Flavonoids and Triterpenoids Isolated From the Ethyl Acetate Extract of M. quadrangulata Leaves.

The new flavonoid (-)-4'-O-methylepicatechin 5-O-ß-D-glucopyranoside (1), along with four known triterpenes (2-5), a steroid (6), and a flavonoid (7) were isolated from the ethyl acetate extract of Maytenus quadrangulata leaves. The chemical structures of the isolated compounds were determined through analysis of 1D NMR (1H and 13C) spectroscopic data, in addition to 2D NMR and spectrometric (MS) data for compound 1. This is the first report of the isolation of daucosterol (6) and (-)-4'-O-methylepigallocatechin (7) from this species. Compounds 1 and 7 were evaluated against the bacteria Staphylococcus aureus and Klebsiella pneumoniae, but neither exhibited activity even at the highest concentration tested.

Two new oleanane triterpenes from Maytenus hookeri.

Two new triterpenes mayteneri A (1), mayteneri B (2), and seven known compounds (3-9) were isolated from stems of Maytenus hookeri Loes. The chemical structures of compounds 1 and 2 were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds 3-9 were determined by comparison of their spectral with those reported. Compounds 4-7 showed significant inhibitory activity for NLRP3 inflammasome, with the IC50 values of 2.36-3.44 µM.

Probing the functions of friedelane-type triterpene cyclases from four celastrol-producing plants.

Triterpenes are among the most diverse plant natural products, and their diversity is closely related to various triterpene skeletons catalyzed by different 2,3-oxidosqualene cyclases (OSCs). Celastrol, a friedelane-type triterpene with significant bioactivities, is specifically distributed in higher plants, such as Celastraceae species. Friedelin is an important precursor for the biosynthesis of celastrol, and it is synthesized through the cyclization of 2,3-oxidosqualene, with the highest number of rearrangements being catalyzed by friedelane-type triterpene cyclases. However, the molecular mechanisms underlying the catalysis of friedelin production by friedelane-type triterpene cyclases have not yet been fully elucidated. In this study, transcriptome data of four celastrol-producing plants from Celastraceae were used to identify a total of 21 putative OSCs. Through functional characterization, the friedelane-type triterpene cyclases were separately verified in the four plants. Analysis of the selection pressure showed that purifying selection acted on these OSCs, and the friedelane-type triterpene cyclases may undergo weaker selective restriction during evolution. Molecular docking and site-directed mutagenesis revealed that changes in some amino acids that are unique to friedelane-type triterpene cyclases may lead to variations in catalytic specificity or efficiency, thereby affecting the synthesis of friedelin. Our research explored the functional diversity of triterpene synthases from a multispecies perspective. It also provides some references for further research on the relative mechanisms of friedelin biosynthesis.

Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus.

BACKGROUND AND AIMS: Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. METHODS: The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. KEY RESULTS: The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. CONCLUSIONS: Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.

Authentication and Quality Control of the Brazilian Traditional Herb "Espinheira-Santa" (Monteverdia ilicifolia) by Morpho-Anatomy and Microscopy.

The leaves of Monteverdia ilicifolia (syn. Maytenus ilicifolia), commonly called espinheira-santa, are widely used in South American traditional medicines to treat gastritis and ulcers. Several products labeled as espinheira-santa are sold as dietary supplements in retail stores and via e-commerce. Many different species with similar leaf morphology are often mistaken for Monteverdia ilicifolia and used as espinheira-santa, including Monteverdia aquifolia (Celastraceae), Citronella gongonha (Cardiopteridaceae), Jodina rhombifolia (Santalaceae), Sorocea bonplandii (Moraceae), and Zollernia ilicifolia (Fabaceae). This study aimed to characterize M. ilicifolia and distinguish it from adulterants using morphological and microscopic techniques. In addition, foreign matter and powder characteristics of botanical materials sold as "espinheira-santa" were analyzed. The morphoanatomical studies of the leaves and stems of M. ilicifolia and its five adulterant species have revealed noteworthy features that can help species identification and quality control of commercial espinheira-santa. This study showed that many commercial espinheira-santa materials were adulterated and of inferior quality.

