Kinmoonosides A-C, three new cytotoxic saponins from the fruits of Acacia concinna, a medicinal plant collected in myanmar

GC/MS and LC-MS Analysis and in-vitro Antioxidant Activity of Essential Oil and Crude Methanol Extract from the Leaves of Acacia Gerrardii Benth. Growing in Saudi Arabia

In this study, I determined the essential oil (EO) chemical composition and crude methanol extract (ME) phytochemical profile of the leaves of Acacia gerrardii (ACGL), a plant growing in Saudi Arabia. Additionally, I assessed their in vitro antioxidant activity. The gas chromatography-mass spectrometry analysis of the EO revealed a high content of oxygenated monoterpenes (79.86 %), primarily dominated by pulegone (35.11 %), carvacrol (27.36 %), and neo-dihydrocarveol (4.67 %). The ME was analyzed by liquid chromatography-mass spectrometry to determine its qualitative chemical profile. Four organic acids, eleven phenolic compounds, sixteen flavonoids, nine terpenoids (eight triterpenoids and one diterpenoid), and one coumarin were found in the ME of ACGL. This extract was found to be dominated by 5,6,4-trihydroxy-7,3-dimethoxyflavone (39.30 %), acteoside (30.27 %), nevadensin (7.55 %), isoacteoside (3.08 %) and apiin (3.23 %), and hesperidin (2.73 %). The phenolic (TPC=127.70±1.47 mg gallic acid equivalents/g of extract) and flavonoid (TFC=85.48±0.12 mg quercetin equivalents/g of extract) contents of the ME were also assessed. The in vitro antioxidant activities of both the EO and ME were evaluated using DPPH, ABTS, and ferrous ion chelating effect assays. Compared to the positive control (vit. E and Vit. C), and both extracts exhibited excellent activity.

Phytoprostanes and phytofurans: Bioactive compounds in aerial parts of Acacia cyanophylla Lindl

The relevance of oxylipins as biomarkers of oxidative stress has been established in recent years. Phytoprostanes and phytofurans are plant metabolites derived from peroxidation of α-linolenic acid (ALA) induced by ROS. Previous findings have suggested new valuable biological properties for these new active compounds in the frame of diverse pathophysiological situations and health constraints. Lipidomic profiling of different aerial parts of the same Acacia cyanophylla Lindl. specimen, was evaluated for the first time here, using LC-MS/MS technology. Analysis revealed the existence of six PhytoPs and three PhytoFs. Stems have the highest amount of these metabolites with 179.35 ng/g and 320.79 ng/g respectively. This first complete profile paves the way to explore Acacia cyanophylla Lindl. as a source of plant oxylipins for therapeutic or pharmaceutical uses.

3-Hydroxybutyrate-containing triterpenoid saponins from Brachyscome angustifolia and their immunogenic activity

Three unique hydroxybutyrate-containing triterpenoid saponins, angustiside A-C (1-3), were isolated from the shoots of Brachyscome angustifolia (Asteraceae). The extensive spectroscopic study showed that their aglycone is a previously undescribed one, 16-hydroxy olean-18-en-28-oic acid, named as angustic acid (1a), and 2 and 3 contain hydroxybutyrate moiety in their side chains. The absolute configuration of 1a was determined to be (3R,5R,9R,13S,16S) by X-ray crystallography. The immunity assay revealed that 2 and 3 containing both acyl chains and branched saccharides significantly enhanced the proliferation of OT-I CD8⁺ T cells and secretion of interferon gamma (IFN-γ), presenting their immunogenic activity.

A review: structure-activity relationship between saponins and cellular immunity

Saponins, which exhibit many different biological and pharmacological activities, are present in a wide range of plant species and in some marine organisms. Notably, the researchers have found that saponins can activate the immune system in mammals. The strength of this function is closely related to the chemical structure of saponins. The present study of the structure-activity relationship suggests that aglycones, glycochains on aglycones and special functional groups of saponins affect the immune activity of saponins. This paper reviews the effects of different saponins on cellular immunity. As well as the structure-activity relationship of saponins. It is hoped that the information integrated in this paper will provide readers with information on the effects of saponins on cellular immunity and promote the further study of these compounds.

