qNMR for profiling the production of fungal secondary metabolites

Multinuclear NMR screening of pharmaceuticals using standardization by 2H integral of a deuterated solvent

NMR standardization approach that uses the ²H integral of deuterated solvent for quantitative multinuclear analysis of pharmaceuticals is described. As a proof of principle, the existing NMR procedure for the analysis of heparin products according to US Pharmacopeia monograph is extended to the determination of Na⁺ and Cl^- content in this matrix. Quantification is performed based on the ratio of a ²³Na (³⁵Cl) NMR integral and ²H NMR signal of deuterated solvent, D₂O, acquired using the specific spectrometer hardware. As an alternative, the possibility of ¹³³Cs standardization using the addition of Cs₂CO₃ stock solution is shown. Validation characteristics (linearity, repeatability, sensitivity) are evaluated. A holistic NMR profiling of heparin products can now also be used for the quantitative determination of inorganic compounds in a single analytical run using a single sample. In general, the new standardization methodology provides an appealing alternative for the NMR screening of inorganic and organic components in pharmaceutical products.

Fungal Guttation, a Source of Bioactive Compounds, and Its Ecological Role-A Review

Guttation is a common phenomenon in the fungal kingdom. Its occurrence and intensity depend largely on culture conditions, such as growth medium composition or incubation temperature. As filamentous fungi are a rich source of compounds, possessing various biological activities, guttation exudates could also contain bioactive substances. Among such molecules, researchers have already found numerous mycotoxins, antimicrobials, insecticides, bioherbicides, antiviral, and anticancer agents in exudate droplets. They belong to either secondary metabolites (SMs) or proteins and are secreted with different intensities. The background of guttation, in terms of its biological role, in vivo, and promoting factors, has been explored only partially. In this review, we describe the metabolites present in fungal exudates, their diversity, and bioactivities. Pointing to the significance of fungal ecology and natural products discovery, selected aspects of guttation in the fungi are discussed.

Development of 1 H-NMR methods for quantitative determination of alkylamides in Zanthoxylum bungeanum and quality evaluation based on its fingerprint

Alkylamides, as the representative hemp flavor and active ingredients, can reflect the quality of Zanthoxylum bungeanum Maxim. However, conjugated triene structure exists in alkylamides, which is easy to be oxidized and decomposed in air, making it difficult to quantify. In this study, a method for the quantitative determination of alkylamides by ¹ H-NMR technology was developed with 85% ethanol as the best extraction solvent, CDCl₃ as the best deuterium dissolution reagent, pyrazine as the internal standard, and triple peaks of hydrogen protons on the amide bond at δ 6.33 ppm as the quantitative signal peak. Meanwhile, methodological verification was carried out to prove the reliability and effectiveness of the method. On this basis, the contents of alkylamides in nine germplasms of Zanthoxylum with monthly dynamics were obtained. The results showed that the alkylamides of Hancheng stingless Z. bungeanum (HC) exhibited the highest content in August (51.92 ± 0.96 mg/g), while the lowest was FG in June (1.23 ± 0.21 mg/g). The results of ¹ H-NMR corresponded to those of HPLC, and the effectiveness of this method was verified. Accumulation dynamic results show that the best harvest period of Z. bungeanum is July and August. Moreover, the quality of nine varieties of Zanthoxylum bungeanum from a common garden was evaluated by the established ¹ H-NMR fingerprint and chemometric analyses. The results showed that Hancheng stingless Z. bungeanum was the best germplasm. This study provides a new strategy for the quantitative determination of alkylamides in Z. bungeanum and improves the quality evaluation system of Z. bungeanum. PRACTICAL APPLICATION: The results provide a new research idea for the analysis of important chemical components of Z. bungeanum. Meanwhile, the study provides a scientific basis for the quality evaluation and high-quality germplasm resources of Z. bungeanum.

Isolation and Determination of Fomentariol: Novel Potential Antidiabetic Drug from Fungal Material

Diabetes mellitus is one of the leading world's public health problems. Therefore, it is of a huge interest to develop new antidiabetic drugs. Apart from traditional therapy of diabetes, nowadays, importance is given to natural substances with antidiabetic potential. Fomes fomentarius is a mushroom widely used for different purposes, due to its range of already confirmed activities. Fomentariol is a constituent of Fomes fomentarius, responsible for its antidiabetic potential. In that respect, it is important to develop a method for isolation and quantification of fomentariol from fungal material, which will be simple and efficient. Multistep, complex extraction applied in the previously reported studies was avoided with ethanol, providing rapid single-step extraction. The presence of fomentariol in ethanolic extract was confirmed by high-resolution mass spectrometry. Semipreparative HPLC method was developed and applied for isolation from ethanol extract and purification of the active compound fomentariol. It was a gradient reversed-phase method with a mobile phase consisting of acetonitrile and 0.1% formic acid in water and total run time of 15 minutes. The amount of 6.5 mg of high-purity fomentariol was determined by quantitative NMR with toluene as internal standard. The isolated and determined amount of substance can be further used for the quantitative estimation of activity of fomentariol.

Chemoselective fluorination and chemoinformatic analysis of griseofulvin: Natural vs fluorinated fungal metabolites

Griseofulvin is a fungal metabolite and antifungal drug used for the treatment of dermatophytosis in both humans and animals. Recently, griseofulvin and its analogues have attracted renewed attention due to reports of their potential anticancer effects. In this study griseofulvin (1) and related analogues (2-6, with 4 being new to literature) were isolated from Xylaria cubensis. Six fluorinated analogues (7-12) were synthesized, each in a single step using the isolated natural products and Selectflour, so as to examine the effects of fluorine incorporation on the bioactivities of this structural class. The isolated and synthesized compounds were screened for activity against a panel of cancer cell lines (MDA-MB-435, MDA-MB-231, OVCAR3, and Huh7.5.1) and for antifungal activity against Microsporum gypseum. A comparison of the chemical space occupied by the natural and fluorinated analogues was carried out by using principal component analysis, documenting that the isolated and fluorinated analogues occupy complementary regions of chemical space. However, the most active compounds, including two fluorinated derivatives, were centered around the chemical space that was occupied by the parent compound, griseofulvin, suggesting that modifications must preserve certain attributes of griseofulvin to conserve its activity.