Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica Bojer ex Hook.

Phytochemical study on the methanolic extract of Sansevieria cylindrica aerial parts lead to the isolation, characterization and structure elucidation of a new steroidal saponin, 1β-hydroxy-kryptogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside (1), a new homoisoflavanone, (3S)-3,7-dihydroxy-8-methoxy-3-(3′,4′-methylenedioxybenzyl) chroman-4-one (2) and the known saponin alliospiroside A (3). To the best of our knowledge, the genin 1β-hydroxy-kryptogenin is reported here for the first time. The structures of the new compounds were determined by UV, IR, EIMS, HRESIMS together with 1D (¹H and ¹³C) and 2D (HSQC and HMBC) NMR spectral analysis. The isolated compounds 1–3 were tested for their radical scavenging activity (DPPH). Compound 2 exhibited activity compared to that of ascorbic acid as a standard. The cytotoxicity of the isolated compounds and the standard doxorubicin was tested against the three human tumor cell lines HT116, MCF-7 and PC-3. The results showed that the isolated compounds were inactive.     

New acylated triterpene saponins from the roots of Securidaca inappendiculata Hassk

Two new acylated triterpene saponins, named as securioside C (1), securioside D (2), and one pair of isomers 3/4, the (Z)–isomer securioside E (3) being new, together with a known triterpene saponin polygalasaponin XLIV (4) were isolated from the roots of Securidaca inappendiculata Hassk. Their structures were established by HRESIMS, 1D and 2D NMR experiments and comparison of their NMR data with previous reported data. In addition, Compounds 1–2, 3/4, 4 were evaluated for cytotoxicities against LLC (Lewis lung carcinoma) and MCF-7 (human breast cancer) cell lines. Compounds 1 and 2 exhibited moderate cytotoxic activities against LLC cells with IC₅₀ values of 45.56 μM and 85.98 μM.     

Polyhydroxyoleanane-type triterpenoids from Combretum molle and their anti-inflammatory activity

A new oleanane-type triterpene saponin, β-d-glucopyranosyl 2α,3β,6β-trihydroxy-23-galloylolean-12-en-28-oate (1), together with four known oleanane-type pentacyclic triterpenoids, combregenin (2), arjungenin (3), arjunglucoside I (4), and combreglucoside (5) were isolated from the stem bark of Combretum molle. Their structures were established mainly on the basis of 1D and 2D NMR spectral data. Compounds 1–3 exhibited more significant activity against carrageenan-induced paw edema in rat compared to compounds 4 and 5.     

Steroidal alkaloid saponins and steroidal saponins from Solanum surattense

A rare 16β-H steroidal alkaloid saponin (1), an avenacoside-type saponin (2), two steroidal saponins (4, 5), one revised-structure steroidal saponin (3) and six known compounds (6-11) were isolated from aerial parts of Solanum surattense Burm. f. Their structures were established on the basis of physical data, as well as by using spectroscopic (HRESIMS, 1D and 2D NMR), and chemical analysis methods. Compounds 1 and 11 showed cytotoxicity against A549 cell line with IC₅₀ values of 20.3 and 15.7 μM, respectively.     

A dinorcassane-type diterpene and a steroidal saponin from Distemonanthus benthamianus Baill. (Caesalpiniaceae)

As part of our search for new bioactive compounds from medicinal plants growing in Cameroon, a previously unreported dinorcassane-type diterpenoid trivially named distemonanthin (1) and a new steroidal saponin, stigmasta-5,22-dien-3-O-β-D-glucopyranosyl-(1→3)-O-β-D-glucopyranoside (2) together with ten known compounds were isolated from the ethyl acetate and n-butanol soluble fractions of the methanol extract from the stem barks of Distemonanthus benthamianus. Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry and by comparison with spectroscopic data reported in the literature. The extract, fractions and some isolated compounds were screened for their antimicrobial properties and a significant inhibition was observed only for the n-butanol fraction against Candida albicans and Candida glabrata with MICs values of 32 and 64 µg/mL, respectively.     

Stilbeno-phenylpropanoids from Gnetum montanum Markgr.

Four new stilbeno-phenylpropanoids, gnetumonins A−C (1−3) and (−)-gnetucleistol F (4), together with two known compounds, gnetupendin A and (+)-gnetofuran A, were isolated from the caulis of Gnetum montanum Markgr. (Gnetaceae). The structures of those new compounds were established by extensive analysis of MS, 1D and 2D NMR spectroscopic data. The relative configurations of 1−3 were elucidated by means of the analysis of shielded effect correlating their key ¹H NMR shift changes.     

Triterpenoid saponins from Albizia boromoensis Aubrév. & Pellegr

As part of our search of new bioactive saponins from Cameroonian medicinal plants, phytochemical investigation of the roots of Albizia boromoensis led to the isolation of four new oleanane-type saponins, named boromoenosides A–D (1–4). Their structures were established by direct interpretation of their spectral data, mainly HRESIMS, 1D NMR (¹H, ¹³C NMR, and DEPT) and 2D NMR (COSY, NOESY, HSQC and HMBC), and by comparison with the literature data. All isolated saponins were assayed for their cytotoxicity against U-87 MG human glioblastoma cell lines and TG1 glioblastoma stem-like cells with no positive activity detected.     

