Cryptobuchanosides A-G: seven previously undescribed triterpene glycosides from Cryptolepis buchananii R.Br. ex Roem. and Schult. with nitric oxide production inhibition activity

In this study, nine triterpene glycosides including seven previously undescribed compounds (1-7), were isolated from leaves of Cryptolepis buchananii R.Br. ex Roem. and Schult. using various chromatographic methods. The chemical structures of the compounds were elucidated to be 3-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (1), 3-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (2), 3-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosyluncargenin C 28-O-β-D-glucopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (3), 3-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosylhederagenin 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (4), 3-O-β-D-glucopyranosylarjunolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (5), 3-O-β-D-glucopyranosyl-(1 → 2)-β- D-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (6), 3-O-β-D-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (7), asiatic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (8), and 3-O-β-D-glucopyranosylasiatic acid 28-O-α-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl ester (9), through infrared, high-resolution electrospray ionization mass spectrometry, one- and two-dimensional nuclear magnetic resonance spectral analyses. The isolates inhibited nitric oxide production in lipopolysaccharide-activated RAW 264.7 cells, with half-maximal inhibitory concentration (IC50) values of 18.8-58.5 µM, compared to the positive control compound, dexamethasone, which exhibited an IC50 of 14.1 µM.

Four New Pentacyclic Triterpene Glycosides Isolated from the Fruits of Cryptolepis buchananii R.Br. ex Roem. & Schult and Their Inhibition of NO Production in LPS-activated RAW264.7 Cells

From the methanol extract of the Cryptolepis buchananii fruits, four undescribed pentacyclic triterpenene glycosides (1-4) and five known pentacyclic triterpenenes (5-9) were isolated. Their structures were determined to be uncargenin C 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (1), 3-O-β-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (2), 3-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (3), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosylasiatic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (4), asiatic acid (5), 2α,3β,23-trihydroxyoleana-11,13(18)-dien-28-oic acid (6), arjunolic acid (7), 6β-hydroxyarjunolic acid (8), and actinidic acid (9) based on analyses of their HR-ESI-MS, 1D and 2D NMR spectra. All the isolates showed significantly NO production inhibition in LPS-activated RAW264.7 cells with the IC50 values ranging from 18.79 to 37.57 μM, compared to that of the positive control compound, dexamethasone, which showed IC50 value of 14.05 μM.

Alkaloids and Iridoids From the Aerial Parts of Rauvolfia cambodiana Pierre ex Pit. and Their Acetylcholinesterase Inhibitory Activity

Objective: Rauvolfia cambodiana has been used as a Vietnamese folk medicine to treat high blood pressure and for sedation and memory loss diseases. However, to date, there have been few studies on the chemical constituents and biological activity of this medicinal plant. This study aimed to find the chemical constituents of R cambodiana and evaluate their enhancement memory properties. Methods: The aerial parts of R cambodiana were powdered and ultrasonically extracted with methanol. The methanol extract was suspended in water and successively partitioned with dichloromethane and ethyl acetate to give dichloromethane, ethyl acetate, and water-soluble extracts. Each extract was fractionated and purified by column and HPLC chromatographic methods. The chemical structures of the isolated compounds were elucidated by analysis of HRESIMS, 1D and 2D NMR spectra, and experimental and TD-DFT calculated ECD spectra. The enhancement memory property of the compounds was evaluated by their in vitro acetylcholinesterase inhibitory activity. Results: Five alkaloids (1-5) and 2 iridoids (6 and 7), including one new one named rauvolcambonine (1), and 6 known compounds, perakine (2), ajmaline (3), 10-hydroxy-16- epi-affinine (4), sitsirikine (5), loganic acid (6), and secoxyloganin (7) were isolated and identified from the aerial parts of R cambodiana. Compounds 4 and 5 significantly showed acetylcholinesterase inhibitory effects in vitro with IC50 values of 30.1 ± 1.4 µM and 65.5 ± 3.3 µM, respectively. The other compounds inhibited acetylcholinesterase with IC50 values ranging from 111.0 ± 6.0 µM to 197.6 ± 19.8 µM. Conclusion: One new (1) and 3 other compounds (2, 4-7) were recorded from R cambodiana for the first time. The NMR spectroscopic data of compound 4 are reported herein for the first time. Our study preliminarily revealed that the vobasenal framework type alkaloids could be active ingredients of Rauvolfia species and responsibility for the enhancement memory property of these plants.