Identification of a Family of Glycoside Derivatives Biologically Active against Acinetobacter baumannii and Other MDR Bacteria Using a QSPR Model

As the rate of discovery of new antibacterial compounds for multidrug-resistant bacteria is declining, there is an urge for the search for molecules that could revert this tendency. Acinetobacter baumannii has emerged as a highly virulent Gram-negative bacterium that has acquired multiple resistance mechanisms against antibiotics and is considered of critical priority. In this work, we developed a quantitative structure-property relationship (QSPR) model with 592 compounds for the identification of structural parameters related to their property as antibacterial agents against A. baumannii. QSPR mathematical validation (R2 = 70.27, RN = −0.008, a(R2) = 0.014, and δK = 0.021) and its prediction ability (Q2LMO = 67.89, Q2EXT = 67.75, a(Q2) = −0.068, δQ = 0.0, rm2¯ = 0.229, and Δrm2 = 0.522) were obtained with different statistical parameters; additional validation was done using three sets of external molecules (R2 = 72.89, 71.64 and 71.56). We used the QSPR model to perform a virtual screening on the BIOFACQUIM natural product database. From this screening, our model showed that molecules 32 to 35 and 54 to 68, isolated from different extracts of plants of the Ipomoea sp., are potential antibacterials against A. baumannii. Furthermore, biological assays showed that molecules 56 and 60 to 64 have a wide antibacterial activity against clinically isolated strains of A. baumannii, as well as other multidrug-resistant bacteria, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa. Finally, we propose 60 as a potential lead compound due to its broad-spectrum activity and its structural simplicity. Therefore, our QSPR model can be used as a tool for the investigation and search for new antibacterial compounds against A. baumannii.

Characterization of Bioactive Compounds from Acacia concinna and Citrus limon, Silver Nanoparticles’ Production by A. concinna Extract, and Their Biological Properties

The applications of bioactive compounds from medicinal plants as therapeutic drugs are largely increasing. The present study selected the bioactive compounds from Acacia concinna (A. concinna) and Citrus limon (C. limon) to assess their phytochemicals, proteins, and biological activity. The plant material was collected, and extraction performed as per the standard procedure. Qualitative analysis was undertaken, and identification of functional organic groups was performed by FTIR and HPLC. Antibacterial, anticancer, antioxidant, antihyperglycemic, antihyperlipidemic, and inhibition kinetics studies for enzymes were performed to assess the different biological activities. Flavonoids and phenols were present in a significant amount in both the selected plants. A. concinna showed significant antimicrobial activity against Z. mobilis, E. coli, and S. aureus, with minimum inhibition zones (MIZ) of 24, 22, and 20 mm, respectively. C. limon strongly inhibited all the tested pathogenic bacteria with maximum and minimum MIZ of 32 and 17 mm. A. concinna silver nanoparticles also exhibited potent antimicrobial activity. Both extracts showed substantial antioxidant, antihyperlipidemic, antidiabetic, anticancer (MCF-7), and anti-urease (antiulcer) properties. To conclude, these plants can be used to treat hyperlipidemia, diabetes, cancer, and gastrointestinal ulcers. They can also serve as antimicrobial and antioxidant agents. Thus, the studied plants must be exploited cost-effectively to generate therapeutic drugs for various diseases.

Plant-Derived Saponins: A Review of Their Surfactant Properties and Applications

In response to increasing natural surfactant demand and environmental concerns, natural plant-based surfactants have been replacing synthetic ones. Saponins belong to a class of plant metabolites with surfactant properties that are widely distributed in nature. They are eco-friendly because of their natural origin and biodegradable. To date, many plant-based saponins have been investigated for their surface activity. An overview of saponins with a particular focus on their surface-active properties is presented in this article. For this purpose, works published in the past few decades, which report better surfactant relevant properties of saponins than synthetic ones, were extensively studied. The investigations on the potential surfactant application of saponins are also documented. Moreover, some biological activities of saponins such as antimicrobial activity, antidiabetic activity, adjuvant potentials, anticancer activity, and others are reported. Plants rich in saponins are widely distributed in nature, offering great potential for the replacement of toxic synthetic surfactants in a variety of modern commercial products and these saponins exhibit excellent surface and biological activities. New opportunities and challenges associated with the development of saponin-based commercial formulations in the future are also discussed in detail.

