra L. rhizomes among which SGGF14 and SGGF21 isolates were found to produce glycyrrhizin by 4.29 and 2.58 µg g-1 dry weight in the first generation of their culture. These isolates were identified as Fusarium solani and Alternaria tenuissima, respectively, based on morphological characteristics and sequence analysis of internal transcribed spacer, TEF1, ATPase, and CAL regions. Subsequently, G. glabra plants were inoculated with these fungal isolates to examine their effect on glycyrrhizin production, plant growth parameters and the expression of key genes involved in glycyrrhizin pathway: SQS1, SQS2, bAS, CAS, LUS, CYP88D6, and CYP72A154. Endophytes were able to enhance glycyrrhizin content by 133%-171% in the plants. Natural control (NC) plants, harboring all natural endophytes, had better growth compared to SGGF14- and SGGF21-inoculated and endophyte-free (EF) plants. Expression of SQS1, SQS2, CYP88D6, and CYP72A154 was upregulated by inoculation with endophytes. LUS and CAS were downregulated after endophyte inoculation. Expression of bAS was higher in SGGF21-inoculated plants when compared with NC, EF, and SGGF14-inoculated plants. CONCLUSIONS: Two selected fungal endophytes of G. glabra can produce glycyrrhizin and enhance glycyrrhizin content in planta by modulating the expression of key genes in glycyrrhizin biosynthetic pathway.

Biotechnological potential of actinomycetes in the 21st century: a brief review.

This brief review aims to draw attention to the biotechnological potential of actinomycetes. Their main uses as sources of antibiotics and in agriculture would be enough not to neglect them; however, as we will see, their biotechnological application is much broader. Far from intending to exhaust this issue, we present a short survey of the research involving actinomycetes and their applications published in the last 23 years. We highlight a perspective for the discovery of new active ingredients or new applications for the known metabolites of these microorganisms that, for approximately 80 years, since the discovery of streptomycin, have been the main source of antibiotics. Based on the collected data, we organize the text to show how the cosmopolitanism of actinomycetes and the evolutionary biotic and abiotic ecological relationships of actinomycetes translate into the expression of metabolites in the environment and the richness of biosynthetic gene clusters, many of which remain silenced in traditional laboratory cultures. We also present the main strategies used in the twenty-first century to promote the expression of these silenced genes and obtain new secondary metabolites from known or new strains. Many of these metabolites have biological activities relevant to medicine, agriculture, and biotechnology industries, including candidates for new drugs or drug models against infectious and non-infectious diseases. Below, we present significant examples of the antimicrobial spectrum of actinomycetes, which is the most commonly investigated and best known, as well as their non-antimicrobial spectrum, which is becoming better known and increasingly explored.

Combining In Vitro, In Vivo, and Network Pharmacology Assays to Identify Targets and Molecular Mechanisms of Spirulina-Derived Biomolecules against Breast Cancer.

The current research employed an animal model of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary gland carcinogenesis. The estrogen receptor-positive human breast adenocarcinoma cell line (MCF-7) was used for in vitro analysis. This was combined with a network pharmacology-based approach to assess the anticancer properties of Spirulina (SP) extract and understand its molecular mechanisms. The results showed that the administration of 1 g/kg of SP increased the antioxidant activity by raising levels of catalase (CAT) and superoxide dismutase (SOD), while decreasing the levels of malonaldehyde (MDA) and protein carbonyl. A histological examination revealed reduced tumor occurrence, decreased estrogen receptor expression, suppressed cell proliferation, and promoted apoptosis in SP protected animals. In addition, SP disrupted the G2/M phase of the MCF-7 cell cycle, inducing apoptosis and reactive oxygen species (ROS) accumulation. It also enhanced intrinsic apoptosis in MCF-7 cells by upregulating cytochrome c, Bax, caspase-8, caspase-9, and caspase-7 proteins, while downregulating Bcl-2 production. The main compounds identified in the LC-MS/MS study of SP were 7-hydroxycoumarin derivatives of cinnamic acid, hinokinin, valeric acid, and α-linolenic acid. These substances specifically targeted three important proteins: ERK1/2 MAPK, PI3K-protein kinase B (AKT), and the epidermal growth factor receptor (EGFR). Network analysis and molecular docking indicated a significant binding affinity between SP and these proteins. This was verified by Western blot analysis that revealed decreased protein levels of p-EGFR, p-ERK1/2, and p-AKT following SP administration. SP was finally reported to suppress MCF-7 cell growth and induce apoptosis by modulating the PI3K/AKT/EGFR and MAPK signaling pathways suggesting EGFR as a potential target of SP in breast cancer (BC) treatment.