Strychnovanosides A - C, Three New Lignan Glycosides from Strychnos vanprukii

Phytochemical study of the methanolic extract of the stems and leaves of Strychnos vanprukii led to the isolation of three new (1-3) and four known (4-7) compounds. Their chemical structures were elucidated to be (+)-lyoniresinol 3 α-O- β-D-allopyranoside (1), (-)-lyoniresinol 3 α-O- β-D-allopyranoside (2), 2 α-[(3,5-dimethoxy-4-hydroxy)-benzoyl]-(-)-lyoniresinol-3 α-O- β-D-glucopyranoside (3), (+)-lyoniresinol 3 α-O- β-D-glucopyranoside (4), (-)-lyoniresinol 3 α-O- β-D-glucopyranoside (5), palicoside (6), and rutin (7) by means of detailed HR-ESI-MS, 1D and 2D NMR spectroscopic analysis. In addition, the absolute configurations of 1–3 were determined by experimental Circular Dichroism (CD) spectra. This is the first report of compounds 5 and 7 from S. vanprukii. Compounds 1 - 7 showed inhibitory effects on NO production in LPS stimulated RAW 264.7 cells with IC50 values of 58.50 ± 2.30, 67.70 ± 2.23, 54.44 ± 1.26, 71.58 ± 3.59, 74.47 ± 2.61, 83.62 ± 2.25, and 47.57 ± 4.01 µM, respectively, compared to a value of 43.24 ± 2.41 µM for the positive control compound, NG-monomethyl-L-arginine (L-NMMA).

Cytotoxic and nitric oxide inhibitory activities of triterpenoids from Lycopodium clavatum L

Using combined chromatographic separation techniques, three new triterpenoids named lycomclavatols A-C (1-3), a new natural product, methyl lycernuate-A (4), as well as seven known compounds (5-11), were isolated from the methanol extract of the whole plants of Lycopodium clavatum. Their chemical structures were established based on 1 D/2D NMR and HR-ESI-MS spectroscopic analyses. Among the isolates, compound 1 exhibited inhibitory activity on NO production in LPS-stimulated BV2 cells (IC₅₀ = 36.0 μM). In addition, 1 was cytotoxic against both HepG2 and A549 cancer cell lines, with IC₅₀ values of 40.7 and 87.0 μM, respectively. Compounds 10 and 11 showed cytotoxicity on only HepG2 and A549 cells, with IC₅₀ values of 91.2 and 57.6 μM, respectively. Our results contribute to understanding more the secondary metabolites produced by L. clavatum and provide a scientific rationale for further investigations of anti-inflammatory and anticancer effects for this valuable medicinal plant.

Chemical constituents from Lycopodiella cernua and their anti-inflammatory and cytotoxic activities

Phytochemical investigation of the whole plants of Lycopodiella cernua resulted in the isolation and identification of three new compounds (1-3), namely lycocernuaside E (1), lycernuic ketone F (2), and lycernuic B (3) and 12 known ones (4-15). Their chemical structures were established based on 1 D/2D NMR spectroscopic and HR-ESI-MS data analyses. Compounds 5, 12, and 13 displayed NO inhibitory effects in LPS-stimulated BV2 cells, with IC₅₀ values of 21.2 ± 1.1, 28.5 ± 1.4, and 21.9 ± 1.1 µM, respectively. In addition, cytotoxic activity of the isolated compounds against MCF7 (breast carcinoma), HepG2 (hepatocarcinoma), and SK-Mel2 (melanoma) cancer cell lines were also reported.