Saponins are responsible for the anti-obesogenic activity of Acacia concinna

Acacia concinna (Willd.) DC. is a medicinal plant sourced mainly from Southeast Asia. The pods of Acacia concinna (A. concinna) are a potential candidate to treat or prevent obesity; however, these medicinal attributes have not been examined in detail. In this study, the anti-obesogenic compounds in A. concinna pods were investigated. Chromatographic separation of the pod extract guided by pancreatic lipase inhibitory activity led to the isolation of saponins. Decomposition analysis of the saponins revealed their chemical composition to be acacic acid, monoterpenes, and five types of sugars (glucose, xylose, rhamnose, quinovose, arabinose). The predicted structures of the saponins from decomposition analysis were confirmed by LC-MS analysis, showing that these saponins are mixture of various derivatives of monoterpenes and sugar units. These saponins inhibited pancreatic lipase activity strongly with an IC₅₀ of 7.9 μg/mL, and reduced lipid accumulation in 3T3-L1 adipocytes at 6.3 μg/mL. The saponins also enhanced lipolysis of 3T3-L1 adipocytes at 3.1 or 6.3 μg/mL by mediating the activity of protein kinase A and extracellular signal-regulated kinase pathways, suggesting that this mechanism is partly responsible for the observed reduction of lipid content in adipocytes. The results underline A. concinna as a potential source of the anti-obesogenic candidates for the future treatment and prevention of obesity.

Bioactive Compounds from Medicinal Plants in Myanmar

Myanmar is a country with rich natural resources and of these, medicinal plants play a vital role in the primary health care of its population. The people of Myanmar have used their own system of traditional medicine inclusive of the use of medicinal plants for 2000 years. However, systematic and scientific studies have only recently begun to be reported. Researchers from Japan, Germany, and Korea have collaborated with researchers in Myanmar on medicinal plants since 2000. During the past two decades, over 50 publications have been published in peer-reviewed journals. Altogether, 433 phytoconstituents, including 147 new and 286 known compounds from 26 plant species consisting of 29 samples native to Myanmar, have been collated. In this contribution, phytochemical and biological investigations of these plants, including information on traditional knowledge are compiled and discussed.

Two new triterpenoids from the roots of Phyllanthus emblica

Two new triterpenes, the seco-friedelane type secofriedelanophyllemblicine and the ursane-derived saponin ursophyllemblicoside were isolated from the roots of the edible fruit-producing Phyllanthus emblica. Their structures were unambiguously elucidated using extensive 1D and 2D NMR analyses, high resolution mass spectrometry and single-crystal X-ray crystallographic analyses along with comparison with literature data. Secofriedelanophyllemblicine represents the first 3,4-secofriedelane bearing a carboxylic acid group substituent at C-20. Ursophyllemblicoside, incorporating the rare 21α hydroxyursolic acid as a sapogenol represents the first example of saponin comprising this aglycone. Secofriedelanophyllemblicine displayed a moderate cytotoxicity against K562 and HepG2 cancer cell lines.

A New Saponin with Anti-HIV-1 Protease Activity fromAcacia pennata

We investigated the phytochemicals from an ethanol extract of Acacia pennata (L.) Willd stems, a Vietnam medicinal plant, which led to the isolation of a new saponin termed 21β- O-[(2 E)-6-hydroxyl-2,6-dimethyl-2,7-octadienoyl] pitheduloside G (1), as well as pitheduloside G (2), a known saponin. The structures of compounds 1 and 2 were elucidated via spectroscopy and compared with those reported in the literature. The isolates (1 and 2) were tested for their inhibitory effects on human immunodeficiency virus type 1 (HIV-1) protease (PR). We found that the new compound, 21β- O-[(2 E)-6-hydroxyl-2,6-dimethyl-2,7-octadienoyl] pitheduloside G (1), possessed potent anti-HIV-1 PR activity, with a half-maximum inhibitory concentration (IC50) value of 2.0 ± 0.2 μM. In contrast, pitheduloside G (2) exhibited much less inhibition, with an IC50value of 18 ± 0.5 μM. Both compounds were nontoxic in human embryonic kidney 293T cells at concentrations effective against HIV-1 PR. This is the first report regarding the isolation of an anti-HIV-1 PR compound (1) from an Acacia plant species.