Application of the Key Characteristics of Carcinogens to Bisphenol A.

The ten key characteristics (KCs) of carcinogens are based on characteristics of known human carcinogens and encompass many types of endpoints. We propose that an objective review of the large amount of cancer mechanistic evidence for the chemical bisphenol A (BPA) can be achieved through use of these KCs. A search on metabolic and mechanistic data relevant to the carcinogenicity of BPA was conducted and web-based software tools were used to screen and organize the results. We applied the KCs to systematically identify, organize, and summarize mechanistic information for BPA, and to bring relevant carcinogenic mechanisms into focus. For some KCs with very large data sets, we utilized reviews focused on specific endpoints. Over 3000 studies for BPA from various data streams (exposed humans, animals, in vitro and cell-free systems) were identified. Mechanistic data relevant to each of the ten KCs were identified, with receptor-mediated effects, epigenetic alterations, oxidative stress, and cell proliferation being especially data rich. Reactive and bioactive metabolites are also associated with a number of KCs. This review demonstrates how the KCs can be applied to evaluate mechanistic data, especially for data-rich chemicals. While individual entities may have different approaches for the incorporation of mechanistic data in cancer hazard identification, the KCs provide a practical framework for conducting an objective examination of the available mechanistic data without a priori assumptions on mode of action. This analysis of the mechanistic data available for BPA suggests multiple and inter-connected mechanisms through which this chemical can act.

Pathway and Production Differences in Branched-Chain Hydroxy Acids as Bioactive Metabolites in Limosilactobacillus fermentum, Ligilactobacillus salivarius, and Latilactobacillus sakei.

Branched-chain hydroxy acids (BCHAs) as bioactive metabolites of Lactobacillaceae include 2-hydroxy isovaleric acid (HIVA), 2-hydroxy isocaproic acid (HICA), and 2-hydroxy-3-methyl isovaleric acid (HMVA). Combining targeted and untargeted metabolomics, this study elucidates differences in extracellular BCHA production in Limosilactobacillus fermentum, Ligilactobacillus salivarius, and Latilactobacillus sakei alongside comparing comprehensive metabolic changes. Through targeted metabolomics, BCHA production among 38 strains exhibited strain specificity, except for L. sakei, which showed significantly lower BCHA production. Explaining the lower production in L. sakei, which lacks the branched-chain amino acid (BCAA)-utilizing pathway, comparison of BCHA production by precursor reaction revealed that the pathway utilizing BCAAs is more dominant than the pathway utilizing pyruvate. Expanding upon the targeted approach, untargeted metabolomics revealed the effects of the reaction compound on other metabolic pathways besides BCHAs. Metabolism alterations induced by BCAA reactions varied among species. Significant differences were observed in glycine, serine, and threonine metabolism, pyruvate metabolism, butanoate metabolism, and galactose metabolism (p < 0.05). These results emphasize the importance of the synergy between fermentation strains and substrates in influencing nutritional components of fermented foods. By uncovering novel aspects of BCAA metabolism pathways, this study could inform the selection of fermentation strains and support the targeted production of BCHAs.

Squirting Cucumber, Ecballium elaterium (L.) A. Ritch: An Update of Its Chemical and Pharmacological Profile.

Ecballium elaterium, also known as squirting cucumber, is a plant which is widespread in temperate regions of Europe, Africa and Asia. The plant is considered to be one of the oldest used drugs. In the last decades, E. elaterium has been widely studied as a source of triterpene metabolites named cucurbitacins, often found as glycosylated derivatives, used by the plant as defensive agents. Such metabolites exhibit several biological activities, including cytotoxic, anti-inflammatory, and anti-cancer. Interestingly, the bioactive properties of E. elaterium extracts have been investigated in dozens of studies, especially by testing the apolar fractions, including the essential oils, extracted from leaves and fruits. The purpose of this review is to provide an overview of the chemical profile of different parts of the plants (leaves, flowers, and seeds) analyzing the methods used for structure elucidation and identification of single metabolites. The pharmacological studies on the isolated compounds are also reported, to highlight their potential as good candidates for drug discovery.