Development of a Cell Suspension Culture System for Promoting Alkaloid and Vinca Alkaloid Biosynthesis Using Endophytic Fungi Isolated from Local Catharanthus roseus

Cell and tissue cultures of Catharanthus roseus have been studied extensively as an alternative strategy to improve the production of valuable secondary metabolites. The purpose of this study was to produce C. roseus callus and suspension cell biomass of good quality and quantity to improve the total alkaloids and bis-indole alkaloids. The young stem derived-callus of C. roseus variety Quang Ninh (QN) was grown on MS medium supplemented with 1.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) plus 1.5 mg/L kinetin, and the growth rate increased by 67-fold after 20 days. The optimal conditions for maintaining the cell suspension culture were 150 mg/50 mL cell inoculum, a medium pH of 5.5 and a culture temperature of 25 °C. The low alkaloid content in the culture was compensated for by using endophytic fungi isolated from local C. roseus. Cell extracts of endophytic fungi—identified as Fusarium solani RN1 and Chaetomium funicola RN3—were found to significantly promote alkaloid accumulation. This elicitation also stimulated the accumulation of a tested bis-indole alkaloid, vinblastine. The findings are important for investigating the effects of fungal elicitors on the biosynthesis of vinblastine and vincristine, as well as other terpenoid indole alkaloids (TIAs), in C. roseus QN cell suspension cultures.

New Truxinic and Truxillic Acid Sucrose Diesters From the Leaves of Trigonostemon honbaensis

A new δ-truxinic acid sucrose diester and a new ε-truxillic acid sucrose diester (named trigohonbanosides E and F) were isolated from the leaves of Trigonostemon honbaensis. Their chemical structures were determined by extensive analysis of their HR-ESI-MS and NMR spectra. At a concentration of 20 µM, trigohonbanosides E and F exhibited weak inhibitory effects on NO production in LPS-activated RAW264.7 cells with inhibitory percentages of 22.7% ± 1.1% and 18.5% ± 1.4%, respectively.

New 3,4-seco-diterpene and coumarin derivative from the leaves of Trigonostemon flavidus Gagnep

Two new compounds named trigoflavidus A (1) and trigoflavidus B (2), and eight known compounds, trigoflavidone (3), heterophypene (4), howpene C (5), 3,4-seco-sonderianol (6), trigonochinene C (7), fraxidin (8), isofraxidin (9), and isofraxetin (10) were isolated from the leaves of Trigonostemon flavidus Gagnep. by various chromatographic methods. Their chemical structures were elucidated via UV, IR, HR-ESI-MS and NMR spectroscopic methods and divided into two groups including six 3,4-seco-diterpenes (1, 3-7) and four coumarins (2, 8-10). Absolute configurations at stereocenters of compound 1 were confirmed by comparison of its CD spectra with those of the TD-DFT calculations. At a concentration of 30 µM, compounds 1-10 exhibited weak cytotoxic activity toward LU1, HepG2, MCF7, and SKMel2 human cell lines (cell viability all over 50%).

Transcriptome sequencing and identification of cytochrome P450 monooxygenases involved in the biosynthesis of maslinic acid and corosolic acid in Avicennia marina

Grey mangrove (Avicennia marina) is a traditional medicine used for the treatment of various diseases, including rheumatism and ulcers; however, the compounds responsible for its curative effects remain largely unknown. Triterpenoids are a diverse group of plant-specialized metabolites derived from a common precursor, 2,3-oxidosqualene. Triterpenoids are potentially responsible for the beneficial effects of A. marina; however, the chemical profiles of triterpenoids in A. marina and their biosynthetic genes have not been identified. Cytochrome P450 monooxygenases (P450s) have key roles in the structural diversification of plant triterpenoids by catalyzing site-specific oxidation of triterpene scaffolds. Recent studies have revealed that the CYP716 family represents the most common clade of P450s involved in triterpenoid biosynthesis. In this study, we performed triterpenoid profiling and RNA sequencing of A. marina leaves. Mining of CYP716 family genes and enzymatic activity assays of encoded proteins revealed that CYP716A259 catalyzed oxidation at the C-28 position of the pentacyclic triterpene skeletons of β-amyrin, α-amyrin, and lupeol to produce oleanolic acid, ursolic acid, and betulinic acid, respectively. The other functionally defined P450, CYP716C53, catalyzed the C-2α hydroxylation of oleanolic acid and ursolic acid to produce maslinic acid and corosolic acid, respectively. The possible involvement of CYP716A259 and CYP716C53 in the biosynthesis of these health-benefiting compounds in A. marina leaves, and the possible contribution of the resulting compounds to the reported bioactivities of A. marina leaf extract, are discussed.

