Manniosides G-J, New Ursane- and Lupane-Type Saponins from Schefflera mannii (Hook.f.) Harms.

Four previously unreported triterpenoid saponins named 3ß-hydroxy-23-oxours-12-en-28-oic acid 28-O-ß-D-glucopyranosyl ester (mannioside G) (1), 23-O-acetyl-3ß-hydroxyurs-12-en-28-oic acid 28-O-ß-D-glucopyranosyl ester (mannioside H) (2), ursolic acid 28-O-[α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl] ester (mannioside I) (3), and 3ß-hydroxy-23-oxolup-20(29)-en-28-oic acid 28-O-ß-D-glucopyranosyl ester (mannioside J) (4) were isolated as minor constituents from the EtOAc soluble fraction of the MeOH extract of the leaves of Schefflera mannii along with the known compounds 23-hydroxyursolic acid 28-O-ß-D-glucopyranosyl ester (5), ursolic acid 28-O-ß-D-glucopyranosyl ester (6), pulsatimmoside B (7) betulinic acid 28-O-[α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranosyl] ester (8), 23-hydroxy-3-oxo-urs-12-en-28-oic acid (9), hederagenin (10), ursolic acid (11), betulinic acid (12), and lupeol (13). Their structures were elucidated by a combination of 1D and 2D NMR analysis and mass spectrometry. The MeOH extract, the EtOAc and n-BuOH fractions, and some of the isolated compounds were evaluated for their antibacterial activity against four bacteria: Staphylococcus aureus ATCC1026, Staphylococcus epidermidis ATCC 35984, Escherichia coli ATCC10536, and Klepsiella pnemoniae ATCC13882. They were also screened for their antioxidant properties, but no significant results were obtained.

Structure elucidation of olasubscorpioside C, a new rotameric biflavonoid glycoside from the stem barks of Olax subscorpioidea (Oliv).

From the n-butanol soluble fraction of the ethanol extract of the medicinal plant Olax subscorpioidea, a previously unreported rotameric biflavonoid glycoside constituted of 4'-O-methylgallocatechin-(4α → 8)-4'-O-methylgallocatechin as aglycone named olasubscorpioside C (1) along with the known 4'-O-methylgallocatechin (2) were isolated. Their structures were determined on the basis of spectrometric and spectroscopic techniques including HRFABMS, 1 H and 13 C NMR, DEPT 135o , HSQC, HMBC, ROESY, and CD followed by comparison with the reported data.

Bioactive Arylnaphthalide Lignans from Justicia depauperata.

Eleven previously undescribed arylnaphthalide lignans (1-11) together with seven known compounds were isolated from the whole plant of Justicia depauperata. The structures of 1-11 were elucidated by spectroscopic analysis and mass spectrometry. Compounds 6 (IC50 = 4.1 µM) and 9 (IC50 = 9.5 µM) displayed cytotoxic activity against the KB-3-1 cervical carcinoma cell line. This report provides an insight into the conformational equilibria occurring in the arylnaphthalide lignan constituents of this plant.

Constituents from ripe figs of Ficus vallis-choudae Delile (Moraceae) with antiplasmodial activity.

Ripe figs, barks, and wood of Ficus vallis-choudae are used in traditional medicine against several conditions including nausea and malaria. However, its use is still to be scientifically documented and validated. Hence, the aim of the present work was to evaluate the antiplasmodial activity of the dichloromethane-methanol (DCM-MeOH (1:1)) crude extract, their hexane, dichloromethane, ethyl acetate, and methanoli fractions, as well as the isolated chemical constituents. The chemical study of the DCM-MeOH (1:1) crude extract of F. vallis-choudae figs led to the isolation of fifteen (15) known compounds identified based on their spectroscopic data [one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR), mass spectrometry] and by comparison of these data with those reported in the literature. Some of the isolated compounds were assessed in vitro for their antiplasmodial activity against Plasmodium falciparum chloroquine-sensitive 3D7 (Pf3D7) and multidrug-resistant Dd2 strains. The dichloromethane fraction exhibited very good antiplasmodial activity against both strains with IC50 values of 13.86 µg/mL and 8.18 µg/mL, respectively. Among the tested compounds, wighteone (2) was the most active against P. falciparum 3D7 (IC50 = 24.6 ± 1.5 µM) and Dd2 (IC50 = 11.9 ± 2.4 µM) strains. The obtained results could justify the traditional uses of F. vallis-choudae against malaria. Wighteone appears to be the most active ingredient. However, further consideration of this compound as starting point for antimalarial drug discovery will depend upon its selectivity of action towards Plasmodium parasites. HIGHLIGHTS: • 15 (fifteen) compounds were isolated from the dichloromethane-methanol extract of Ficus vallis-choudae. • Their structures were determined on the basis of their spectroscopic data. • The dichloromethane fraction showed promising activities on the Pf3D7 and PfDd2 strains with IC50 values of 13.86 and 8.18 µg/mL, respectively. • Wighteone was the most active compound against PfDd2 (IC50 = 11.9 ± 2.4 µM).

