New Tyramine- and Aporphine-Type Alkamides with NO Release Inhibitory Activities from Piper puberulum

Amide alkaloids and neolignans from Piper hongkongense and their inhibitory activities of PCSK9 expression

Four undescribed amide alkaloids hongkongensines A-C and 1-(1-oxo-6-hydroxy-2E,4E-dodecadienyl)-piperidine, five known amide alkaloids, and three known neolignans were isolated from the aerial part of Piper hongkongense. The planar structures of these compounds were determined by detailed analyses of HR-ESI-MS and NMR data. The absolute configurations of hongkongensines A-C were elucidated by single-crystal X-ray diffraction analysis and ECD calculations. Moreover, the inhibitory activities of PCSK9 expression in vitro for all compounds were assessed by PCSK9 AlphaLISA screening. Kadsurenone (10) displayed a significant inhibitory activity at 5 μM with an inhibition rate of 51.98%, compared with 55.55% of berberine (BBR 5 μM).

Triterpenoids and triterpenoid saponins from Vitex negundo and their anti-inflammatory activities

Seven undescribed polyoxygenated ursane-type triterpenoids (vitnegundins A-G), three undescribed triterpenoid saponins (vitnegundins H-J), and 17 known ones were isolated from an EtOH extract of the aerial parts of Vitex negundo L. The structures of the undescribed compounds were established by extensive spectroscopic analysis. The absolute configurations of vitnegundins A, B, and E were determined by single-crystal X-ray diffraction data. Vitnegundins B-D are pentacyclic triterpenoids possessing rare cis-fused C/D rings and vitnegundins C-H represent undescribed ursane-type triterpenoids with 12,19-epoxy moiety. In the biological activity assay, vitnegundin A, vitnegundin E, and swinhoeic acid displayed inhibitory effects against LPS-induced NO release in BV-2 microglial cells, with IC50 values of 11.8, 44.2, and 19.6 μM, respectively.

Comparative metabolite analysis of Piper sarmentosum organs approached by LC-MS-based metabolic profiling

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal and food plant widely distributed in the tropical and subtropical regions of Asia, offering both health and culinary benefits. In this study the secondary metabolites in different organs of P. sarmentosum were identified and their relative abundances were characterized. The metabolic profiles of leaves, roots, stems and fruits were comprehensively investigated by liquid chromatography high-resolution mass spectrometry (LC-HR-MS) and the data subsequently analyzed using multivariate statistical methods. Manual interpretation of the tandem mass spectrometric (MS/MS) fragmentation patterns revealed the presence of 154 tentatively identified metabolites, mostly represented by alkaloids and flavonoids. Principle component analysis and hierarchical clustering indicated the predominant occurrence of flavonoids, lignans and phenyl propanoids in leaves, aporphines in stems, piperamides in fruits and lignan-amides in roots. Overall, this study provides extensive data on the metabolite composition of P. sarmentosum, supplying useful information for bioactive compounds discovery and patterns of their preferential biosynthesis or storage in specific organs. This can be used to optimize production and harvesting as well as to maximize the plant's economic value as herbal medicine or in food applications.

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.

Aporphine alkaloids and a naphthoquinone derivative from the leaves of Phaeanthus lucidus Oliv. and their α-glucosidase inhibitory activity

Three previously undescribed aporphine alkaloids, phaeanthuslucidines E-G, one previously undescribed naphthoquinone derivative, phaeanthusnaphthoquinone, and three known compounds were isolated from an EtOAc extract of the leaves of Phaeanthus lucidus Oliv. The structures of all previously undescribed compounds were established through extensive spectroscopic investigations and high-resolution mass spectroscopy. The 6aR configuration of phaeanthuslucidines E-G was assigned by comparing their ECD spectra and specific rotation values with the reported known compounds. Some isolated compounds were evaluated for their α-glucosidase inhibitory activity. Among these compounds, phaeanthuslucidine E showed the highest α-glucosidase inhibitory activity with an IC50 value of 17.9 ± 0.4 μM. The molecular docking of phaeanthuslucidine E was further studied.

Comprehensive review of the phytochemistry, pharmacology, pharmacokinetics, and toxicology of alkamides (2016-2022)

Alkamides refer to a class of natural active small-molecule products composed of fatty acids and amine groups. These compounds are widely distributed in plants, and their unique structures and various pharmacological activities have caught the attention of scholars. This review provides a collection of literatures related to the phytochemistry, pharmacological effects, pharmacokinetics, and toxicity of alkamides published in 2016-2022 and their summary to provide references for further development of this class of ingredients. A total of 234 components (including chiral isomers) were summarized, pharmacological activities, such as anti-inflammatory, antitumor, antidiabetic, analgesic, neuroprotective, insecticidal, antioxidant, and antibacterial, and miscellaneous properties of alkamides were discussed. In addition, the pharmacokinetic characteristics and toxicity of alkamides were reviewed. However, information on the pharmacological mechanisms of the action, drug safety, and pharmacokinetics of alkamides is limited and thus requires further investigation and evaluation.

