Cytotoxic oleane-type triterpene saponins from Glochidion eriocarpum

Mechanisms of Action of Sea Cucumber Triterpene Glycosides Cucumarioside A0-1 and Djakonovioside A Against Human Triple-Negative Breast Cancer

Breast cancer is the most prevalent form of cancer in women worldwide. Triple-negative breast cancer is the most unfavorable for patients, but it is also the most sensitive to chemotherapy. Triterpene glycosides from sea cucumbers possess a high therapeutic potential as anticancer agents. This study aimed to identify the pathways triggered and regulated in MDA-MB-231 cells (triple-negative breast cancer cell line) by the glycosides cucumarioside A0-1 (Cuc A0-1) and djakonovioside A (Dj A), isolated from the sea cucumber Cucumaria djakonovi. Using flow cytometry, fluorescence microscopy, immunoblotting, and ELISA, the effects of micromolar concentrations of the compounds on cell cycle arrest, induction of apoptosis, the level of reactive oxygen species (ROS), mitochondrial membrane potential (Δψm), and expression of anti- and pro-apoptotic proteins were investigated. The glycosides caused cell cycle arrest, stimulated an increase in ROS production, and decreased Δψm in MDA-MB-231 cells. The depolarization of the mitochondrial membrane caused by cucumarioside A0-1 and djakonovioside A led to an increase in the levels of APAF-1 and cytochrome C. This, in turn, resulted in the activation of caspase-9 and caspase-3 and an increase in the level of their cleaved forms. Glycosides also affected the expression of Bax and Bcl-2 proteins, which are associated with mitochondria-mediated apoptosis in MDA-MB-231 cells. These results indicate that cucumarioside A0-1 and djakonovioside A activate the intrinsic apoptotic pathway in triple-negative breast cancer cells. Additionally, it was found that treatment with Cuc A0-1 resulted in in vivo inhibition of tumor growth and metastasis of murine solid Ehrlich adenocarcinoma.

Cytotoxic Effects of Oleanane-type Saponins from Lysimachia laxa

Phytochemical investigation of the methanol extract of the aerial parts of Lysimachia laxa led to the isolation of four new oleanane-type saponins, lysimosides A-D (1-4) and one known compound, lysimachigenoside B (5). Their structures were elucidated using a combination of HR-ESI-MS, 1D and 2D-NMR spectral data, chemical methods, and comparison with previous literature. The cytotoxic activity of these compounds was evaluated against human lung cancer (A-549) and human breast cancer (MCF-7) cell lines. All compounds exhibited cytotoxic activity against A-549 and MCF-7 cell lines with IC50 values ranging from 6.1-16.0 μM, comparable to the positive control, mitoxantrone. Interestingly, oleanane-type saponins with an acetyl group (2-4) exhibited increased cytotoxic activities compared to those without an acetyl group (1).

Discovery of Four New Compounds from Macropanax membranifolius and Their Cytotoxic Activity

A phytochemical investigation of the methanolic extract of the Macropanax membranifolius C.B. Shang leaves led to the isolation of three new flavans, (2R,3R)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (1), (2S,3S)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (2), (2S,3R)-4'-O-methylcatechin 5-O-β-D-glucopyranoside (3), one new triterpene glycoside 3-O-β-D-xylopyranosyl-(1→6)-[β-D-xylopyranosyl-(1→2)]-β-D-glucopyranosyl-oleanolic acid 28-O-β-D-glucopyranoside (4), together with nine known compounds (5-13). Their chemical structures were elucidated based on HR-ESI-MS, NMR spectroscopic data. The absolute configurations of compounds 1-3 were established by electronic circular dichroism (ECD) spectra. At concentration of 20 μM, compounds 1-13 showed the percentages of dead cell in the range of 2.14 % to 33.61 % against KB, HepG2, HL60, P388, HT29, and MCF7 cancerous cell lines by SRB assay.