23-Hydroxyursolic Acid Isolated from the Stem Bark of Cussonia bancoensis Induces Apoptosis through Fas/Caspase-8-Dependent Pathway in HL-60 Human Promyelocytic Leukemia Cells.

The natural product 23-hydroxyursolic acid (23-HUA) is a derivative of ursolic acid, which is known to induce cancer cell apoptosis. However, apoptotic effects and mechanisms of 23-HUA have not been well characterized yet. Herein, we investigated the molecular mechanisms of 23-HUA-induced apoptosis in HL-60 human promyelocytic leukemia cells. 23-HUA-treated HL-60 cells showed apoptotic features including internucleosomal DNA condensation and fragmentation as well as externalization of phosphatidylserine residues. 23-HUA induced a series of mitochondrial events including disruption of mitochondrial membrane potential (ΔΨm), cytochrome c and Smac/DIABLO release and loss of balance between pro-apoptotic and anti-apoptotic Bcl-2 proteins in HL-60 cells. In addition, 23-HUA activated caspase-8, caspase-9 and caspase-3. Pretreatment with a broad caspase inhibitor (z-VAD-fmk), a caspase-3 inhibitor (z-DEVD-fmk), and a caspase-8 inhibitor (z-IETD-fmk) significantly attenuated 23-HUA-induced DNA fragmentation. After 23-HUA-induced apoptosis, proteins expression levels of FasL, Fas and FADD constituting the death-inducing signaling complex (DISC) were upregulated in HL-60 cells. Moreover, transfection with Fas or FADD siRNA significantly blocked 23-HUA-induced DNA fragmentation and caspases activation. Taken together, these findings indicate that 23-HUA induces apoptosis in HL-60 human promyelocytic leukemia cells through formation of DISC and caspase-8 activation leading to loss of ΔΨm and caspase-3 activation.

Traditional herbal remedies and dietary spices from Cameroon as novel sources of larvicides against filariasis mosquitoes?

In Cameroon, many dietary spices are used by traditional healers to cure several diseases such as cancer and microbial infections. Aframomum daniellii, Dichrostachys cinerea and Echinops giganteus are Cameroonian spices widely used as flavourings and as food additives. Moreover, they are traditionally herbal remedies employed to treat several diseases, as well as to control populations of insect pests. In this research, we analysed the chemical composition of A. daniellii, D. cinerea and E. giganteus essential oils and we evaluated their larvicidal potential against larvae of the filariasis and West Nile virus vector Culex quinquefasciatus. The essential oils were obtained from different plant parts by hydrodistillation and their composition was analysed by GC-MS. The three spices exhibited different volatile chemical profiles, being characterized by 1,8-cineole, sabinene and ß-pinene (A. daniellii), geraniol and terpinen-4-ol (D. cinerea), and silphiperfol-6-ene and presilphiperfolan-8-ol (E. giganteus). Results showed that the highest larvicidal toxicity on Cx. quinquefasciatus was exerted by D. cinerea essential oil (LC50 = 39.1 µL L-1), followed by A. daniellii (pericarp essential oil: LC50 = 65.5 µL L-1; leaves: LC50 = 65.5µL L-1; seeds: LC50 = 106.5µL L-1) and E. giganteus (LC50 = 227.4 µL L-1). Overall, the chance to use the D. cinerea essential oil against Cx. quinquefasciatus young instars seems promising, since it is effective at moderate doses and could be an advantageous alternative to build newer mosquito control tools.

