Triterpenoid saponins and C-glycosyl flavones from stem bark of Erythrina abyssinica Lam and their cytotoxic effects.

Six new compounds including two oleanane-type triterpenoid saponins (1, 2) and four C-glycosyl flavones (3–6), along with a known saponin (7), three di-C-glycosyl flavones (8–10) and a glycosyl auronol (11), were isolated from the stem bark of Erythrina abyssinica Lam. The structures of the new compounds, identified as 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (1), 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (2), 6-C-β-glucopyranosyl-8-C-β-quinovopyranosyl apigenin (3), 6-C-β-quinovopyranosyl-8-C-β-glucopyranosyl apigenin (4), 8-C-[6″-O-α-l-rhamnopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (5) and 8-C-[6″-O-β-d-xylopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (6), were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and acid hydrolysis. These new compounds together with the known saponins 7 were evaluated for their cytotoxic activity against MCF-7 (estrogen dependent) and MDA-MB-231 (estrogen independent) cell lines. The new saponin 2 exhibited the highest cytotoxic activity among tested compounds, exerting a selective inhibitory effect against the proliferation of MCF-7 cells, with lower IC₅₀ value (12.90 μM) than that of the positive control, resveratrol (13.91 μM). Structure–activity relationship of these compounds is also discussed.     

Cytotoxic cardiac glycosides and coumarins from Antiaris toxicaria

Eight new cardiac glycosides/aglycones (antiaritoxiosides A–G, 1–7, and antiarotoxinin B, 8), two new coumarins (anticarins A–B, 41–42), and two new flavanones (antiarones L–K, 43–44) were isolated from trunk bark of Antiaris toxicaria together with 53 known compounds. The new structures were established by extensive analysis of spectroscopic data. Compound 1 (10-carboxy and 3α-hydroxy) and compounds 3–6 (10-hydroxy) contain unique substituents that are rarely found in cardiac glycosides. The cytotoxic effects of isolated compounds against ten human cancer cell lines, KB, KB-VIN, A549, MCF-7, U-87-MG, PC-3, 1A9, CAKI-1, HCT-9 and S-KMEL-2, were tested using the sulforhodamine B assay. Five compounds (12, 16, 20, 22, and 31) showed significant cytotoxicity against all ten cancer cell lines, with notable potency at the ng/mL level against some cell lines, which merits further development as clinical trial candidates.     

Chemical constituents from Gentianella turkestanorum (Gentianaceae)

Phytochemical investigation of Gentianella turkestanorum (Gentianaceae) afforded nineteen compounds, including six xanthones (1–6), two triterpenoids (7–8), eight flavones (9–16) and three iridoids (17–19). Here, we firstly reported that 1-hydroxy-3,5-dimethoxyxanthone (4), 1, 8-dihydroxy-3-methoxyxanthone (5), apigenin (9), quercetin (10), luteolin-7-O-glucoside (12) and three other compounds (1, 8-dihydroxy-3-methoxyxanthone (5), apigenin-7-O-gluco (1″ → 3‴) glucoside (15) and luteolin-7-O-gluco (1″ → 3‴) glucoside (16)) could be isolated from G. turkestanorum. The occurrence of chemical data and the sequence data might be employed as common constituents of the genera Gentianella, Lomatogonium and Swertia.     

Chemical constituents of Peperomia tetraphylla (Forst. F.) Hooker et Arnott

Sixteen compounds were isolated from the whole herbs of Peperomia tetraphylla (Forst. F.) Hooker et Arnott by phytochemical methods, including eight flavonoids (1–3, 6, 7, 14–16), three lignans (8–10), three beta sitosterols (4, 5, 11), and two phenolic acids (12, 13). Their structures were identified by the analysis of NMR and MS, as well as the comparisons to the reported data. Among them, 2″-O-xylosylisoswertisin (14) was firstly isolated from the Piperaceae family, as well as ten compounds (1–4, 7, 10–11, 13, 15–16) were isolated from P. tytraphylla for the first time. Moreover, the chemotaxonomic significance of constituents isolated from P. tytraphylla was also discussed.     

