Spasmolytic activity of aurapten analogs

A review of the pharmacological and therapeutic effects of auraptene

There is a growing awareness in herbal medications as they are usually safe and devoid of significant adverse effects. Auraptene is a natural bioactive monoterpene coumarin ether and is consumed all over the world. There is growing evidence of the therapeutic benefits of auraptene. Auraptene, also known as auraptene and 7-geranyloxycoumarin, is a bioactive monoterpene coumarin from Rutaceae family, which is isolated from Citrus aurantium (Seville orange) and Aegle marmelos (bael fruit). Auraptene is a highly pleiotropic molecule, which can modulate intracellular signaling pathways that control inflammation, cell growth, and apoptosis. It has a potential therapeutic role in the prevention and treatment of various diseases due to its anti-inflammatory and antioxidant activities as well as its excellent safety profile. In the present article, various pharmacological and therapeutic effects of auraptene were reviewed. Different online databases using keywords such as auraptene, therapeutic effects and pharmacological effects were searched until the end of September 2018, for this purpose. Auraptene has been suggested to be effective in the treatment of a broad range of disorders including inflammatory disorders, dysentery, wounds, scars, keloids, and pain. In addition, different studies have demonstrated that auraptene possesses numerous pharmacological properties including anti-inflammatory, anti-oxidative, anti-diabetic, anti-hypertensive and anti-cancer as well as neuroprotective effects. The present review provides a detailed survey of scientific researches regarding pharmacological properties and therapeutic effects of auraptene.

Auraptene and Its Role in Chronic Diseases

Auraptene (7-geranyloxycoumarin) is the best known and most abundant prenyloxycoumarin present in nature. It is synthesized by various plant species, mainly those of the Rutaceae and Umbeliferae (Apiaceae) families, comprising many edible fruits and vegetables such as lemons, grapefruit and orange. Auraptene has shown a remarkable effect in the prevention of degenerative diseases, in particular it has been reported to be one the most promising known natural chemopreventive agents against several types of cancer. The aim of this chapter is to review the effects of auraptene in the prevention and treatment of different chronic diseases.

Hypotensive activity of auraptene, a monoterpene coumarin from Citrus spp

CONTEXT

Citrus spp. (Rutaceae) are well-documented for their cardioprotective properties. Auraptene is a bioactive monoterpene coumarin ether abundantly present in the Citrus spp.

OBJECTIVE

To investigate the hypotensive activity of auraptene.

METHODS

Different groups of normotensive rats (n = 5 in each group) were subjected to single intravenous injections of auraptene (125, 250 and 500 µg/kg), nifedipine (as positive control; 63, 125 and 250 µg/kg) or negative control [DMSO/normal saline (1:3)]. Mean arterial blood pressure (MABP) and heart rate (HR) were evaluated following each treatment.

RESULTS

A dose-dependent hypotensive effect was observed following auraptene injection, which was significant at 250 and 500 µg/kg (p < 0.001) but not 125 µg/kg (p > 0.05). With respect to the positive control, nifedipine reduced MABP at all tested doses, dose-dependently and significantly (p < 0.001). The MABP lowering effect of auraptene was found to be significantly lower than that of nifedipine (p < 0.001).

CONCLUSION

In light of the present findings, auraptene has moderate hypotensive activity. Further investigations are recommended to explore the effects of higher doses as well as oral administration of this phytochemical.

Excited-State Proton Transfer in 7-Hydroxy-4-methylcoumarin along a Hydrogen-Bonded Water Wire

TDDFT, RI-CC2, and CIS calculations have been performed for the nondissociative excited-state proton transfer (ESPT) in the S1 state of 7-hydroxy-4-methylcoumarin (7H4MC) along a H-bonded water wire of three water molecules bridging the proton donor (OH) and the proton acceptor (C[double bond]O) groups (7H4MC.(H2O)3). The observed structural reorganization in the water-wire cluster is interpreted as a proton-transfer (PT) reaction along the H2O solvent wire. The shift of electron density within the organic chromophore 7H4MC due to the optical excitation appears to be the driving force for ESPT. All the methods used show that the reaction path occurs in the 1pipi* state, and no crossing with a Rydberg-type 1pisigma* state is found. TDDFT and RI-CC2 calculations predict an exoergic reaction of the excited-state enol-to-keto transformation. The S1 potential energy curve reveals well-defined Cs minima of enol- and keto-clusters, separated by a single barrier with a height of 17-20 kcal/mol. After surmounting this barrier, spontaneous PT along the water wire is observed, leading without any further barrier to the keto structure. The TDDFT and RI-CC2 methods appear to be reliable approaches to describe the energy surfaces of ESPT. The CIS method predicts an endoergic ESPT reaction and an energy barrier, which is too high.

Excited State Properties of 7-Hydroxy-4-methylcoumarin in the Gas Phase and in Solution. A Theoretical Study

TDDFT/B3LYP and RI-CC2 calculations with different basis sets have been performed for vertical and adiabatic excitations and emission properties of the lowest singlet states for the neutral (enol and keto), protonated and deprotonated forms of 7-hydroxy-4-methylcoumarin (7H4MC) in the gas phase and in solution. The effect of 7H4MC-solvent (water) interactions on the lowest excited and fluorescence states were computed using the Polarizable Continuum Method (PCM), 7H4MC-water clusters and a combination of both approaches. The calculations revealed that in aqueous solution the pi pi* energy is the lowest one for excitation and fluorescence transitions of all forms of 7H4MC studied. The calculated excitation and fluorescence energies in aqueous solution are in good agreement with experiment. It was found that, depending on the polarity of the medium, the solvent shifts vary, leading to a change in the character of the lowest excitation and fluorescence transition. The dipole-moment and electron-density changes of the excited states relative to the ground state correlate with the solvation effect on the singlet excited states and on transition energies, respectively. The calculations show that, in contrast to the ground state, the keto form has a lower energy in the pi pi* state as compared to enol, demonstrating from this point of view the energetic possibility of proton transfer from the enol to the keto form in the excited state.

New metal complexes of 4-methyl-7-hydroxycoumarin sodium salt and their pharmacological activity

Complexes of copper (II), zinc (II), nickel (II), cobalt (II) and iron (III) with 4-methyl-7-hydroxycoumarin sodium salt (Mendiaxon, Hymecromone) were synthesized by mixing of equimolar amounts of the respective metal nitrates and 4-methyl-7-hydroxycoumarin sodium salt in water. The complexes were characterized and identified by elemental analysis, conductivities, IR, 1H NMR spectroscopy and mass spectral data. DTA and TGA have been applied to study the compositions of the compounds. Thermal analysis of the complexes indicate the formation of compounds which correspond to the compositions Met(HL)2 x nH2O, where Met = Cu, Zn, Ni, Co; n = 2, 3 or 4 and Fe(HL)3 x 5H2O. The newly synthesized compounds were assayed for acute intraperitoneal and per oral toxicity, influence on blood clotting time and the most active complex was investigated for spasmolytic activity.