Trifasciatosides A-J, Steroidal Saponins from Sansevieria trifasciata.

Four previously unreported steroidal saponins, trifasciatosides A-D (1-4), three pairs of previously undescribed steroidal saponins, trifasciatosides E-J (5a, b-7a, b) including acetylated ones, together with twelve known compounds were isolated from the n-butanol soluble fraction of the methanol extract of Sansevieria trifasciata. Their structures were elucidated on the basis of detailed spectroscopic analysis, including (1)H-NMR, (13)C-NMR, (1)H-(1)H correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC), total correlated spectroscopy (TOCSY), nuclear Overhauser enhancement and exchange spectroscopy (NOESY), electrospray ionization-time of flight (ESI-TOF)-MS and chemical methods. Compounds 2, 4, and 7a, b exhibited moderate antiproliferative activity against HeLa cells.

Antimicrobial and antioxidant flavonoids from the leaves of Oncoba spinosa Forssk. (Salicaceae).

BACKGROUND: Naturally occurring flavonoids have been reported to possess various pharmacological properties. The aim of this study was to evaluate the antimicrobial and antioxidant activities of the MeOH extract and flavonoids from the leaves of Oncoba spinosa, a plant used for the treatment of syphilis, wounds and sexual impotence. METHODS: The plant extract was prepared by maceration in methanol and sequentially fractionated by column chromatography. The structures of isolated compounds were elucidated on the basis of spectral studies and comparison with published data. The MeOH extract and its isolated compounds were evaluated for their antibacterial and antifungal activities by broth microdilution method. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and trolox equivalent antioxidant capacity (TEAC) assays were used to detect the antioxidant activity. The samples were tested spectrophotometrically for their hemolytic properties against human red blood cells. RESULTS: The fractionation of the MeOH extract afforded five known flavonoids including kaempferol (1), quercetin (2), apigenin-7-O-ß-D-glucuronopyranoside (3), quercetin 3-O-ß-D-galactopyranoside (4) and quercetin 3-O-α-L-rhamnopyranosyl (1 → 6) ß-D-glucopyranoside (5). The MeOH extract displayed weak to moderate antimicrobial activities (MIC = 256-2048 µg/ml). Quercetin 3-O-α-L-rhamnopyranosyl (1 → 6) ß-D-glucopyranoside (5) and quercetin (2) were respectively the most active compounds against bacteria (MIC = 8-64 µg/ml) and fungi (MIC = 64 - 128 µg/ml). These tested samples also showed high radical-scavenging activities (EC50 = 5.08 - 70.56 µg/ml) and gallic acid equivalent antioxidant capacities (TEAC = 53.76 - 89.86 µg/ml) when compared with vitamin C (EC50 = 4.72 µg/ml). The MeOH extract and compounds 2-5 were non-toxic to human red blood cells indicating their high selectivity to be used as antimicrobial and antioxidant drugs. CONCLUSION: The MeOH extract of O. spinosa as well as compounds 2 - 5 could be a potential source of natural antimicrobial and antioxidant products.

Pyrroloquinolones B-F: Five unusual alkaloids from Vernonia glabra (Steetz) Vatke (Asteraceae).

Five unusual alkaloids featuring a pyrrolo[1,2-a]quinolone skeleton (pyrroloquinolones B-F, 1-5) were isolated from the ethanol extract of the whole plant of Vernonia glabra (Steetz) Vatke, along with sixteen known compounds. Their structures were established by means of spectroscopic (1D and 2D NMR, UV, IR, and ECD) and high resolution mass spectrometric techniques as well as by comparison of their spectroscopic data with those reported in the literature. The ethanol extract and some isolated compounds were assessed for their antibacterial activity against four bacterial strains. The extract was significantly active against Staphylococcus aureus ATCC1026 and S. epidermidis ATCC35984 (MIC = 64 µg/mL). All the tested compounds showed moderate activity against S. epidermidis (16 ≤ MIC ≤ 64 µg/mL). Furthermore, this is the first report on tricyclic pyrrolo[1,2-a]quinolone alkaloids from a plant source. A biosynthetic pathway for the formation of these compounds is also proposed.

Chemical constituents and antimicrobial activity of the aerial part of Solanum betaceum Cav. (Solanaceae).

