Synthesis of novel derivatives of murrayafoline A and their inhibitory effect on LPS-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells

Molecular Hybridization of Alkaloids Using 1,2,3-Triazole-Based Click Chemistry

Alkaloids found in multiple species, known as 'driver species', are more likely to be included in early-stage drug development due to their high biodiversity compared to rare alkaloids. Many synthetic approaches have been employed to hybridize the natural alkaloids in drug development. Click chemistry is a highly efficient and versatile reaction targeting specific areas, making it a valuable tool for creating complex natural products and diverse molecular structures. It has been used to create hybrid alkaloids that address their limitations and serve as potential drugs that mimic natural products. In this review, we highlight the recent advancements made in modifying alkaloids using click chemistry and their potential medicinal applications. We discuss the significance, current trends, and prospects of click chemistry in natural product-based medicine. Furthermore, we have employed computational methods to evaluate the ADMET properties and drug-like qualities of hybrid molecules.

Synthesis of glycyrrhetinic acid-modified liposomes to deliver Murrayafoline A for treatment of hepatocellular carcinoma

Hepatocellular carcinoma is a common type of cancer associated with a high mortality rate. Among several bioactive compounds, Murrayafoline A (MuA) has been proved as a bio substance that exhibits great potentials in treating liver cancer. In order to overcome the high cytotoxicity and low solubility of MuA, a delivery system based on nanocarriers is necessary to deliver MuA towards the desired target. In the present study, 18β-glycyrrhetinic acid (GA), which is known as a ligand for liver targeting, was used to construct the cholesterol-poly (ethylene glycol)-glycyrrhetinic acid (GA-PEG-Chol) conjugate and liposome for MuA administration. The compound was then examined for therapeutic efficacy and safety in HUVEC and HepG2 cells in 2D and 3D cell cultures. Results have shown that MuA-loaded liposomes had IC₅₀ value of 2 µM in HepG2 and had the cytosolic absorption of 8.83 ± 0.97 ng/10⁵ cells, while The IC50 value of MuA-loaded liposomes in HUVEC cell lines was 15 µM and the the cytosolic absorption was recorded as 3.62 ± 0.61 cells. The drug test on the 3D cancer sphere platform of the HepG2 cancer sphere showed that MuA-loaded GA liposomes had the highest efficacy at a concentration of 100 µg/mL. In short, these results suggest that MuA-loaded GA liposomes have the potential for maintenance drug delivery and liver targeting.

A low-cost, flexible extruder for liposomes synthesis and application for Murrayafoline A delivery for cancer treatment

Liposomal encapsulation is a drug delivery strategy with many advantages, such as improved bioavailability, ability to carry large drug loads, as well as controllability and specificity towards various targeted diseased tissues. Currently, most preparation techniques require an additional extrusion or filtering step to obtain monodisperse liposomes with the size of less than 100 nm. In this study, a compact liposome extruder was designed at a cost of $4.00 and used to synthesize liposome suspensions with defined particle size and high homogeneity for Murrayafoline A (Mu-A) loading and release. The synthesized MuA-loaded liposomes displayed a biphasic drug release and remained stable under the storage condition of 4°C. They also significantly reduced the viability of HepG2 cells in the cancer spheroids by 25%. The low-cost, flexible liposome extruder would allow the researchers to study liposomes and their applications in a cost-effective manner.

Anti-tumor effect of liposomes containing extracted Murrayafoline A against liver cancer cells in 2D and 3D cultured models

Murrayafoline A (MuA) is a natural compound with diverse biological activities, including cytotoxicity against cancer cells, but suffers from poor water solubility and low specificity. In order to improve the potential of MuA as a candidate for cancer treatment, MuA-loaded liposomes were prepared with the liposomal membrane consisting of dioleoylphosphatidylcholine and cholesterol. Dynamic light scattering measurements showed that the MuA-loaded liposomes had a z-average particle size of 104.3 ± 6.4 nm (mean ± SD; n = 3) and a polydispersity index of 0.15 ± 0.02 (mean ± SD; n = 3). The encapsulation efficiency was 55.3 ± 2.3% (mean ± SD; n = 3). The in vitro cytotoxicity of encapsulated MuA was attenuated at IC50 = 21.97 µg/mL compared to 6.24 µg/mL for free MuA, against HepG2. In contrast, MuA-loaded liposomes were significantly more effective at inhibiting cell growth in HepG2 cancer spheroids, which indicated that they were able to reach the interior layers of the microtumor. Taken together, these results showed that the encapsulation of MuA in liposomes is a good research direction to improve this natural compound’s potential as a candidate for cancer treatment.

