Purification of coumarins, including meranzin and pranferin, from grapefruit by solvent partitioning and a hyphenated chromatography

Coumarins as Fungal Metabolites with Potential Medicinal Properties

Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins’ biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins’ biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.

UHPLC/MS and NMR-Based Metabolomic Analysis of Dried Water Extract of Citrus-Type Crude Drugs

Citrus-type crude drugs (CCDs) are commonly used to formulate decoctions in Kampo formula (traditional Japanese medicine). Our previous study reported metabolomic analyses for differentiation of the methanol extracts of Citrus-type crude drugs (CCDs) using ultra-HPLC (UHPLC)/MS, and ¹³C- and ¹H-NMR. The present study expanded the scope of its application by analyzing four CCD water extracts (Kijitsu, Tohi, Chimpi, and Kippi); these CCDs are usually used as decoction ingredients in the Kampo formula. A principal component analysis score plot of processed UPLC/MS and NMR analysis data indicated that the CCD water extracts could be classified into three groups. The loading plots showed that naringin and neohesperidin were the distinguishing components. Three primary metabolites, α-glucose, β-glucose, and sucrose were identified as distinguishing compounds by NMR spectroscopy. During the preparation of CCD dry extracts, some compounds volatilized or decomposed. Consequently, fewer compounds were detected than in our previous studies using methanol extract. However, these results suggested that the combined NMR- and LC/MS-based metabolomics can discriminate crude drugs in dried water extracts of CCDs.

Fungal Endophytes as Efficient Sources of Plant-Derived Bioactive Compounds and Their Prospective Applications in Natural Product Drug Discovery: Insights, Avenues, and Challenges

Fungal endophytes are well-established sources of biologically active natural compounds with many producing pharmacologically valuable specific plant-derived products. This review details typical plant-derived medicinal compounds of several classes, including alkaloids, coumarins, flavonoids, glycosides, lignans, phenylpropanoids, quinones, saponins, terpenoids, and xanthones that are produced by endophytic fungi. This review covers the studies carried out since the first report of taxol biosynthesis by endophytic Taxomyces andreanae in 1993 up to mid-2020. The article also highlights the prospects of endophyte-dependent biosynthesis of such plant-derived pharmacologically active compounds and the bottlenecks in the commercialization of this novel approach in the area of drug discovery. After recent updates in the field of 'omics' and 'one strain many compounds' (OSMAC) approach, fungal endophytes have emerged as strong unconventional source of such prized products.

Evaluation of furanocoumarins from seeds of the wild parsnip (Pastinaca sativa L. s.l.)

Although the wild parsnip (Pastinaca sativa L. s.l.) fruits are known to contain linear and angular furanocoumarins, the individual components of the seeds have not been fully identified and quantitated, and, in the case of immature seeds, reported. In view of this, the main furanocoumarin compounds were extracted using pyridine, and were isolated using semi-preparative high-performance liquid chromatography. The structural elucidation of isolated compounds was done based on detailed spectral analysis conducted by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI/MS), ¹H and ¹³C NMR and, where possible, by gas chromatography-mass spectrometry (GC-MS). The quantitative analysis of furanocoumarin compounds in the wild parsnip was conducted by analytical ultra-performance liquid chromatography (UPLC-DAD), calculated against the standard curves of isolated compounds. The total yields of furanocoumarin compounds from the seeds after extraction with pyridine were 107.2-222.8 mg g^-1 (fresh weight) and 50.2-66.4 mg g^-1 (soluble dry matter). Thirteen furanocoumarins were identified. The main compounds (percentage in FW) in immature seeds were bergapten (40.8), pimpinellin (10.5), methoxsalen (5.7), isopimpinellin (4.3), imperatorin (3.2), and phellopterin (7.2). Seven constituents previously not described in P. sativa seeds and its products were identified, namely, byakangelicol (14.4), heraclenin (8.5), isobergapten (2.5), byakangelicin (1.3), heraclenol (0.5), psoralen (0.3), and isobyakangelicin (0.8). The latter is a new compound of the Apiaceae family. Extraction of immature seeds using pyridine gave a much higher yield and a greater variety of furanocoumarins. This indicates that the wild parsnip, along with other Apiaceae family plants, may be an important source of bioactive compounds.

Rapid and Efficient Desulfonation Method for the Analysis of Glucosinolates by High-Resolution Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry

The goal of our present research was to develop a simple and rapid method for the quantitation of desulfoglucosinolates (desulfoGLS) without using column chromatography. The proposed method involves extraction, concentration, incubation of glucosinolates with a sulfatase enzyme, and HPLC analysis. Identification of desulfoGLS in green kohlrabi was performed by LC-HR-ESI-QTOF-MS in positive-ionization mode. A total of 11 desulfoGLS were identified with neoglucobrassicin (3.32 ± 0.05 μmol/g DW) as the predominant indolyl, whereas progoitrin and sinigrin were the major aliphatic desulfoGLS. The levels of the aliphatic desulfoGLS glucoiberin, progoitrin, and glucoerucin at 7 h were found to be 3.6-, 1.9-, and 1.6-fold higher, respectively, than those produced through the conventional method. This technique was successfully applied in the identification of desulfoGLS from cabbage. The developed method has fewer unit operations, has maximum recovery, and is reproducible in the determination of desulfoGLS in a large number of Brassicaceae samples in a short time.

Chemistry and health effects of furanocoumarins in grapefruit

Furanocoumarins are a specific group of secondary metabolites that commonly present in higher plants, such as citrus plants. The major furanocoumarins found in grapefruits (Citrus paradisi) include bergamottin, epoxybergamottin, and 6′,7′-dihydroxybergamottin. During biosynthesis of these furanocoumarins, coumarins undergo biochemical modifications corresponding to a prenylation reaction catalyzed by the cytochrome P450 enzymes with the subsequent formation of furan rings. Because of undesirable interactions with several medications, many studies have developed methods for grapefruit furanocoumarin quantification that include high-performance liquid chromatography coupled with UV detector or mass spectrometry. The distribution of furanocoumarins in grapefruits is affected by several environmental conditions, such as processing techniques, storage temperature, and packing materials. In the past few years, grapefruit furanocoumarins have been demonstrated to exhibit several biological activities including antioxidative, -inflammatory, and -cancer activities as well as bone health promotion both in vitro and in vivo. Notably, furanocoumarins potently exerted antiproliferative activities against cancer cell growth through modulation of several molecular pathways, such as regulation of the signal transducer and activator of transcription 3, nuclear factor-κB, phosphatidylinositol-3-kinase/AKT, and mitogen-activated protein kinase expression. Therefore, based on this review, we suggest furanocoumarins may serve as bioactive components that contribute, at least in part, to the health benefits of grapefruit.