No Evidence Was Found for the Presence of Terreolides, Terreumols or Saponaceolides H-S in the Fruiting Bodies of Tricholoma terreum (Basidiomycota, Agaricales).

Two different collections of the gilled wild fungus Tricholoma terreum, collected in Italy, were subjected to phytochemical analysis. The fungal material was confidently identified by analysis of the ITS genomic sequences. Using both HR-LC-MS and NMR techniques, no evidence was found for the presence in the fruiting bodies of terreolides, terreumols or saponaceolides H-S, in striking contrast with the isolation of these terpenoids by Chinese authors from a mushroom collected in France and identified as T. terreum. The main cytotoxic terpenoid identified and isolated from the extracts of the specimens investigated in this work was the C30 derivative saponaceolide B, which had been previously isolated from T. saponaceum and other T. terreum collections. Although saponaceolide B is a rather labile molecule, easily degradable by heat or in acidic conditions, our study indicated that none of the extraction protocols used produced saponaceolide H-S or terreolide/terreumol derivatives, thus excluding the possibility that the latter compounds could be extraction artifacts. Considered together, these findings point to the need for the unambiguous identification of mushroom species belonging to the complex genus Tricholoma, characterized by high variability in the composition of metabolites. Moreover, based on our data, T. terreum must be considered an edible mushroom.

Significance of Soy-Based Fermented Food and Their Bioactive Compounds Against Obesity, Diabetes, and Cardiovascular Diseases.

Soybean-based fermented foods are commonly consumed worldwide, especially in Asia. These fermented soy-products are prepared using various strains of Bacillus, Streptococcus, Lactobacillus, and Aspergillus. The microbial action during fermentation produces and increases the availability of various molecules of biological significance, such as isoflavones, bioactive peptides, and dietary fiber. These dietary bio active compounds are also found to be effective against the metabolic disorders such as obesity, diabetes, and cardiovascular diseases (CVD). In parallel, soy isoflavones such as genistein, genistin, and daidzin can also contribute to the anti-obesity and anti-diabetic mechanisms, by decreasing insulin resistance and oxidative stress. The said activities are known to lower the risk of CVD, by decreasing the fat accumulation and hyperlipidemia in the body. In addition, along with soy-isoflavones fermented soy foods such as Kinema, Tempeh, Douchi, Cheonggukjang/Chungkukjang, and Natto are also rich in dietary fiber (prebiotic) and known to be anti-dyslipidemia, improve lipolysis, and lowers lipid peroxidation, which further decreases the risk of CVD. Further, the fibrinolytic activity of nattokinase present in Natto soup also paves the foundation for the possible cardioprotective role of fermented soy products. Considering the immense beneficial effects of different fermented soy products, the present review contextualizes their significance with respect to their anti-obesity, anti-diabetic and cardioprotective roles.

Improving the Composition and Bioactivity of Cocoa (Theobroma cacao L.) Bean Shell Extract by Choline Chloride-Lactic Acid Natural Deep Eutectic Solvent Extraction Assisted by Pulsed Electric Field Pre-Treatment.

An environmentally friendly method for the release of cocoa bean shell (CBS) extracts is proposed in this paper. This work aims to investigate the effect of pulsed electric field (PEF) pre-treatment on subsequent solid-liquid extraction (SLE) of metabolites with choline chloride-lactic acid natural deep eutectic solvent (NaDES) and bioactivity of cocoa bean shell (CBS) extract. Two different media for PEF application were evaluated: water and chlorine chloride-lactic acid. Total polyphenols (TPC), total flavonoids (TFC), individual major compounds, and antioxidant and antibacterial activity of CBS extracts were assessed. The performance of PEF-assisted extraction was compared with SLE and ultrasound-assisted extraction (UAE). The proposed method improved the release of TPC up to 45% and TFC up to 48% compared with the conventional extraction. The CBS extract showed medium growth inhibition of Escherichia coli and high growth inhibition of Salmonella sp, Listeria monocytogenes, and Staphylococcus aureus. Thus, an extract with enhanced antioxidant and antibacterial properties was obtained.

Exploration of the chemical constituents and its antioxidant, antibacterial activities of endophytic fungi isolated from the medicinal plant Dillenia indica.