Chemical Composition, Antioxidant Properties, α-Glucosidase Inhibitory, and Antimicrobial Activity of Essential Oils from Acacia mollissima and Acacia cyclops Cultivated in Tunisia

The genus Acacia is quite large and can be found in the warm subarid and arid parts, but little is known about its chemistry, especially the volatile parts. The volatile oils from fresh flowers of A. mollissima and A. cyclops (growing in Tunisia) obtained by hydrodistillation were analyzed by GC then GC/MS. Eighteen (94.7% of the total oil composition) and 23 (97.4%) compounds were identified in these oils, respectively. (E,E)-α-Farnesene (51.5%) and (E)-cinnamyl alcohol (10.7%) constituted the major compounds of the flower oil of A. mollissima, while nonadecane (29.6%) and caryophyllene oxide (15.9%) were the main constituents of the essential oil of A. cyclops. Antioxidant activity of the isolated oils was studied by varied assays, i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS); the isolated oils showed lowest IC₅₀ (4 - 39 μg/ml) indicating their high antioxidant activity. The α-glucosidase inhibitor activity was also evaluated and Acacia oils were found to be able to strongly inhibit this enzyme with IC₅₀ values (81 - 89 μg/ml) very close to that of acarbose which was used as positive control. Furthermore, they were tested against five Gram-positive and Gram-negative bacteria and one Candida species. Essential oil of A. mollissima was found to be more active than that of A. cyclops, especially against Pseudomonas aeruginosa (MIC = 0.31 mg/ml and MBC = 0.62 mg/ml).

Chemical composition and allelopathic potential of essential oils obtained from Acacia cyanophylla Lindl. Cultivated in Tunisia

Acacia cyanophylla Lindl. (Fabaceae), synonym Acacia saligna (Labill.) H. L.Wendl., native to West Australia and naturalized in North Africa and South Europe, was introduced in Tunisia for rangeland rehabilitation, particularly in the semiarid zones. In addition, this evergreen tree represents a potential forage resource, particularly during periods of drought. A. cyanophylla is abundant in Tunisia and some other Mediterranean countries. The chemical composition of the essential oils obtained by hydrodistillation from different plant parts, viz., roots, stems, phyllodes, flowers, and pods (fully mature fruits without seeds), was characterized for the first time here. According to GC-FID and GC/MS analyses, the principal compound in the phyllode and flower oils was dodecanoic acid (4), representing 22.8 and 66.5% of the total oil, respectively. Phenylethyl salicylate (8; 34.9%), heptyl valerate (3; 17.3%), and nonadecane (36%) were the main compounds in the root, stem, and pod oils, respectively. The phyllode and flower oils were very similar, containing almost the same compounds. Nevertheless, the phyllode oil differed from the flower oil for its higher contents of hexahydrofarnesyl acetone (6), linalool (1), pentadecanal, α-terpineol, and benzyl benzoate (5) and its lower content of 4. Principal component and hierarchical cluster analyses separated the five essential oils into four groups, each characterized by its main constituents. Furthermore, the allelopathic activity of each oil was evaluated using lettuce (Lactuca sativa L.) as a plant model. The phyllode, flower, and pod oils exhibited a strong allelopathic activity against lettuce.

Dispersion of multiwalled carbon nanotubes in Acacia extract and it's utility as an antimicrobial agent

This work deals with the preparation of a multiwalled carbon nanotubes (MWCNTs) dispersion in Acacia extract (AE) and checks its antimicrobial activity.

Antimicrobial activity of saponin-rich fraction from Camellia oleifera cake and its effect on cell viability of mouse macrophage RAW 264.7

BACKGROUND

As a by-product of oil production, several million tons of Camellia oleifera cake is discarded every year in China. The aim of this study was to evaluate the antimicrobial activity of a saponin-rich fraction isolated from C. oleifera cake and investigate its effect on the cell viability of RAW 264.7, a macrophage-like cell line present in almost all mouse tissues.

