Biogenic silver nanoparticles from fungal sources: Synthesis, characterization, and antifungal potential.

Nano-biotechnology is quickly developing as an important field of modern research, generating the most promising applications in medicine and agriculture. Biosynthesis of silver nanoparticles using biogenic or green approach provide ecofriendly, clean and effective way out for the synthesis of nanoparticles. The main aim of the study was to synthesize silver nanoparticles (AgNPs) from Aspergillus niger, Aspergillus flavus and Pencillium chrysogenum using a green approach and to test the antifungal activity of these synthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV-visible spectroscopy, SEM (scanning electron microscopy), FTIR (Fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). The investigation confirmed the creation of AgNPs by the fungi Aspergillus niger, Aspergillus flavus and Pencillium chrysogenum, as evidenced by prominent plasmon absorbance bands at 420 and 450 nm.The biosynthesized AgNPs were 80-100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Agar well diffusion method was performed to evaluate the antifungal activity of AgNPs against various plant pathogenic fungi. An efficient and strong antifungal activity was shown by these biosynthesized nanoparticles against serious plant pathogenic fungi, viz. Aspergillus terreus, Fusarium oxysporum, Penicillium citrinum, Rhizopus stolonifer and Mucor mucedo. The biosynthesized AgNPs at various concentrations caused significant zone of inhibition in the test fungal pathogens. Silver nanoparticles (AgNPs) biosynthesized from Aspergillus niger at highest concentrations showed maximum zone of inhibition against Penicillium citrinum (19.33 ± 0.57 mm) followed by Rhizopus stolonifer (17.66 ± 0.57), Aspergillus terreus (16.33 ± 1.54 mm), Fusarium oxysporum (14.00 ± 1.00 mm) and Mucor mucedo (13.33 ± 1.15 mm) respectively. Therefore, the findings clearly indicate that silver nanoparticles could play a significant role in managing diverse plant diseases caused by fungi.

Preparation, characterization and antifungal activity of iron oxide nanoparticles.

Iron oxide nanoparticles with particle size 10-30 nm were prepared by a green approach using tannic acid as reducing and capping agent. These nanoparticles were characterized by X-ray diffractometry (XRD), high resolution field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The prepared iron oxide nanoparticles were also evaluated for their antifungal activity against Trichothecium roseum, Cladosporium herbarum, Penicillium chrysogenum, Alternaria alternata and Aspergillus niger. The antifungal activity was observed as inhibition in spore germination and by determining the zone of inhibition of fungal pathogens caused by different concentrations of iron oxide nanoparticles on culture media. It was observed from the present study that Fe2O3 nanoparticles showed significant antimycotic activity against all the tested fungal pathogens. Highest inhibition in spore germination was caused against T. roseum (87.74%) followed by C. herbarum (84.89%). The highest zone of inhibition by iron oxide nanoparticles was reported against P. chrysogenum (28.67 mm) followed by A. niger (26.33 mm), T. roseum (22.67 mm), A. alternata (21.33 mm) and least against C. herbarum (18.00 mm). Activity index was recorded highest against P. chrysogenum (0.81). The MIC value of Fe2O3 NP varies between 0.063 and 0.016 mg/ml for different fungal pathogens that is comparable with the MIC value shown by the standard, revealing the efficacy of iron oxide NP's against different fungal pathogens.

Diversity and Ethno-Mycopharmacological Insights of Medicinal Mushrooms of the Bangus Valley of Jammu and Kashmir, India.

The present study was carried out in various regions of Jammu and Kashmir, India, for the diversity and pharmacology of wild mushrooms. The valley is bestowed with alpine meadows and dense coniferous forest. Because of its isolation, security concerns, and line of control, most of these locations either have been little investigated or are entirely undiscovered. During the intensive survey of various locations, 20 mushroom species were collected from the surveyed areas. The ethno-mycological information was gathered from tribal communities and local herbalists (hakims). It was observed that 16 species were used against cold, constipation, liver and skin disorders, digestion problems, wound healing, and the like. However, these medicinal mushrooms are losing their relevance, so there is an urgent need to explore and preserve this knowledge for future use as medicine.

Chemical Composition and Antimicrobial Properties of Morchella crassipes (Ascomycota) from Kashmir Valley (India).

In the current era, wild macrofungi are being focused for developing and overing novel bioactive compounds for the management of agricultural, horticultural, and other infectious diseases. In that view, current research work was designed to evaluate the biochemical composition and medicinal properties of Morchella crassipes mushroom. The mycochemical screening of aqueous extract exposed the incidence of glycosides, free amino acids and proteins, alkaloids, carbs, flavonoids, terpenoids, phenolic compounds and tannins, except volatile oils, resins, steroids, and anthraquinones. However, hexane extract exhibited the occurrence of glycosides, alkaloids, volatile oils, steroids and terpenoids while as all other phytochemicals were not detected. The gas chromatography mass spectrometry profiling has disclosed the identification of three predominant naturally occurring bioactive volatile monoterpenoids, namely neral, citral, and epoxy-linalool oxide with well-known biological activities. The methanolic extract resulted in strong antifungal efficacy against the tested fungal strains such as Penicillium chrysogenum (20.33 ± 0.57 mm) followed by Pythium ultimum (15.33 ± 0.76 mm) and Aspergillus niger (12.50 ± 0.50 mm) at highest concentrations. Likewise, marked antibacterial effects were reported in case of Staphylococcus aureus (15.16 ± 0.76 mm), followed by Salmonella gallinarum (14.33 ± 0.57 mm) and Escherichia coli (13.66 ± 0.57 mm), respectively. This data may offer baseline information regarding the bioactive metabolites and opening new ways for conducting trails to find natural management strategies to combat multi drug resistant pathogens in horticulture, agriculture, and aquaculture.

