A new mixed inhibitor of adenosine deaminase produced by endophytic Cochliobolus sp. from medicinal plant seeds

Phytochemical analysis and anti-infective potential of fungal endophytes isolated from Nigella sativa seeds

Endophytic fungi, particularly from higher plants have proven to be a rich source of antimicrobial secondary metabolites. The purpose of this study is to examine the antimicrobial potential of three endophytic fungi Aspergillus sp. SA1, Aspergillus sp. SA2, and Aspergillus sp. SA3, cultivated from Nigella sativa seeds against Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 13883), MRSA (ATCC 33591), and human pathogen Candida albicans (ATCC 10231). Furthermore, the most active cultivated endophytic fungi were molecularly identified via internal transcribed spacer (ITS) sequencing. HR-ESIMS guided approach has been used successfully in chemical profiling of 26 known bioactive secondary metabolites (1-26), which belongs to different classes of natural compounds such as polyketides, benzenoids, quinones, alcohols, phenols or alkaloids. Finally, in-silico interactions within active site of fungal Cyp51 and bacterial DNA gyrase revealed possibility of being a hit-target for such metabolites as antimicrobials.

Secondary Metabolites from the Coral-Derived Fungus Aspergillus austwickii SCSIO41227 with Pancreatic Lipase and Neuraminidase Inhibitory Activities

The coral-derived fungus Aspergillus austwickii SCSIO41227 from Beibu Gulf yielded four previously uncharacterized compounds, namely asperpentenones B-E (1-4), along with twelve known compounds (5-16). Their structures were elucidated using HRESIMS and NMR (1H and 13C NMR, HSQC, HMBC), among which the stereo-structure of compounds 1-3 was determined by calculated ECD. Furthermore, compounds 1-16 were evaluated in terms of their enzyme (acetylcholinesterase (AChE), pancreatic lipase (PL), and neuraminidase (NA)) inhibitory activities. These bioassay results revealed that compounds 2 and 14 exerted noticeable NA inhibitory effects, with IC50 values of 31.28 and 73.64 μM, respectively. In addition, compound 3 exhibited a weak inhibitory effect against PL. Furthermore, these compounds showed the potential of inhibiting enzymes in silico docking analysis to demonstrate the interactions between compounds and proteins.

Antimicrobial and Cytotoxic Activities of the Secondary Metabolites of Endophytic Fungi Isolated from the Medicinal Plant Hyssopus officinalis

According to the World Health Organization, it is estimated that by 2050, drug-resistant infections could cause up to 10 million deaths annually. Therefore, finding a new generation of antibiotics is crucial. Natural compounds from endophytic fungi are considered a potential source of new-generation antibiotics. The antimicrobial and cytotoxic effects of ethyl acetate extracts of nine endophytic fungal isolates obtained from Hyssopus officinalis were investigated for bioassay-guided isolation of the natural compounds. An extract of isolate VII showed the highest antimicrobial activities against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus (30.12 ± 0.20 mm and 35.21 ± 0.20 mm) and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa (30.41 ± 0.23 mm and 25.12 ± 0.25 mm) among the tested extracts of isolates. Molecular identification of isolate VII confirmed it as Chaetomium elatum based on sequencing of its ITS genes, and it was discovered that this was the first time C. elatum had been isolated from H. officinalis. This isolate was cultured at a large scale for the isolation and identification of the active compound. Penicillic acid was isolated for the first time from C. elatum and its chemical structure was established by NMR spectroscopy. The penicillic acid showed strong antibacterial activities against Bacillus subtilis and Staphylococcus aureus with 20.68 mm and 25.51 mm inhibition zones, respectively. In addition, MIC and MBC values and antibiofilm activities of penicillic acid were determined. It was found that penicillic acid reduced the level of biofilms in proportion to antibacterial activity.

Glycosides and flavonoids from the extract of Pueraria thomsonii Benth leaf alleviate type 2 diabetes in high-fat diet plus streptozotocin-induced mice by modulating the gut microbiota

Twenty glycoside derivatives and nine flavonoids from the leaves of Pueraria (P. thomsonii) were isolated by column chromatography and characterized by nuclear magnetic resonance spectroscopy (NMR) and high performance liquid chromatography (HPLC). The contents of twenty glycosides and nine flavonoids from the extract of P. thomsonii leaf (PL) were 173.3 mg g^-1 and 134.7 mg g^-1, respectively. Two flavonoids with the highest content were robinin (49.28 mg g^-1) and puerarin (42.87 mg g^-1). Six flavonoids, i.e. puerarin, robinin, rutin, quercetin, quercitrin, and kaempferol showed more inhibitory effects against α-glucosidase than acarbose. PL could effectively increase the level of insulin, decrease the content of fasting blood glucose, reduce lipid accumulation in plasma, ameliorate oxidative injury and inflammation, and relieve liver and kidney damage in diabetic mice. Moreover, PL could increase intestinal probiotics to improve metabolic disorders caused by diabetes and decrease the level of Clostridium celatum to relieve inflammation. This study suggested that PL or its glycoside derivatives and flavonoids regulating glycolipid metabolism and inflammation levels might have the potential to be used to control type 2 diabetes.

Anti-leishmanial compounds from microbial metabolites: a promising source

Leishmania is a complex disease caused by the protozoan parasites and transmitted by female phlebotomine sandfly. The disease affects some of the poorest people on earth with an estimated 700,000 to 1 million new cases annually. The current treatment for leishmaniasis is toxic, long, and limited, in view of the high resistance rate presented by the parasite, necessitating new perspectives for treatment. The discovery of new compounds with different targets can be a hope to make the treatment more efficient. Microbial metabolites and their structural analogues with enormous scaffold diversity and structural complexity have historically played a key role in drug discovery. We found thirty-nine research articles published between 1999 and 2021 in the scientific database (PubMed, Science Direct) describing microbes and their metabolites with activity against leishmanial parasites which is the focus of this review. KEY POINTS: • Leishmania affects the poorest regions of the globe • Current treatments for leishmaniasis are toxic and of limited efficacy • Microbial metabolites are potential sources of antileishmania drugs.