A new saponin namely diosgeninoside (25 R-spirost-5-en-3-O-[ß-D-glucopyranosyl (1→2) - ß-D-glucuronic acid]) and a new fatty acid betacic acid: (Z)-8(S*),9(S*),10(R*)-trihydroxy-11-octadecenoic acid together with six known compounds: N-trans-coumaroyl tyramine, ergosta-7,22-dien-3ß,5α,6ß-triol, ß-sitosterol, and ß-sitosterol-3-O-ß-D-glucopyranoside, L-threitol and soya-cerebroside I were isolated from the methanolic extract of Solanum betaceum. The structures were elucidated by interpretation of their 1D and 2D NMR spectra and spectrometric data. The methanolic extract, the EtOAc and n-BuOH fractions, and several isolated compounds were tested for antibacterial activity against four bacteria (Staphylococcus aureus; Staphylococcus epidermidis; Escherichia coli; and Pseudomonas aeruginosa). The methanolic extract and the EtOAc fraction showed moderate activity against Staphylococcus aureus and Pseudomonas aeruginosa with MIC value of 128 µg/mL. Compound 1 showed moderate activity against Staphylococcus aureus with MIC value of 64 µg/mL.

Exploring Cassia mimosoïdes as a promising natural source of steroids with potent anti-cancer, urease inhibition, and antimicrobial properties.

The genus Cassia is a rich source of physiologically active secondary metabolites, including a novel compound named 21-methylene-24-ethylidene lophenol, alongside 15 known compounds. These compounds were characterized using different spectroscopic techniques. They exhibited promising antimicrobial activity, particularly against bacteria causing gastrointestinal infections. Compound 1 showed strong anti-bacterial activity against H. pylori and S. aur with MIC values of 0.28 and 0.12 µg mL-1 respectively. The study investigated their impact on H. pylori, a contributor to ulcer development, by inhibiting the urease enzyme. Inhibiting urease can reduce H. pylori's pathogenic potential, evident from the fact that the compounds evaluated toward urease enzyme showed higher inhibitory activity (1.024 ± 0.43 6.678±0.11 µM) compared to standard thiourea (IC50 = 18.61 ± 0.11 µM). Molecular docking studies confirmed their inhibitory action, with compound 7 notably outperforming thiourea in inhibiting urease (-6.95 kcal mol-1vs. -3.13 kcal mol-1). Additionally, these compounds showed positive effects on liver functioning, which H. pylori can impair. Compound 9 shows the best response against human HepG2 liver cancer cell lines i.e., % viability is 14.47% ± 0.69 and IC50 is 7.8 µM ± 0.21. These compounds hold potential as lead compounds for addressing gastrointestinal and liver disorders caused by H. pylori.

New bioactive flavonoid glycosides with antioxidant activity from the stem bark of Olax subscorpioidea Oliv.

A previously unreported gallocatechin glycoside, (2 R,3S) 4'-O-methyl-gallocatechin-3-O-α-ʟ-rhamnopyranoside (1) and an unseparable mixture of two previously undescribed dihydromyricetin glycosides, (2 R,3R) 4'-O-methyl-dihydromyricetin-3-O-α-ʟ-rhamnopyranoside (2a) and (2 R,3S) 4'-O-methyl-dihydromyricetin-3-O-α-ʟ-rhamnopyranoside (2 b) along with three known compounds were isolated from the n-butanol soluble fraction of the stem bark of Olax subscorpioidea Oliv. Their structures were elucidated by detailed spectroscopic analyses, including 1H NMR, 13C NMR, 1H-1H COSY, HSQC, HMBC, NOESY, HR-ESI-MS and chemical methods. The crude ethanol extract, the fractions, and some of the isolated compounds were screened for their antioxidant and antibacterial activities. They showed significant antioxidant activities with EC50 ranging from 6.29 to 18.19 µg/mL in 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and EC50 ranging from 85.77 to 86.39 mmol FeSO4/g in ferric reducing antioxidant power (FRAP) methods compared with 2.29 µg/mL and 3.52 mmol FeSO4/g for the positive control (ʟ-ascorbic acid). Nevertheless, no inhibition was observed against the tested bacterial strains at a MIC less than 256 µg/mL.

Siamoside A: a new C-glycosylated flavone from Senna siamea (Lam.) H. S. Irwin & Barneby (Caesalpiniaceae).

