Humirianthenolides,new degraded diterpenoids from Humirianthera rupestris

The tuber of Humirianthera rupestris (Icacinaceae) contains the degraded diterpenoids 3β,20-epoxy-30α- hydroxy- 14-oxo-9β-podocarpan-19,6β-olide (humirianthenolide A), 3β,20-epoxy-3α,14α-dihydroxy-9β-podocarpan-19,6β- olide (humirianthenolide B), 3β,20; 16,14-diepoxy-3α-hydroxy-17-nor-15-oxo-9β-abiet-13-en-19,6β-olide (humirianthenolide C), 3β,20-epoxy-3α,14-dihydroxy-13-oxo-9β-podocarp-8(14)-en-19,6β-olide (humirianthenolide D), 3β,20-epoxy-3α-hidroxy-14-oxo-8α,9β-podocarpan-19,6β-olide (humirianthenolide E) and 3β,20-epoxy-3α,14β- dihydroxy-8α,9β-podocarpan-19,6β-olide (humirianthenolide F). ¹H NMR and ¹³C NMR spectroscopy were efrective for the determination of the humirianthenolide structures.     

Sterols with unusual nuclear unsaturation from three cultured marine dinoflagellates

Several new 4α-methyl sterols with unusual unsaturation in the Δ⁸⁽¹⁴⁾-or Δ¹⁴-positions, 4α,24S-dimethyl-5α-cholest-8 (14)-en-3β-ol, 4α-methyl-24ξ-ethyl-5α-cholest-8(14)-en-3β-ol, 4α-methyl-24(Z)-ethylidene-5α-cholest-8(14)- en-3β-ol, 4α,23 (or 22),24ξ-trimethyl-5α-cholesta-8(14),22-dien-3β-ol, 4α,24S(or 23ξ)-dimethyl-5α-cholest-14-en-3β-ol and 14-dehydrodinosterol, have been isolated from extracts of the cultured marine dinoflagellates Amphidinium carterae, A. corpulentum and Glenodinium sp. 4α-Methyl-24ξ-ethyl-5α-cholestan-3β-ol was isolated from the steryl ester fraction of Glenodinium sp. The structures of these new sterols are based upon extensive 360 MHz ¹H NMR and MS analyses.     

Glechomanolides and eudesmanolides from Smyrnium perfoliatum

In addition to five known sesquiterpenoids, six new compounds were isolated from Smyrnium perfoliatum. The new compounds were 1β-acetoxy-eudesma-3,7(11),8-trien-8,12-olide, 1β-acetoxyeudesma-4(15),7(11),8-trien-8,12-olide, 1β-10α;4α,5β-diepoxy-8β-isobutoxy-glechomanolide, 1β, 10α;4α,5β-diepoxy-8α-isobutoxy-glechomanolide, 1β,4α-dihydroxy-2α,3α-epoxy-eudesma-7(11),8-dien-8,12-olide, 1β,4α-dihydroxy-2α,3α-epoxy-8β-methoxy-eudesma-7(11)-en-8α,12-olide.     

Roles of Fe-Histidine bonds in stability of hemoglobin: Recognition of protein flexibility by Q Sepharose

Using various mutants, we investigated to date the roles of the Fe-histidine (F8) bonds in cooperative O₂ binding of human hemoglobin (Hb) and differences in roles between α- and β-subunits in the α₂β₂ tetramer. An Hb variant with a mutation in the heme cavity exhibited an unexpected feature. When the β mutant rHb (βH92G), in which the proximal histidine (His F8) of the β-subunit is replaced by glycine (Gly), was subjected to ion-exchange chromatography (Q Sepharose column) and eluted with an NaCl concentration gradient in the presence of imidazole, yielded two large peaks, whereas the corresponding α-mutant, rHb (αH87G), gave a single peak similar to Hb A. The β-mutant rHb proteins under each peak had identical isoelectric points according to isoelectric focusing electrophoresis. Proteins under each peak were further characterized by Sephadex G-75 gel filtration, far-UV CD, ¹H NMR, and resonance Raman spectroscopy. We found that rHb (βH92G) exists as a mixture of αβ-dimers and α₂β₂ tetramers, and that hemes are released from β-subunits in a fraction of the dimers. An approximate amount of released hemes were estimated to be as large as 30% with Raman relative intensities. It is stressed that Q Sepharose columns can distinguish differences in structural flexibility of proteins having identical isoelectric points by altering the exit rates from the porous beads. Thus, the role of Fe-His (F8) bonds in stabilizing the Hb tetramer first described by Barrick et al. was confirmed in this study. In addition, it was found in this study that a specific Fe-His bond in the β-subunit minimizes globin structural flexibility.     

Two new eudesmane sesquiterpenoids from Daucus carota L.

