Glycopentanolones A-D, four new geranylated quinolone alkaloids from Glycosmis pentaphylla

Biological activity of natural 2-quinolinones

While natural products have undeniably played a crucial role in drug discovery, challenges such as limited availability and complex synthesis methods have hindered the identification of lead compounds. At the core of numerous natural and synthetic compounds, each displaying distinct biological behaviours, lies the foundational structure of 2-quinolinone. Compounds with this structural motif exhibit a broad range of effects in different tissues. Furthermore, specific members showcase therapeutic potential for various disorders. Despite the significance of these compounds, the current review literature has not provided a comprehensive overview, underscoring the essential contribution of this article in exploring their biological functions. This study examines the biological activity of selected 2-quinolinone alkaloids across diverse organisms, unveiling their potential as a source of innovative bioactive natural products.

Intramolecular Palladium(II)-Catalyzed Regioselective 6-endo or 6-exo C-H Benzannulation: An Approach for the Diversity-Oriented Synthesis of Quinolinone Derivatives from Pyridones

Herein, a new intramolecular palladium(II)-catalyzed regioselective 6-endo-trig or 6-exo-trig annulation through direct C-H activation is presented as a method for the diversity-oriented synthesis of highly substituted quinolinones from pyridones. The reaction occurs under mild conditions and exhibits excellent regioselectivity, good functional group tolerance, and broad applications. This innovative approach has been successfully utilized in the synthesis of Glycopentanolone A and an intermediate of (R)-(+)-Tipifarnib.

Structurally diverse sulphur-containing amides from Glycosmis craibii with their potential antiproliferative activities

Fourteen new sulphur-containing amides, glycocramides A-N (1-14), as well as nine known analogues (15-23) were isolated and characterized from Glycosmis craibii Tanaka. The chemical structures of new sulphur-containing amides 1-14 were ambiguously elucidated by extensive spectroscopic methods, while the known compounds 15-23 were identified by the comparison of their experimental spectral data with those described data in the literatures. The antiproliferative effects of all isolated sulphur-containing amides were evaluated in vitro. As a result, part of sulphur-containing amides showed remarkable inhibitory effects against MGC-803 cell line with IC₅₀ values ranging from 13.12 ± 0.10 to 20.03 ± 0.13 μM. These research results suggest that the sulphur-containing amides are potentially to be developed as a new natural anti-tumor drugs.

Penicacids H-J, three new mycophenolic acid derivatives from the marine-derived fungus Rhizopus oryzae

Chemical investigation of secondary metabolites in crude methanol extract of a solid rice medium of a marine-derived fungus, Rhizopus oryzae, has enriched the metabolic profile of this genus by affording three mycophenolic acid derivatives recognized as new fungal metabolites trivially named as penicacids H–J (1–3), along with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5). Structure elucidation of isolated compounds was unambiguously determined based on extensive 1D and 2D NMR spectroscopic analyses together with comparing coupling constant and optical rotation values with those reported for related congeners in literature. All isolated compounds were assessed for their antibacterial activity against four different bacterial microorganisms and they revealed moderate to weak activities with minimum inhibitory concentration (MIC) values ranging from 62.5 to 250 μg mL⁻¹.

Penicacids H–J (1–3), three new natural MPA derivatives, were purified from a marine-derived fungus, Rhizopus oryzae, together with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5).

Ethnomedicinal uses, phytochemistry, pharmacological activities and toxicological profile of Glycosmis pentaphylla (Retz.) DC.: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Glycosmis pentaphylla (Retz.) DC. is a perennial shrub indigenous to the tropical and subtropical regions of India, China, Sri Lanka, Myanmar, Bangladesh, Indonesia, Malaysia, Thailand, Vietnam, Philippine, Java, Sumatra, Borneo and Australia. The plant is used extensively within these regions as a traditional medicine for the treatment of a variety of ailments including cough, fever, chest pain, anemia, jaundice, liver disorders, inflammation, bronchitis, rheumatism, urinary tract infections, pain, bone fractures, toothache, gonorrhea, diabetes, cancer and other chronic diseases.