Diastereoselective synthesis of spiro[carbazole-3,5'-pyrimidines] and spiro[carbazole-3,1'-cyclohexanes] via four-component reaction

Functionalized spiro[carbazole-3,5'-pyrimidines] and spiro[carbazole-3,1'-cyclohexanes] were efficiently synthesized in satisfactory yields with high diastereoselectivity by CuSO4 catalyzed multicomponent reaction of indole-2-acetate, aromatic aldehyde and 1,3-dimethylbarbituric acid or dimedone. The reaction was finished with sequential Diels-Alder reaction of both in situ generated indole-2,3-quinodimethane and a dienophile. Additionally, the initially formed spiro[carbazole-3,5'-pyrimidines] were converted to dehydrogenated spiro[carbazole-3,5'-pyrimidines] by DDQ oxidation. The initially formed spiro[carbazole-3,1'-cyclohexanes] were converted to δ-valerolactone-substituted carbazoles by a DDQ promoted Baeyer-Villiger oxidation process.

Optimization of Murrayafoline A ethanol extraction process from the roots of Glycosmis stenocarpa, and evaluation of its Tumorigenesis inhibition activity on Hep-G2 cells

Glycosmis stenocarpa is a species of shrub found in the Northern provinces of Vietnam. Its roots contain different carbazolic derivatives, mainly Murrayafoline A (Mu-A), which exhibits valuable biological activities. In this study, we performed an extraction of Mu-A from the roots of G. stenocarpa and optimized this process using response surface methodology (RSM) according to a central composite design, with three independent parameters including extraction time (min), extraction temperature (°C), and solvent/material ratio (mL/g). Two dependent variables were the Mu-A content (mg/g raw materials) and extraction efficiency (%). The optimal conditions to extract Mu-A were found to be as follows: extraction temperature, 67°C; extraction time, 165 min; and solvent/material ratio, 5:1. Under these conditions, the Mu-A content and extraction efficiency were 38.94 ± 1.31 mg/g raw materials and 34.98 ± 1.18%, respectively. Mu-A exhibited antiproliferation and antitumor-promoting activity against the HepG-2 cell line. The present optimization work of Mu-A extraction from G. stenocarpa roots contributed to the attempt of designing a large-scale extraction process for the compound and further exploitation of its potential in vivo applications.

Recent approaches to the synthesis of tetrahydrocarbazoles

The tetrahydrocarbazole (THC) motif is ubiquitous in natural products and biologically active compounds.

Fischer indole synthesis applied to the total synthesis of natural products

In this review, we are trying to underscore the application of FIS in one of the crucial step of indole construction in the total synthesis of biologically active natural products.

Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A

BACKGROUND AND PURPOSE

The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca(2+) currents carried by the Cav 1.2 channels [ICa1.2 ] of rat cardiomyocytes. As only few drugs stimulate ICa1.2 , this study was designed to analyse the effects of MuA on vascular Cav 1.2 channels.

EXPERIMENTAL APPROACH

Vascular activity was assessed on rat aorta rings mounted in organ baths. Cav 1.2 Ba(2+) current [IBa1.2 ] was recorded in single rat aorta and tail artery myocytes by the patch-clamp technique. Docking at a 3D model of the rat, α1c central pore subunit of the Cav 1.2 channel was simulated in silico.

KEY RESULTS

In rat aorta rings MuA, at concentrations ≤14.2 μM, increased 30 mM K(+) -induced tone and shifted the concentration-response curve to K(+) to the left. Conversely, at concentrations >14.2 μM, it relaxed high K(+) depolarized rings and antagonized Bay K 8644-induced contraction. In single myocytes, MuA stimulated IBa1.2 in a concentration-dependent, bell-shaped manner; stimulation was stable, incompletely reversible upon drug washout and accompanied by a leftward shift of the voltage-dependent activation curve. MuA docked at the α1C subunit central pore differently from nifedipine and Bay K 8644, although apparently interacting with the same amino acids of the pocket. Neither Bay K 8644-induced stimulation nor nifedipine-induced block of IBa1.2 was modified by MuA.

CONCLUSIONS AND IMPLICATIONS

Murrayafoline A is a naturally occurring vasoactive agent able to modulate Cav 1.2 channels and dock at the α1C subunit central pore in a manner that differed from that of dihydropyridines.