Phytochemical investigation of the methanol extracts from the leaves and bark of Senna siamea resulted in the isolation of one new flavone C-glycoside: apigenin-8-C-[6''-(E)-feruloyl]-ß-D-glucopyranoside] (1), together with sixteen known compounds including quercetin-3-O-α-L-rhamnoside (2), vitexin (3), isovitexin (4), quercetin-3-O-ß-D-glucopyranoside (5), quercetin-3-O-ß-D-arabinopyranoside (6), quercetin (7), kaempferol (8), methyl inositol (9), sucrose (10), betulinic acid (11), vanillic acid (12), stigmastane-3ß,6α-diol (13), aurantiamide acetate (14), robinetinidol (15), catechin (16) and epicatechin (17). The structures of these compounds were established on the basis of their spectroscopic (1 D and 2 D NMR) and mass spectrometric (ESI-TOF-MS) data. The methanol extracts, fractions and some of the isolated compounds were screened for their antimicrobial properties against five microbial strains. The methanol extract and the ethyl acetate fraction from the bark showed very weak antifungal activity against C. glabrata with the same MIC value of 128 µg/mL. Compound 7 was weakly active against C. albicans with MIC of 32 µg/mL.

A new phenolic glycoside from the leaves of Flacourtia flavescens Willd.

Chemical study of the methanol extract from the leaves of Flacourtia flavescens led to the isolation of a new phenolic glucoside (1) along with fifteen known secondary metabolites namely shanzhiside methyl ester (2), aurantiamide acetate (3), caffeic acid methyl ester (4), caffeic acid (5), apigenin (6), luteolin (7), kaempferol (8), quercetin (9), gyrophoric acid (10), luteolin-7-O-ß-D-glucopyranoside (11), luteolin-4'-O-ß-D-glucopyranoside (12), kaempferol-7-O-α-L-rhamnopyranoside (13), kaempferol-3-O-ß-D-glucopyranosyl-(1→6)-O-α-L-rhamnopyranoside (14), kaempferol-3,7-O-α-L-dirhamnopyranoside (15) and (2S,3S,4R,8E)-2-((2'R)-2'-hydroxy-octadecanoylamino)-lignocerane-1,3,4-triol-8-ene (16). Their structures were elucidated by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active (MIC = 32 and 64 µg/mL) against E. coli and E. faecalis, respectively. Compounds 1, 2, 2b, 5, 8, 9, and 12 (MIC = 16-32 µg/mL) were moderately active against some tested bacteria.

Desmoarylcoumarin and episoyasapogenol B: two new compounds from Desmodium salicifolium (Poir.) DC (Fabaceae).

A new 3-arylcoumarin, 7-hydroxy-6-(1,1-dimethylallyl)-2',5'-dihydroxy-4'-(3,3dimethylprenyl)-3-arylcoumarin (desmoarylcoumarin) 1, a previously unreported oleanane-type triterpenoid, 3ß,22ß,23-trihydroxyolean-12-en (episoyasapogenol B) 2, together with five known flavonoids including darbergioidin (3), isoferreirin (4), quercetin (5), vitexin (6), swertizin (7), and one carbohydrate, sucrose (8) were isolated from the methanolic extract of the roots of Desmodium salicifolium. Their structures were elucidated mainly by extensive spectroscopic analysis (1D and 2D) and mass spectrometric (HRFAB-MS) data. The methanolic extract, EtOAc and n-BuOH fractions as well as some isolated compounds were assessed for their antibacterial and antioxidant activities. The EtOAc fraction exhibited moderate activity against Enterococcus faecalis with MIC value of 128 µg/mL. The methanolic extract and the EtOAc fraction displayed DPPH scavenging activity with EC50 values of 5.99 and 2.06 µg/mL, respectively. Compound 1 showed a moderate antibacterial activity against Enterococcus faecalis with a MIC of 16 µg/mL. It also showed moderate DPPH scavenging activity.

Mimonoside D: a new triterpenoid saponin from Mimosa diplotricha Sauvalle (Fabaceae).

