Coumarins. X. Spectral studies on some linear furanocoumarins

Hogweed Seed Oil: Physico-Chemical Characterization, LC-MS Profile, and Neuroprotective Activity of Heracleum dissectum Nanosuspension

The seeds of dissected hogweed (Heracleum dissectum Ledeb., Apiaceae) are the source of hogweed oil (HSO), which is still underexplored and requires careful chemical and biological studies. The performed physico-chemical analysis of HSO elucidated basic physical characteristics and revealed the presence of fatty acids, essential oil components, pigments, and coumarins. High-performance liquid chromatography with photodiode array detection and electrospray ionization triple quadrupole mass spectrometric detection (HPLC-PDA-ESI-tQ-MS/MS) identified 38 coumarins that were characterized and quantified. Various furanocoumarins were the major components of HSO polyphenolics, including imperatorin, phellopterin, and isoimperatorin, and the total coumarin content in HSO varied from 181.14 to 238.42 mg/mL. The analysis of storage stability of the selected compounds in HSO indicated their good preservation after 3-year storage at cold and freezing temperatures. The application of the CO₂-assisted effervescence method allowed the production of an HSO nanosuspension, which was used in a brain ischemia model of rats. The HSO nanosuspension enhanced cerebral hemodynamics and decreased the frequency of necrotic processes in the brain tissue. Thus, H. dissectum seeds are a good source of coumarins, and HSO nanosuspension promotes neuroprotection of the brain after lesions, which supports earlier ethnopharmacological data.

Isofraxidin: Synthesis, Biosynthesis, Isolation, Pharmacokinetic and Pharmacological Properties

Isofraxidin (7-hydroxy-6, 8-dimethoxy coumarin) (IF) is a hydroxy coumarin with several biological and pharmacological activities. The plant kingdom is of the most prominent sources of IF, which, among them, Eleutherococcus and Fraxinus are the well-known genera in which IF could be isolated/extracted from their species. Considering the complex pathophysiological mechanisms behind some diseases (e.g., cancer, neurodegenerative diseases, and heart diseases), introducing IF as a potent multi-target agent, which possesses several herbal sources and the multiple methods for isolation/purification/synthesis, along with the unique pharmacokinetic profile and low levels of side effects, could be of great importance. Accordingly, a comprehensive review was done without time limitations until February 2020. IF extraction methods include microwave, mechanochemical, and ultrasound, along with other conventional methods in the presence of semi-polar solvents such as ethyl acetate (EtOAc). In addition to the isolation methods, related synthesis protocols of IF is also of great importance. From the synthesis point of view, benzaldehyde derivatives are widely used as precursors for IF synthesis. Along with the methods of isolation and biosynthesis, IF pharmacokinetic studies showed hopeful in vivo results of its rapid absorption after oral uses, leading to different pharmacological effects. In this regard, IF targets varieties of inflammatory mediators including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), tumor necrosis factor-α (TNF-α), and matrix metalloproteinases (MMPs). thereby indicating anticancer, cardioprotective, and neuroprotective effects. This is the first review on the synthesis, biosynthesis, isolation, and pharmacokinetic and pharmacological properties of IF in combating different diseases.

Furanocoumarin Content, Antioxidant Activity, and Inhibitory Potential of Heracleum verticillatum, Heracleum sibiricum, Heracleum angustisectum, and Heracleum ternatum Extracts against Enzymes Involved in Alzheimer's Disease and Type II Diabetes

Hexane extracts of Heracleum verticillatum, H. sibiricum, H. angustisectum, and H. ternatum were studied for their furanocoumarin content antioxidant potential and acetylcholinesterase and α-amylase inhibitory activities. Quantification of the furanocoumarins was performed by ¹ H-NMR. Pimpinellin was found to be the main component in the roots of all studied species. Bergapten and imperatorin were the major compounds in the fruits of H. sibiricum and H. verticillatum, respectively, while byakangelicol dominated in H. angustisectum and H. ternatum fruits. The leaf and fruit extracts of H. angustisectum demonstrated the highest DPPH radical scavenging activity and TEAC (IC₅₀ 0.58 mg/mL and 1.83 mm, respectively). The root extracts of H. verticillatum and H. angustisectum were found to be the most effective against acetylcholinesterase (IC₅₀ 0.30 and 0.34 mg/mL, respectively). The studied extracts were not active or demonstrated a weak inhibitory effect (%Inh. up to 29.7) towards α-amylase.

Antiviral and cytotoxic evaluation of coumarins from Prangos ferulacea

CONTEXT

Prangos ferulacea (L.) Lindl. (Apiaceae) is a perennial plant found in the Middle-East, where it is commonly used as an antispasmodic and anti-inflammatory agent. It is a rich source of coumarins.

OBJECTIVE

To purify several coumarins from P. ferulacea and to screen their cytotoxicity and anti-herpes activity.

