Sequential extraction, characterization and antioxidant activity of polysaccharides from Fritillaria pallidiflora Schrenk

Fungi are known to produce a wide range of secondary metabolites such as pigments, antibiotics, vitamins, amino acids, and organic compounds that have several useful biological activities such as antifungal, antiinflammatory, antioxidant, antimicrobial, and anticancer and also have wide range of biotechnological applications in food, pharmaceutical, and cosmetic industries as well as in agriculture. Antibiotics such as β-lactam, cholesterol-lowering drug, lovastatin, and penicillin are some of the important fungal metabolites that have diverse biotechnological applications in pharmaceutical industries and in the field of medicine. On the other hand, several of these fungal secondary metabolites also have potentially harmful biological activities such as mycotoxins and phytotoxins. There are various biosynthetic pathways followed by the fungi to produce secondary metabolites such as β-lactam, cyclic peptide, diterpenes, diketopiperazines, polyketides, sesquiterpenes, and a combination of these pathways. There are wide ranges of fungal communities producing potentially important secondary metabolites including Penicillium notatum, Cephalosporium acremonium, Penicillium griseofulvum, Streptomyces griseus, Monascus purpureus, Micromonospora purpurea, Tolypocladium inflatum, Aspergillus niger, Aspergillus parasiticus, and Beauveria bassiana. The potential biological applications of secondary metabolites of fungi will be useful for sustainable development.

Fungal secondary metabolites and their biotechnological applications for human health

To combat salinity, plants need easily accessible, safe and sustainable mechanisms for optimum growth. Recently, endophytes proved to be the promising candidates that helped the host plant to thrive under stress conditions. Therefore, the aim was to discover endophytic strain(s) and their mechanism of action to alleviate salt stress in maize. Keeping the diverse role of endophytes in view, 9 endophytic fungi from the spines of Euphorbia milli L. were isolated. Among the isolated fungal isolates, isolate FH1 was selected for further study on the basis of high antioxidant activity and capability to produce high indole-3-acetic acid (IAA), indole-3-acetamide (IAM), phenol and flavonoid contents. The 18S rDNA sequence homology and phylogenetic analysis of the fungal isolate FH1 revealed to be Yarrowia lipolytica. Furthermore, the inoculation of Y. lipolytica FH1 had significantly promoted plant growth attributes in treated maize as compared to positive (salt stress) and negative (salt stress free) controls. Likewise, differences in chlorophyll, carotenes, electrolyte leakage, leaf relative water, peroxidase, catalase, ABA, IAA and proline contents were observed between treated maize and controls. Interestingly, Y. lipolytica FH1 inoculated plants showed lower endogenous ABA and higher endogenous IAA contents. From the results, we have concluded that Y. lipolytica inoculation has promoted the growth of maize plants through controlled metabolism and hormonal secretions (ABA and IAA) under salinity stress. Because of the fact, Y. lipolytica can be tried as an eco-friendly bio-fertilizer to achieve optimum crop productivity under saline conditions.

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An endophytic isolate of the fungus Yarrowia lipolytica produces metabolites that ameliorate the negative impact of salt stress on the physiology of maize.

Summary Medicinal plants have been used for thousands of years in folk medicines and still are used for their health benefits. In our days medicinal plants are exploited for the isolation of plant-derived drugs as they are very effective and have relatively less or no side effects. However, the natural resources of medicinal plants are gradually exhausted and access to plant bioactive compounds is challenged by the low levels at which these products accumulate in native medicinal plants. For instance, to meet the market demands of 3 Kg per year of vinca alkaloids, powerful plant-derived anticancer drugs, 1.5×106 Kg dry leaves are required. In this regard, this review aims to highlight the fact that endophytic fungi residing in medicinal plants are capable to biosynthesize pharmacologically active secondary metabolites similar or identical to those produced by their host medicinal plant. Furthermore, the evolutionary origin of the genes involved in these metabolic pathways as well as the approaches designed to enhance the production of these metabolites by the isolated endophytic fungi are also discussed.