A new naturally acetylated triterpene saponin from Nigella sativa

A new glycosylated triterpene 1 was identified as 3-O-[β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl]-11-methoxy-16-hydroxy-17-acetoxy hederagenin from an ethanolic extract of seeds of Nigella sativa Linn. Identification of the naturally acetylated saponin was based on chemical and spectroscopic analyses including FABMS, ¹H, ¹³C, and 2D NMR and DEPT. The saponin was a penta hydroxy pentacyclic triterpene, in which one hydroxyl group was acetylated and other one was methylated naturally.     

Chemical constituents of the medicinal plant Indigofera spicata Forsk (Fabaceae) and their chemophenetic significance

The chemical investigation of the whole plant of Indigofera spicata Forsk (Fabaceae), a medicinal plant from Cameroon, resulted in the isolation of a new benzofuran, named spibenzofuran (1a), together with ten known secondary metabolites including one benzofuran (2), one flavonoid (3), one saponin (6), two triterpenes (4 and 5), two steroids (8 and 11), one phthalate (7) and two fatty acids (9 and 10). All these compounds have been isolated for the first time from this plant. The structures of the isolated compounds were established by spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR and by comparison of our data with the reported data. The isolated compounds might be considered as the chemophenetic markers of this species, and antibacterial and urease inhibitory activities of some isolated compounds were assessed.     

Triterpenoids and triterpenoid saponins from the aerial parts of Fagonia indica Burm

As part of our search of new bioactive compounds from indigenous medicinal plants, phytochemical investigation of the aerial parts of Fagonia indica Burm led to the isolation of seven compounds including two new compounds, namely, indicacin (1) and fagonicin (2), and five known compounds (3–7) from the methanol extract. Compounds 6 and 7 are hitherto unreported from this plant. The structures of the new compounds were elucidated from their spectral data, mainly HREIMS, 1D NMR (¹H, ¹³C NMR, and DEPT) and 2D NMR (COSY, NOESY, HSQC and HMBC), and by comparison with the literature data. The new compounds 1 and 2 were assayed for their cytotoxicity against human colorectal cancer cell line H-29. Compound 1 exhibited 51.40% cytotoxicity at 6.25 μM/mL dose whereas compound 2 demonstrated 39.3% cytotoxicity at the same dose.     

Macathiohydantoins P–R,three new thiohydantoin derivatives from Maca (Lepidium meyenii)

Three new thiohydantoins with a 2-thioxoimidazolidin-4-one nucleus, named macathiohydantoins P–R (1–3), along with one known analog (4), were isolated from the roots of Lepidium meyenii. Their structures were elucidated by means of analysis of extensive spectroscopic data, including ¹D NMR, ²D NMR and HRESIMS. The thiohydantoins (1–4) were isolated as racemic mixtures, which were further separated by chiral semi-preparative HPLC to afford the corresponding enantiomers. Their absolute configuration of C-5 was assigned by comparison of optical rotation values with those reported in the literature. All thiohydantoin derivatives were evaluated for their cytotoxicities against five human cancer cell lines.     

Meroterpenes isolated from the endophytic fungus Guignardia mangiferae

Two new guignardones and one tricycloalternarene derivatives, named guignardone D, E (2–3) and tricycloalternarene F (4), and the known guignardone A (1) were isolated from Guignardia mangiferae, an endophytic fungus from the leaves of Viguiera arenaria (Asteraceae), after fermentation in Czapek medium. Structures were established on the basis of their spectroscopic data, including ¹H NMR, ¹³C NMR, HMQC, HMBC and HRESI-MS.     

Three new compounds isolated from the bulbs of Fritillaria pallidiflora Schrenk and their anti-inflammatory activity

Three new compounds, 17β-cevanin-6-oxo-5α,20β-diol yibeinine (1), 2-(tetrahydro-5-(2-hydroxyphenyl)-2H-pyran-3-yl) phenol (2), 1,3-O-diferuloyl-2-methoxypropane diol (3), as well as four known compounds (4–7), have been isolated from the ethanol extract of dried bulbs of Fritillaria pallidiflora Schrenk. All structures were determined based on their spectroscopic data (1D and 2D NMR (including ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HSQC, HSQC-TOCSY, and NOESY experiments), and MS). Biological evaluation showed that compounds 1–4 inhibited the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 cells with IC₅₀ values of 18.0, 38.7, 29.5, and 47.1 μM, respectively. These results indicated that compound 1 has potential anti-inflammatory activity.     

