Triterpene saponins from Myrsine pellucida

Unveiling new myrsinoic acids and AChE ligands from Myrsine guianensis (Aubl.) Kuntze

Molecular dereplication and drug-like discovery are important tools for exploring the chemical profile of metabolites in a complex mixture. In order to establish a workflow for discovering novel acetylcholinesterase (AChE) ligands, we performed the chemical study of Myrsine guianensis (Aubl.) Kuntze (Primulaceae). To carry out the bioprospection, nine extracts were obtained from different parts of the plant. Through the dereplication approaches, seventeen metabolites were annotated. In order to confirm the putative inferences, a HPLC preparative method was developed to isolate three known myrsinoic acids, A(1), B(2) and C(3). Along with, we are reporting the obtention of two new congeners, G(5) and H(6), which their structures were elucidated by NMR and HRMS data. Besides that, two extracts were submitted to affinity assays to accelerate the discovery of AChE ligands. Desorbates were analyzed through LC-HRMS for calculating the affinity ratio (AR). Thus, (1) presented AR = 4.59, therefore was considered a potential ligand.

Hepatoprotective role of myricitrin isolated from Mimusops elengi Linn. leaves extract on γ-radiation-induced liver damage in rats: Phyto-biochemical investigations

The hepatoprotective effects of methanol extract of Mimusops elengi Linn. (M. elengi L.) leaves and isolated pure myricitrin (3-, 4-, 5-, 5, 7-five hydroxyflavone-3-O-α-l-rhamnoside) (Myr) were evaluated in male rats exposed to γ-irradiation. The extraction of M. elengi L. leaves was performed using ethyl acetate (EtOAC). Seven groups of rats were used: control group, irradiated (IRR) group (6 Gy of γ-rays in a single dose), vehicle group (oral administration of 0.5% carboxymethyl cellulose for 10 days), EtOAC extract group (100 mg/kg body weight of extract, orally for 10 days), EtOAC + IRR group (administration of extract and exposure to γ-rays on Day 7), Myr group (50 mg/kg body weight Myr, orally for 10 days), and Myr + IRR group (administration of Myr and exposure to γ-rays on Day 7). High-performance liquid chromatography and 1H-nuclear magnetic resonance were used to isolate and characterize the compounds from M. elengi L. leaves. Enzyme-linked immunosorbent assay was used for biochemical analyses. Identified compounds were Myr, myricetin 3-O-galactoside, myricetin 3-O-rahmnopyranoside (1 → 6) glucopyranoside, quercetin, quercitol, gallic acid, α-,β-amyrin, ursolic acid, and lupeol. Serum aspartate transaminase and alanine transaminase activities were significantly increased, while serum protein and albumin levels were significantly decreased after irradiation. Hepatic levels of tumor necrosis factor-α, prostaglandin 2, inducible nitric oxide synthase, interleukin-6 (IL-6), and IL-12 were increased following irradiation. Improvements were observed in most serological parameters after treatment with extract or pure Myr, with histological analyses confirming decreased liver injury in treated rats. Our study demonstrates that pure Myr has a greater hepatoprotective effect than M. elengi leaf extracts against irradiation-induced hepatic inflammation.

Triterpenoid saponins from Anagallis monelli ssp. linifolia (L.) Maire and their chemotaxonomic significance

Thirteen undescribed triterpenoid saponins named monellosides A-M, were isolated from the aerial parts of Anagallis monelli ssp. linifolia (L.) Maire, together with ten known oleanane-type glycosides. Their structures were elucidated by 1D and 2D-NMR spectroscopy (COSY, TOCSY, HSQC, HMBC and ROESY) as well as high resolution mass spectrometry (HR-ESI-MS) and acid hydrolysis. Monellosides A-M have a carbohydrate chain linked on the C-3 of the aglycone with a common β-d-glucopyranosyl-(1 → 4)-α-l-arabinopyranosyl sequence which was further glycosylated by a glucose and/or a xylose. The sequence β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)-]α-l-arabinopyranosyl was common to all the 13,28-epoxy-oleanane core skeleton except one compound. In order to discuss the reclassification of Anagallis in Primulaceae, we compared saponins from species of Myrsinaceae and Primulaceae families and showed that these species were characterized by a pentacyclic triterpenoid saponin with a 13,28-epoxy bridge skeleton. Our phytochemical results increase the knowledge of saponins of the genus Anagallis, their chemotaxonomy and stimulate the evaluation of the biological activities of these saponins.