Phytochemical investigation of Eremostachys moluccelloides Bunge (Lamiaceae)

Phytochemical investigation of the aerial parts of Eremostachys moluccelloides Bunge led to the identification of a new diterpene, 2β,14-dihydroxy −11-formyl- 12-carboxy-13-des-isopropyl-13-hydroxymethyl-abieta-8,11,13- triene- 16(17)- lactone (1), along with the known compounds 12, 18-dicarboxy-14-hydroxy-13-des -isopropyl-13-hydroxymethyl- abieta-8,11,13-triene-16(17)-lactone (2), 5-hydroxy-3′,4′,7-trimethoxyflavone (3), 5-hydroxy-4’,7-dimethoxyflavone (4), luteolin-7-O-β-glucoside (5), verbascoside (6), luteolin 7-O-(6″-O-β-D-apiofuranosyl) -β-D-glucopyranoside (7), chlorogenic acid (8), echinacoside (9), apigenin-7-O-β-D-glucoside (10), p-coumaric acid (11), vanillic acid (12), apigenin-7-O-(6″-E-p-coumaroyl)-β-D-glucopyranoside (13), apigenin-7-O-(3″,6″-E-p-dicoumaroyl)-β-glucoside (14), lamalbide (15), 6β-hydroxy-7-epi-loganin (16), phloyoside II (17) The structures were elucidated on the basis of 1D and 2D NMR spectroscopy, UV, MS and by comparison with compounds previously reported in the literature. Compounds 1–4, 8, 9, 11, 12, 14 have not been reported previously from any species within the genus Eremostachys. Compounds 1–14, 17 were obtained from this species for the first time. The chemotaxonomic significance of the isolated compounds is discussed.     

Chemical constituents from the leaves of Cinnamomum parthenoxylon (Jack) Meisn. (Lauraceae)

Phytochemical investigation of the ethanolic extract from the leaves of Cinnamomum parthenoxylon (Jack) Meisn. led to the isolation of (3R, 4R, 3′R, 4′R)-6,6′-dimethoxy-3, 4, 3′, 4′-tetrahydro-2H, 2′H-[3, 3′]bichromenyl-4, 4′-diol (1), 4-hydroxybenzaldehyde (2), 1,2,4-trihydroxybenzene (3), kaempferol-3-O-α-l-rhamnoside (4), herbacetin (5), quercetin-3-O-α-l-rhamnoside (6), daucosterol (7), and β-sitosterol (8). The structures were established by extensive analysis of their MS and NMR spectroscopic data and comparison with literature data. In the present research, all of the isolated compounds 1–8 are reported for the first time in the species C. parthenoxylon. Compounds 1–6 were firstly isolated from genus Cinnamomum. Compounds 1, 3, 5 and 6 have not been reported from any species in Lauraceae family. The chemotaxonomic significance of the isolated compounds is discussed.     

Phytochemical and chemotaxonomic study on Dianella ensifolia (L.) DC

Phytochemical investigation of the roots of Dianella ensifolia led to the isolation of eleven known compounds, including two aromatics (1, 2), two chromones (3, 4), and seven flavonoids (5–11). The structures of these compounds were elucidated on the basis of spectral analysis and comparison with data reported in literature. In the present research, all of the isolated compounds 1–11 were reported for the first time in the species D. ensifolia. Compounds 1–4 and 7–11 were firstly isolated from the genus Dianella. Compounds 1, 2, 8, and 9 have not been reported from any species in Liliaceae family. The chemotaxonomic significance of the isolated compounds was summarized.     

Ulmosides A and B: Flavonoid 6-C-glycosides from Ulmus wallichiana,stimulating osteoblast differentiation assessed by alkaline phosphatase

Chemical investigation of Ulmus wallichiana stem bark resulted in isolation and identification of three new compounds (2S,3S)-(+)-3′,4′,5,7-tetrahydroxydihydroflavonol-6-C-β-d-glucopyranoside (1), (2S,3S)-(+)-4′,5,7-trihydroxydihydroflavonol-6-C-β-d-glucopyranoside (3) and 3-C-β-d-glucopyranoside-2,4,6-trihydroxymethylbenzoate (8), together with five known flavonoid-6-C-glucosides (2, 4–7). Their structures were elucidated using 1D and 2D NMR spectroscopic analysis. The absolute stereochemistry in compounds 1 and 3 were established with the help of CD data analysis and comparison with the literature data analysis. All the isolated compounds (1–8) were assessed for promoting the osteoblast differentiation using primary culture of rat osteoblast as an in vitro system. Compounds 1–3 and 5 significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity.     