Hysterolides A-I, dimeric or monomeric sesquiterpene lactones from Parthenium hysterophorus L

Nine undescribed sesquiterpene lactones, including two pseudoguaianolide dimers (1 and 2), a pseudoguaiac dilactone (3), and six pseudoguaianolides (4-9), along with 13 known analogues (10-22) were isolated from Parthenium hysterophorus. Among them, hysterolide A (1) possesses an unusual carbon skeleton with a unique cyclobutane ring connecting two pseudoguaianolides. Hysterolide C (3) is a sesquiterpene dilactone incorporating a bicyclo[5.1.0]octane core. Spectroscopic analyses, 13C NMR and ECD calculations, and X-ray diffraction elucidated their structures and absolute configurations. Moreover, all the isolates were assayed for their anti-inflammatory activities by inhibiting LPS-induced nitric oxide production in BV-2 microglia cells, wherein, nine compounds displayed significant inhibitory activities with IC50 of 0.52-6.32 μM. Furthermore, the preliminary structure-activity relationship was also established.

Three new phenylpropanoid glucosides and a new tyramine-type alkamide from Piper puberulum

Three new phenylpropanoid glycosides, piperpubelide (1), 1-propionyl-3-hydroxy-phenyl-4-O-β-D-glucopyranoside (2), and 1-propionyl-4-hydroxy-phenyl-3-O-β-D-glucopyranoside (3), a new tyramine-type alkamide, puberulumine L (4), together with thirteen known compounds (5-17) were isolated from Piper puberulum (Benth.) Maxim. Their structures were elucidated by analysis of spectroscopic data involving NMR, IR, UV, and HRESIMS data. Calculated and experimental ECD was used to confirm the configuration of compound 1. Compounds 14, 16, and 17 exhibited relatively positive DPPH radical scavenging activities, with corresponding EC50 of 10.23, 24.12, and 21.83 μM, respectively. In addition, compound 5 inhibited LPS-induced NO production in BV-2 microglia with an IC50 value of 18.05 μM.

Medicinal patterns of vines used in Chinese herbal medicine: a quantitative study

ETHNOPHARMACOLOGICAL RELEVANCE

The botanical characteristics of twinning, climbing vine plants conceptually take shape to interlink the meridians and collaterals system throughout the human body by expelling climatic evils (e.g., wind, dampness). Thus, vines have displayed great medicinal properties in traditional Chinese medicine (TCM).

AIM OF THE STUDY

Although some popular vine species have been intensively investigated, the comparable features and medicinal specifications among a vast collection of taxonomic groups based on data visualization methods are relatively lacking in attention. Moreover, the translatability of vines from ancient ethnomedical evidence to modern medical system has not been well established. This review tends to quantitatively summarize the strength of vines in healthcare from the perspectives of medicinal part, traditional function, clinical spectrum, phytochemistry divergence, pharmacological attributes, toxicity as well as the progress of proprietary drug development.

MATERIALS AND METHODS

Medicinal vines were retrieved from databases of drug standards and curated catalogues. Synonyms of plant origin across different datasets were normalized by accepted scientific names in the World Flora Online. The distribution patterns and rank of plant origin, medicinal parts, traditional functions and target conditions, as well as the correlation between phytochemical composition and clinical applications were analyzed and visualized.

RESULTS

A total of 121 crude drugs from 36 families, 77 genera, 133 species of vines were obtained and analyzed. The Fabaceae, Menispermaceae and Rubiaceae were the highest ranked families of medicinal vines. Not surprisingly, stem was the most dominant medical part. Moreover, "eliminate wind" displayed a hub node in the traditional function co-occurrence network. In addition to joint impediment disorders, these vines particularly displayed a wide range of therapeutic modalities toward conditions from various organ systems. Chemotaxonomic properties-oriented phytochemical analysis was performed and the chemical diversity among medicinal vines complementarily determined a certain group of therapeutic domains. Particularly, the anti-inflammatory effect and antiarthritic effect were highlighted for treating rheumatic diseases. Using integral animal models and cultured cells, modern pharmacological actions of medicinal vines have been largely observed and validated according to their traditional ethnopharmacology. Furthermore, a small proportion of vine species are well-known toxic plants. Successful drug development pipelines in rheumatic, cardiovascular, liver, malignant and infectious diseases have offered the capacity to generate new treatment options that are being sought out from vine plants.