AIM OF THE REVIEW

This review aims to present up-to-date information regarding the taxonomy, botany, distribution, ethnomedicinal uses, phytochemistry, pharmacology and toxicological profile of G. pentaphylla. The presented information was analyzed critically to understand current work undertaken on this species and explore possible future prospects for this plant in pharmaceutical research.

MATERIALS & METHODS

Bibliographic databases, including Google Scholar, PubMed, Web of Science, ScienceDirect, SpringerLink, Wiley Online Library, Semantic Scholar, Europe PMC, Scopus, and MEDLINE, were explored thoroughly for the collection of relevant information. The structures of phytoconstituents were confirmed with PubChem and SciFinder databases. Taxonomical information on the plant was presented in accordance with The Plant List (version 1.1).

RESULTS

Extensive phytochemical investigations into different parts of G. pentaphylla have revealed the presence of at least 354 secondary metabolites belonging to structurally diverse classes including alkaloids, amides, phenolic compounds, flavonoids, glycosides, aromatic compounds, steroids, terpenoids, and fatty derivatives. A large number of in vitro and in vivo experiments have demonstrated that G. pentaphylla had anticancer, antimutagenic, antibacterial, antifungal, anthelmintic, mosquitocidal, antidiabetic, antihyperlipidemic, anti-oxidant, anti-inflammatory, analgesic, antipyretic, anti-arsenicosis, and wound healing properties. Toxicological studies have established the absence of any significant adverse reactions and showed that the plant had a moderate safety profile.

CONCLUSIONS

G. pentaphylla can be suggested as a source of inspiration for the development of novel drugs, especially anticancer, antimicrobial, anthelmintic, and mosquitocidal agents. Moreover, bioassay-guided investigations into its diverse classes of secondary metabolites, especially the large pool of nitrogen-containing alkaloids and amides, promises the development of novel drug candidates. Future pharmacological studies into this species are also warranted as many of its traditional uses are yet to be validated scientifically.

Traditional uses, phytochemistry, pharmacology, toxicology and formulation aspects of Glycosmis species: A systematic review

The present article is a systematic and constructive review of the traditional medicinal uses, chemistry, pharmacology, toxicology, and formulation aspects of Glycosmis species. The genus Glycosmis comprise 51 accepted species broadly distributed in Australia, China, India, and South-East Asia. Traditionally, Glycosmis species are used in folk medicines to treat cancer, anaemia, rheumatism, fever, cough, liver-related problems, skin ailments, intestinal worm infections, wounds, and facial inflammation. This review aims to provide readers with the latest information highlighting chemical constituents isolated from the Glycosmis species, plant parts utilized for their isolation and their pharmacological activities. So far, 307 chemical constituents have been isolated and characterized from different species of the genus Glycosmis; among these constituents, alkaloids, flavonoids, terpenoids, phenolics, and sulphur-containing amides are the major bioactive compounds. Modern pharmacological studies have shown that the crude extracts and compounds isolated from this genus exhibit a broad spectrum of biological activities like anticancer, antimicrobial, anti-inflammatory, antipyretic, antidiabetic, antioxidant, larvicidal, insecticidal, hepatoprotective, wound healing, antiviral, antidiarrheal, and anxiolytic. The carbazole and acridone alkaloids from this genus have shown potential anticancer activity in various in vitro and in vivo studies. Rare scaffolds like dimeric carbazoles, dimeric acridone alkaloids, flavanocoumarins and sulphur-containing amides from this genus need further exploration for their potential bioactivity. This article also briefs about the toxicological screening and discusses various polyherbal and nano formulation aspects of Glycosmis species. Most of the pharmacological studies reported from this genus were carried out in vitro. An in-depth in vivo and toxicology evaluation of the crude extracts and isolated specialized compounds is required to explore the full therapeutic potential of this genus.