Chemical constituents of Gardneria ovata wall

A phytochemical investigation on the aerial parts of Gardneria ovata Wall resulted in the isolation and identification of 14 compounds, including three gardneria glycoalkaloids (1–2 and 6), seven gardneria alkaloids (3–5 and 7–10), and four oxindole alkaloids (11–14). The structure of compound 1 was elucidated by means of spectroscopic analysis, including HRESIMS together with 1D and 2D NMR experiments. Compounds 1–2 and 11–14 are the first time reported from of G. ovate, while the compounds 3–4, 6, and 8 are also the characteristic secondary metabolites of the title plant. The chemotaxonomic significance and distribution of these monoterpenoid indole alkaloids in Gardneria genus are discussed.     

Chemical constituents from Laggera pterodonta

A phytochemical investigation on the aerial parts of Laggera pterodonta resulted in the isolation and identification of fourteen compounds, including six sesquiterpenoids (1–6), five flavonoids (7–11), one lignan (12), and two pyrrole alkaloids (13, 14). Among them, compounds 1–3, 7–9, and 11 are the characteristic class of secondary metabolites of L. pterodonta. Compounds 4 and 5 were firstly isolated from L. pterodonta and this is the first report of the presence of compounds 6, 10, and 12 from the genus Laggera. Pyrrole alkaloids 13 and 14 may serve as potential chemotaxonomic markers for L. pterodonta and could be used to distinguish among species of Compositae.     

Sterols,aromatic compounds,and cerebrosides from the Hericium erinaceus fruiting body

Chemical investigation of the methanolic extract from the fruiting bodies of Hericium erinaceus, led to the isolation of fifty-one compounds including thirty-five ergostane-type sterols (1–35), fourteen aromatic compounds (36–49), and two cerebrosides (50 and 51). Their structures were identified based on spectroscopic analyses and by comparison of their spectral data with those reported in literature. This is the first comprehensive low-polarity chemical investigation of H. erinaceus. Thirty-one of the compounds (6–8, 11–35, 39, 41, and 49) were isolated for the first time from the genus Hericium and the family Hericiaceae. The chemotaxonomic relationship between H. erinaceus and other Hericium species was also discussed.     

Fatty acid derivatives and dammarane triterpenes from the glandular trichome exudates of Ibicella lutea and Proboscidea louisiana

Ibicella lutea and Proboscidea louisiana, both of the Martyniaceae family, are known for rich glandular trichomes on their leaves and stems. Chemical investigations of the glandular trichome exudates on leaves of the two plants furnished three types of secondary metabolites, glycosylated fatty acids, glycerides (2-O-(3,6-diacetyloxyfattyacyl)glycerols and 2-O-(3-acetyloxyfattyacyl)glycerols) and dammarane triterpenes. The glycosylated fatty acids from I. lutea were determined to be 6(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-octadecanoic acid (1A), -eicosanoic acid (1B) and -docosanoic acid (1C), as well as their respective deacetyl congeners (2A, 2B and 2C), whereas P. louisiana furnished 8(S)-(6-O-acetyl-β-d-glucopyranosyloxy)-eicosanoic acid (3A) and -docosanoic acid (3B) and their respective deacetyl congeners (4A and 4B), together with 2B. Both plants contained 12 identical 2-O-[(3R,6S)-3,6-diacetyloxyfattyacyl]glycerols (5A-L), in which the fatty acyl moieties contained between 17 and 21 carbon atoms. The corresponding mono-acetyloxy compounds, 2-O-[(3R)-3-acetyloxyfattyacyl]glycerols (6A–L) were detected in both plants. Among these glycerides, ten compounds (5A, 5C, 5F, 5H, 5K, 6A, 6C, 6F, 6H and 6K) had iso-fattyacyl structures and four (5E, 5J, 6E and 6J) had anteiso-fattyacyl structures. A previously unknown dammarane triterpene, betulatriterpene C 3-acetate (7), was isolated together with three known dammarane triterpenes, 24-epi-polacandrin 1,3-diacetate (8), betulatriterpene C (9) and 24-epi-polacandrin 3-acetate (10) from I. lutea, whereas 12 dammarane triterpenes, named probosciderols A–L (12–23), and the known compound betulafolienetriol (11) were isolated from P. louisiana. The structures of these compounds were elucidated by spectroscopic analysis including 2D-NMR techniques and chemical transformations. The 6-O-acetylglucosyloxy-fatty acids 1A–C (42%) and the dammarane triterpenes 7–10 (31%) were the two most abundant constituents in the glandular trichome exudate of I. lutea, whereas the dammarane triterpenes 11–23 (47%) and the glucosyloxy-fatty acids (4A, 4B and 2B) (38%) were the most abundant constituents in the glandular trichome exudate of P. louisiana.     

