Cytotoxic constituents from the fruit of Solanum aculeastrum.

A new triterpene, aculeastrumone A (1), a new triterpene saponin aculeastrumoside A (2), and eleven known compounds (3-13) were isolated from MeOH/Water (80/20) extract of the fruits of Solanum aculeastrum (Solanaceae). Their structures were established by detailed 1D and 2D NMR spectroscopic studies and mass spectrometry. The isolated compounds were evaluated against three human cancer cells ((MCF-7 (breast cancer), NCI-H460 (lung cancer), and Hela (cervical cancer)) and normal human fibroblast (BJ) cell lines. Among them, saponins 2-5, 7-8, and Carpesterol 10 possess significant cytotoxic activity with IC50 ≤ 10 µM against the three cancer cell lines.

Schweinfurthiamide, a new alkaloid isolated from the tuber roots of Asparagus flagellaris Baker (Liliaceae).

The phytochemical investigations of the tuber roots of Asparagus flagellaris led to the isolation of a new alkaloid, schweinfurthiamide (1) and eight known compounds. The structures of the isolated compounds were elucidated using spectroscopic techniques 1D and 2D NMR (1H, 13C, COSY, HMBC, HMQC, HSQC-TOCSY). The absolute configuration of 1 was unambiguously determined using DP4+ calculations. Compound 1 showed significant cytotoxicity against MCF-7 (breast cancer), NCI-H460 (lung cancer), and Hela (cervical cancer) cancer cell lines with IC50 values of 1.18 ± 0.02 µM, 2.25 ± 0.19 µM, and 4.23 ± 0.26 µM, respectively and no toxicity against normal human fibroblast (BJ).

In Vitro and In Silico Evaluation of Anticholinesterase and Antidiabetic Effects of Furanolabdanes and Other Constituents from Graptophyllum pictum (Linn.) Griffith.

Graptophyllum pictum is a tropical plant noticeable for its variegated leaves and exploited for various medicinal purposes. In this study, seven compounds, including three furanolabdane diterpenoids, i.e., Hypopurin E, Hypopurin A and Hypopurin B, as well as with Lupeol, ß-sitosterol 3-O-ß-d-glucopyranoside, stigmasterol 3-O-ß-d-glucopyranoside and a mixture of ß-sitosterol and stigmasterol, were isolated from G. pictum, and their structures were deduced from ESI-TOF-MS, HR-ESI-TOF-MS, 1D and 2D NMR experiments. The compounds were evaluated for their anticholinesterase activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BchE), as well as their antidiabetic potential through inhibition of α-glucosidase and α-amylase. For AChE inhibition, no sample had IC50 within tested concentrations, though the most potent was Hypopurin A, which had a percentage inhibition of 40.18 ± 0.75%, compared to 85.91 ± 0.58% for galantamine, at 100 µg/mL. BChE was more susceptible to the leaves extract (IC50 = 58.21 ± 0.65 µg/mL), stem extract (IC50 = 67.05 ± 0.82 µg/mL), Hypopurin A (IC50 = 58.00 ± 0.90 µg/mL), Hypopurin B (IC50 = 67.05 ± 0.92 µg/mL) and Hypopurin E (IC50 = 86.90 ± 0.76 µg/mL). In the antidiabetic assay, the furanolabdane diterpenoids, lupeol and the extracts had moderate to good activities. Against α-glucosidase, lupeol, Hypopurin E, Hypopurin A and Hypopurin B had appreciable activities but the leaves (IC50 = 48.90 ± 0.17 µg/mL) and stem (IC50 = 45.61 ± 0.56 µg/mL) extracts were more active than the pure compounds. In the α-amylase assay, stem extract (IC50 = 64.47 ± 0.78 µg/mL), Hypopurin A (IC50 = 60.68 ± 0.55 µg/mL) and Hypopurin B (IC50 = 69.51 ± 1.30 µg/mL) had moderate activities compared to the standard acarbose (IC50 = 32.25 ± 0.36 µg/mL). Molecular docking was performed to determine the binding modes and free binding energies of Hypopurin E, Hypopurin A and Hypopurin B in relation to the enzymes and decipher the structure-activity relationship. The results indicated that G. pictum and its compounds could, in general, be used in the development of therapies for Alzheimer's disease and diabetes.