MATERIALS AND METHODS

Acetone extract of roots of P. ferulacea was subjected to several chromatographic separations to render pure coumarins (1-8). Anti-herpes virus effects of 1-7 were evaluated at concentration 2.5, 5, and 10 µgmL(-1), on a confluent monolayer of Vero cells infected with 25 PFU of HSV1. Cytotoxic effects of 1 and 2 were evaluated on an A2780S cell line using the MTT assay. The cells were exposed to a series of concentrations of coumarins (0.01-2.5 mM, 37°C, 72 h).

RESULTS

Compounds 1-8 were identified as osthole, isoimperatorin, oxypeucedanin, psoralen, oxypeucedanin hydrate, gosferol, oxypeucedanin methnolate, and pranferol. This is the first report of occurrence of 4 and 7 in this plant. Compound 1 showed a viability of 9.41% ± 2.4 at 2.5 mM on A2780S cells (IC50 = 0.38 mM). The cell survival of 2 at 2.5 mM was 46.86% ± 5.5 with IC50 equal to 1.1 mM.

DISCUSSION AND CONCLUSION

Compound 1 shows cytotoxic effects on the A2780S cell line. Compound 2 is a cyclooxygenase-2 inhibitor and the A2780S cell line does not express COX-2 which may interpret the non-toxic effect of the compound on this cell line. None of the tested compounds showed an anti-HSV effect at non-toxic concentrations.

Furanocoumarins from Dorstenia foetida

The linear furanocoumarins 5-(2,3-epoxy-3-methyl-butoxy)-chalepensin, 5-methoxy-3-(3-methyl-2,3-dihydroxybutyl)-psoralen-diacetate (7), 5-methoxy-3-[3-(β-D-glucopyranosyloxy)-2-acetyloxy-3-methyl-butyl]-psoralen and 5-(3-methyl-2,3-dihydroxybutyloxy)-3-[3-(β-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-psoralen, and the coumarin derivative 7-hydroxy-5-methoxy-6-carboxymethyl-3-[3-(β-D-glucopyranosyloxy)-2-hydroxy-3-methyl-butyl]-coumarin were isolated from the leaves of Dorstenia foetida (Moraceae) along with the known compounds psoralen, bergapten, isopimpinellin, phellopterin, 5-methoxychalepensin and turbinatocoumarin. Further furanocoumarins were characterized by ESI-MS/MS investigations. The nonpolar extracts of D. foetida exhibit antifungal, antibacterial and cytotoxic activity, however, no anthelminthic activity.

C-7 oxygenated coumarins from the fruits of Micromelum minutum

A new 7-oxygenated coumarin, 7-demethylmurralonginol isovalerate (1), and a new natural product, murralonginol (2), together with seven known 7-oxygenated coumarins, murralonginol isovalerate (3), murralongin (4), micromelin (5), scopoletin (6), microminutin (7), murrangatin (8), and minumicrolin (9), were isolated from the fruits of Micromelum minutum. The structures of these compounds were established on the basis of their 1D and 2D NMR spectroscopic data. Among these isolates, compounds 2 and 4 - 9 exhibited cytotoxicity against cholangiocarcinoma cell line, KKU-100.

Minor furanocoumarins and coumarins in grapefruit peel oil as inhibitors of human cytochrome P450 3A4

A new cyclic acetal (1) of marmin (6',7'-dihydroxy-7-geranyloxycoumarin), two new cyclic acetals (5, 6) of 6',7'-dihydroxybergamottin, and the known compounds marmin (2), 7-geranyloxycoumarin (3), bergamottin (4), and 6',7'-dihydroxybergamottin (7) were isolated from grapefruit peel oil. All compounds were tested for inhibitory activity against intestinal cytochrome P450 3A4, an enzyme involved in the "grapefruit/drug" interactions in humans. Coumarins (1-3) exhibited negligible inhibitory activity, while the furanocoumarins (4-7) showed potent in vitro inhibitory activity with IC(50) values of 2.42, 0.13, 0.27, and 1.58 microM, respectively.

Fingerprint analysis of the fruits of Cnidium monnieri extract by high-performance liquid chromatography–diode array detection–electrospray ionization tandem mass spectrometry

A method incorporating high-performance liquid chromatography (HPLC) with electrospray ionization (ESI) and tandem mass spectrometry (MS), with parallel analysis by HPLC with UV detection using a diode-array detector (DAD) was developed for the qualitative characterization of coumarin and chromone constituents in the fruits of Cnidium monnieri. The chromatographic separations were performed on a Diamonsil C18 column (4.6 mm x 200 mm, 5 microm) with water with 50 mM ammonium acetate and 2% acetic acid (A) and acetonitrile (B) as the mobile phase. According to the characteristic UV spectra, the information of molecular weight and structure provided by ESI-MS/MS, 13 coumarin and 7 chromone components were detected and identified. This method is rapid and reliable for identification of the constituents in the complex herbal system, and the fragmentation patterns proposed could be extended to the similar compounds.