Topoisomerase II inhibitors from the roots of Stellera chamaejasme L.

Three new compounds, including one daphnane diterpene (1), one sesquiterpene (6), and one lignan (7) have been isolated from the Stellera chamaejasme L., together with five other known compounds, including four daphnane diterpenenoids (2–5) and one lignan (8). The structures of the new compounds were elucidated by spectroscopic analysis. The cytotoxicities of compounds 1–8 towards human lung adenocarcinoma cells (A549 cells) were evaluated using a sulforhodamine B assay. All of the compounds displayed significant cytotoxicity, with IC₅₀ values in the ranging of 0.2 nM to 2.0 μM. Mechanistic studies revealed that the antitumor activities of compounds 1–3 and 7 were derived from their inhibition of topoisomerase II (Topo II). Furthermore, as a Topo II inhibitor, compound 1 was found to effectively induced G2-M phase cell cycle arrest and apoptosis in cancer cells.     

Phenolic constituents from the roots of Rosa laevigata (Rosaceae)

Chemical investigation of the root of Rosa laevigata led to the isolation of sixteen phenolic compounds, including seven flavonoids (1–7), five condensed tannins (8–12), two stilbenes (13 and 14) and two benzoic acid derivatives (15 and 16). Their structures were identified as (+)-catechin (1), (+)-gallocatechin (2), (2R, 3S, 4S)-cis- leucocyanidin (3), (2R, 3S, 4S)-cis-leucofisetinidin (4), (2S, 3R, 4R)-cis- leucofisetinidin (5), dehydrodicatechin A (6), phloridzin (7), procyanidin B3 (8), fisetinidol-(4α, 8)-catechin (9), guibourtinidol- (4α, 8)-catechin (10), ent- isetinidol -(4α, 6)-catechin (11), fisetinidol-(4β, 8)-catechin (12), (Z)-3-methoxy-5-hydroxy- stilbene (13), (Z)-piceid (14), gallic acid (15) and 4-hydroxybenzoic acid- 4-O-β-D-glucopyranoside (16). Among them, compounds 3–7, 9–14, and 16 were isolated from R. laevigata for the first time, and compounds 3–7, 9, 10, 12–14 and 16 were reported for the first time from the genus Rosa. The chemotaxonomic significance of these compounds was summarized.     

Phytochemical study on the leaves of Wollemia nobilis

In this work, a phytochemical study performed on the leaves of the rare species, Wollemia nobilis W.G. Jones, K.D. Hill & J.M. Allen, is reported. By means of classical column chromatography and NMR Spectroscopy and Mass Spectrometry, nine compounds were evidenced. These were: pheophorbide a (1), isocupressic acid (2), acetyl-isocupressic acid (3), sandaracopimaric acid (4), agathic acid (5), 7–4′-4‴-tri-O-methyl-agathisflavone (6), 7–4′-7″-4‴-tetra-O-methyl-agathisflavone (7), caffeic acid (8) and shikimic acid (9). Compared to our previous phytochemical analysis on the male cones, some further compounds were identified i.e. compounds 1, 5, 6, 7 and 8. This confirmed the previous chemotaxonomic considerations of the species but also added new ones which were discussed within the text. In addition, a possible different accumulation of secondary metabolites in the tissues and organs of this plant was even noticed.     

A new methoxylated flavone from Lonicera hypoglauca and its chemotaxonomic significance

Phytochemical investigation of the stems and leaves of Lonicera hypoglauca Miq. led to the isolation of one novel methoxylated flavone, acunminatin (7,2′,4′-trihydroxyl-5,5′- methoxyflavone) (1), and fourteen known compounds (2–15), including six flavonoids (mearnsetin 2, kaempferol 3, acacetin 4, 5,7,3′,4′-tetramethoxyflavone 5, tricin 6, and 5,7,3′,4′,5′-pentamethoxyflavone 7), two coumarins (umbelliferone 8 and scopoletin 9), two phenylpropanoids (trans-ferulic acid 10 and chlorogenic acid 11), two iridoid glycosides (loganin 12 and sweroside 13), and two triterpenoids (uvaol 14 and ursolic acid 15). The structures of the compounds were identified by spectroscopic analysis and by comparing their spectral data with those reported in the literature. Five of these compounds (1, 2, 4, 5, and 7) were isolated from the L. genus for the first time, and compounds 6–8 and 14–15 were isolated for the first time from L. hypoglauca. The chemotaxonomic significance of the isolated compounds in the L. genus and the Caprifoliaceae family are discussed herein.     

