Cholinesterase inhibitors assessment of aporphine alkaloids from Annona crassiflora and molecular docking studies

Four unreported aporphine alkaloids with antifungal activities from Artabotrys hexapetalus

In this study, the extract from Artabotrys hexapetalus showed strong antifungal activity against phytopathogenic fungi in vitro. Four unreported aporphine alkaloids, hexapetalusine A-D (1-4), were isolated from stems and roots of Artabotrys hexapetalus (L.f.) Bhandari, along with six known aporphine alkaloids (5-10). Their chemical structures were elucidated by extensive spectroscopic analysis. The absolute configurations of 1-3 were determined using single-crystal X-ray diffractions and ECD calculations. Hexapetalusine A-C (1-3) were special amidic isomers. Additionally, all isolated compounds were evaluated for their antifungal activity against four phytopathogenic fungi in vitro. Hexapetalusine D (4) exhibited weak antifungal activity against Curvularia lunata. Liriodenine (5) displayed significant antifungal activity against Fusarium proliferatum and Fusarium oxysporum f. sp. vasinfectum, which is obviously better than positive control nystatin, suggesting that it had great potential to be developed into an effective and eco-friendly fungicide.

Application of effect-directed analysis using TLC-bioautography for rapid isolation and identification of antidiabetic compounds from the leaves of Annona cherimola Mill

INTRODUCTION

Type 2 diabetes mellitus is a globally prevalent chronic disease characterised by hyperglycaemia and oxidative stress. The search for new natural bioactive compounds that contribute to controlling this condition and the application of analytical methodologies that facilitate rapid detection and identification are important challenges for science. Annona cherimola Mill. is an important source of aporphine alkaloids with many bioactivities.

OBJECTIVE

The aim of this study is to isolate and identify antidiabetic compounds from alkaloid extracts with α-glucosidase and α-amylase inhibitory activity from A. cherimola Mill. leaves using an effect-directed analysis by thin-layer chromatography (TLC)-bioautography.

METHODOLOGY

Guided fractionation for α-glucosidase and α-amylase inhibitors in leaf extracts was done using TLC-bioassays. The micro-preparative TLC was used to isolate the active compounds, and the identification was performed by mass spectrometry associated with web-based molecular networks. Additionally, in vitro estimation of the inhibitory activity and antioxidant capacity was performed in the isolated compounds.

RESULTS

Five alkaloids (liriodenine, dicentrinone, N-methylnuciferine, anonaine, and moupinamide) and two non-alkaloid compounds (3-methoxybenzenepropanoic acid and methylferulate) with inhibitory activity were isolated and identified using a combination of simple methodologies. Anonaine, moupinamide, and methylferulate showed promising results with an outstanding inhibitory activity against both enzymes and antioxidant capacity that could contribute to controlling redox imbalance.

CONCLUSIONS

These high-throughput methodologies enabled a rapid isolation and identification of seven compounds with potential antidiabetic activity. To our knowledge, the estimated inhibitory activity of dicentrinone, N-methylnuciferine, and anonaine against α-glucosidase and α-amylase is reported here for the first time.

Scientific Advances in the Last Decade on the Recovery, Characterization, and Functionality of Bioactive Compounds from the Araticum Fruit (Annona crassiflora Mart.)

Araticum (Annona crassiflora Mart.) is a native and endemic species to Brazilian Cerrado whose fruits have high sensorial, nutritional, bioactive, and economic potential. Its use in local folk medicine, associated with recent scientific findings, has attracted growing interest from different industrial sectors. Therefore, understanding the scientific advances achieved so far and identifying gaps to be filled is essential to direct future studies and transform accumulated knowledge into innovative technologies and products. In this review, we summarize the phytochemical composition, bioactivities, and food products from araticum fruit that have been reported in the scientific literature over the past 10 years. The compiled data showed that araticum fruit parts contain a wide range of bioactive compounds, particularly phenolic compounds, alkaloids, annonaceous acetogenins, carotenoids, phytosterols, and tocols. These phytochemicals contribute to different biological activities verified in araticum fruit extracts/fractions, including antioxidant, anti-inflammatory, anti-Alzheimer, anticancer, antidiabetic, anti-obesity, antidyslipidemic, antinociceptive, hepatoprotective, healing of the cutaneous wound, antibacterial, and insecticide effects. Despite the promising findings, further studies-particularly toxicological (especially, with byproducts), pre-clinical, and clinical trials-must be conducted to confirm these biological effects in humans and assure the safety and well-being of consumers.

In Vitro and In Silico Evaluation of Cholinesterase Inhibition by Alkaloids Obtained from Branches of Abuta panurensis Eichler

Alkaloids are natural products known as ethnobotanicals that have attracted increasing attention due to a wide range of their pharmacological properties. In this study, cholinesterase inhibitors were obtained from branches of Abuta panurensis Eichler (Menispermaceae), an endemic species from the Amazonian rainforest. Five alkaloids were isolated, and their structure was elucidated by a combination of 1D and 2D 1H and 13C NMR spectroscopy, HPLC-MS, and high-resolution MS: Lindoldhamine isomer m/z 569.2674 (1), stepharine m/z 298.1461 (2), palmatine m/z 352.1616 (3), 5-N-methylmaytenine m/z 420.2669 (4) and the N-trans-feruloyltyramine m/z 314.1404 (5). The compounds 1, 3, and 5 were isolated from A. panurensis for the first time. Interaction of the above-mentioned alkaloids with acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes was investigated in silico by molecular docking and molecular dynamics. The molecules under investigation were able to bind effectively with the active sites of the AChE and BChE enzymes. The compounds 1–4 demonstrated in vitro an inhibitory effect on acetylcholinesterase with IC50 values in the range of 19.55 µM to 61.24 µM. The data obtained in silico corroborate the results of AChE enzyme inhibition.