Two new eudesmane sesquiterpenoids were isolated from the fruits of Daucus carota L. The structures were established based on the interpretation of high-resolution MS and 1D- and 2D-NMR data, the absolute configuration of compound 1 was determined by single-crystal X-ray diffraction. The new compounds were elucidated as (1βH, 3βH, 5βH, 7αH)-4α, 10α-dimethyl-7β-isopropyl-1α, 3α, 4β, 11-tetrahydroxy decahydronaphthalene (1) and (1βH, 3βH, 5βH, 7αH)-4α, 10α-dimethyl-7β-isopropyl-1α, 3α, 4β-trihydroxy decahydronaphthalene-11-O-β-d-glucopyranoside (2). The compound 1 showed significant antioxidant activity.     

Cleavage of oligosaccharides by rat kidney sialidase Influence of substrate structure

The specificity of the sialidase activity present in rat kidney cortex (12 000 × g pellet) was studied with various tritiated oligosaccharidic substrates: (i) αNeuAc2 → 3βGall → 4Glc-itol[³H], αNeuAc2 → 6βGall → 4Glc-itol[³H] and αNeuAc2 → 8αNeuAc2 → 3βGall → 4Glc-itol[³H] from bovine colostrum; (ii) α-NeuAc2 → 6βGall → 4βGlcNAc-itol[³H], αNeuAc2 → 3βGal1 → 4βGlcNAcl → 2αManl → 3βMan1 → 4GlcNAc-itol[³H]. αNeuAc2 → 6βGall → 4βGlcNAcl → 2αManl α 3(βGall → 4GlcNAcl → 2αManl → 6)βManl → 4GlcNAc-itol [³H]et αNeuAc2 → 6βGall → 4βGlcNAcl → 2αManl-3(αNeuAc2 → 6βGall → 4βGlcNAcl → 2αManl → 6)βManl 4GlNAc-itol[³H] isolated from the urine of a patient with mucolipidosis I. The enzyme cleaves α2 → 3 and α2 → 8 linkages at a greater rate than the α2 → 6 bonds. Its activity decreases with the length of the oligosaccharidic chain. Substitution of a glucose moiety by Nacetylglucosamine results in diminished activity. The specificity of rat kidney sialidase differs from that reported for other mammalian of viral sialidases.     

Sesquiterpene lactones,flavonoids and anthraquinones from Asphodeline globifera and Asphodeline Damascena

The known compounds chrysoeriol, apigenin, luteolin, acacetin, scutellarein, 6-methoxyluteolin, apigenin 7-glucoside, luteolin 7-glucoside, esculetin, chrysophanol, asphodeline, mircocarpin, sitosterol, 1-β-acetoxyeudesman-4(15),7(11)dien-2α,12-olide and 1-β-acetoxy-8β-hydroxyeudesman-4(15),7(11)-dien-8α,12-olide were isolated from Asphodeline globifera and A. damascena. A new sesquiterpene lactone 1-β-acetoxy-8β-ethoxyeudesman-4(15),7(11)dien-8α, 12-olide was also characterized. These are the first reports of sesquiterpene lactones in Asphodeline and in the Liliaceae.     

Steroidal saponins from the leaves of Cordyline fruticosa (L.) A. Chev. and their cytotoxic and antimicrobial activity

Three new steroidal saponins, spirosta-5,25(27)-diene-1β,3β-diol-1-O-α-l-rhamnopyranosyl-(1→2)-β-d-fucopyranoside (fruticoside H) 1, 5α-spirost-25(27)-ene-1β,3β-diol-1-O-α-l-rhamnopyranosyl-(1→2)-(4-O-sulfo)-β-d-fucopyranoside (fruticoside I) 2, and (22S)-cholest-5-ene-1β,3β,16β,22-tetrol 1-O-β-galactopyranosyl-16-O-α-l-rhamnopyranoside (fruticoside J) 3, together with the known quercetin 3-O-β-d-glucopyranoside, quercetin 3-O-[6-trans-p-coumaroyl]-β-d-glucopyranoside, quercetin 3-rutinoside, apigenin 8-C-β-d-glucopyranoside and farrerol, were isolated from the leaves of Cordyline fruticosa. Their structures were elucidated by spectroscopic techniques (¹H NMR, ¹³C NMR, HSQC, ¹H–¹H COSY, HMBC, TOCSY, NOESY), mass spectrometry (HRESIMS, Tandem MS–MS), chemical methods and by comparison with published data. Compounds 1 and 2 showed moderate cytotoxic activity against MDA-MB 231 human breast adenocarcinoma cell line, HCT 116 human colon carcinoma cell line, and A375 human malignant melanoma cell line, while compound 3 was not active. Compound 2 also showed a moderate antibacterial activity against the Gram-positive Enterococcus faecalis.     