Chemical constituents from Melodinus cochinchinensis (Lour.) Merr. and their chemotaxonomic significance

A phytochemical investigation on the twigs and leaves of Melodinus cochinchinensis (Lour.) Merr. resulted in the isolation and identification of 22 compounds, including seven sesamin-type lignans (1–7), three pentacyclic triterpenes (8–10), one anthraquinone (11), one flavanone (12), two phenolic compounds (13 and 14), five aspidosperma-type indole alkaloids (15–19), and three eburnan-type indole alkaloids (20–22). The structures of these compounds were elucidated by means of spectroscopic analysis, including HREIMS together with 1D and 2D NMR experiments, and comparison with reported data. Among them, compounds 1/4, 2/5, and 3/6 are three pairs epimers at C-7''. Compounds 1–6, 8 and 11 were firstly isolated from the family Apocynaceae, whereas 17 was isolated from Melodinus species for the first time. Compound 8 was only found in Juglans hopeiensis, while 11 was only found in roots of Rubia cordifolia. Compounds 1–6, 8, 11 and 15–22 could be considered as chemotaxonomic markers for M. cochinchinensis. Furthermore, the chemotaxonomic significance and distribution of these isolates in Melodinus genus are discussed in detail.     

Phytochemical and chemotaxonomic study on the Lichen Lethariella cladonioides

The comprehensive phytochemical research of Lethariella cladonioides (Nyl.) Krog, (Parmeliaceae), a lichen in southwest China, resulted in isolation of eighteen compounds (1–18), including a new phenolic acid 3,5-dihydroxy-4-methylbenzaldehyde (1) and seventeen known compounds, nine phenolic acids (2–10), one dibenzofuran (11), two depsides (12 and 13), one alkane (14), one glucoside (15), two polyols (16 and 17), and one fatty acid (18). The structures of these compounds were assigned by detailed interpretations of spectroscopic data (1D and 2D NMR, HR-ESI-MS) and comparisons with the published data. Among them, 3,5-dihydroxy-4-methylbenzaldehyde (1) is a new one. (−)-hydroxypropan-2′,3′-diol-orsellinate (10) have not been reported from any species in the lichens. Compounds 6, 7, 9, 12, 14, 16 and 18 were firstly isolated from the genus Lethariella (Motyka) Krog. Compounds 2, 6, 7, 9, 10, 12, 14, 16 and 18 were reported from L. cladonioides firstly. The chemotaxonomic significance of these compounds was also discussed.     

Chemical constituents of the roots of Scorzonera divaricata and their chemotaxonomic significance

The phytochemical study of the roots of Scorzonera divaricata Turcz led to the isolation of 27 compounds, including eight sterols (1–8), one lignan (9), two cumarins (10, 11), five phenylpropanoids (12–16), six benzene derivatives (17–22), methyl-β-D-fructofuranoside (23), monolinolein (24), and three aliphatic acids (25–27). The structures of isolated compounds were identified using NMR and ESI-MS spectroscopic methods and comparing them with those previously reported. Except for β-daucosterol (8), scopoletin (10) and caffeic acid (16) from S. divaricata, this is the first report of the other 24 compounds from S. divaricata. Among them, eleven compounds (2–6, 11, 17, 19, 20, 23, 25) were reported from genus Scorzonera for first time, suggesting that they could be used to distinguish S. divaricata from the other species of Scorzonera. Furthermore, the chemotaxonomic significance of isolated compounds from S. divaricata has also been discussed.     

Chemical constituents from Cistanche sinensis (Orobanchaceae)

Phytochemical investigation of 70% aqueous EtOH extract of Cistanche sinensis led to the isolation of fifteen compounds (1–15), including nine phenylethanoid glycosides (PhGs, 1–9), five iridoid glycosides (10–14), and one lignan glycoside (15). Their structures were determined on the basis of 1D- and 2D-NMR experiments and by comparison with physical data of known compounds. Among the isolated compounds, 1 was identified as a new compound, three compounds (9, 14, and 15) were firstly reported from the genus Cistanche, and seven compounds (2–6, 11, and 12) were isolated from C. sinensis for the first time. PhGs with a 6′-O-rhamnosyl moiety such as cistansinenside B (1), poliumoside (7), and 2′-O-acetylpoliumoside (9) could serve as chemotaxonomic markers to differentiate C. sinensis from other species of Cistanche.