Dammarane triterpenoids with rare skeletons from Gynostemma pentaphyllum and their cytotoxic activities.

Three unreported dammarane-type triterpenoids with rare skeletons (1-3), along with one undescribed gypenoside (4), were isolated from the aerial parts of Gynostemma pentaphyllum using diverse chromatographic materials and pre-HPLC. Their structures were elucidated on the basis of spectroscopic and spectrometric data, while the absolute configurations of 1-3 were assessed via electronic circular dichroism (ECD) analyses. Notably, compounds 1-3 possess a 3,19-hemiketal bridge in the A ring.

Melicopteline A-E, Unusual Cyclopeptide Alkaloids with Antiviral Activity against Influenza A Virus from .

In the search for antiviral cyclopeptides against influenza A virus, five unprecedented Caryophyllaceae-type cyclopeptides (-) were isolated from the leaves of . Their chemical structures and absolute configurations were unambiguously determined by means of advanced Marfey's analysis and comprehensive spectroscopic analyses including two-dimensional nuclear magnetic resonance and MS/MS fragmentation. Interestingly, compounds - contain an unusual heterocycle, a 3a-hydroxypyrroloindole moiety, which was biosynthetically formed by a nucleophilic cyclization from the least abundant amino acid, tryptophan, precursor and has aroused a great interest in the aspect of chemical diversity and biological activity.

Triterpenoids from the genus Gynostemma: Chemistry and pharmacological activities.

Ethnopharmacological Relevance: G. pentaphyllum, also known as Jiao-Gu-Lan, has been used traditionally as folk remedies for many diseases, including diabetes mellitus, metabolic syndrome, aging, and neurodegenerative diseases in China and some countries in East and Southeast Asia. It is considered as an "immortality herb" in Guizhou Province, because it was consumed regularly by the elderly native inhabitants.

Neuroprotective Effects of Triterpenoids from against Amyloid β-Induced Neuronal Damage.

Alzheimer's disease (AD), a neurocognitive impairment affecting human mental capacity, is related to the accumulation of amyloid-β peptide (Aβ) and the hyperphosphorylation of tau protein. In addition to modern therapies approved for AD treatment, natural products with antioxidant and anti-inflammatory properties have been studied for their potential to prevent AD pathogenesis. Six new noroleanane triterpenoids from the fruit peels of were isolated, and their structures were determined by diverse spectroscopic methods.

Antiviral activity of furanocoumarins isolated from Angelica dahurica against influenza a viruses H1N1 and H9N2.

Ethnopharmacological Relevance: Angelica dahurica (Hoffm.) Benth. & Hook.

Antiviral Activities of Compounds Isolated from (Pine Tree) against the Influenza A Virus.

was screened in an ongoing project to discover anti-influenza candidates from natural products. An extensive phytochemical investigation provided 26 compounds, including two new megastigmane glycosides ( and ), 21 diterpenoids (), and three flavonoids (). The chemical structures were elucidated by a series of chemical reactions, including modified Mosher's analysis and various spectroscopic measurements such as LC/MS and 1D- and 2D-NMR.

Constituents of the Edible Leaves of with Potential Analgesic Activity.

has long been consumed as a popular vegetable and tea in Southeast Asian countries, including Malaysia and southern mainland China, and is effective in the treatment of colds and inflammation. In the search for active metabolites that can explain its traditional use as an antipyretic, six new phloroacetophenone derivatives (-) along with seven known compounds (, , and -) were isolated from the leaves of . Their chemical structures were confirmed by extensive spectroscopic analysis including NMR, IR, ECD, and HRMS.

Oligostilbenes from the leaves of Gnetum latifolium and their biological potential to inhibit neuroinflammation.

Oligostilbenes are polyphenol oligomers derived from resveratrol and are commonly produced by members of the Gnetaceae family, and many researchers have focused on their anti-inflammatory activities. The EtOAc fraction of a Gnetum latifolium extract showed inhibitory activity against neuroinflammation induced by the transfection of Aβ into microglial BV-2 cells. The bioassay-guided isolation of the 70% EtOH extract of this plant resulted in three previously undescribed resveratrol oligostilbenes and ten known stilbene derivatives.

Eudesmane Glycosides from Ambrosia artemisiifolia (Common Ragweed) as Potential Neuroprotective Agents.

In Alzheimer's disease, amyloid-β (Aβ) accumulation in the brain results in neuronal cell death and is one of the major causes of dementia. Because the current therapeutic agents are not yet sufficiently effective or safe, there have been attempts to find new neuroprotective chemicals against Aβ-induced cytotoxicity. A 70% EtOH extract of whole plants of Ambrosia artemisiifolia (common ragweed) was selected after the screening of a natural extract library.