Evaluation of Cytotoxicity and Antifungal Activity of Friedelanes from Salacia elliptica Roots.

Plants from Salacia genus are used in traditional medicine for a wide range of diseases. Previous studies reported bioactive pentacyclic triterpenoids from S. elliptica leaves and branches. In this study, the novel pentacyclic triterpenoid 7α,15α-dihydroxyfriedelan-3-one (1) was obtained from the roots of Salacia elliptica, along with seven known compounds: friedelan-3-one (2), friedelan-3ß-ol (3), friedelan-1,3-dione (4), friedelan-3,15-dione (5), 15α-hydroxyfriedelan-3-one (6), 15α,26-dihydroxyfriedelan-3-one (7), and 26-hydroxyfriedelan-3,15-dione (8). Additionally, one steroid, spinasterol (9), was also identified. The chemical structures of all compounds were established through 1 H and 13 C-NMR. Compound 1 was analysed by additional 2D experiments (HMBC, HSQC, COSY, and NOESY) for complete elucidation. Furthermore, the cytotoxicity of compounds 2, 3, 6, 7 and 8 against the A549 lung cancer cells model was evaluated. The flow cytometry analysis revealed a significant cytotoxic activity similar to that exhibited by the triterpenoid lupeol. Additionally, compounds 2, 3, 6, and 7 were tested for in vitro antifungal activity against Candida, Cryptococcus and Sporothrix strains. However, all compounds showed no activity at the tested concentrations.

Two new dihydro-ß-agarofuran sesquiterpenes from the roots of Celastrus angulatus.

Two new dihydro-ß-agarofuran sesquiterpenes chiapen T (1) and chiapen U (2), along with chiapen A (3), 1ß-hydroxy-2ß,6α,12-triacetoxy-8ß-(ß-nicotinoyloxy)-9ß-(benzoyloxy)-ß-dihydroagarofuran (4), wilforlide B (5), 3-hydroxy-2-oxo-3-friedelen-29-oic acid (6), epikatonic acid (7), 22-epi-maytenfolic acid (8), maytenoic acid (9), wilforic acid F (10), wilforic acid B (11), were reported for the first time from the Celastrus angulatus. The structures of all the compounds were elucidated by HR-ESI-MS, 1 D and 2 D NMR spectra, as well as single-crystal X-ray diffraction analyses. Compounds 1 and 2 were examined for anti-inflammatory activity, respectively. None of them showed potent activity.

Two new chemical constituents from the stem and branch of Tripterygium wilfordii.

A chemical investigation of 95% ethanol extract from the stem and branch of Tripterygium wilfordii has resulted in the isolation and characterization of two new compounds, one neolignan (1) and one phenylalanine derivative (2), as well as four known compounds (3-6). The structures of the new compounds were determined based on extensive spectroscopic analyses. The absolute configuration of compound 1 was defined by X-ray crystallographic analyses and electronic circular dichroism calculation. In addition, compounds 2 and 4-6 exhibited inhibitory effects against NO production in LPS-induced RAW 264.7 macrophages with the IC50 value ranging from 3.51 µM to 30.40 µM.

An extensive review on phytochemistry and pharmacological activities of Indian medicinal plant Celastrus paniculatus Willd.

