Isoquinoline alkaloids from Asimina triloba

Isolation, biological activity, and synthesis of isoquinoline alkaloids

Covering: 2019 to 2023Isoquinoline alkaloids, an important class of N-based heterocyclic compounds, have attracted considerable attention from researchers worldwide. To follow up on our prior review (covering 2014-2018) and present the progress of this class of compounds, this review summarizes and provides updated literature on novel isoquinoline alkaloids isolated during the period of 2019-2023, together with their biological activity and underlying mechanisms of action. Moreover, with the rapid development of synthetic modification strategies, the synthesis strategies of isoquinoline alkaloids have been continuously optimized, and the total synthesis of these classes of natural products is reviewed critically herein. Over 250 molecules with a broad range of bioactivities, including antitumor, antibacterial, cardioprotective, anti-inflammatory, neuroprotective and other activities, are isolated and discussed. The total synthesis of more than nine classes of isoquinoline alkaloids is presented, and thirteen compounds constitute the first total synthesis. This survey provides new indications or possibilities for the discovery of new drugs from the original naturally occurring isoquinoline alkaloids.

13C NMR spectroscopic data of aporphine alkaloids

This study involves aporphine alkaloids identified through ¹³C Nuclear Magnetic Resonance (NMR) spectroscopic data. For the present publication, articles were selected from several databases on aporphine alkaloids from 1994 to 2021. In this class, more than 700 compounds have been registered, with 221 were included in this section, among which 122 were characterized for the first time in the investigated period. The study also addresses their biosynthetic pathways, classifying substances according to their structural characteristics based on established literature. Furthermore, pharmacological activities related to the aporphine alkaloids highlighted in this section are also presented, giving an overview of the various applications of these compounds.

Benzoylcyclopropane Derivatives from Hypoxis hemerocallidea Corms

Two monobenzoylcyclopropane (hypoxhemerol A (1: ) and hypoxhemeroloside G (2: )) and three dibenzoylcyclopropane (hypoxhemerol B (3: ), hypoxhemeroloside H (4: ), and hypoxhemeroloside I (5: )) derivatives were isolated from the hydro-alcoholic extract of Hypoxis hemerocallidea corms. This is the first instance where benzoylcyclopropane analogs were isolated from any natural source. Structure elucidation was mainly based on 1D- and 2D-NMR and HRESIMS data. The absolute configuration (2R, 4R) of 1: was determined via NOESY NMR and experimental and calculated ECD data analyses. Compounds 1: -5: and 11 recently reported metabolites (hypoxoside, obtuside A, interjectin, acuminoside, curcapicycloside, and hypoxhemerolosides A - F) were screened for in vitro antimicrobial activity against various bacterial and fungal strains. Curcapicycloside and acuminoside exhibited antibacterial activity against Escherichia coli with 78 and 79% inhibition at 20 µg/mL, respectively. Hypoxhemeroloside A showed mild antifungal activity against Cryptococcus neoformans with 63% inhibition at 20 µg/mL.

Identification of alkaloidal compounds from leaves and roots of Stephania succifera by HPLC-QTOF-MS and prediction of potential bioactivity with PharmMapper

INTRODUCTION

The roots of Stephania succifera are used in traditional medicine for the treatment of several diseases. Research on this plant has mainly focused on bioactive alkaloids from the roots, and no previous work on compounds from the abundant leaves has yet been reported.

OBJECTIVE

To identify and compare alkaloidal compounds in S. succifera roots and leaves and to predict the potential bioactivity of some alkaloids.

METHODS

High-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) was employed to identify alkaloidal compounds from S. succifera. The potential targets and bioactivities of most alkaloids were predicted using the PharmMapper server.

RESULTS

Fifty-six alkaloidal compounds, including protoberberine-, aporphine-, proaporphine-, benzylisoquinoline-, and lactam-type alkaloids, were identified or tentatively identified in S. succifera roots and leaves based on the HPLC-MS data. Forty-one compounds have not been previously reported in S. succifera and eight of them have not been previously reported in the literature. Twenty-four alkaloidal compounds were found in both roots and leaves. Twelve potential targets with different indications were predicted for some alkaloids.

CONCLUSION

Comparison of chemical constituents and their potential bioactivities for S. succifera roots and leaves indicated that diverse bioactive alkaloids were present in the leaves as well as the roots. PharmMapper provided new directions for bioactivity screening. This study will be helpful for further understanding the medicinal components of S. succifera and the rational utilisation of plant resources.