CONCLUSIONS

Medicinal vines are rich sources of Chinese Material Medica (CMM) and good fit for a variety of clinical manifestations beyond arthritis and rheumatic diseases. In addition to stem, other parts are also popular for both medicines and dietary supplements. Vine plants provide extensive biologically relevant chemical space for developing value-creating drugs. Thus, our analysis can be useful for further motivating and strengthening the preclinical and clinical research of vine-derived remedies.

Metabolite Profiling of Allium hookeri Leaves Using UHPLC-qTOF-MS/MS and the Senomorphic Activity of Phenolamides

The plant Allium hookeri, a member of the Allium genus, has a rich history of culinary and medicinal use. Recent studies have unveiled its potent antioxidant and anti-inflammatory properties. While research on A. hookeri has demonstrated its neuroprotective and anti-neuroinflammatory effects, the specific bioactive compounds responsible for these effects remain unidentified in prior research. This study utilized an untargeted metabolomic approach, employing HRESI-qTOF MS/MS-based molecular networking, to comprehensively profile the chemical composition of metabolites in A. hookeri and identify new compounds within the plant. As a result, ten compounds, comprising one novel flavonoid (2) and nine known compounds (1 and 3-10), were isolated and identified through NMR analysis. The inhibitory effects of all isolated compounds on the senescent cell-associated secretory phenotype (SASP), which is pivotal in neuroprotective actions, were evaluated. Biological activity testing revealed N-trans-feruloyltyramine (7) to be the most potent compound, effectively inhibiting SASP markers and contributing to the senomorphic activities of A. hookeri. These findings underscore the potential of phenolamides from A. hookeri as a promising source of bioactive compounds for mitigating senescence-associated diseases.

Chemical profiling and simultaneous quantification of major bioactive constituents from Cocculus hirsutus by UPLC-QqQ-MS

Cocculus hirsutus is a widely used herb in traditional systems of medicine for the treatment of various diseases. In the present study, five alkaloids (1-5), two flavonoids (6-7), one triterpenoid (8), and three steroids (9-10) were isolated from the roots of Cocculus hirsutus and further crude extract was analyzed by LC-Q-Tof-MS/MS in positive ionization mode leading to the identification of ten metabolites through comparison of exact molecular masses from their MS/MS spectra, mass fragmentation studies and with literature data. In addition, a method was developed and validated for the quantification of four bio-active compounds [Sinococuline (1), Magnoflorine (2), (E)-N-feruloyltyramine (3), and 20-Hydroxyecdysone (10)] using UPLC-QqQ-MS in multiple reaction monitoring (MRM) mode for the first time. The method has shown good linearity with correlation coefficients (r2) higher than 0.9916 for all four compounds. The intra- and inter-day precision were in the range of 0.3-6.1% and from 0.7% to 8.8%, respectively. The matrix effects of all the four analytes were found in the range of 94.7 ± 2.8-112.7 ± 3.7%. Overall, our study provides a reliable and rapid approach by hyphenated LC-MS/MS using high-resolution mass spectrometers for identification and quantification of bioactive constituents from the root extracts of Cocculus hirsutus.

Deciphering anti-infectious compounds from Peruvian medicinal Cordoncillos extract library through multiplexed assays and chemical profiling

High prevalence of parasitic or bacterial infectious diseases in some world areas is due to multiple reasons, including a lack of an appropriate health policy, challenging logistics and poverty. The support to research and development of new medicines to fight infectious diseases is one of the sustainable development goals promoted by World Health Organization (WHO). In this sense, the traditional medicinal knowledge substantiated by ethnopharmacology is a valuable starting point for drug discovery. This work aims at the scientific validation of the traditional use of Piper species ("Cordoncillos") as firsthand anti-infectious medicines. For this purpose, we adapted a computational statistical model to correlate the LCMS chemical profiles of 54 extracts from 19 Piper species to their corresponding anti-infectious assay results based on 37 microbial or parasites strains. We mainly identified two groups of bioactive compounds (called features as they are considered at the analytical level and are not formally isolated). Group 1 is composed of 11 features being highly correlated to an inhibiting activity on 21 bacteria (principally Gram-positive strains), one fungus (C. albicans), and one parasite (Trypanosoma brucei gambiense). The group 2 is composed of 9 features having a clear selectivity on Leishmania (all strains, both axenic and intramacrophagic). Bioactive features in group 1 were identified principally in the extracts of Piper strigosum and P. xanthostachyum. In group 2, bioactive features were distributed in the extracts of 14 Piper species. This multiplexed approach provided a broad picture of the metabolome as well as a map of compounds putatively associated to bioactivity. To our knowledge, the implementation of this type of metabolomics tools aimed at identifying bioactive compounds has not been used so far.