A new triterpenoid saponin (Mimonoside D: 3-O-α-L-arabinopyranosyl-3ß-hydroxyolean-12-en-28-oic acid 28-O-ß-D-xylopyranosyl-(1→2)-ß-D- glucopyranoside ester (1)) was isolated from the aerial parts of Mimosa diplotricha Sauvalle together with nine known compounds: 7,4'-dihydroxyflavone (2), kaempferol (3), lupeol (4), betulinic acid (5), ß-sitosterol (6), ß-sitosterol-3-O-ß-D-glucopyranoside (7), lutein (8), 5,2'-dihydroxy-7,4',5'-trimethoxyflavone (9) and vitexin (10). Their structures were elucidated on the basis of spectroscopic (1 D and 2 D nuclear magnetic resonance) and high-resolution mass spectrometric data as well as by comparison of their spectral data with those of related compounds. Compounds 2, 7 and 8 had already been isolated from M. diplotricha, while compounds 3, 4, 5 and 6 have been isolated from other Mimosa species. Compound 2 moderately inhibited Proteus mirabilis (MIC = 32 µg/mL), weakly inhibited Pseudomonas aeruginosa (MIC = 64 µg/mL) and very weakly inhibited Staphylococcus aureus (MIC = 128 µg/mL) and Enterococus faecalis (MIC = 128 µg/mL).

Antibacterial activities of the extracts, fractions and compounds from Dioscorea bulbifera.

BACKGROUND: Dioscorea bulbifera is an African medicinal plant used to treat microbial infections. In the present study, the methanol extract, fractions (DBB1 and DBB2) and six compounds isolated from the bulbils of D. bulbifera, namely bafoudiosbulbins A (1), B (2), C (3), F (4), G (5) and 2,7-dihydroxy-4-methoxyphenanthrene (6), were tested for their antimicrobial activities against Mycobacteria and Gram-negative bacteria involving multidrug resistant (MDR) phenotypes expressing active efflux pumps. METHODS: The microplate alamar blue assay (MABA) and the broth microdilution methods were used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples. RESULTS: The results of the MIC determinations indicated that when tested alone, the crude extract, fractions DBB1 and DBB2 as well as compounds 2 to 5 were able to prevent the growth of all the fifteen studied microorganisms, within the concentration range of 8 to 256 µg/mL. The lowest MIC value for the methanol extract and fractions (16 µg/mL) was obtained with DBB1 and DBB2 on E, coli AG100A and DBB2 on Mycobacterium tuberculosis MTCS2. The lowest value for individual compounds (8 µg/mL) was recorded with compound 3 on M. smegmatis and M. tuberculosis ATCC and MTCS2 strains respectively. The activity of the samples on many MDR bacteria such as Enterobacter aerogenes EA289, CM64, Klebsiella pneumoniae KP63 and Pseudomonas aeruginosa PA124 was better than that of chloramphenicol. When tested in the presence of the efflux pump inhibitor against MDR Gram-negative bacteria, the activity of most of the samples increased. MBC values not greater than 512 µg/mL were recorded on all studied microorganisms with fraction DBB2 and compounds 2 to 5. CONCLUSIONS: The overall results of the present investigation provided evidence that the crude extract D. bulbifera as well as some of the compounds and mostly compounds 3 could be considered as potential antimicrobial drugs to fight against MDR bacteria.

Two new triterpenoid saponins: telephiifoliosides A and B from the roots of Corrigiola litoralis subsp. telephiifolia (Pourr.) Briq.

The polar fraction of the MeOH extract of the roots of Corrigiola litoralis subsp. telephiifolia (Pourr.) Briq. (Caryophyllaceae) was investigated for its constituents and two previously unreported monodesmosides triterpene saponins, telephiifoliosides A and B (1 and 2), along with the known bonushenricoside A (3) were isolated. Their structures were elucidated by combined spectroscopic and spectrometric techniques (1H NMR, 13C NMR, HSQC, 1H-1H COSY, HMBC, TOCSY, NOESY, HRESIMS) and chemical methods. The structures of the new saponins were established as; 3-O-α-L-arabinopyranosyljaligonic acid (1), and 3-O-α-L-arabinopyranosylphytolaccagenin ester (2). Upon evaluation of the antiproliferative activity on human malignant epithelial (HeLa) cells, none of the isolated compounds was efficient at the concentration of 33 µM. [Formula: see text]HighlightsThis is the first phytochemical study on Corrigiola litoralis subsp. telephiifolia.Two new saponins were isolated from the roots of Corrigiola litoralis subsp. telephiifolia.The isolated compounds were tested for their antiproliferative activity.