Notes on Culturable Endophytic Microorganisms Isolated from 14 Medicinal Plants in Vietnam: A Diversity Analysis to Predict the Host-Microbe Correlations

Endophytes can generate a cornucopia of marvelous bioactive secondary metabolites useful for mankind but their biodiversity and associations with host plants are still elusive. In this study, we explored the culturable endophytic microorganisms associated with 14 medicinal plants that are of high socio-economic value and/or reportedly endemic to northern Vietnam. Specifically, we isolated the endophytic microorganisms by applying surface sterilization methods and identified them based on morphological and rDNA sequence analyses. Agglomerative Hierarchical Clustering (AHC) and Principal Component Analysis (PCA) were used to analyze the correlations between the taxonomic affiliations of the culturable endophytes and the characteristics of their hosts. Most of the culturable endophytes obtained were bacteria (80), and few of those were actinomycetes (15) and fungi (8). Many of them are reported to be endophytes of medicinal plants for the first time. A number of plants (5) are also reported for the first time to contain microbial endophytes, while some plants with powerful pharmaceutical potential harbor unique endophytes. Furthermore, our results reveal a strikingly close relation between the compositions of bacterial and fungal isolates from plants having anti-bacterial activity and those from plants having anti-inflammatory activity, or between the compositions of the microbial endophytic isolates from plants having anti-cancer activity and those from plants having antioxidant activity. Altogether, the results provide new findings which can be inspiring for further in-depth studies to explore and exploit the relationships between medicinal plants and their associated endophytes in northern Vietnam and world-wide.

In vitro antiviral activities of ethanol and aqueous extracts of Vietnamese traditional medicinal plants against Porcine Epidemic Diarrhea virus: a coronavirus family member

Porcine epidemic diarrhea virus (PEDV) causes diarrhea in pigs leading to severe illnesses and high mortality rates. The development of medicinal agents to treat PEDV infection is therefore crucial. In this study, antiviral activities against PEDV of ethanol and aqueous extracts of 17 Vietnamese traditional medicinal plants were evaluated using the cytopathic effect-based assay. The results showed that 14 out of 17 medicinal plants could inhibit the cytopathic effect of PEDV. The ethanol extract of Stixis scandens was identified as the most active extract with its MIC (minimum inhibitory concentration) being 0.15 μg/mL. Other plant extracts also displayed strong antiviral activity against PEDV, including Anisomeles indica, Pericampylus glaucus and Croton kongensis. The results demonstrate that certain medicinal plants have a high antiviral potential and may serve as a lead to develop novel pharmaceutical agents to cure PED as well as the diseases caused by other coronaviruses.

Morpho-Functional Consequences of Swiss Cheese Knockdown in Glia of Drosophila melanogaster

Glia are crucial for the normal development and functioning of the nervous system in many animals. Insects are widely used for studies of glia genetics and physiology. Drosophila melanogaster surface glia (perineurial and subperineurial) form a blood–brain barrier in the central nervous system and blood–nerve barrier in the peripheral nervous system. Under the subperineurial glia layer, in the cortical region of the central nervous system, cortex glia encapsulate neuronal cell bodies, whilst in the peripheral nervous system, wrapping glia ensheath axons of peripheral nerves. Here, we show that the expression of the evolutionarily conserved swiss cheese gene is important in several types of glia. swiss cheese knockdown in subperineurial glia leads to morphological abnormalities of these cells. We found that the number of subperineurial glia nuclei is reduced under swiss cheese knockdown, possibly due to apoptosis. In addition, the downregulation of swiss cheese in wrapping glia causes a loss of its integrity. We reveal transcriptome changes under swiss cheese knockdown in subperineurial glia and in cortex + wrapping glia and show that the downregulation of swiss cheese in these types of glia provokes reactive oxygen species acceleration. These results are accompanied by a decline in animal mobility measured by the negative geotaxis performance assay.

Apoptotic, necrotic, and antiproliferative activity of diosgenin and diosgenin glycosides on cervical cancer cells