Aporphines: A privileged scaffold in CNS drug discovery

Aporphine alkaloids embedded in 4H-dibenzo[de,g]quinoline four-ring structures belong to one of the largest subclasses of isoquinoline alkaloids. Aporphine is a privileged scaffold in the field of organic synthesis and medicinal chemistry for the discovery of new therapeutic agents for central nervous system (CNS) diseases, cancer, metabolic syndrome, and other diseases. In the past few decades, aporphine has attracted continuing interest to be widely used to develop selective or multitarget directed ligands (MTDLs) targeting the CNS (e.g., dopamine D_1/2/5, serotonin 5-HT_1A/2A/2C and 5-HT₇, adrenergic α/β receptors, and cholinesterase enzymes), thereby serving as valuable pharmacological probes for mechanism studies or as potential leads for CNS drug discovery. The aims of the present review are to highlight the diverse CNS activities of aporphines, discuss their SAR, and briefly summarize general synthetic routes, which will pave the way for the design and development of new aporphine derivatives as promising CNS active drugs in the future.

Neuroprotective and acetylcholinesterase inhibitory activities of alkaloids from Solanum lyratum Thunb.: An in vitro and in silico analyses

The n-BuOH extract from the herb of Solanum lyratum Thunb. (Solanaceae) was purified by various chromatographic methods, which led to the isolation of seven undescribed alkaloids ((-)-(7'S)-N-feruloyltyramine A, (+)-(7'R)-N-feruloyltyramine A, (+)-(7'S)-N-solanamide A, (-)-(7'R)-N-solanamide A, 7'S-perillascens, solanpyrrole A, and (Z)-asmurratetra A) and 13 known alkaloids, including four pairs of enantiomers. Extensive spectroscopic data and electronic circular dichroism (ECD) calculations were applied to determine the structures of the undescribed compounds. In in vitro biological activity assays, (-)-(7'S)-N-feruloyltyramine A and (+)-(7'R)-N-feruloyltyramine A exhibited pronounced neuroprotective effects against SH-SY5Y cell damage with survival rates of 75.98% and 76.61%, respectively, at 50 μM. Additionally, (-)-(7'S)-N-feruloyltyramine A and N-cis-feruloyl-3'-methoxy-tyramine displayed acetylcholinesterase (AChE) inhibitory effects with IC₅₀ values of 7.41 ± 1.76 μM and 9.21 ± 0.89 μM, respectively. Molecular docking simulations revealed that (-)-(7'S)-N-feruloyltyramine A had a binding site for AChE. These findings reveal the structural diversity of the bioactive compounds in S. lyratum and provides insights into the use of this information for the production of functional components in the pharmaceutical industry.

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.

Characterization and Bioactive Potential of Secondary Metabolites Isolated from Piper sarmentosum Roxb

Piper sarmentosum Roxb. (Piperaceae) is a traditional medicinal plant in South-East Asian countries. The chemical investigation of leaves from this species resulted in the isolation of three previously not described compounds, namely 4″-(3-hydroxy-3-methylglutaroyl)-2″-β-D-glucopyranosyl vitexin (1), kadukoside (2), and 6-O-trans-p-coumaroyl-D-glucono-1,4-lactone (3), together with 31 known compounds. Of these known compounds, 21 compounds were isolated for the first time from P. sarmentosum. The structures were established by 1D and 2D NMR techniques and HR-ESI-MS analyses. The compounds were evaluated for their anthelmintic (Caenorhabditis elegans), antifungal (Botrytis cinerea, Septoria tritici and Phytophthora infestans), antibacterial (Aliivibrio fischeri) and cytotoxic (PC-3 and HT-29 human cancer cells lines) activities. Methyl-3-(4-methoxyphenyl)propionate (8), isoasarone (12), and trans-asarone (15) demonstrated anthelmintic activity with IC₅₀ values between 0.9 and 2.04 mM. Kadukoside (2) was most active against S. tritici with IC₅₀ at 5.0 µM and also induced 94% inhibition of P. infestans growth at 125 µM. Trans-asarone (15), piperolactam A (23), and dehydroformouregine (24) displayed a dose-dependent effect against B. cinerea from 1.5 to 125 µM up to more than 80% inhibition. Paprazine (19), cepharadione A (21) and piperolactam A (23) inhibited bacterial growth by more than 85% at 100 µM. Only mild cytotoxic effects were observed.