Celastrus paniculatus is a traditional herb belonging to the family Celastraceae and is widely used for a number of medicinal activities in the Indian Unani and Ayurvedic systems. In this study, the extensive literature search was carried out on phytochemistry, ethnobotanical uses and pharmacological activities of C. paniculatus (Willd.) in various scientific databases as well as patents. Research on phytochemical investigation has shown the presence of monoterpenes (linalool, α-terpinyl acetate, nerol acetate), sesqueterpene esters (such as malkanguniol, malkangunin, valerenal, globulol, viridiflorol, cubenol and agarofuran derivatives), diterpenoids (such as phytone, isophytol), triterpenoids (such as lupeol, pristimerin, paniculatadiol, zeylasteral, zeylasterone, ß-amyrin, squalene), alkaloids (celapanin, celapanigin, celapagin, paniculatine, celastrine, maymyrsine), fatty acids, steroids (ß-sitosterol, carpesterol benzoate), flavonoids (paniculatin), benzoic acid, and vitamin C in this plant. All the reported pharmacological activities of this plant could be due to the presence of these phytochemicals. This plant possesses strong antioxidant activity which includes total flavonoid content, total phenolic content, nitric oxide scavenging activity and free radical scavenging activity. This plant possesses multiple pharmacological activities including cognition-enhancing, neuroprotective, antipsychotic, anti-depressant, antibacterial, anti-arthritic, anti-malarial, analgesic, anti-inflammatory, anti-fertility, cardiovascular, locomotor, anxiolytic, wound healing activity, anti-spasmodic, hypolipidemic, anti-cancerous and iron-chelating activity with different extracts of this plant as well as various phytoconstituents present in this plant. The objective of this review article is to discuss in detail the reported ethnopharmacological uses, phytochemistry and various pharmacological activities of C. paniculatus.

Three new sesquiterpene polyol esters from Celastrus angulatus.

Three new sesquiterpene polyol ester compounds angulatins S-U, together with three known compounds were isolated from Celastrus angulatus Maxim. According to mainly 1D NMR and 2D NMR analysis, the structures of the new compounds were completely determined as angulatin S (1ß-furoyloxy-2ß,8α-diisobutanoyloxy-9ß-benzoyloxy-15-acetoxy-4α,6α-dihydroxy-ß-dihydroagarofuran), angulatin T (1ß,2ß,6α-triacetoxy-8ß,15-diisobutanoyloxy-9α-benzoyloxy-ß-dihydroagrofuran), and angulatin U (1ß,6α,15-triacetoxy-8ß-isobutanoyloxy-9α-benzoyloxy-ß-dihydroagarofuran).

Pentacyclic Triterpenoids Isolated from Celastraceae: A Focus in the 13C-NMR Data.

The Celastraceae family comprises about 96 genera and more than 1.350 species, occurring mainly in tropical and subtropical regions of the world. The species of this family stand out as important plant sources of triterpenes, both in terms of abundance and structural diversity. Triterpenoids found in Celastraceae species display mainly lupane, ursane, oleanane, and friedelane skeletons, exhibiting a wide range of biological activities such as antiviral, antimicrobial, analgesic, anti-inflammatory, and cytotoxic against various tumor cell lines. This review aimed to document all triterpenes isolated from different botanical parts of species of the Celastraceae family covering 2001 to 2021. Furthermore, a compilation of their 13C-NMR data was carried out to help characterize compounds in future investigations. A total of 504 pentacyclic triterpenes were compiled and distinguished as 29 aromatic, 50 dimers, 103 friedelanes, 89 lupanes, 102 oleananes, 22 quinonemethides, 88 ursanes and 21 classified as others.

One new sesquiterpene pyridine alkaloid from the stems and leaves of Euonymus fortunei.

A new sesquiterpene pyridine alkaloid (1), along with four known compounds (2-5), were isolated from the stems and leaves of Euonymus fortunei. The new structure was determined by extensive spectroscopic analyses (IR, UV, NMR, HRESIMS and ECD). In addition, compound 3 showed a stronger anti-respiratory syncytial virus (RSV) activity with an IC50 value of 1.20 ± 0.10 µM than the positive control ribavirin with an IC50 value of 5.62 ± 0.49 µM.[Formula: see text].

The Methionine 549 and Leucine 552 Residues of Friedelin Synthase from Maytenus ilicifolia Are Important for Substrate Binding Specificity.