(25R)-spirost-5-en-3β-ol, also known as diosgenin (DSG), exerts antiproliferative activity on diverse cell lines, induces apoptosis, and acts as a chemopreventative agent. However, the relationship between DSG glycosides and apoptotic, necrotic, and antiproliferative activity remains unclear. It is in this regard that we report the antiproliferative, necrotic, and apoptotic activities of DSG and its glycoside derivatives: (25R)-spirost-5-en-3β-yl O-β-D-glucopyranoside (3GD), (25R)-spirost-5-en-3β-yl O-α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranoside (3GRD); and (25R)-spirost-5-en-3β-yl O-α-L-rhamnopyranosyl-(1 → 2)-O-[α-L-rhamnopyranosyl-(1 → 4)]-β-D-glucopyranoside), also known as dioscin (DSC), in in vitro assays of cervical HeLa and CaSki cancer cells. The results demonstrated that DSG glycosidic derivatives preserved their antiproliferative activity. However, in both cancer cell lines, 3GD and 3GRD were less potent than DSG, while DSC was more potent than DSG. With respect to necrotic activity, all tested compounds showed no or low activity on the two cervical cancer cell lines. Regarding apoptosis, the results showed that DSG glycosides were better apoptosis-inducers than DSG, suggesting that glucose and rhamnose residues play a central role in enhancing the apoptotic activity of DSG. Finally, DSG and its glycosidic derivatives were shown to affect the proliferative potential of lymphocytes (non-tumour cells) to a lesser extent than cancer cells, suggesting that these compounds have selective action. In conclusion, the results indicate that DSG and its glycosidic derivatives are promising anticancer compounds since they are compounds with low necrotic activity and selective action.

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.

Oleanane-type Saponins from Glochidion hirsutum and Their Cytotoxic Activities

Five new oleanane-type saponins, hirsutosides A - E, were isolated from the leaves of Glochidion hirsutum (Roxb.) Voigt. Their structures were elucidated as 21β-benzoyloxy-3β,16β,23,28-tetrahydroxyolean-12-ene 3-O-β-d-glucopyranoside (1), 21β-benzoyloxy-3β,16β,23,28-tetrahydroxyolean-12-ene 3-O-β-d-glucopyranosyl-(1 → 3)-β-d-glucopyranoside (2), 21β-benzoyloxy-3β,16β,23,28-tetrahydroxyolean-12-ene 3-O-6-acetyl-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucopyranoside (3), 21β-benzoyloxy-3β,16β,23,28-tetrahydroxyolean-12-ene 3-O-β-d-glucopyranosyl-(1 → 3)-〈-l-arabinopyranoside (4), and 21β-benzoyloxy-3β,16β,23-trihydroxyolean-12-ene-28-al 3-O-β-d-glucopyranosyl-(1 → 3)-α-l-arabinopyranoside (5). All isolated compounds were evaluated for cytotoxic activities on four human cancer cell lines, HepG-2, A-549, MCF-7, and SW-626 using the SRB assay. Compounds 1, 2, 4, and 5 showed significant cytotoxic activities against all human cancer cell lines with IC₅₀ values ranging from 3.4 to 10.2 μm. Compound 3 containing acetyl group at glc C(6″) exhibited weak cytotoxic activity with IC₅₀ values ranging from 47.0 to 54.4 μm.

Sesquiterpenes from the Vietnamese Marine Sponge Dysidea Fragilis

Two new sesquiterpenes, named dysinidins A-B (3, 4) along with two known sesquiterpenes, furodysinin lactone (1) and O-methyl furodysinin lactone (2), were isolated from the Vietnamese marine sponge Dysidea fragilis. Their structures were determined by 1D- and 2D-NMR spectroscopies and HR ESI MS, as well as by comparison with reported literature data. None of compounds showed inhibitory growth of human lung cancer cell lines, A-549 and H-1975 (IC50 > 30μM).

Oleanane-type saponins from Glochidion glomerulatum and their cytotoxic activities

Eight oleanane-type saponins, glomerulosides A-H, were isolated from leaves of Glochidion glomerulatum. All isolated compounds were evaluated for cytotoxic activity on four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7. Glomerulosides C and E, which contain a benzoyloxy group at C-22, showed significant cytotoxic activities against the A-549, HT-29, and OVCAR cancer cell lines with IC50 values ranging from 5.9 to 9.8μM. Glomeruloside A showed cytotoxicity on HT-29 and OVCAR cell lines with IC50 values of 7.3 and 6.6μM, respectively. Moreover, glomeruloside B exhibited significant activity on A-549 and HT-29 cancer cell lines with IC50 values of 9.7 and 7.5μM. In contrast, glomerulosides F-H, lacking a benzoyloxy group, showed only moderate cytotoxic activity.