Alkylated Isocoumarins fromPituranthos Scoparius

Two isocoumarins have been isolated from the ethyl acetate extract of the root of Pituranthos scoparius: 3-n-propyl-5-methoxy-6-hydroxy-isocoumarin and 3-n-propyl-5,7-dimethoxy-6-hydroxy-isocoumarin. Their structures were assigned by spectral analysis.

Antimicrobial constituents of Foeniculum vulgare

A phenyl propanoid derivative, dillapional(1) was found to be a antimicrobial principle of the stems of Foeniculum vulgare (Umbelliferae) with MIC values of 125, 250 and 125/ against Bacillus subtilis, Aspergillus niger and Cladosporium cladosporioides, respectively. A coumarin derivative, scopoletin(2) was also isolated as marginally antimicrobial agent along with inactive compounds, dillapiol(3), bergapten(4), imperatorin(5) and psolaren(6) from this plant. The isolates 1-6 were not active against the Escherichia coli.

Indolopyridoquinazoline alkaloid from Leptothyrsa sprucei

The indolopyridoquinazoline alkaloid, 3-hydoxyrutaecarpine, was isolated from Leptothyrsa sprucei, along with 8-methoxypsoralen, 5-methoxypsoralen, imperatorin, isoimperatorin, kaempferol 3-O-alpha-L-rhamnopyranoside, clematine and cnidioside B. The usefulness of the gradient 1H-15N HMBC NMR spectroscopy in the structure elucidation of 3-hydroxyrutaecarpine is noted.

Furanocoumarins from Dorstenia gigas

A series of linear and angular prenylated furanocoumarins and a benzofuran derivative were isolated from leaves and twigs of Dorstenia gigas (Moraceae), a plant occurring endemically on Socotra Island (Yemen). The structures were elucidated by spectroscopic methods (NMR, MS, UV) and chemical derivatization.

Minor furocoumarins of Murraya koenigii

Xanthotoxin, isobyakangelicol, phellopterin, gosferol, neobyakangelicol, byakangelicol, byakangelicin and isogosferol are reported as minor furocoumarins of Murraya koenigii seeds.

Coumarins and bicoumarin from Ferula sumbul: anti-HIV activity and inhibition of cytokine release

The methanol extract of the dried roots of Ferula sumbul afforded two furanocoumarin esters, fesumtuorin A, B, one bicoumarin, fesumtuorin C, five spirobicoumarins, fesumtuorin D, E, F, G and H, along with nineteen known coumarins. Their structures were established on the basis of spectroscopic studies. Some of the isolated compounds showed anti-HIV activity and very weak inhibition of cytokine release.

Minor constituents from Bupleurum fruticosum roots

A new triterpenoid saponin, 23-acetoxy,16 alpha-hydroxy-13,28-epoxyolean-11-en-3 beta-yl--beta-D-glucopyranosyl- (1-->2)---beta-D-glucopyranosil(1-->3)-beta-D-fucopyranoside, has been isolated from the roots of Bupleurum fruticosum, along with eight coumarins, scopoletin, scoparone, prenyletin, capensin, fraxetin, aesculetin,7-(3-methyl-2-butenyloxy-6-methoxycoumarin, 7-(2-hydroxy-3-methyl-3-butenyloxy)-6-methoxycoumarin and 5,7-dihydroxy-6-methoxy-8-(3-methyl-2-butenyl)coumarin. The last compound has not been previously encountered in nature. The structures were determined by analysis of NMR spectral data including two-dimensional techniques.

Suksdorfin: an anti-HIV principle from Lomatium suksdorfii, its structure-activity correlation with related coumarins, and synergistic effects with anti-AIDS nucleosides

Suksdorfin (1), which is isolated from the fruit of Lomatium suksdorfii, was found to be able to inhibit HIV-1 replication in the T cell line, H9, with an average EC50 value of 2.6 +/- 2.1 microM. In addition, suksdorfin was also suppressive during acute HIV-1 infections of peripheral blood mononuclear cells, monocyte/macrophages and the promonocytic cell line, U937. Combinations of 1 and the anti-HIV nucleosides ddI and ddC demonstrated statistical synergy in inhibiting HIV-1 replication (ddC > ddI). However, the viral inhibition mediated by combining 1 with AZT was not statistically synergistic. Furthermore, the presence of suksdorfin did not antagonize the suppression mediated by the three nucleoside reverse transcriptase inhibitors. Comparison of the structure and activity of 1 with those of ten related compounds indicated that the dihydroseselin type of pyranocoumarin possessing a 4'-isovaleryl group is important to suksdorfin's enhanced anti-HIV activity.