Two new sphingolipids from the stem bark of Synsepalum msolo (Sapotaceae).

Synsepalum msolo commonly known as Bang Bali in Bali-Nguemba, Cameroon is used in traditional medicine against various diseases. The leaves and stem bark extracts were subjected to silica gel and Sephadex LH20 column chromatography to yield pure compounds. The structures of the compounds were determined by detail analysis of NMR and Mass spectroscopic data and by comparison with data reported in the literature. Amongst the isolates, were two new sphingolipids: synsepaloside B (1), synsepaloside C (2), and five known compounds: (+)-catechin (3), (-)-epicatechin (4), myricitrin (5), triacontanol (6), and aurantiamide acetate (7). Compounds 1-5 were screened for their antibacterial and anti-yeast activities on several microorganisms. All the tested compounds exhibited weak antibacterial (MIC ≥ 200 µg/mL) and anti-yeast (MIC > 200 µg/mL) activities as compared to standard: ciprofloxacin 0.468 < MIC >0.234 µg/mL and fluconazole MIC = 0.05 µg/mL, respectively.

New triterpene saponins from the roots of Acacia macrostachya (Mimosaceae).

Four new oleanane-type saponins, macrostachyaosides A, B, C, and D (1-4) were isolated from the roots of Acacia macrostachya. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR data and HR-ESI-MS analyses. At concentrations of 100 µM of each compounds, none of the tested compounds caused a significant growth reduction against HL60 cells.

Triterpene saponins from the roots of Acacia albida Del. (Mimosaceae).

Seven previously undescribed bidesmosidic triterpenoid saponins named albidosides A - G, were isolated from a methanol extract of the roots of Acacia albida. Their structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry and determined to be bidesmosides of oleanolic acid and of 16α-hydroxyoleanolic acid. Albidosides B - G were assayed for their cytotoxicity against HeLa and HL60 cells using MTT method and microscopic observation.

Steroidal saponins from Chlorophytum deistelianum.

Phytochemical investigation of the aerial parts of Chlorophytum deistelianum led to the isolation of four previously undescribed steroidal saponins called chlorodeistelianosides A-D with five known ones. Their structures were established mainly by extensive 1D and 2D NMR spectroscopic techniques and mass spectrometry as (25R)-3ß-[(ß-D-glucopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→4)]-ß-D-xylopyranosyl-(1→3)-[ß-D-glucopyranosyl-(1→2)]-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranosyl)oxy]-5α-spirostan-12-one, (24S,25S)-24-[(ß-D-glucopyranosyl)oxy]-3ß-[(ß-d-glucopyranosyl-(1→2)-[ß-D-xylopyranosyl-(1→3)]-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranosyl)oxy]-5α-spirostan-12-one, (25R)-26-[(ß-D-glucopyranosyl)oxy]-2α-hydroxy-22α-methoxy-5α-furostan-3ß-yl ß-D-glucopyranosyl-(1→2)-[ß-D-xylopyranosyl-(1→3)]-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranoside, and (25R)-26-[(ß-D-glucopyranosyl)oxy]-3ß-[(ß-D-glucopyranosyl-(1→2)-[ß-D-xylopyranosyl-(1→3)]-ß-D-glucopyranosyl-(1→4)-ß-D-galactopyranosyl)oxy]-5α-furost-20(22)-en-12-one. Cytotoxicity of most compounds was evaluated against one human cancer cell line (SW480) and one rat cardiomyoblast cell line (H9c2). Among them, three known spirostane-type glycosides exhibited cytotoxicity on both cell lines with IC50 ranging from 8 to 10 µM.

Antrocarines A-F, antiplasmodial ergostane steroids from the stem bark of Antrocaryon klaineanum.

During a study on the chemistry and biological activity of Antrocaryon klaineanum Pierre, six new sterols including 4,24(28)-ergostadiene-6α,7α-diol (1), 6α-methoxy-4,24(28)-ergostadiene-7α,20S-diol (2), 6α-methoxy-4,24(28)-ergostadien-7α-ol (3), 20S-hydroxy-24(28)-ergosten-3-one (4), 7α-hydroxy-4,24(28)-ergostadien-3-one (5), and 24(28)-ergostene-3ß,6α-diol (6) were characterized by physical and spectroscopic means. The known steroids 7 and 8 were also isolated. The crude extract and the isolated compounds were evaluated for their ability to inhibit the 3D7 strain of Plasmodium falciparum. Compounds 2, 3, and 8 showed potent activity while that of the crude extract was moderate.