Chemical Constituents of Vitex trifolia Leaves

Using various chromatographic methods, one new lanostane triterpene, 3 α-hydroxylanosta-8,24 E-dien-26-oic acid (1), one new lignan, matairesinol 4'- O-β-D-glucopyranoside (2) along with five known compounds, ecdysone (3), 20-hydroxyecdysone (4), 20-hydroxyecdysone 2,3-monoacetonide (5), turkesterone (6), and polypodine B (7) were isolated from the leaves of Vitex trifolia L. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, CD, and by comparing with the NMR data reported in the literature.

A New Cycloartane Glucoside from Rhizophora stylosa

Nine secondary metabolites, including a new cycloartane glucoside, rhizostyloside (1), were isolated from a methanol extract of Rhizophora stylosa leaves through several chromatographic experiments. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and HR-ESI-MS data and by comparison with literature values. Compound 1 exhibited significant cytotoxicity against three human cancer cell lines: KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), and SK-Mel-2 (melanoma). In addition, 1 strongly activated caspase-3/7 in LU-1 cells.

A new cycloartane glucoside from Rhizophora stylosa

Nine secondary metabolites, including a new cycloartane glucoside, rhizostyloside (1), were isolated from a methanol extract of Rhizophora stylosa leaves through several chromatographic experiments. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and HR-ESI-MS data and by comparison with literature values. Compound 1 exhibited significant cytotoxicity against three human cancer cell lines: KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), and SK-Mel-2 (melanoma). In addition, 1 strongly activated caspase-3/7 in LU-1 cells.

Two novel iridoids from Morinda longifolia

Six secondary metabolites, including two novel iridoids, longifolides A (1) and B (2), were isolated by various chromatographic methods from a methanol extract of branches and leaves of Morinda longifolia Craib. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and FTICR-MS data, as well as by comparison of them with literature values.

Two Novel Iridoids from Morinda longifolia

Six secondary metabolites, including two novel iridoids, longifolides A (1) and B (2), were isolated by various chromatographic methods from a methanol extract of branches and leaves of Morinda longifolia Craib. The structures of the compounds were determined on the basis of NMR spectroscopic (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY) and FTICR-MS data, as well as by comparison of them with literature values.

Cucurbitane-type triterpene glycosides from the fruits of Momordica charantia

Four new cucurbitane-type triterpene glycosides, charantosides D-G (1-4) were isolated from a methanol extract of Momordica charantia fruits. The structures of these compounds were determined by chemical and spectroscopic methods to be (19R)-5 beta,19-epoxy-25-methoxycucurbita-6,23-diene-3 beta,19-diol 3-O-beta-D-glucopyranoside, (19R)-5 beta, 19-epoxy-25-methoxycucurbita-6,23-diene-3 beta,19-diol 3-O-beta-D-allopyranoside, 7 beta-methoxycucurbita-5,23E,25-triene-3 beta-ol 3-O-beta-D-allopyranoside, and 3 beta,7 beta-dihydroxycucurbita-5,23E,25-triene- 19-al 3-O-beta-D-allopyranoside.

Cucurbitane-type Triterpene Glycosides from the Fruits of Momordica charantia

Four new cucurbitane- type triterpene glycosides, charantosides D-G (1–4) were isolated from a methanol extract of Momordica charantia fruits. The structures of these compounds were determined by chemical and spectroscopic methods to be (19 R)-5 β,19-epoxy-25-methoxycucurbita-6,23-diene-3 β,19-diol 3- O-β-D-glucopyranoside, (19 R)-5 β,19-epoxy-25-methoxycucurbita-6,23-diene-3 β,19-diol 3- O-β-D-allopyranoside, 7 β-methoxycucurbita-5,23 E,25-triene-3 β-ol 3- O-β-D-allopyranoside, and 3 β,7 β-dihydroxycucurbita-5,23 E,25-triene-19-al 3- O-β-D-allopyranoside.