Friedelin, a pentacyclic triterpene found in the leaves of the Celastraceae species, demonstrates numerous biological activities and is a precursor of quinonemethide triterpenes, which are promising antitumoral agents. Friedelin is biosynthesized from the cyclization of 2,3-oxidosqualene, involving a series of rearrangements to form a ketone by deprotonation of the hydroxylated intermediate, without the aid of an oxidoreductase enzyme. Mutagenesis studies among oxidosqualene cyclases (OSCs) have demonstrated the influence of amino acid residues on rearrangements during substrate cyclization: loss of catalytic activity, stabilization, rearrangement control or specificity changing. In the present study, friedelin synthase from Maytenus ilicifolia (Celastraceae) was expressed heterologously in Saccharomyces cerevisiae. Site-directed mutagenesis studies were performed by replacing phenylalanine with tryptophan at position 473 (Phe473Trp), methionine with serine at position 549 (Met549Ser) and leucine with phenylalanine at position 552 (Leu552Phe). Mutation Phe473Trp led to a total loss of function; mutants Met549Ser and Leu552Phe interfered with the enzyme specificity leading to enhanced friedelin production, in addition to α-amyrin and ß-amyrin. Hence, these data showed that methionine 549 and leucine 552 are important residues for the function of this synthase.

Chemodiversity of Essential Oils from Nine Species of Celastraceae.

Extracts and compounds obtained from several species of Celastraceae family are reported as potential sources of drugs due to their diverse pharmacological properties. Nevertheless, essential oil composition from these species is still little known. This work aimed at the analysis of essential oils obtained from different Brazilian Celastraceae species. A total of seventeen oils were obtained using hydrodistillation process and analyzed by gas chromatography/mass spectrometry (GC/MS). Principal component analysis (PCA) allowed the identification of a chemical composition pattern among the analyzed essential oils. Some compounds were more frequent among Celastraceae species, such as cis- and trans-linalool oxide (14/17 oil samples), nerylacetone (13/17), linalool (11/17), ß-ionone (10/17), α-ionone (9/17), nerolidol (10/17), decanal (10/17), and dodecanoic acid (10/17). These results contribute to the chemophenetics of Celastraceae species.

Cytotoxic Activity of Triterpenoids from Cheiloclinium cognatum Branches against Chronic and Acute Leukemia Cell Lines.

Cheiloclinium cognatum (Miers) A.C.Sm. is an endemic species of Brazilian Cerrado that belongs to Celastraceae family. The phytochemical study of C. cognatum branches led to the identification of ten triterpenoids (TPs), 3ß-acyloxyurs-12-ene (1), friedelin (2), ß-friedelinol (3), glut-5-en-3ß-ol (4), α-amyrin (5), ß-amyrin (6), ß-sitosterol (7), canophyllol (8), 29-hydroxyfriedelan-3-one (9) and friedelane-3ß,29-diol (10). TPs 4, 5 and 6 are described for the first Cheiloclinium genus and TPs 8 and 9 were isolated in expressive amounts. Their cytotoxic activities were evaluated against THP-1 and K562 leukemia cell lines. TPs 3 and 5 were the most active, exhibiting lower or similar IC50 against both cell lines when compared to the controls. Their mechanisms of action were investigated suggesting an intrinsic mitochondrial pathway of apoptosis evidenced by up-regulation of BAK mRNA expression. Chemometric studies indicated that their activities may be related to their molecular size and shape as well as electronic interactions of C-3 hydroxy group with molecular targets.

Natural Nitrogenous Sesquiterpenoids and Their Bioactivity: A Review.

Nitrogenous sesquiterpenoids fromnatural sourcesare rare, so unsurprisingly neither the potentially valuable bioactivity nor thebroad structural diversity of nitrogenous sesquiterpenoids has been reviewed before. This report covers the progressduring the decade from 2010 to February 2020 on the isolation, identification, and bioactivity of 391 nitrogen-containing natural sesquiterpenes from terrestrial plant, marine organisms, and microorganisms. This complete and in-depth reviewshouldbe helpful for discovering and developing new drugs of medicinal valuerelated to natural nitrogenous sesquiterpenoids.

Maytenin Plays a Special Role in the Regulation of the Endophytic Bacillus megaterium in Peritassa campestris Adventitious Roots.