Steroidal saponins from Dioscorea preussii.

Three new steroidal saponins, named diospreussinosides A-C (1-3), along with two known ones (4, 5) were isolated from rhizomes of Dioscorea preussii. Their structures were elucidated mainly by 1D and 2D NMR spectroscopic analysis and mass spectrometry as (25S)-17α,25-dihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranoside (1), (25S)-17α,25-dihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (2), and (24S,25R)-17α,24,25-trihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (3). The spirostane-type skeleton of compound 3 possessing an unusual dihydroxylation pattern on the F-ring is reported for the first time. Cytotoxicity of compounds 2-5 was evaluated against two human colon carcinoma cell lines (HT-29 and HCT 116).

Secondary metabolites from polar fractions of Piper umbellatum.

Seven known secondary metabolites were isolated from the methanol extract of the branches of Piper umbellatum. The identification of these compounds was mainly achieved by 2D NMR spectroscopic techniques and FAB-MS. Among them, the known cepharadiones A and B can be considered aschemotaxonomic markers of the genus Piper.

Triterpenoid saponins from Hydrocotyle bonariensis Lam.

Phytochemical investigation of the under-ground parts of Hydrocotyle bonariensis led to the isolation of five oleanane-type triterpenoid saponins, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-22-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-28-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-R(1)-barrigenol, and 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-22-O-(2-methylbutyroyl)-A(1)-barrigenol, together with the known saniculoside-R1. Their structures were established by 2D NMR techniques and mass spectrometry. Six compounds were evaluated against two human colon cancer cell lines, HCT 116 and HT-29. Two compounds showed weak cytotoxicity with IC(50) 24.1 and 24.0, 83.0 and 83.6 µM against HT-29 and HCT 116, respectively.

Antimicrobial and immunomodulatory properties of prenylated xanthones from twigs of Garcinia staudtii.

Phytochemical investigation of the methanol extract of the twigs of Garcinia staudtii yielded four new prenylated xanthones, staudtiixanthones A-D (1-4), along with eleven known compounds. Their structures were determined by analysis of 1D and 2D NMR spectra and by comparison of spectroscopic data with those previously reported. Some of these compounds have been evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The new compounds were also screened for phagocyte chemiluminescence, neutrophil chemotaxis, T-cell proliferation, cytokine production from mononuclear cells and cytotoxicity. They were found to exhibit potent immunomodulatory activities.

Induction of neuronal differentiation in neurosphere stem cells by ellagic acid derivatives.

A bioassay-guided fractionation of methanol extracts of stem barks, combined with screening based on Epidermal Growth Factor (EGF)-responsive neural stem cells (erNSCs) differentiation assay, has been used. This study resulted in the isolation of 3,3'-di-O-methylellagic acid 1, 3,3'-di-O-methyl ellagic acid-4-O-beta-D-xylopyranoside 2, ellagic acid 3, and arjunolic acid 4. Among them, compounds 1 and 2 exhibit potent induction of neuronal differentiation in neurosphere stem cells with no cytotoxic effect. These results indicate that compounds 1 and 2 may be useful as pharmacological agents for the treatment of neurodegenerative diseases. These compounds may account, for the use of T. superba in folk medicine for nervous system and mental disorders.

Antimicrobial pentacyclic triterpenoids from Terminalia superba.

Antibacterial bioassay-guided fractionation of the methanol extract of the stem bark of Terminalia superba led to the isolation of four new triterpene glucosides (1-4) which were characterized as 2 alpha,3 beta-dihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (1), 2 alpha,3 beta, 21 beta-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (2), 2 alpha,3 beta, 29-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (3) and 2 alpha,3 beta,23,27-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (4) together with the known triterpene 2 alpha,3 beta,23-trihydroxyolean-12-en-28-oic acid (5). Structures were established by spectroscopic methods including one- and two-dimensional NMR, EI-MS and HR-EI-MS. The antibacterial activity of 1-5 was also investigated against two gram-positive (Bacillus subtilis, Staphylococcus aureus), and four gram-negative (Escherichia coli, Shigella flexenari, Pseudomonas aeruginosa, Salmonella typhi) bacterial strains.

alpha-glucosidase inhibitors from Garcinia brevipedicellata (Clusiaceae).