RESULTS

The saponin-rich fraction was isolated from C. oleifera cake in several steps and had a saponin content of 95.42 ± 0.10% (w/w). It showed significant inhibitory activity against the bacteria Staphylococcus aureus, Escherichia coli and Bacillus subtilis and the fungi Mucor racemosus, Aspergillus oryzae, Rhizopus stolonifer, Saccharomyces cerevisiae and Penicillium glaucum, with minimum inhibitory concentrations of 31.3, 31.3, 62.5, 250, 250, 250, 31.3 and 125 µg ml(-1) respectively. In addition, mouse macrophage RAW 264.7 pretreated with the saponin-rich fraction (80-200 µg mL(-1) ) exhibited a significant loss of cell viability in a dose-dependent manner.

CONCLUSION

These results may be useful for the future application of saponins from C. oleifera cake. However, the potential use of the saponin-rich fraction as an antimicrobial agent should be decided according to the target micro-organisms in order to avoid causing harm in humans.

Advances in saponin-based adjuvants

Saponins are natural glycosides of steroid or triterpene which exhibited many different biological and pharmacological activities. Notably, saponins can also activate the mammalian immune system, which have led to significant interest in their potential as vaccine adjuvants. The most widely used saponin-based adjuvants are Quil A and its derivatives QS-21, isolated from the bark of Quillaja saponaria Molina, which have been evaluated in numerous clinical trials. Their unique capacity to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens makes them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines. However, Quillaja saponins have serious drawbacks such as high toxicity, undesirable haemolytic effect and instability in aqueous phase, which limits their use as adjuvant in vaccination. It has driven much research for saponin-based adjuvant from other kinds of natural products. This review will summarize the current advances concerning adjuvant effects of different kinds of saponins. The structure-activity relationship of saponin adjuvants will also be discussed in the light of recent findings. It is hoped that the information collated here will provide the reader with information regarding the adjuvant potential applications of saponins and stimulate further research into these compounds.

Bioactive Complex Triterpenoid Saponins from the Leguminosae Family

Many classes of phytochemical products are finding therapeutic use, for example, complex triterpenoid saponins containing in their structures monoterpene moieties. Some of these compounds possess cytotoxic, anti-HIV and adjuvant activities. This review aims to give an overview of these complex triterpenoid saponins with biological activity from the Leguminosae.

Triterpenoidal Saponins and Prosapogenins from Albizia Lebbeck (Leguminosae)

Four new echinocystic acid glycosides (1–4) were isolated from the dried seeds of Albizia lebbeck. The alkaline hydrolysate of the saponin fraction yielded two new prosapogenins (5–6). Their structures were determined by extensive NMR and spectroscopic analysis.

Cytotoxic triterpenoid saponins of Albizia gummifera from the Madagascar rain forest

Bioassay-guided fractionation of an EtOH extract obtained from the roots of the Madagascan plant Albizia gummifera led to the isolation of three new cytotoxic oleanane-type triterpenoid saponins, gummiferaosides A-C (1-3). The structures of these new compounds were elucidated using 1D and 2D NMR experiments and mass spectrometry. Compounds 1-3 showed cytotoxicity against the A2780 human ovarian cancer cell line with IC50 values of 0.8, 1.5, and 0.6 microg/mL, respectively.

Immunological adjuvant activities of saponin extracts from the pods of Acacia concinna

Pods of Acacia concinna (Leguminosae) contain several saponins. In this study, four saponin fractions which were acetone fraction (AAC), aqueous fraction (WAC), hydromethanolic fraction (HAC) and methanolic fraction (MAC) were generated and their haemolytic activities and surface activities were determined in comparison with quillaja saponin (QS). There were no significant differences between the haemolytic activities of MAC and QS. However, the surface tensions of MAC was significantly lower than QS (p < 0.001). Furthermore, the immunomodulatory effect and the adjuvant potential of MAC on the cellular and humoral immune response of BALB/c mice against ovalbumin were investigated. The splenocyte proliferations induced by MAC were significantly higher than QS at the concentrations of 200, 400, 800 and 1000 microg/ml (p < 0.05). BALB/c mice were immunized subcutaneously either with OVA 20 microg alone or with OVA 20 microg combining with QS (10 microg) or MAC (10 and 40 microg). Ten days after the second immunization, concanavalin A (Con A)-, pokeweed mitogen (PWM)-, and OVA-stimulated splenocyte proliferation and OVA-specific antibodies in serum were measured. The results suggested that MAC (40 microg) could activate T and B cells. In addition, OVA-specific IgG, IgG1 IgG2a and IgG2b antibody levels in serum were significantly enhanced by MAC (40 microg) as compared with OVA control group (p < 0.001). This finding suggested that MAC might be effect on Th1 and Th2 helper T cells. In conclusion, the results indicated that MAC at a dose of 40 microg could be used as vaccine adjuvant to increase immune responses.