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Endophytic fungi residing in medicinal plants have the ability to produce the same or similar pharmacologically active secondary metabolites as their hosts

Endophytes are microorganisms that colonize the interior of host plants without causing apparent disease. They have been widely studied for their ability to modulate relationships between plants and biotic/abiotic stresses, often producing valuable secondary metabolites that can affect host physiology. Owing to the advantages of microbial fermentation over plant/cell cultivation and chemical synthesis, endophytic fungi have received significant attention as a mean for secondary metabolite production. This article summarizes currently reported results on plant-endophyte interaction hypotheses and highlights the biotechnological applications of endophytic fungi and their metabolites in agriculture, environment, biomedicine, energy, and biocatalysts. Current bottlenecks in industrial development and commercial applications as well as possible solutions are also discussed.

Production of bioproducts by endophytic fungi: chemical ecology, biotechnological applications, bottlenecks, and solutions.

Diverse fungal endophytes are rich fungal resources for the production of an enormous quantity of natural products. In the present study, 53 fungal endophytes were isolated from the bulbs of Fritillaria unibracteata var. wabuensis (FUW). Of these, 49 strains were identified and grouped into 17 different taxa, and priority was conferred to the Fusarium genus. All fungal fermented filtrates displayed antioxidant activities. The DPPH activity, total antioxidant capacities (ABTS), reduction power (FRAP), total phenolic content (TPC), total flavonoid content (TFC) and total saponin content (TSC) were evaluated using petroleum ether, ethyl acetate, n-butyl alcohol and ethanol fractions extracted from five representative fungal cultures. The last three fractions showed more potent antioxidant activity than the first fraction. Significant positive correlations were found between the compositions (TPC, TFC and TSC) and antioxidant capacities (DPPH, ABTS and FRAP). In addition, multifarious natural antioxidant components were identified from the fungal extracts, including gallic acid, rutin, phlorizin, 2,4-di-tert-butylphenol and 2,6-di-tert-butyl hydroquinone; these were determined preliminarily by TLC-bioautography, HPLC and GC-MS analysis. This study showed abundant fungal resources in FUW. Phenolics, flavonoids and saponins are crucial bioactive constituents in these abundant fungal endophytes and can be viewed as new potential antioxidant resources.

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Fungal endophyte-derived Fritillaria unibracteata var. wabuensis: diversity, antioxidant capacities in vitro and relations to phenolic, flavonoid or saponin compounds.

Extraction, purification and antioxidation of a polysaccharide from Fritillaria unibracteata var. wabuensis

Exopolysaccharides from the fungal endophytic Fusarium sp. A14 isolated from Fritillaria unibracteata Hsiao et KC Hsia and their antioxidant and antiproliferation effects.

The invention belongs to the technical field of biosynthesis and discloses a biosynthetic method and an application of bulbus fritillariae cirrhosae endophytic fungus mediated nano-silver. A bulbus fritillariae cirrhosae endophytic fungus soak solution and a silver nitrate solution are subjected to a reaction, and nano-silver 4-AgNPs and 13-AgNPs are prepared from bulbus fritillariae cirrhosae endophytic fungi CBY4 and CBY13 with the biosynthetic method after 15 bulbus fritillariae cirrhosae endophytic fungi are screened primarily; in the biosynthetic process, the synthetic conditions are as follows: pH is 3-11, concentration of the silver nitrate solution is 2 mmol/L, illumination intensity is 2000 Lux, and the temperature is 50 DEG C. It is discovered for the first time that the endophytic fungi CBY4 and CBY13 separated from bulbus fritillariae cirrhosae have nano-silver synthesizing capacity, the reaction conditions more suitable for nano-silver synthesis are obtained by optimization, and synthesized nano-silver has certain bacteriostatic and antitumor activity.

Tian-Jiao Su

Papers

Fungal endophyte-derived Fritillaria unibracteata var. wabuensis: diversity, antioxidant capacities in vitro and relations to phenolic, flavonoid or saponin compounds.

Extraction, purification and antioxidation of a polysaccharide from Fritillaria unibracteata var. wabuensis

Exopolysaccharides from the fungal endophytic Fusarium sp. A14 isolated from Fritillaria unibracteata Hsiao et KC Hsia and their antioxidant and antiproliferation effects.

Biosynthetic method and application of bulbus fritillariae cirrhosae endophytic fungus mediated nano-silver