Cytotoxic 13,28 Epoxy Bridged Oleanane-Type Triterpenoid Saponins from the Roots of Ardisia crispa

Ardisiacrispin D–F (1–3), three new 13,28 epoxy bridged oleanane-type triterpenoid saponins, together with four known analogues (4–7) were isolated from the roots of Ardisia crispa. The structures of 1–7 were elucidated based on 1D and 2D-NMR experiments and by comparing their spectroscopic data with values from the published literatures. Ardisiacrispin D–F (1–3) are first examples that the monosaccharide directly linked to aglycone C-3 of triterpenoid saponins in genus Ardisia are non-arabinopyranose. In the present paper, all compounds are evaluated for the cytotoxicity against three cancer cell lines (HeLa, HepG2 and U87 MG) in vitro. The results show that compounds 1, 4 and 6 exhibited significant cytotoxicity against Hela and U87 MG cells with IC₅₀ values in the range of 2.2 ± 0.6 to 9.5 ± 1.8 µM. The present investigation suggests that roots of A. crispa could be a potential source of natural anti-tumor agents and their triterpenoid saponins might be responsible for cytotoxicity.

Role of Saponins in Plant Defense Against Specialist Herbivores

The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae) is a very destructive crucifer-specialized pest that has resulted in significant crop losses worldwide. DBM is well attracted to glucosinolates (which act as fingerprints and essential for herbivores in host plant recognition) containing crucifers such as wintercress, Barbarea vulgaris (Brassicaceae) despite poor larval survival on it due to high-to-low concentration of saponins and generally to other plants in the genus Barbarea. B. vulgaris build up resistance against DBM and other herbivorous insects using glucosinulates which are used in plant defense. Aside glucosinolates, Barbarea genus also contains triterpenoid saponins, which are toxic to insects and act as feeding deterrents for plant specialist herbivores (such as DBM). Previous studies have found interesting relationship between the host plant and secondary metabolite contents, which indicate that attraction or resistance to specialist herbivore DBM, is due to higher concentrations of glucosinolates and saponins in younger leaves in contrast to the older leaves of Barbarea genus. As a response to this phenomenon, herbivores as DBM has developed a strategy of defense against these plant biochemicals. Because there is a lack of full knowledge in understanding bioactive molecules (such as saponins) role in plant defense against plant herbivores. Thus, in this review, we discuss the role of secondary plant metabolites in plant defense mechanisms against the specialist herbivores. In the future, trials by plant breeders could aim at transferring these bioactive molecules against herbivore to cash crops.

Cytotoxic triterpenoid saponins from Lysimachia foenum-graecum

Eleven oleanane-type triterpenoid saponins, foegraecumosides A-K, and eight known ones, were isolated from the aerial parts of Lysimachia foenum-graecum. Their structures were elucidated by spectroscopic data analyses and chemical methods. All isolated saponins were evaluated for their cytotoxicity against four human cancer cell lines (NCI-H460, MGC-803, HepG2, and T24). Seven saponins containing the aglycone cyclamiretin A exhibited moderate cytotoxicity against all tested human cancer cell lines, with IC₅₀ values of 9.3-24.5 μM. Simultaneously, the cytotoxic activities of foegraecumosides A and B, lysichriside A, ardisiacrispins A and B, cyclaminorin, and 3-O-α-L-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-α-l-arabinopyranosyl-cyclamiretin A were tested on drug-resistant lung cancer cell lines (A549 and A549/CDDP, respectively). Ardisiacrispin B displayed moderate cytotoxicity against A549/CDDP, with an IC₅₀ value of 8.7 μM and a resistant factor (RF) of 0.9.

A new triterpenoid saponin from Ardisia gigantifolia

A new triterpenoid saponin, named 3-O-β-d-glucopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 3)]-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)]-α-l-arabinopyranosyl-3β,16α,28,30-tetrahydroxy-olean-12-ene (1), along with four known triterpenoids (2-5), was isolated from the rhizomes of Ardisia gigantifolia. Their structures were elucidated by spectroscopic methods. Compounds 1-4 showed cytotoxic activity against Hela, EJ, BCG, and HepG-2 cell lines. The percentage of early apoptotic cells after treatment with 1 was significantly increased compared with control cells (p < 0.05).

Alkyl phenols and saponins from the roots of Labisia pumila (Kacip Fatimah)

Recently, there is a remarkable boom in the sales of Labisia pumila (Kacip Fatimah) in the Malaysian market, as an extract of the plant is used to gain energy and libido as well as to treat many other ailments. A chemical analysis of its roots was undertaken and three metabolites, demethylbelamcandaquinone B (1), fatimahol (2), and dexyloprimulanin (3) together with 21 known compounds including epoxyoleanane glycosides, alkenated phenolics, cerebroside, glycerogalactolipids, and lipids were isolated and identified. Structure elucidation was achieved by spectroscopic and chemical studies. The MeOH extract of KF and compounds 12 and 13 exhibited moderate in vitro antibacterial activity.