Peritassa campestris (Celastraceae) root bark accumulates potent antitumor quinonemethide triterpenes (QMTs). When grown in their natural habitat, plants of the family Celastraceae produce different QMTs such as celastrol (3) and pristimerin (4). However, when they are inserted in in vitro culture systems, they accumulate maytenin (1) as the main compound. Recently, Bacillus megaterium was detected as an endophytic microorganism (EM) living inside P. campestris roots cultured in vitro. We hypothesized that compound (1) controls EM growth more efficiently, and that the presence of EMs in the root culture causes compound (1) to accumulate. For the first time, this work has explored plant-microorganism interaction in a species of the family Celastraceae by co-culture with an EM. Live endophytic bacteria were used, and QMT accumulation in P. campestris adventitious roots was our main focus. The antimicrobial activity of the main QMTs against endophytic B. megaterium was also evaluated. Our results showed that compound (1) and maytenol (5) were more effective than their precursors QMTs (3) and (4) in controlling the EM. Co-culture of B. megaterium with roots significantly reduced bacterial growth whereas root development remained unaffected. Compound (1) production was 24 times higher after 48 hr in the presence of the highest B. megaterium concentration as compared to the control. Therefore, P. campestris adventitious roots affect the development of the endophyte B. megaterium through production of QMTs, which in turn can modulate production of compound (1).

Bioactive terpenoids from Euonymus verrucosus var. pauciflorus showing NO inhibitory activities.

In our continuous search for new nitric oxide (NO) inhibitory compounds as potential anti-inflammatory agents or lead compounds for inflammatory diseases, the chemical constituents of Euonymus verrucosus var. pauciflorus were investigated, leading to the isolation of eleven terpenoids including six new diterpenoids, designated as euonymupenes A-F. The structures were elucidated on the basis of NMR and ECD data analysis. Euonymupenes A, C, and F feature rare labdane-type norditerpenoid skeletons. The NO inhibitory effects were evaluated and all of the isolates were found to inhibit lipopolysaccharide (LPS)-induced NO production in murine microglial BV-2 cells. Western blotting analysis indicated that the most active compound (5) can regulate iNOS (inducible nitric oxide synthase) expression. The further molecular docking studies exhibited the affinities of bioactive compounds with iNOS.

Two new sesquiterpene pyridine alkaloids from root barks of Celastrus angulatus.

Two new sesquiterpene pyridine alkaloids, Chinese bittersweet alkaloid A (1) and Chinese bittersweet alkaloid B (2), together with five known compounds 3ß- hydroxyolean-9(11),12-diene, ß-sitosterol, 1ß,2ß,6α,15ß-tetraacetoxy-8ß,9α- dibenzoyloxy-ß-dihydroagarofuran, angulatin A and angulatin J, were isolated from the root barks of Celastrus angulatus. The structures of 1 and 2 were elucidated as 1ß,6α,8ß,9ß-tetraacetoxy-2ß,4α-dihydroxy-15ß-isobutanoyloxy-(3,12)-evoninoyloxy-ß-dihydroagarofuran and 1ß,2ß,6α,8ß,9ß-pentaacetoxy-4α-hydroxy-15ß- isobutanoyloxy- (3,12)- evoninoyloxy-ß-dihydroagarofuran mainly by NMR spectroscopic means.

Using UHPLC-MS Profiling for the Discovery of New Dihydro-ß-Agarofurans from Australian Celastraceae Plant Extracts.

An analytical method using UHPLC-MS was developed and applied to 16 crude CH2Cl2 extracts from Australian Celastraceae plants; the endemic plant materials were accessed from Griffith University's NatureBank resource and included bark, fruit, leaf, root, twig and mixed samples, all of which were collected from Queensland, Australia. The generated UHPLC-MS data were analysed and dereplicated using the scientific databases Dictionary of Natural Products and SciFinder Scholar in order to potentially identify new dihydro-ß-agarofurans from local Celastraceae plants. These investigations led to the large-scale extraction and isolation work on a prioritised fruit sample that belonged to the rainforest plant Denhamia celastroides. Chemical investigations resulted in the purification of four new natural products, denhaminols O⁻R (1⁻4), along with the related and known compound, denhaminol G (5). The structures of all the new compounds were determined via detailed analysis of NMR and MS data.