Assam, India being the pool for ethnomedicinal plants harbors diverse endophytic fungi constituting major bioactive metabolites. The present study was designed to screen the antioxidant, antibacterial activities along with the chemical constituents of the endophytic fungi isolated from the fruits of Dillenia indica (commonly known as Otenga in Assam). Screening of such metabolic compounds and their antioxidant, antibacterial activities can have tremendous potential in suppressing certain diseases. Agar well diffusion method has been used to carry out the antibacterial assay against three pathogenic bacteria two gram positive [Bacillus subtilis (MTCC No. 441); Staphylococcus aureus (MTCC No. 740)] and one gram negative [Escherichia coli (MTCC No. 739)]. Aspergillus fumigatus of ethyl acetate extract showed a prominent activity against Staphylococcus aureus followed by Aspergillus flavus and Aspergillus niger. Antioxidants have the potential to neutralize and inhibit the action of free radicals. The highest scavenging activity was exhibited by ethyl acetate extract of Aspergillus fumigatus in DPPH assay. Furthermore, the phytochemical screening revealed the presence of flavonoids, alkaloids, terpenoids and saponins. Result showed that ethyl acetate extract of Aspergillus fumigatus showed the highest phenolic content (236.81 ± 0.2 mg.g-1) and least was shown by Aspergillus flavus (92.12 ± 1.4 mg.g-1). Total flavonoids content for Aspergillus fumigatus (39.08 ± 0.2 mg.g-1) was found to be highest compared to other isolates. Molecular identification of the endophytic fungus showing highest activity was done based on 18S rRNA. The sequenced was submitted in Genbank with accession number MH540721 showing high similarities with Aspergillus fumigatus strain 3,162,954. A. fumigatus strain is subjected to GC/MS analysis that revealed the chemical constituents 2-isopropyl-5-methyl-1-heptanol, dodecane, 1-fluoro-pentanoic acid, 2-ethylhexyl ester, 1-octanol, 2-butyl-1-dodecanol. Thus, the present work reveals that endophytic fungi colonizing in ethnomedicinal plant Dillenia indica could be a promising source for antioxidant and antibacterial activity. Further work is needed to add value in various therapeutic and pharmaceutical fields.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits.

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Comprehensive Overview: The Effect of Using Different Solvents for Barley Extraction with Its Anti-Inflammatory and Antioxidant Activity.

Barley (Hordeum vulgare L.) is one of the world's oldest cereal crops. There is considerable interest in barley's potential usage in human diets. Barley is rich in bioactive metabolites such as high content of ß-glucan, fiber, and vitamin E. It is also well-known as a rich source of phytochemical derivatives, namely, phenolic acids, flavonols, chalcones, flavones, proanthocyanidins, and flavanones. Phenolic compounds are recognized as excellent dietary materials with antioxidant and anti-inflammatory activities. This review was written to give an overview of the main components that are separated from barley using different solvents. Even though there were numerous biological activities for barely, the antioxidant, as well as the anti-inflammatory, are the main focus of this review.

Antifungal Effect of Bacillus velezensis ZN-S10 against Plant Pathogen Colletotrichum changpingense and Its Inhibition Mechanism.

In order to optimize crop production and mitigate the adverse impacts associated with the utilization of chemical agents, it is necessary to explore new biocontrol agents. Bacillus velezensis has been widely studied as a biocontrol agent because of its efficient and ecofriendly plant disease control mechanisms. This study shows that the strain ZN-S10 effectively reduces the area of leaf spots caused by the pathogen Colletotrichum changpingense ZAFU0163-1, which affects conidia production and germination, inhibits mycelium growth, and induces mycelium deformation. In antifungal experiments with crude extracts, we observed a delay in the cell cycle of conidia, which may be responsible for the inhibition of conidial germination. Among the bioactive metabolites detected through integrated LC-MS- and GC-MS-based untargeted metabolomics, 7-O-Succinyl macrolactin A, telocinobufagin, and surfactin A may be the main antifungal metabolites of strain ZN-S10. The presence of 7-O-Succinyl macrolactin A could explain the cell damage in germ tubes. This is the first report of telocinobufagin detected in B. velezensis. These results are significant for understanding the inhibitory mechanisms employed by B. velezensis and should serve as a reference in the production of biocontrol agents.