Mass spectral fragmentation analysis of triterpene saponins from Ardisia crenata Sims by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

We used the electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) technique to study the characteristic mass fragmentation patterns of eight triterpene saponins from Ardisia crenata Sims. Eight triterpene saponins were analyzed using parent mass list-triggered data-dependent multiple-stage accurate mass analysis at a resolving power of 100,000 in the external calibration mode. The chemical formula with unsaturation numbers was calculated from accurate m/z values of precursor, and product ions were obtained and used to assign the structures of eight triterpene saponins and two trace unknown compounds. The mass accuracies obtained for all full-scan MS and MS(n) spectra were within 7 ppm (< 5 ppm in most cases) in the ESI negative-ion mode. On FTICR-MS and FTICR-MS/MS, the eight triterpene saponins showed characteristic mass fragmentation patterns that facilitated the identification of their structural types, including the individual monosaccharide types, the monosaccharide numbers, and the sequences of the substituted saccharide groups. We proposed their fragmentation mechanisms. Based on their characteristic mass fragmentation patterns and fragmentation mechanisms, two unknown trace triterpene saponins were identified in the mixture.

Cytotoxic triterpenoid saponins from the roots of Ardisia crenata

Ardisiacrenoside I (1), a new triterpenoid pentasaccharide with an unusual glycosyl glycerol side chain, was isolated from Ardisia crenata together with five closely related triterpenoid saponins. Their structures were elucidated by a combination of mass spectrometry, IR, 1D, and 2D NMR spectroscopy. Their cytotoxic activities were evaluated against several different human tumor cell lines by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) method.

Myrsicorianol, A New Prenylated Benzoic Acid Derivative from Myrsine Coriacea

A new prenylated benzoic acid derivative, named myrsicorianol (1), was isolated from the fruits of Myrsine coriacea and its structure was determined by spectral analysis, including 1D- and 2D-NMR experiments. Myrsinoic acid A and a mixture of the p-benzoquinones, embelin, rapanone and 2,5-dihydroxy-3-pentadecyl-1,4-benzoquinone (homorapanone) were also obtained from the fruits, whilst the bark afforded myrsinoic acid A, myrsinoic acid B, 3-(3′,7′-dimethyl-2′,6′-octadienyl)-4-hydroxybenzoic acid and 3-(3′,7′-dimethyl-2′,6′-octadienyl)-4-methoxybenzoic acid.

Biologically active triterpenoid saponins from Ardisia japonica

Eleven new triterpenoid saponins, ardisianosides A (1), B (2), C (4), D (5), E (6), F (7), G (15), H (16), I (17), J (18), and K (19), together with 10 known saponins, were isolated from the whole plants of Ardisia japonica. The structures of the new saponins were established on the basis of extensive 1D and 2D NMR and MS studies coupled with chemical degradations. The cytotoxic activities of saponins 1-21 are reported against three human cancer cell lines, namely, HL-60 myeloid leukemia, KATO-III stomach adenocarcinoma, and A549 lung adenocarcinoma cells.

Saponins, classification and occurrence in the plant kingdom

Saponins are a structurally diverse class of compounds occurring in many plant species, which are characterized by a skeleton derived of the 30-carbon precursor oxidosqualene to which glycosyl residues are attached. Traditionally, they are subdivided into triterpenoid and steroid glycosides, or into triterpenoid, spirostanol, and furostanol saponins. In this study, the structures of saponins are reviewed and classified based on their carbon skeletons, the formation of which follows the main pathways for the biosynthesis of triterpenes and steroids. In this way, 11 main classes of saponins were distinguished: dammaranes, tirucallanes, lupanes, hopanes, oleananes, taraxasteranes, ursanes, cycloartanes, lanostanes, cucurbitanes, and steroids. The dammaranes, lupanes, hopanes, oleananes, ursanes, and steroids are further divided into 16 subclasses, because their carbon skeletons are subjected to fragmentation, homologation, and degradation reactions. With this systematic classification, the relationship between the type of skeleton and the plant origin was investigated. Up to five main classes of skeletons could exist within one plant order, but the distribution of skeletons in the plant kingdom did not seem to be order- or subclass-specific. The oleanane skeleton was the most common skeleton and is present in most orders of the plant kingdom. For oleanane type saponins, the kind of substituents (e.g. -OH, =O, monosaccharide residues, etc.) and their position of attachment to the skeleton were reviewed. Carbohydrate chains of 18 monosaccharide residues can be attached to the oleanane skeleton, most commonly at the C3 and/or C17 atom. The kind and positions of the substituents did not seem to be plant order-specific.