Prenylated Phenolic Compounds from the Leaves of Sabia limoniacea and Their Antiviral Activities against Porcine Epidemic Diarrhea Virus.

Porcine epidemic diarrhea virus (PEDV), a serious swine epidemic, has been rampant in Asia since the 1990s. Despite the widespread use of PEDV vaccines, the occurrence of PEDV variants requires the discovery of new substances that inhibit these viruses. During a search for PEDV inhibitory materials from natural sources, seven new sabphenosides (1-7) and a new flavonoid (8), as well as eight known phenolic compounds (9-16), were obtained from the leaves of Sabia limoniacea.

Dereplication by High-Performance Liquid Chromatography (HPLC) with Quadrupole-Time-of-Flight Mass Spectroscopy (qTOF-MS) and Antiviral Activities of Phlorotannins from .

is edible seaweed that is found in Asian countries, such as Japan and Korea; and, its major components include fucoidan and phlorotannins. Phlorotannins that are isolated from are well-known to have an antioxidant effect and strong antiviral activity against porcine epidemic diarrhea virus (PEDV), which has a high mortality rate in piglets. In this study, the bioactive components were determined based on two different approaches: (i) bio-guided isolation using the antiviral activity against the H1N1 viral strain, which is a representative influenza virus that originates from swine and (ii) high-resolution mass spectrometry-based dereplication, including relative mass defects (RMDs) and HPLC-qTOFMS fragmentation analysis.

Hydroxyoleoside-type seco-iridoids from Symplocos cochinchinensis and their insulin mimetic activity.

As part of an ongoing study of new insulin mimetic agents from medicinal plants, the 70% EtOH extract of Symplocos cochinchinensis was found to have a stimulatory effect on glucose uptake in 3T3-L1 adipocyte cells. The intensive targeted isolation of this active extract resulted in ten new hydroxyoleoside-type compounds conjugated with a phenolic acid and monoterpene (1-6 and 8-11), as well as four known compounds (7 and 12-14). The chemical structures of the new compounds were determined based on spectroscopic data analysis (H and C NMR, HSQC, HMBC, NOESY and MS).

12,23-Dione dammarane triterpenes from Gynostemma longipes and their muscle cell proliferation activities via activation of the AMPK pathway.

The aging population is growing rapidly around the world and there is also an increase in sarcopenia, which is characterized by decreased muscle mass, strength and function in the elderly population. AMP-activated protein kinase (AMPK) is an essential sensor and regulator of glucose, lipid and energy metabolism throughout the body. Previous studies have shown that AMPK pathway activation by regular exercise and appropriate dietary control have beneficial effects on skeletal muscle.

Insulin Mimetic Activity of 3,4- Seco and Hexanordammarane Triterpenoids Isolated from Gynostemma longipes.

As part of ongoing research to find new antidiabetic agents from medicinal plants, the chemical composition of Gynostemma longipes, an ethnomedicinal plant used to treat type 2 diabetes mellitus by local communities in Vietnam, was investigated. Ten new dammarane triterpenes, including two 3,4- seco-dammarane analogues, secolongipegenins S1 and S2 (1 and 2), a 3,4- seco-hexanordammarane, secolongipegenin S3 (3), two hexanordammarane glycosides, longipenosides ND1 and ND2 (4 and 5), and five other dammarane glycosides, longipenosides GL1-GL5 (6-10), were isolated from a 70% EtOH extract of the whole G. longipes plant.

Flavone glycosides from Sicyos angulatus and their inhibitory effects on hepatic lipid accumulation.

A library of extracted natural materials (Korea Bioactive Natural Material Bank) have been screened to discover candidates for the treatment of non-alcoholic liver disease (NAFLD), and the 70% ethanol extract of Sicyos angulatus was found to inhibit hepatic lipid accumulation. Bioassay-guided fractionation of this bioactive extract yielded five previously undescribed flavonoid glycosides and one previously undescribed flavonolignan glycoside along with seven known flavonoid glycosides. The chemical structures of these compounds were elucidated by a combination of extensive spectroscopic analysis, including MS, NMR and UV techniques.

Hypoglycemic triterpenes from Gynostemma pentaphyllum.

To search for bioactive gypenosides and their analogues, a saponin enriched fraction and its hydrolyzate from Gynostemma pentaphyllum were phytochemically investigated. Fractionation by diverse chromatographic methods, including HPLC, Sephadex LH-20, silica gel, and C18 reverse phase silica gel, led to the isolation and purification of twelve triterpenes, including five undescribed and seven known. The chemical structures of all compounds were determined as analyzed by nuclear magnetic resonance (NMR), high resolution mass spectrometry (HR-MS), infrared spectrum (IR), optical rotation, and chemical transformations.