Fungal-mediated synthesis of silver nanoparticles: a novel strategy for plant disease management.

Various traditional management techniques are employed to control plant diseases caused by bacteria and fungi. However, due to their drawbacks and adverse environmental effects, there is a shift toward employing more eco-friendly methods that are less harmful to the environment and human health. The main aim of the study was to biosynthesize silver Nanoparticles (AgNPs) from Rhizoctonia solani and Cladosporium cladosporioides using a green approach and to test the antimycotic activity of these biosynthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV-visible spectroscopy, SEM (scanning electron microscopy), FTIR (fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). During the study, the presence of strong plasmon absorbance bands at 420 and 450 nm confirmed the AgNPs biosynthesis by the fungi Rhizoctonia solani and Cladosporium cladosporioides. The biosynthesized AgNPs were 80-100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Assessment of the antifungal activity of the silver nanoparticles against various plant pathogenic fungi was carried out by agar well diffusion assay. Different concentration of AgNPs, 5 mg/mL 10 mg/mL and 15 mg/mL were tested to know the inhibitory effect of fungal plant pathogens viz. Aspergillus flavus, Penicillium citrinum, Fusarium oxysporum, Fusarium metavorans, and Aspergillus aflatoxiformans. However, 15 mg/mL concentration of the AgNPs showed excellent inhibitory activity against all tested fungal pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

Ethnomycological studies of some wild medicinal and edible mushrooms in the Kashmir Himalayas (India).

The medicinal use of mushrooms has a very long tradition in Asian countries because of their use as a valuable tonic, food, and in herbal medicines. A study was carried out to document the indigenous uses of various mushrooms growing in the Kashmir Himalayas. After consulting local herbal healers (Hakims) and people from tribal communities inhabiting inaccessible hinterlands of the region regarding the use of mushrooms growing in their locality, it was found that 35 species of mushrooms belonging to different ecological and taxonomical groups were used for their nutritional and medicinal values. These mushrooms were used for their activities against a broad spectrum of diseases, ranging from simple skin diseases to present-day complex diseases such as diabetes and tumors.

Nutritional values and antioxidant potential of some edible mushrooms of Kashmir valley.

Mushrooms are considered rich in proteins, carbohydrates and other nutrients. The present study was carried out to evaluate some edible mushrooms of Kashmir valley for their protein, carbohydrate and lipid contents. The highest protein content was found in Boletus edulis (2.20g) followed by Agaricus bisporus (1.80g), Pleurotus ostreatus (1.68g), Morchella esculenta (1.62g) and Pleurotus sajor caju (1.6g). Carbohydrate content also showed variation in all the five tested edible mushroom species, the highest carbohydrate content observed in Boletus edulis (6.0g) followed by Agaricus bisporus (4.85g), Pleurotus ostreatus (4.30g), Morchella esculenta (4.25g) and Pleurotus sajor caju (3.35g) respectively. Similar results were observed for lipid content. The present study was also investigated for the antioxidant potential of aqueous extract of mushroom species by the methods of DPPH radical scavenging activity, hydroxyl radical scavenging activity and superoxide radical scavenging activity. All these in vitro antioxidant activities were concentration dependent, which were compared with standard antioxidant Catechin.

Microwave synthesis of nanoparticles and their antifungal activities.

Microwave assisted approach was adopted for obtaining copper (II) oxide and Iron (III) oxide nanoparticles using leaves extract of Euphorbia helioscopia. Tanins component extracted from Euphorbia helioscopia were responsible for the formation of stable nanoscopic particles. Nanoparticles of iron and copper oxide was characterized using powder X-ray Diffractometer (PXRD), Scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDAX) and Transmission Electron Microscopy (TEM). PXRD result confirmed the formation of α-phase and monoclinic iron and copper oxide nanoparticles respectively. Nanoparticles of iron and copper oxide were of spherical shape with average diameter in range of 7-10 nm. Antifungal potential of fabricated oxide nanoparticles was tested using Cladosporium herbarum as role model fungus. Iron oxide nanoparticles exhibit greater antifungal activities against the Cladosporium herbarum as compared to copper oxide nanoparticles.

Scientific Study of Gentiana kurroo Royle.

The present investigation was carried out to review and highlight the potential phytochemicals and medicinal phenomena of the critically endangered medicinal plant, Gentiana kurroo Royle of the western and north-western Himalayas. The medicinal plant is heavily exploited for root and rhizome. Due to its endemic nature and the high rate of exploitation from its natural habitat, this species had become critically endangered. The phytochemical screening of the plant revealed that the plant contains some vital phyto-constituents (iridoids, xanthones, C-glucoxanthone mangiferin, and C-glucoflavones) that have a medicinal value for various acute and chronic diseases. Several researchers have carried out experimental work to validate the folkloric use of the medicinal plant for different ailments like antibacterial, antioxidant, anti-arthritic, anti-inflammatory, analgesic activities and anti-diabetic activity. However, it is yet to be confirmed the antifungal activity of the same plant. Because of endemic nature and high rate of exploitation there is need for alternative method called bio-prospecting of Endophytes from the plant, to carry out the production and characterization of bioactive metabolites for pharmacological uses and can become a conservative tool for the medicinal plant.