Triterpenoid Saponins from Lysimachia davurica

Three new saponins were isolated from the whole plants of Lysimachia davurica. On the basis of 1D and 2D NMR ((1)H-(1)HCOSY, HMBC, HMQC, and TOCSY) techniques, MS, and hydrolysis, their structures were found to be 3-O-beta-D-glucopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-alpha-L-arabinopyranosyl-13,28-epoxy-3beta-hydroxy-16-oleanaone (1), 3-O-beta-D-glucopyranosyloxyuronic acid-(1-->2)-beta-D-xylopyranosyl-cyclamiretin A (2), and 3-O-beta-D-glucopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-cyclamiretin A (3), respectively. Compounds 2 and 3 showed significant cytotoxicities against human A-2780 cells.

Phytochemistry and antimycobacterial activity of Chlorophytum inornatum

In a project to investigate plant derived natural products from the Liliaceae with activity against fast-growing strains of mycobacteria, we have identified two new metabolites from Chlorophytum inornatum. The active principle, a new homoisoflavanone (1) was identified as 3-(4'-methoxybenzyl)-7,8-methylenedioxy-chroman-4-one. The metabolite assigned as 7-(1'-hydroxyethyl)-2-(2''-hydroxyethyl)-3,4-dihydrobenzopyran (2) was characterised by extensive 1- and 2D NMR spectroscopy. The antimycobacterial activity of this plant was mainly due to the homoisoflavonoid which exhibited minimum inhibitory values ranging from 16-256 microg/ml against four strains of fast-growing mycobacteria.

A review of natural products with antileishmanial activity

Infections caused by protozoa of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The incidence of the disease has increased since the emergence of AIDS. In the absence of a vaccine, there is an urgent need for effective drugs to replace/supplement those in current use. The plant kingdom is undoubtedly valuable as a source of new medicinal agents. The present work constitutes a review of the literature on plant extracts and chemically defined molecules of natural origin showing antileishmanial activity. The review refers to 101 plants, their families, and geographical distribution, the parts utilized, the type of extract and the organism tested. It also includes 288 compounds isolated from higher plants and microorganisms, classified into appropriate chemical groups. Some aspects of recent antileishmanial-activity-directed research on natural products are discussed.

Bioactivity of crude extracts and some constituents of Blutaparon portulacoides (Amaranthaceae)

Crude extracts (aerial parts and roots, both dried), methylenedioxyflavonol, and a mixture of acyl steryl glycosides isolated from Blutaparon portulacoides, were assayed for their toxicity against Trypanosoma cruzi trypomastigotes and Leishmania amazonensis amastigotes from axenic cultures. The antimicrobial activity was also investigated, in a screening conducted using fifteen strains of Gram-positive and Gram-negative bacteria, along with the yeasts, Candida albicans and Candida tropicalis. To assess the antibacterial activity of the isolated compounds, the minimum inhibitory concentrations (MICs) were determined. There are no reports of acyl steryl glycosides in the genus Blutaparon and their biological activities are being evaluated for the first time.

Triterpenoid saponins from Ardisia mamillata

Two saponins were isolated from the roots of Ardisia mamillata HANCE. Their structures were established on the basis of MALDI-TOFMS, 1H, 13C NMR and 2D NMR (COSY, HOHAHA, HETCOR, HMBC and ROESY) spectra, and on chemical evidence, to be ardisimamilloside A, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-alpha-L-arabinopyranosyl]-3beta, 16alpha,28alpha-trihydroxy-13beta,28-epoxy-oleanan+ ++-30-al; and ardisimamilloside B, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-( 1 --> 2)]-alpha-L-arabinopyranosyl]-beta3-hydroxy-13beta,28- epoxy-oleanan-16-oxo-30-al.

A triterpenoid saponin from Cyclamen coum

A new triterpenoid saponin, coumoside A, has been isolated from the whole plant of Cyclamen coum and the structure of this novel saponin (C58H92O27) has been deduced by NMR methods based on 1H, 13C, DEPT, 1H-1H COSY, HETCOR, NOESY-NMR experiments and the FAB-mass spectrum. It has the structure 3 beta-O-[beta-D-glucopyranosyl-(1-6)-[alpha-L-arabinopyranosyl- (1-2)]-beta-D-glucopyranosyl-(1-4)-[beta-D-glucopyranosyl-(1-2)]-alpha-L -arabinopyranosyl]-16 alpha-hydroxy-30,28 beta-lactone-olean-12-ene and is called coumoside.