In our continuous search for alpha-glucosidase inhibitors from plants, four new depsidones named brevipsidones A-D (1-4) were isolated from stem bark of Garcinia brevipedicellata together with known damnacanthal, scopoletin and a mixture of stigmasterol and beta-sitosterol. Structural elucidations were made by spectroscopic analyses including 2D-NMR data.

Alpha-glucosidase inhibitors ellagic acid derivatives with immunoinhibitory properties from Terminalia superba.

Fractionation of stem barks of Terminalia superba yielded two new ellagic acid derivatives, 3,4'-di-O-methylellagic acid 3'-O-beta-D-xylopyranoside (1) and 4'-O-galloy-3,3'-di-O-methylellagic acid 4-O-beta-D-xylopyranoside (2) together with known 3,3'-di-O-methylellagic acid, ellagic acid and 3,3'-di-O-methylellagic acid 4'-O-beta-D-xylopyranoside. Compounds (1) and (2) showed significant alpha-glucosidase inhibition activity and possessed significant immunoinhibitory activities with no cytotoxic effects.

Bioactive aristolactams from Piper umbellatum.

Four alkaloids named piperumbellactams A-D (1-4) were isolated from branches of Piper umbellatum together with known N-hydroxyaristolam II (5), N-p-coumaroyl tyramine (6), 4-nerolidylcatechol (7), N-trans-feruloyltyramine, E-3-(3,4-dihydroxyphenyl)-N-2-[4-hydroxyphenylethyl]-2-propenamide, beta-amyrin, friedelin, apigenin 8-C-neohesperidoside, acacetin 6-C-beta-d-glucopyranoside, beta-sitosterol, its 3-O-beta-d-glucopyranoside and its 3-O-beta-d-[6'-dodecanoyl]-glucopyranoside. Glycosidase inhibition, antioxidant and antifungal activities of these compounds were evaluated. Compounds 1-3 showed moderate alpha-glucosidase enzyme inhibition with IC50 values 98.07+/-0.44, 43.80+/-0.56 and 29.64+/-0.46, respectively. In DPPH radical scavenging assay, compounds 2, 3 and 6 showed potent inhibitory activity while compounds 4, 5 and 7 showed potent antifungal activity.

Further cytotoxic sesquiterpene lactones from Elephantopus mollis KUNTH.

Three new sesquiterpene lactones, (4betaH)-5alpha-hydroxy-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(10),11(13)-guaiadien-12,6alpha-olide (1), (4betaH)-8alpha-(2-methylbut-2-enoyloxy)-2-oxo-1(5),10(14),11(13)-guaiatrien-12,6alpha-olide (2) and 2,5-epoxy-2beta-hydroxy-4alpha-methoxy-8alpha-(2-methylbut-2-enoyloxy)-4(15),10(14),11(13)-germacratrien-12,6alpha-olide (3), have been isolated from roots and stems of Elephantopus mollis together with two known sesquiterpene lactones (4, 5). The identification of the isolates was accomplished by spectroscopic methods. Compounds (1-5) exhibited significant cytotoxic activities against mouse neuroblastoma B104 cells.

Cytotoxic triterpene and sesquiterpene lactones from Elephantopus mollis and induction of apoptosis in neuroblastoma cells.

Activity-guided fractionation of root and leaf extracts from Elephantopus mollis led to the isolation of a new triterpene (1) and a new sesquiterpene lactone (2) together with five known sesquiterpene lactones (3-7). The structures of compounds 1 and 2 were determined based on their spectroscopic data. The cytotoxic activity of the isolated compounds was evaluated against neuroblastoma B104 cells. The sesquiterpene lactone-type compounds 2-7 were highly cytotoxic. Among these, compound (5) was the most cytotoxic and induced apoptosis of neuroblastoma B104 cells in a dose- and time-dependent manner. No significant difference was observed for cytotoxicity of compound 5 towards all 3 cell lines tested.