Final report of the safety assessment of Acacia catechu gum, Acacia concinna fruit extract, Acacia dealbata leaf extract, Acacia dealbata leaf wax, Acacia decurrens extract, Acacia farnesiana extract, Acacia farnesiana flower wax, Acacia farnesiana gum, Acacia senegal extract, Acacia senegal gum, and Acacia senegal gum extract

These ingredients are derived from various species of the acacia plant. Only material derived from Acacia senegal are in current use according to industry data. The concentration at which these ingredients are reported to be used ranges from 9% in mascara to 0.0001% in tonics, dressings, and other hair-grooming aids. Gum arabic is a technical name for Acacia Senegal Gum. Gum arabic is comprised of various sugars and glucuronic acid residues in a long chain of galactosyl units with branched oligosaccharides. Gum arabic is generally recognized as safe as a direct food additive. Little information is available to characterize the extracts of other Acacia plant parts or material from other species. Acacia Concinna Fruit Extract was generally described as containing saponins, alkaloids, and malic acid with parabens and potassium sorbate added as preservatives. Cosmetic ingredient functions have been reported for Acacia Decurrens Extract (astringent; skin-conditioning agent--occlusive) and Acacia Farnesiana Extract (astringent), but not for the other Acacias included in this review. Toxicity data on gum arabic indicates little or no acute, short-term, or subchronic toxicity. Gum arabic is negative in several genotoxicity assays, is not a reproductive or developmental toxin, and is not carcinogenic when given intraperitoneally or orally. Clinical testing indicated some evidence of skin sensitization with gum arabic. The extensive safety test data on gum arabic supports the safety of Acacia Senegal Gum and Acacia Senegal Gum Extract, and it was concluded that these two ingredients are safe as used in cosmetic formulations. It was not possible, however, to relate the data on gum arabic to the crude Acacias and their extracts from species other than Acacia senegal. Therefore, the available data were considered insufficient to support the safety of Acacia Catechu Gum, Acacia Concinna Fruit Extract, Acacia Dealbata Leaf Extract, Acacia Dealbata Leaf Wax, Acacia Decurrens Extract, Acacia Farnesiana Extract, Acacia Farnesiana Flower Wax, Acacia Farnesiana Gum, and Acacia Senegal Extract in cosmetic products. The additional data needed to complete the safety assessment for these ingredients include (1) concentration of use; (2) identify the specific chemical constituents, and clarify the relationship between crude Acacias and their extracts and the Acacias and their extracts that are used as cosmetic ingredients; (3) data on contaminants, particularly relating to the presence of pesticide residues, and a determination of whether Acacia melanoxylon is used in cosmetics and whether acamelin (a quinone) and melacacidin (a flavin) are present in the Acacias that are being used; (4) skin sensitization study (i.e., dose response to be determined); (5) contact urticaria study at use concentration; and (6) ultraviolet (UV) absorption spectrum; if there is significant absorbance in the UVA or UVB range, then a photosensitization study may be needed. It was also noted that other data may be needed after clarification of the chemical constituents of the Acacia-derived ingredients.

Triterpenoid saponin anthranilates from Albizia grandibracteata leaves ingested by primates in Uganda

Three new oleanane-type triterpene saponins (1-3), named grandibracteosides A-C, were isolated from the methanolic extract of leaves of Albizia grandibracteata, a species consumed by primates in the Kibale National Park, Uganda. The structures of the saponins were established using 1D and 2D NMR experiments and mass spectrometry and confirmed by acid and alkaline hydrolysis. The crude extract and the pure compounds showed significant inhibitory activity against KB and MCF7 tumoral cell lines in vitro. The compounds are glycosides of acacic acid acylated by an o-aminobenzoyl unit. This is the first report of such ester saponins in dicotyledonous plants. Studies of the primate diet may provide a useful method for finding naturally occurring compounds of medicinal significance.