Rare hydroperoxyl guaianolide sesquiterpenes from Pulicaria undulata

Pulicaria species, such as Pulicaria undulata, are rich in sesquiterpene lactones. The methylene chloride/methanol (1:1) extract of P. undulata resulted in the isolation of new sesquiterpenes (1–4), as well as previously reported metabolites (5–14). Structures were elucidated by spectroscopic analyses. Using a mouse peritoneal macrophage bioassay, lipopolysaccharide-induced nitric oxide inhibition was observed with the eudesman-type sesquiterpene 1β,4β-dihydroxy-5αH,7αH,8α-guaia-10(14),11(13)-dien-8β,12-olide (11) at an EC₅₀ of 7.2 μM.     

Sesquiterpene lactones of Helianthus gracilentus

A series of four 2α-hydroxy-8β-acyloxygermacrolides and the heliangolide niveusin A were isolated from a dichloromethane extract of Helianthus gracilentus. The germacrolides include a new compound, 2α-hydroxy-8β-isovaleroyloxycostunolide. The terpenoid constituents of H. gracilentus are very similar to those of H. pumilus, which on morphological grounds is considered to be closely related to H. gracilentus.     

Terpenoids and other constituents from Euphorbia bupleuroides

The phytochemical investigation of the roots of Euphorbia bupleuroides Desf. (Euphorbiaceae) yielded three new compounds named 4,20-dideoxy(4α)phorbol-12-benzoate-13-isobutyrate (1), 25-hydroperoxycycloart-3β-ol (2), and 3β,7β-dihydroxy-4α,14α-dimethyl-8β,9β-epoxy-5α-ergosta-24(28)-ene (3), together with 17 known compounds 4–20. Their structures were established from analysis of 1D (¹H, ¹³C and DEPT) and 2D NMR (COSY, HSQC, HMBC and NOESY) data, and of mass spectrometry (HRESIMS), and by comparison with literature data.     

A New Phenolic Glycoside from Chloranthus multistachys(Chloranthaceae)

A new phenolic glycoside, named syringic acid-4-O-α-L-rhamnopyranoside (1), together with three known compounds were isolated from the MeOH extract of the whole plants of Chloranthus multistachys. Their structures were elucidated on the basis of extensive spectroscopic. To the best of our knowledge, the three known compounds, 1β,4β-dihydroxy-5α, 8β(H)-eudesm-7 (11) Z-en-8, 12-olide (2), 1β, 4α-dihydroxy-5α, 8β(H)-eudesm-7 (11) Z-en 8, 12-olide (3), and (–) (7S,8R) dihydrodehydrodiconifery alcohol (4) were all isolated from this plant for the first time.     

New steroidal saponins of Agave americana

Two new saponins, agavasaponin E and agavasaponin H have been isolated from the methanolic extract of Agave americana leaves and their structures elucidated. Agavasaponin E is 3-O-[β-d-xylopyranosyl-(1→2glc1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-α-d-galactopyranosyl]-(25R)-5α-spirostan-12-on-3β-ol, whereas agavasaponin H is 3-O-[β-d-xylopyranosyl-(1→2 glc 1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3 glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-β-d-galactopyranosyl]-26-O-[β-d-glucopyranosyl]-(25R)-5α-furostan-12-on-3β,22α,26-triol.     

Chemotaxonomic significance of lindenane sesquiterpenoid dimers and eudesmane sesquiterpenoids from Chloranthus henryi Hemsl. var. hupehensis (Pamp.) K. F. Wu

Seventeen known compounds were isolated from the 95% alcohol extract of the aerial parts of Chloranthus henryi Hemsl. var. hupehensis (Pamp.) K. F. Wu, including five lindenane sesquiterpenoid dimers (1–5) and twelve eudesmane sesquiterpenoids (6–17). In the present research, compounds 3 sarcaglabrin C, 6 neolitacumone C, 7 ent-Atractylenolide III and 8 dehydrocarissone were reported from the Chloranthus genus for the first time, and compounds 1 spicachlorantin B, 2 chloramultilide C, 4 shizukaol B, 5 japonicone C, 9 6α-hydroxyeudesma-4(15),7(11),8(9)-triene-12,8-olide, 10 ent-(3R)-3-hydroxyatractylenolide III, 11 8βH-hydroxyeudesma-4(14),7(11)-dien-12,8-olide, 12 lasianthuslactone A, 13 (5S,6R,8S,10R)-6-hydroxyeudesma-4(15),7(11)-diene-12,8-olide, 14 4β-hydroxy5α,8β(H)-eudesm-7(11)-en-8,12-olide, 15 4β,8β-dihydroxy-5α(H)-eudesm-7(11)-en-8,12-olide, 16 curcolonol and 17 1β, 8β-dihydroxyeudesm - 3,7(11)-dien-8α,12-olide were firstly isolated from the plant. Their structures were elucidated on the basis of extensive spectroscopic and chemical analyses. Moreover, the chemotaxonomic significance of the isolated compounds is discussed.     