Discrimination of different geographic varieties of Gymnema sylvestre, an anti-sweet plant used for the treatment of type 2 diabetes.

Gymnema sylvestre (Retz.) R.Br.

Polyoxygenated Steroids from the Sponge Clathria gombawuiensis.

Six new polyoxygenated steroids (1-6) along with clathriol (7) were isolated from the Korean marine sponge Clathria gombawuiensis. Based upon the results of combined spectroscopic analyses, the structures of gombasterols A-F (1-6) were elucidated to be those of highly oxygenated steroids possessing a 3β,4α,6α,7β-tetrahydroxy or equivalent (7β-sodium O-sulfonato for 3) substitution pattern and a C-15 keto group as common structural motifs. The relative and absolute configurations of these steroids, including the rare 14β configuration of 1-4, were determined by a combination of NOESY, J-based analyses, the 2-methoxy-2-(trifluoromethyl)phenylacetic acid (MTPA) method, and X-ray crystallographic analysis.

C-Methylated Flavonoid Glycosides from Pentarhizidium orientale Rhizomes and Their Inhibitory Effects on the H1N1 Influenza Virus.

Thirteen C-methylated flavonoid glycosides (1-13), along with 15 previously known flavonoids (14-28), were isolated from rhizomes of Pentarhizidium orientale. Among these compounds, matteuorienates D-K (1-8) were obtained as analogues of matteuorienates A-C (14-16), which contain a characteristic 3-hydroxy-3-methylglutaryl (HMG) moiety. The structures of 1-13 were characterized by spectroscopic analysis and chemical derivatization.

PTP1B inhibitors from the seeds of Iris sanguinea and their insulin mimetic activities via AMPK and ACC phosphorylation.

To find PTP1B inhibitors from natural products, two new compounds (1 and 2), along with nine known compounds (3-11), were isolated from a methanol-soluble extract of Iris sanguinea seeds. The structures of compounds 1 and 2 were determined based on extensive spectroscopic data analysis including UV, IR, NMR, and MS. The IC value of compound 5 on protein tyrosine phosphatase 1B (PTP1B) inhibitory activity is 7.

Antiviral escin derivatives from the seeds of Aesculus turbinata Blume (Japanese horse chestnut).

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and high fatality of piglets, influencing the swine industry. Japanese horse chestnut (seed of Aesculus turbinata) contains many saponin mixtures, called escins, and has been used for a long time as a traditional medicinal plant. Structure-activity relationship (SAR) studies on escins have revealed that acylations at C-21 and C-22 with angeloyl or tigloyl groups were important for their cytotoxic effects.

Anti-influenza effect of the major flavonoids from Salvia plebeia R.Br. via inhibition of influenza H1N1 virus neuraminidase.

To determine the compounds responsible for its anti-influenza activities, we isolated the three flavonoids, 6-hydroxyluteolin 7-O-β-d-glucoside (1), nepitrin (2), homoplantaginin (3) from the MeOH extract of Salvia plebeia R.Br. and identified them by comparing the spectroscopic data with that reported in the literature.

Sesquiterpenoids with Various Carbocyclic Skeletons from the Flowers of Chrysanthemum indicum.

A phytochemical investigation of the flowers of Chrysanthemum indicum yielded sesquiterpenoids 1-25 with various carbocyclic skeletons, including 10 new (1-10) and 15 known (11-25) analogues. The structures were elucidated via their physical data, while the absolute configuration of compounds 6, 8, and 10 was assessed via electronic circular dichroism analysis. The evaluation of the effect of sesquiterpenoids on porcine epidemic diarrhea virus (PEDV) replication showed that compounds 1-5, 12, 14, 16, 17, 19, and 21 increased cell viability against cell death in PEDV-injected cells.

Anthraquinones from Morinda longissima and their insulin mimetic activities via AMP-activated protein kinase (AMPK) activation.

AMP-activated protein kinase (AMPK) activators are known to increase energy metabolism and to reduce body weight, as well as to improve glucose uptake. During for searching AMPK activators, a new anthraquinone, modasima A (10), along with eighteen known analogues (1-9 and 11-19) were isolated from an ethanol extract of the roots of Morinda longissima Y. Z.

Antiviral activities of compounds from aerial parts of Salvia plebeia R. Br.

Ethnopharmacological Relevance: Salvia plebeia R. Br. is an edible plant widely spread in many countries.