Bioactive Metabolites from Terrestrial and Marine Actinomycetes.

Actinomycetes inhabit both terrestrial and marine ecosystems and are highly proficient in producing a wide range of natural products with diverse biological functions, including antitumor, immunosuppressive, antimicrobial, and antiviral activities. In this review, we delve into the life cycle, ecology, taxonomy, and classification of actinomycetes, as well as their varied bioactive metabolites recently discovered between 2015 and 2023. Additionally, we explore promising strategies to unveil and investigate new bioactive metabolites, encompassing genome mining, activation of silent genes through signal molecules, and co-cultivation approaches. By presenting this comprehensive and up-to-date review, we hope to offer a potential solution to uncover novel bioactive compounds with essential activities.

Elucidation of the melitidin biosynthesis pathway in pummelo.

Specialized plant metabolism is a rich resource of compounds for drug discovery. The acylated flavonoid glycoside melitidin is being developed as an anti-cholesterol statin drug candidate, but its biosynthetic route in plants has not yet been fully characterized. Here, we describe the gene discovery and functional characterization of a new flavonoid gene cluster (UDP-glucuronosyltransferases (CgUGTs), 1,2 rhamnosyltransferase (Cg1,2RhaT), acyltransferases (CgATs)) that is responsible for melitidin biosynthesis in pummelo (Citrus grandis (L.) Osbeck). Population variation analysis indicated that the tailoring of acyltransferases, specific for bitter substrates, mainly determine the natural abundance of melitidin. Moreover, 3-hydroxy-3-methylglutaryl-CoA reductase enzyme inhibition assays showed that the product from this metabolic gene cluster, melitidin, may be an effective anti-cholesterol statin drug candidate. Co-expression of these clustered genes in Nicotiana benthamiana resulted in the formation of melitidin, demonstrating the potential for metabolic engineering of melitidin in a heterologous plant system. This study establishes a biosynthetic pathway for melitidin, which provides genetic resources for the breeding and genetic improvement of pummelo aimed at fortifying the content of biologically active metabolites.

Amelioration in traditional farming system by exploring the different plant growth-promoting attributes of endophytes for sustainable agriculture.

Agriculture demands environmentally friendly, economic and stable agro-practices for achievement of global food security challenges. Exploration of beneficial plant-microbe interactions and input of microbial inoculants has been getting great attention for improvement of traditional agriculture system. Endophytes are beneficial partners of plants; they live inside the host with mutual association. The advantageous role of endophytes is gaining great importance from last century in agricultural research due to their valuable role in enhancement of crop yield and disease management. Endophytes exhibit various plant growth-promoting attributes by production of many bioactive metabolites and by different mechanisms. Development of modern biotechnological approaches to explore the hidden interaction of plants and microbes can be useful tools for establishment of novel bioinoculants for particular crop. In this review, we provide the knowledge about the endophytes, mode of action and their role in the development of sustainable agriculture system for human welfare.

Screening of secondary metabolites and antioxidant potential of endophytic fungus Penicillium citrinum and host Digitaria bicornis by spectrophotometric and electrochemical methods.

Perennial grasses are hosts to an extremely diverse assemblage of endophytic fungi, but their significance is still underexplored. In the present study, an endophytic fungus was isolated from the aerial regions of Digitaria bicornis (Lam.) Roem. & Schult. and was characterized by morphological and molecular methods (ITS rDNA region), as Penicillium citrinum Thom. The crude extracts of endophytic fungus and host were recovered and evaluated for their antioxidant potential by spectrophotometric and electrochemical methods. The present study was also an attempt to compare the anti-radical power of extracts by spectrophotometric (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), hydrogen peroxide and nitric oxide radical scavenging assay) and electrochemical (cyclic voltammetry) methods and suggested that cyclic voltammetry could be used routinely instead of assaying by more number of spectrophotometric methods. The results indicated that the ethyl acetate extract of P. citrinum and methanolic extract of D. bicornis has potential compounds with antioxidant and other pharmaceutical activities. Nine and 17 antioxidant biomolecules, respectively, in P. citrinum and D. bicornis extracts were detected by OHR-LC-MS and the presence of function group of the bioactive compounds was confirmed by FTIR spectroscopy. Finally, the study also reported that the extracts of P. citrinum and D. bicornis have several bioactive compounds with application in commercial pharmaceutical industries.