New polychlorinated bibenzyls from Rhododendron minutiflorum

Five new polychlorinated bibenzyls (1-5) along with 3 known compounds (6-8) were isolated from the stems and leaves of Rhododendron minutiflorum. The chemical structures of all the isolates were determined by spectroscopic methods, and compounds 1 and 2 were further verified by single-crystal X-ray diffraction analyses. Compounds 1-5 were halogenated compounds which bear three to five chlorine atoms in their chemical structures. Biologically, compounds 2, 5 and 6 showed varying degrees of toxicity toward the Asian citrus psyllid (Diaphorina citri) with LD₅₀ values 27.15, 17.02 and 16.20 mg/L, respectively. These values were comparable to the positive control matrine (LD₅₀ = 11.86 mg/L), which were calculated using observations on day 6. Meanwhile, compound 4 had α-glucosidase inhibitory activity with IC₅₀ value of 17.87 ± 0.74 μM.

Survey of natural products reported by Asian research groups in 2021

The new natural products reported in 2021 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2021 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.

Protective effects of Liensinine, Isoliensinine, and Neferine on PC12 cells injured by amyloid-β

Excessive accumulation of amyloid-β (Aβ) is the leading cause of Alzheimer's disease (AD). Liensinine, Isoliensinine, and Neferine are main alkaloids in lotus seed embryos. In this paper, the protective effects of Liensinine, Isoliensinine, and Neferine on Aβ_25-35 -injured PC12 cells were studied. It was found that Liensinine, Isoliensinine, and Neferine could improve the viability and reduce the apoptosis of PC12 cell induced by Aβ_25-35 . These three alkaloids could also reduce the level of intracellular free Ca²⁺ and CaM expression in Aβ_25-35 -treated cells, thereby inhibiting the phosphorylation of CaMKII and tau. In addition, these three compounds can inhibit the production of ROS in PC12 cells injured by Aβ_25-35 . Our results suggest for the first time that Liensinine, Isoliensinine, and Neferine can inhibit hyperphosphorylation of tau protein by inhibiting the Ca²⁺ -CaM/CaMKII pathway, thereby reducing the apoptosis and death of PC12 cells damaged by Aβ_25-35 . PRACTICAL APPLICATIONS: This study highlighted the protective effects and mechanisms of three main active ingredients (Liensinine, Isoliensinine, and Neferine) in the lotus embryo on a typical cell model of Alzheimer's disease (AD). The results revealed that three alkaloids in this healthy food might exert therapeutic potential for AD.

UV-guided isolation of enantiomeric polyacetylenes from Bupleurum scorzonerifolium Willd. with inhibitory effects against LPS-induced NO release in BV-2 microglial cells

UV-guided fractionation led to the isolation of thirteen new polyacetylenes (1-13) from the roots of Bupleurum scorzonerifolium Willd. All polyacetylenes were analyzed as racemates since the lack of optical activity and Cotton effects in the ECD spectra. The sequent chiral-phase HPLC resolution successfully gave twelve pairs of enantiomers 1a/1b and 3a/3b-13a/13b. Their structures were elucidated based on the HRESIMS and NMR data analyses. The absolute configurations were determined by the combination of Snatzke's method, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Using Griess methods and MTT assays, polyacetylenes 1a, 3a, 4a/4b-12a/12b, and 13a displayed inhibitory activities against LPS-induced NO release in BV-2 microglial cells.

New enantiomeric lignans and new meroterpenoids with nitric oxide release inhibitory activity from Piper puberulum

Six new lignans with various type of linkage between two C6-C3 fragments (1a, 1b, 2a, 2b, 3, 4), two new meroterpenoids (5, 6) and 24 known compounds (7-30) were isolated from an EtOH extract of the stems and leaves of Piper puberulum. The absolute configurations of enantiomers 1a and 1b were determined by single-crystal X-ray diffraction analysis, 2a and 2b were determined by comparing their calculated and experimental ECD spectra. Biogenetically, all the new lignans may come from the polymerization of two molecules of hydroxychavicol (30). In the anti-neuroinflammation activity assay, the IC₅₀ values of fifteen compounds were lower than those of the positive control minocycline, and compound 1a showed good activity, but its enantiomer 1b showed no activity. Compound 1a have notable anti-neuroinflammatory activity, and can significantly decrease mRNA levels of proinflammatory cytokines (IL-1β, IL-6, TNF-α) in a dose-dependent manner.