Recent Advances in One-Pot Modular Synthesis of 2-Quinolones

It is known that 2-quinolones are broadly applicable chemical structures in medicinal and agrochemical research as well as various functional materials. A number of current publications about their synthesis and their applications emphasize the importance of these small molecules. The early synthetic chemistry originated from the same principle of the classical Friedländer and Knorr procedures for the preparation of quinolines. The analogous processes were developed by applying new synthetic tools such as novel catalysts, the microwave irradiation method, etc., whereas recent innovations in new bond forming reactions have allowed for novel strategies to construct the core structures of 2-quinolones beyond the bond disconnections based on two classical reactions. Over the last few decades, some reviews on structure-based, catalyst-based, and bioactivity-based studies have been released. In this focused review, we extensively surveyed recent examples of one-pot reactions, particularly in view of modular approaches. Thus, the contents are categorized as three major sections (two-, three-, and four-component reactions) according to the number of reagents that ultimately compose atoms of the core structures of 2-quinolones. The collected synthetic methods are discussed from the perspectives of strategy, efficiency, selectivity, and reaction mechanism.

Anti-inflammatory and antiproliferative prenylated sulphur-containing amides from the leaves of Glycosmis pentaphylla

Glycosmis pentaphylla (Retz.) DC (Rutaceae) has been traditionally considered as anti-cancer and anti-inflammatory medicine. However, active compounds of sulphur-containing amides remain largely unknown. In the present work, eighteen previously undescribed sulphur-containing amides (1-18) and three known analogues (19-21) were isolated from the leaves of G. pentaphylla. Their structures were elucidated by NMR spectroscopy and mass spectrometry. All isolated prenylated sulphur-containing amides were evaluated for their anti-inflammatory properties together with antiproliferative activities in vivo. Prenylated sulphur-containing amides exhibited significant inhibitory effects against nitric oxide (NO) production stimulated by lipopolysaccharide in mouse macrophage RAW 264.7 cells with the IC₅₀ values ranging from 0.16 ± 0.10 to 16.74 ± 2.81 μM. Meanwhile, sulphur-containing amides also exhibited considerable antiproliferative activities against HepG2 cell line with IC₅₀ values ranging from 7.47 ± 0.91 to 16.23 ± 0.80 μM. These findings enrich and improve the research on the structural diversity and biological activity of sulphur-containing amides and provide phytochemical and pharmacological evidence for the further development and utilization of the leaves of G. pentaphylla in pharmaceutical industry.

A new indole alkaloid from the stems of Glycosmis puberula var. craibii

A phytochemical investigation on the stems of Glycosmis puberula var. craibii led to the isolation of a new indole alkaloid (named glycosmiscrol A, 1), together with four known compounds (2-5). The new structure was elucidated by detailed analysis of comprehensive spectroscopic methods. All isolated compounds were evaluated for their antiproliferative activities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1-5 showed significant antiproliferative effects with IC₅₀ values ranging from 0.16 to 8.58 µM.

A stilbene dimer and flavonoids from the aerial parts of Chromolaena odorata with proprotein convertase subtilisin/kexin type 9 expression inhibitory activity

Investigation of components of the chloroform-soluble and ethyl acetate-soluble extracts of the aerial parts of Chromolaena odorata L. selected by PCSK9 mRNA expression monitoring assay in HepG2 cells led to the isolation of a new stilbene dimer, (+)-8b-epi-ampelopsin A (1), and 30 known compounds (2-31). The structures of the isolates were established by interpretation of NMR spectroscopic data and the stereochemistry of the new stilbene (1) was proposed based on ECD and NMR calculations. Among the isolates, 1, 5,6,7,4'-tetramethoxyflavanone (6), 5,6,7,3',4'-pentamethoxyflavanone (7), acacetin (18), and uridine (21) were found to inhibit PCSK9 mRNA expression with IC₅₀ values of 20.6, 21.4, 31.7, 15.0, and 13.7 µM, respectively. Furthermore, the most abundant isolate among the selected compounds, 6, suppressed PCSK9 and low-density lipoprotein receptor protein expression in addition to downregulating the mRNA expression of HNF-1α.