Chemotaxonomy and Antibacterial Activity of the Extracts and Chemical Constituents of Psychotria succulenta Hiern. (Rubiaceae).

The use of natural products for medicinal purposes is becoming more and more common nowadays, as evidenced by the presence in plants of secondary metabolites with different potentials such as antioxidant and antibacterial properties. We evaluated in this work the antimicrobial activities of the extracts and some isolated compounds from the seeds of Psychotria succulenta Hiern. (Rubiaceae), a Cameroonian medicinal plant traditionally used to cure microbial infections. The ethanol extract was prepared by maceration and extracted with ethyl acetate and n-butanol. The EtOAc (m = 168 g) and n-BuOH (m = 20 g) extracts were further fractionated by silica gel column chromatography to isolation of compounds. Their structures were elucidated by spectroscopic analysis and by comparison with published data. The antibacterial activity of extracts and compounds was assessed by evaluating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against pathogenic bacteria. Thirteen compounds including four alkaloids (veprisine (1), naucleofficine III (2), vepridimerine B (3), and vepridimerine C (4)), three triterpenes (barbinervic acid (5), 3-O-α-L-rhamnopyranosyl quinovic acid (6), and oleanolic acid (7)), one steroid (ß-sitosterol-3-O-ß-D-glucopyranoside (8)), four phenolic compounds (scopoletin (9), gallic acid (10), quercetin-3-O-ß-D-glucopyranoside (11), and kaempferol 3-O-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside (12)), and one iridoid (borreriagenin (13)) were isolated from the EtOAc and n-BuOH extracts. These compounds were identified by 1D and 2D NMR combined analysis as well as by melting point comparison. The EtOH, EtOAc, and n-BuOH extracts exhibited significant antibacterial activities (MIC = 32-128 µg/mL; MBC = 64-256 µg/mL) against Staphylococcus aureus (Gram-positive bacterium), Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia (Gram-negative bacteria). Among the isolated compounds, scopoletin (9) showed a moderate activity against Klebsiella pneumoniae with MIC and MBC values of 16 µg/mL and 32 µg/mL, respectively. It appears that, chemotaxonomically, some of the isolated compounds have already been obtained from the genus Psychotria but to the best of our knowledge, this is the first report on the phytochemical investigation of P. succulenta. Although many other studies need to be achieved, our results support the use of P. succulenta in traditional medicine to cure infectious diseases particularly those caused by the tested bacteria.

Pennogenin-3-O-α-L-Rhamnopyranosyl-(1→2)-[α-L-Rhamnopyranosyl-(1→3)]-ß-D-Glucopyranoside (Spiroconazol A) Isolated from Dioscorea bulbifera L. var. sativa Induces Autophagic Cell Death by p38 MAPK Activation in NSCLC Cells.

In our previous study, we reported the isolation of pennogenin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-ß-D-glucopyranoside (spiroconazol A), a steroidal saponin, from the flowers of Dioscorea bulbifera L. var. sativa. In the present study, we aimed to investigate the effects of spiroconazol A on autophagy and its underlying mechanisms in A549 and NCI-H358 human non-small cell lung cancer (NSCLC) cells. Spiroconazol A inhibited the proliferation of NSCLC cells in a concentration- and time-dependent manner. To determine the type of programmed cell death induced by spiroconazol A, we performed a characterization of apoptosis in spiroconazol A-treated A549 cells. Our results showed that spiroconazol A significantly suppressed A549 cell viability but did not influence cell apoptosis because phosphatidylserine and caspase activation were not detected. Furthermore, spiroconazol A treatment upregulated the expression of LC3-II and autophagy-related Beclin-1 protein, suggesting that spiroconazol A induces autophagy in A549 cells. Moreover, spiroconazol A activated the phosphorylation of p38 mitogen-activated protein kinase (MAPK) but did not affect the phosphorylation of Janus kinase or ERK1/2. Notably, SB203580, a p38 MAPK inhibitor, had a significant inhibitory effect on spiroconazol A-induced autophagic cell death in A549 cells. Our results indicated that spiroconazol A-induced autophagy is dependent on p38 MAPK signaling and has potential as a therapeutic target in NSCLC.