Oleanane-type Triterpene Saponins from Glochidion glomerulatum

Two new oleanane-type triterpene saponins, named glomeruloside I (1) and glomeruloside II (2), were isolated from the leaves of Glochidion glomerulatum (Miq.) Boerl. Their structures were determined by extensive spectroscopic methods, including 1D- and 2D-NMR, MS data, and chemical methods.

Chemical components from the leaves of Ardisia insularis and their cytotoxic activity

One new oleanane triterpene glycoside, ardinsuloside (1), and twelve known compounds, demethoxybergenin (2), norbergenin (3), bergenin (4), 4-O-galloylbergenin (5), quercitrin (6), myricitrin (7), myricetin 3-O-(3''-O-galloyl)-α-L-rhamnopyranoside (8), desmanthine-2 (9), epicatechin 3-O-galloyl ester (10), 3'-methoxyepicatechin 3-O-galloyl ester (11), gallic acid (12), and methyl galloate (13) were isolated from the leaves of Ardisia insularis. Their structures were established on the basis of spectral and chemical evidence, which were in agreement with those reported in literature. The cytotoxic activities of these compounds were evaluated on three cancer cell lines namely A-549 (human lung cancer), HT-29 (Human colon adenocarcinoma), and OVCAR (human ovarian carcinoma). The results revealed that compound 1 inhibited A-549, HT-29, and OVCAR cell lines with IC50 values of 8.5 ± 1.2, 16.4 ± 3.1, and 13.6 ± 2.4 μM, respectively. The remaining compound showed weak cytotoxic activity. This result indicated that compound 1 could be useful in the treatment of cancer disease.

The apoptotic effect of D Rhamnose β-hederin, a novel oleanane-type triterpenoid saponin on breast cancer cells

There is growing interest in development of natural products as anti-cancer and chemopreventive agents. Many triterpenoids have been proved as potential agents for chemoprevention and therapy of breast cancer. Ginsenosides from ginseng, which mostly belong to dammarane-type triterpenoids, have gained great attention for their anti-breast cancer activity with diverse mechanisms. However, studies of other kinds of triterpenoid saponins on breast cancer are limited. Previously, we purified and identified a novel oleanane-type triterpene saponin named D Rhamnose β-hederin (DRβ-H) from Clematis ganpiniana, a Chinese traditional anti-tumor herb. In the present study, DRβ-H showed strong inhibitory activity on the growth of various breast cancer cells and induced apoptosis in these cells. DRβ-H inhibited PI3K/AKT and activated ERK signaling pathway. PI3K inhibitor LY294002 synergistically enhanced DRβ-H-induced apoptosis whereas MEK inhibitor U0126 reduced the apoptosis rate. Moreover, DRβ-H regulated the ratio of pro-apoptotic and anti-apoptotic Bcl-2 family proteins. Furthermore, DRβ-H induced depolarization of mitochondrial membrane potential which released Apaf-1 and Cytochrome C from the inter membrane space into the cytosol, where they promoted caspase-9 and caspase-3 activation. This is the first report on the pro-apoptotic effects of DRβ-H, a novel oleanane-type triterpenoid saponin, on breast cancer cells and its comprehensive apoptosis pathways. It implied that oleanane-type triterpenoid saponin DRβ-H could be a promising candidate for chemotherapy of breast cancer.

Research Progress on Natural Triterpenoid Saponins in the Chemoprevention and Chemotherapy of Cancer

Triterpenoid saponins are glycosides with remarkable structural and bioactive diversity. They are becoming increasingly significant in the treatment of cancer due to their efficacy and safety. This chapter provides an update on the sources, pharmacological effects, structure-activity relationships, and clinical studies of anticancer triterpenoid saponins with a particular focus on the molecular mechanisms underlying their therapeutic properties. The correlative references and study reports described were collected through PubMed. The anticancer triterpenoid saponins enable the inhibition of cancer formation and progression by modulating multiple signaling targets related to cellular proliferation, apoptosis, autophagy, metastasis, angiogenesis, inflammation, oxidative stress, multidrug resistance, cancer stem cells, and microRNAs. This review provides new insights into the molecular basis of triterpenoid saponins in the chemoprevention and chemotherapy of cancer.