Three new hetisine-type diterpenoid alkaloids from Aconitum coreanum

Three new hetisine-type diterpenoid alkaloids, Guan-fu base V (GFV, 1), Guan-fu base W (GFW, 2) and Guan-fu base X (GFX, 3) were isolated from the roots of Aconitum coreanum (Lèvl.) Rapaics. Their structures were established by direct interpretation of their spectral data, mainly high resolution electrospray ionization mass spectrometry (HR-ESI-MS), ¹D and ²D NMR (¹H–¹H COSY, ROESY, HSQC and HMBC). GFX is the third N-oxygenated hetisine-type diterpenoid alkaloid isolated from A. coreanum.     

Ecdysteroids from the flowers of Aerva javanica

Four new ecdysteroids (1–4), along with three known steroids, β-ecdysone (5), 5-β-2-deoxyintegristerone A (6) and 24-epi-makisterone A (7) (Fig. 1), were isolated from the methanolic extract of the flowers of Aerva javanica by using normal and reverse phase chromatography. The structures of the new compounds (1–4) were determined due to 1D (¹H and ¹³C), 2D NMR (HSQC, HMBC, COSY, NOESY) techniques and high resolution mass spectrometry (HREIMS). The known compounds (5–7) were characterized based on the 1D NMR spectroscopy and mass spectrometry and by comparison with the literature values. All isolates were evaluated for their inhibitory activities against enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and lipoxygenase (LOX).     

Unusual D:B-friedobaccharane and oxygenated friedelane-type triterpenoids from Salvadorean Celastraceae species

Three new triterpenoids, including two rare D:B-friedobaccharanes (leonatriol, 1 and leonatriolone, 2) and a 2,3-seco-2,24-epoxy-3,24-olide-D:A-friedooleanane (cassinolide, 3) were isolated from the root bark of Cassine xylocarpa and Celastrus vulcanicola, collected in El Salvador. Their stereostructures were elucidated on the basis of spectroscopic analyses, mainly ¹D and ²D NMR techniques, spectrometric analyses, and comparison with data reported in the literature. The absolute configuration of 1 and 2 were determined by the application of the Riguera ester procedure and biogenetic considerations. The possible biogenetic pathway for cassinolide (3) is also discussed.     

Steroidal saponins from the fresh tubers of Ophiopogon japonicus

Eleven novel furostanol saponins, named ophiofurospisides C–E, G–N (1–3, 5–12), one new spirostanol saponin, named ophiopogonin R (13), were isolated from the fresh tubers of Ophiopogon japonicus. Their structures were determined on the basis of spectroscopic techniques (1D and 2D NMR) and HRESIMS. The isolated furostanol saponins possessed two sugar chains located at C-3 and C-26, respectively. Six furostanol saponins (1, 5–9) with disaccharide moiety linked at position C-26 of the aglycone were rare in the plant kingdom.     

Phenylpropanoids and triterpenoids from Tripterygium regelii and their anti-inflammatory activities

Two new compounds named cleroserroside C (1), schisphenlignan O (2), as well as twenty-one known compounds (3–23) were isolated from the roots of Tripterygium regelii. The structures of the new compounds were determined by 1D and ²D NMR spectra and HR-ESI-MS data. The known compounds were determined by comparing the ¹D NMR data in the literature. All compounds were evaluated for anti-inflammatory activity using the LPS-induced RAW264.7 inflammatory cell model, and the results showed that compounds 1, 8-11, 15-16, and 20-21 had good anti-inflammatory activity (IC₅₀ < 20 μM). The cytotoxicity of all compounds was tested by CCK-8 assay, using RAW264.7 cells. The results showed that all compounds had no cytotoxicity to RAW264.7 in the range of 0 ~ 200 μM.     

Novel metabolites from the roots of Cadaba natalensis

From an extract of the roots of Cadaba natalensis Sond. the novel macrocyclic dibenzo-diazacyclododecanedione 1 was isolated together with (S)-2-ethyl-2-methyloxazolidin-5-one (2a). In addition, the five known compounds were obtained. Of these, (R)-5-ethyl-5-methyloxazolidin-2-one (3) is reported as a natural product for the first time. The structures of the isolated compounds were elucidated by analysis of the spectral data, 1D NMR (¹H, ¹³C, and DEPT), 2D NMR (COSY, HMQC, HMBC, and NOESY), and HRESIMS, as well as by the comparison with previously reported data.     

Five new iridoïd dimers from the fruits of Canthium subcordatum DC (syn. Psydrax subcordata DC)

Five new iridoid dimers, canthiumosides 1–5 (1–4 and 5a), together with nine known compounds, shanzhigenin methyl ester (6), 1-epishanzhigenin methyl ester (6′), linearin (7), 1-epilinearin (7′), mussaenoside (8), shanzhiside methyl ester (9), 3′,4′,7-trihydroxyflavone (10), betulinic acid (11), and oleanolic acid (12) were isolated from the fruits of Canthium subcordatum DC (Syn. Psydrax subcordata (DC) Bridson). The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D NMR (¹H, ¹³C and DEPT) and 2D NMR (¹H–¹H COSY, HSQC, HMBC, and NOESY), and by comparison with the literature.