Chemical constituents and antioxidant activity of Ficus callosa

One new megastigmane glycoside, ficalloside (1), and eleven known compounds, were isolated from methanol extract of Ficus callosa leaves by repeated column chromatography. Their structures were established on the basis of spectral and chemical evidence. The antioxidant activities of these compounds were measured using the oxygen radical absorbance capacity (ORAC) assay. Compound 8 exhibited potent antioxidant activity of 10.6 microM trolox equivalents at the concentration of 2 microM. At this concentration, compounds 4-7 and 9-12 showed significant antioxidant activity with ranging of 2.1-6.1 microM trolox equivalents.

Chemical Constituents and Antioxidant Activity of Ficus callosa

One new megastigmane glycoside, ficalloside (1), and eleven known compounds, were isolated from methanol extract of Ficus callosa leaves by repeated column chromatography. Their structures were established on the basis of spectral and chemical evidence. The antioxidant activities of these compounds were measured using the oxygen radical absorbance capacity (ORAC) assay. Compound 8 exhibited potent antioxidant activity of 10.6 μM trolox equivalents at the concentration of 2 μM. At this concentration, compounds 4-7 and 9-12 showed significant antioxidant activity with ranging of 2.1~6.1 μM trolox equivalents.

Inhibitors of osteoclast formation from rhizomes of Cibotium barometz

Eight compounds (1-8) were isolated from a methanol extract of Cibotium barometz rhizomes including two new furan derivatives, cibotiumbarosides A (1) and B (2), and a new glycoglycerolipid, cibotiglycerol (4). Their structures were elucidated by chemical and spectroscopic methods. Compounds 2-5 each showed inhibition of osteoclast formation with no affect on BMM cell viability.

Unusual 22S-spirostane Steroids from Dracaena cambodiana

From the methanol extract of Dracaena cambodiana roots two unusual 22S-spirostane steroids (1β,3β,14α,20R,22S,25R)-spirost-5-ene-1,3, 14-triol (1) and (1β,3β,14α,15α,20R,22S,25R)-spirost-5-ene-tetrol (2) have been isolated, together with a known 22R-spirostane compound, namogenin B (3). Their structures were elucidated by spectroscopic and spectrometric methods, including HRMS and extensive 1D and 2D NMR spectroscopy. Compound 1 showed significant antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Fusarium oxysporum, with MIC values of 45.0, 25.0 and 50.0 μg/mL, respectively.

Dibenzocyclooctadiene lignans and lanostane derivatives from the roots of Kadsura coccinea and their protective effects on primary rat hepatocyte injury induced by t-butyl hydroperoxide

A new dibenzocyclooctadiene lignan, acetylepigomisin R ( 1), and a new 3,4-seco-lanostane-type triterpene, seco-coccinic acid F ( 2), along with three known dibenzocyclooctadiene lignans, isovaleroylbinankadsurin A ( 3), kadsuralignan J ( 4), and binankadsurin A ( 5), and one lanostane-type triterpene, 20( R),24( E)-3-oxo-9 beta-lanosta-7,24-dien-26-oic acid ( 6), were isolated from the methanol extract of the Kadsura coccinea roots. Their structures were elucidated on the basis of spectroscopic evidence including ESI-MS, HR-EI-MS, 1D and 2D NMR. The protective effects of these compounds were evaluated in primary cultured rat hepatocytes intoxicated with 1.2 mM T-butyl hydroperoxide. Compounds 1, 3, and 5 showed protective effects with ED (50) values of 135.7, 26.1, and 79.3 microM, respectively.

Unusual 22S-spirostane steroids from Dracaena cambodiana

From the methanol extract of Dracaena cambodiana roots two unusual 22S-spirostane steroids (1beta,3beta,14alpha,20R,22S,25R)-spirost-5-ene-1,3,14-triol (1) and (lbeta,3beta,14alpha,15alpha,20R,22S,25R)-spirost-5-ene-tetrol (2) have been isolated, together with a known 22R-spirostane compound, namogenin B (3). Their structures were elucidated by spectroscopic and spectrometric methods, including HRMS and extensive 1D and 2D NMR spectroscopy. Compound 1 showed significant antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Fusarium oxysporum, with MIC values of 45.0, 25.0 and 50.0 microg/mL, respectively.