Haemolytic acylated triterpenoid saponins from Harpullia austro-caledonica

Eight new acylated triterpenoid saponins were isolated from the stem bark of Harpullia austro-caledonica along with the known harpuloside (9). Their structures were established using 1D and 2D NMR and mass spectrometry as 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (1), 3-O-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl barringtogenol C (2), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (3), 3-O-alpha-L-arabinofuranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (4), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl protoaescigenin (5), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (6), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (7), 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (8). The EtOH extract of the stem bark showed in vitro cytotoxic activity against KB cells (90% at 10 microg/ml). At a concentration of 5 microg/ml, the saponin mixture showed haemolytic activity and caused 100% haemolysis of a 10% suspension of sheep erythrocytes.

Biological activities and distribution of plant saponins

Plant saponins are widely distributed amongst plants and have a wide range of biological properties. The more recent investigations and findings into their biological activities were summarized. Isolation studies of saponins were examined to determine which are the more commonly studied plant families and in which families saponins have been identified.

In vitro effects of aqueous seeds extract of Acacia cyanophylla on the opsonized zymosan-induced superoxide anions production by rat polymorphonuclear leukocytes

In vitro studies were carried out in rat pleural polymorphonuclear leukocytes (PMNs) activated by opsonized zymosan (OZ) to investigate the effects of aqueous extract from Acacia cyanophylla seeds on superoxide anions generation. PMNs were collected, after induction of an acute inflammatory reaction, by injection in the rat pleural cavity, of a suspension of calcium pyrophosphate (CaPP) crystals (pleurisy with CaPP) or serum (pleurisy with serum). The results obtained indicate that Acacia cyanophylla aqueous seeds extract had, in vitro, a significant stimulatory effect, in a dose dependent manner, on the PMN superoxide anions generation. It also corrected the diminution of superoxide anions production induced by diclofenac pre-treated PMNs. It could be concluded from the results of this study that the stimulatory properties of Acacia cyanophylla seeds aqueous extract may at least be due to the presence of polyphenols such tannins and/or lignins. Further investigations are needed to determine clearly the mechanisms mediating the generation of superoxide radicals in this phenomenon.

Isolation and structures of avicins D and G: in vitro tumor-inhibitory saponins derived from Acacia victoriae

Two new saponins named avicins D (1) and G (2) were isolated from the seed pods of the desert legume plant Acacia victoriae. The structures, elucidated by 1D and 2D NMR studies and by chemical means, were characterized as acacic acid-bearing oligosaccharides at C-3 and C-28 with a side chain linked to C-21 comprised of two monoterpene carboxylic acids and a quinovose moiety. Both compounds exhibited potent cytotoxicity (apoptosis) against human T-cell leukemia (Jurkat cells) in vitro.

Synthesis of a typical N-acetylglucosamine-containing saponin, oleanolic acid 3-yl alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranoside

Oleanolic acid 3-yl alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-2-acetamido-2-deoxy-beta-D-glucopyranoside, a cytotoxic saponin isolated from Acacia tenuifolia and Albizia subdimidiata with a typical structure of the N-acetylglucosamine-containing plant saponins, was synthesized. The synthesis adopted a stepwise glycosylation fashion employing glycosyl trifluoroacetimidates 5 and 9 and thioglycoside 12 as donors.

Two bioactive saponins from Albizia subdimidiata from the Suriname rainforest

Bioassay-guided fractionation of a methanol extract of Albizia subdimidiata using the engineered yeast strains 1138, 1140, 1353, and Sc7 of Saccharomyces cerevisiae as the bioassay tool resulted in the isolation of the two active saponins 1 and 2; one of these, albiziatrioside A (1), is described for the first time. The structures of 1 and 2 were established on the basis of HRMS, 1D and 2D NMR spectral data, and GC--MS analysis of the sugar units. Both isolated compounds showed significant cytotoxicity against the A2780 cell line.