Dominance of Δ5-sterols in eight species of the cactaceae

The sterols from eight species in seven genera of the Cactaceae are 24-alkyl-Δ⁵-sterols. In all eight species, Echinopsis tubiflora, Pereskia aculeata, Hylocereus undatus, Notocactus scopa, Epiphyllum sp., Schlumbergera bridgesii, Opuntia comonduensis and O. humifusa, the dominant sterol is sitosterol (24α-ethylcholest-5-en-3β-ol) at 66–87% of the total sterol composition with the 24ξ-methylcholest-5-en-3β-ol present at 8–33%. Stigmasterol (24α-ethylcholesta-5,22E-dien-3β-ol) is present at 2–8% of the total sterol in P. aculeata, H. undatus, N. scopa and Epiphyllum sp. whereas cholesterol (cholest-5-en-3β-ol) is present in six species at levels of <0.1–5.0%. Avenasterol (24-ethylcholesta-7,24(28)Z-dien-3/gb-ol) and sitostanol (24α-ethyl-5α-cholestan-3β-ol) are each present in two species.     

Sesquiterpene lactones from Artemisia maritima

Two new sesquiterpene lactones have been isolated from Artemisia maritima and the structures have been assigned on the basis of their spectral properties as 1-oxo-6β,7α,11βH,14β-methylgermacra-4(5)-ene-12,6-olide and 1-oxo-6β,7α,11βH-germacra-4(5),10(14)-dien-12,6-olide.     

Solanopubamides a and b,two further steroidal alkaloids from solanum pu bescens

Two new steroidal alkaloids, solanopubamides A and B, were isolated from the aerial parts of Solanum pubescens. Their structures were elucidated as 3β-formylamino-5α,22αH,25βH-solanidan-23β-ol (solanopubamine A) and 3β-acetylamino-5α,22αH,25βH-solaiiidan-23β-ol (solanopunamide B) by spectral and chemical methods.     

Sesquiterpene lactones from Smyrnium cordifolium

In addition to previously obtained furanosesquiterpenes, two new eudesmanolides and a new glechomanolide were isolated from the fruits of Smyrnium cordifolium, while the roots gave two new eudesmanolides. The new compounds from the fruits were 1β-acetoxy-eudesman-4(15), 7(11)-dien-8,12-olide, 1β-acetoxy-8β-hydroxy-eudesman-4(15),7(11)-dien-8,12-olide, 1β,10α;4α,5β-diepoxy-8-hydroxy-glechomanolide, those obtained from the roots were smyrnicordiolide and the corresponding 8β-hydroxy derivative belonging to a new type of oxepine derivative.     

Two new cembranic diterpenoids from the flowers of Nicotiana tabacum L.

Two new cembranoids, together with fifteen known ones, were isolated from the flowers of Nicotiana tabacum L. The structures of the new compounds were established as (1βH,2E,4αOH,6αOH,7E,10αH,11αH,12βOH)-10,11-epoxy-2,7-cembradiene-4,6,12-triol (1) and (1βH,2E,4αOH,6αOH,7E,10βH,11βH,12αOH)-10,11-epoxy-2,7-cembradiene-4,6, 12-triol (2) by using spectroscopic analysis, including HRESIMS, IR, one- and two-dimensional NMR. A plausible biogenetic relationship of the isolated cembranoids was proposed. The antitumor activities of selected compounds against a panel of three human cancer HepG2, A549 and HCT-116 cell lines were evaluated by the MTT assay. Compound 5 exhibited moderate activity against Hep-G2 cell lines with an IC₅₀ value of 14.38 μM.     

Antiproliferative and apoptotic sesquiterpene lactones from Carpesium faberi

Four new (1-4) and 13 known (5-17) sesquiterpene lactones along with two known diterpenes (18, 19) were isolated from the whole plant of Carpesium faberi. The new structures were elucidated by means of spectroscopic techniques and some chemical transformations to be pseudoguaian-1α(H)-8α,12-olide-4β-O-β-d-glucopyranoside (1), 4β,10α-dihydroxy-5α(H)-1,11(13)-guaidien-8α,12-olide (2), 4β,10β-dihydroxy-5α(H)-1, 11(13)-guaidien-8β,12-olide (3), and (4S)-acetyloxyl-11(13)-carabren-8β,12-olide (4). All isolates were tested against MCF-7 human breast cancer cells using the MTT assay. Among them, the sesquiterpene lactones (except tomentosin 17) possessing an α-methylene-γ-lactone moiety were found to have in vitro antiproliferative activities, with IC₅₀ values of 3.0-38.8 μg/mL. The effects of four selected sesquiterpene lactones (guaianolide 2, carabranolide 4, pseudoguaianolide 9, eudesmanolide 13) on the cell cycle were examined using flow cytometry (FCM).