Novel Diterpenoids from Salvia dugesii

Two novel rearranged clerodane diterpenoids, dugesin A ( 1 ) and dugesin B ( 2 ), were isolated from the aerial parts of Salvia dugesii, together with five known clerodane diterpenoids: isosalvipuberulin ( 3 ), salvipuberulin ( 4 ), tilifodiolide ( 5 ), salvifolin ( 6 ), and salvifaricin ( 7 ). Their structures were elucidated on the basis of different spectroscopic techniques. The isolation and identification of these compounds are significant from both biosynthetisis and chemotaxonomy points of view.     

An unusual bisnor-clerodane diterpenoid from Polyalthia simiarum

The stem bark of Polyalthia simiarum has yielded a new bisnor-type clerodane diterpenoid, 2-oxo-14,15-bisnor-3,11E-kolavadien-13-one (1), and three previously known clerodane derivatives, kolavenic acid (2), 16beta-hydroxycleroda-3,13(14)Z-dien-15,16-olide (3), and 16-oxocleroda-3,13(14)E-dien-15-oic acid (4). The structures of these compounds were unambiguously determined by extensive NMR studies as well as by comparison with related compounds. Till now this is the second report of the occurrence of any unusual C-18 clerodane diterpenoid from nature. The crude light petroleum extract and the purified compound 3 demonstrated moderate free radical scavenging activity with IC50 values of 21.5 and 23.5 microg/mL, respectively.     

Chemical constituents of malagasy liverworts, part V: prenyl bibenzyls and clerodane diterpenoids with nitric oxide inhibitory activity from Radula appressa and Thysananthus spathulistipus

3Beta,4beta:15,16-diepoxy-13(16),14-clerodadiene (1) and a new clerodane diterpenoid designated thysaspathone (2) were isolated from the liverwort Thysananthus spathulistipus, while Radula appressa produced radulannin A (3), radulannin L (4), 2-geranyl-3,5-dihydroxybibenzyl (5), 2(S)-2-methyl-2-(4-methyl-3-pentenyl)-7-hydroxy-5-(2-phenylethyl) chromene (o-cannabichromene) (6), 6-hydroxy-4-(2-phenylethyl) benzofuran (7), and o-cannabicyclol (8). All of the isolated compounds inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and the greatest inhibition was attributed to compound 5, with an IC50 value of 4.5 microM.     

Identification of minor secondary metabolites from the latex of Croton lechleri (Muell-Arg) and evaluation of their antioxidant activity

Dragon's blood (Sangre de drago), a viscous red sap derived from Croton lechleri Muell-Arg (Euphorbiaceae), is extensively used by indigenous cultures of the Amazonian basin for its wound healing properties. The aim of this study was to identify the minor secondary metabolites and test the antioxidant activity of this sustance. A bioguided fractionation of the n-hexane, chloroform, n-butanol, and aqueous extracts led to the isolation of 15 compounds: three megastigmanes, four flavan-3-ols, three phenylpropanoids, three lignans, a clerodane, and the alkaloid taspine. In addition to these known molecules, six compounds were isolated and identified for the first time in the latex: blumenol B, blumenol C, 4,5-dihydroblumenol A, erythro-guaiacyl-glyceryl-beta-O-4'- dihydroconiferyl ether, 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-propane-1,3-diol and floribundic acid glucoside. Combinations of spectroscopic methods ((1)H-, (13)C- NMR and 2D-NMR experiments), ESI-MS, and literature comparisons were used for compound identification. In vitro antioxidant activities were assessed by DPPH, total antioxidant capacity and lipid peroxidation assays. Flavan-3-ols derivatives (as major phenolic compounds in the latex) exhibited the highest antioxidant activity.     

Two New Furanoid Diterpenoids from Tinospora sagittata

Two new clerodane‐based furanoid diterpenoids, tinosagittones A and B ( 1 and 2 , resp.), were isolated from the roots of Tinospora sagittata, together with five known diterpenoids, i.e., columbin ( 3 ), its glucoside palmatoside C ( 4 ), isocolumbin ( 5 ), 6‐hydroxycolumbin ( 6 ), and tinophylloloside ( 7 ). Their structures were established by mass spectrometry and spectroscopic methods, especially 2D‐NMR techniques.     

A Benzofuranoid and Two Clerodane Diterpenoids from Pulicaria wightiana

Methyl 5‐formyl‐1‐benzofuran‐6‐carboxylate ( 1 ) and the two clerodane diterpenes, methyl 6‐oxocleroda‐3,13‐dien‐15,16‐olid‐18‐oate ( 2 ) and 2β‐(2‐methylbutanoyl)cleroda‐3,13‐dien‐15,16‐olid‐18‐oic acid ( 3 ), together with 15 known compounds, were isolated from the aerial parts of Pulicaria wightiana. The structures of the new compounds 1, 2 , and 3 were established by spectroscopic (mainly 1D‐ and 2D‐NMR) methods.     

Two New Diterpenes from Solidago canadensis

Two new clerodane‐type diterpenes, solidagocanins A and B ( 1 and 2 , resp.), as well as two known compounds, mellein ( 3 ) and physcion ( 4 ), were isolated from the aerial parts of Solidago canadensis. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR techniques.     

Dinorditerpene,Diterpenes, Alkaloids,and Coumarins from Clausena dunniana

The new dinorditerpene 14,15‐dinorclerod‐3‐ene‐2,13‐dione ( 2 ), the eight new clerodane diterpenes 4, 5, 7 – 10, 13 , and 14 , and the new furoquinoline alkaloid 15 , besides thirty known compounds, were isolated from the aerial part of Clausena dunniana collected in Xishuangbanna, the south of China. The structures were elucidated by spectroscopic analysis including 1D‐ and 2D‐NMR.     

Eight new clerodane diterpenoids from the bark of Ptychopetalum olacoides

Eight new clerodane type diterpenoids, named 7-oxo-kolavelool (1), 7alpha-hydroxykolavelool (2), 6alpha,7alpha-dihydroxykolavenol (3), 12-oxo-hardwickiic acid (4), ptycholide I (5), ptycholide II (6), ptycholide III (7), and ptycholide IV (8) were isolated from the MeOH extract of the bark of a Brazilian medicinal plant, Ptychopetalum olacoides. The structures of 1-8 were elucidated by analyzing spectroscopic data and by comparing their NMR data with those of the previously reported compounds kolavelool (la), kolavenol (3a), hardwickiic acid (4a), and ptychonolide (5a). Compounds 5 and 6 existed as a 1:1 mixture of inseparable epimers at C-15.     

Chemical Constituents from Croton insularis

Three new clerodane‐type terpenoids, furocrotinsulolide A ( 1 ), furocrotinsulolide B ( 2 ), and crotinsulactone ( 3 ), as well as a new phenolic disaccharide ( 4 ) have been isolated from the aerial parts of Croton insularis, together with eight known compounds. Their structures were established by in‐depth 1D‐ and 2D‐NMR spectroscopy, mass spectroscopy, and quantum‐mechanical calculations.     

Two new cytotoxic clerodane diterpenoids from Casearia membranacea

In addition to casearlucin A (3), two new clerodane diterpenes, caseamembrols A (1) and B (2) have been isolated from the leaves and twigs of Casearia membranacea by bioassay-guided fractionation. The structures of the new compounds were established on the basis of extensive 1D- and 2D-NMR spectroscopic analysis. Compounds 1-3 exhibited significant cytotoxicity against human prostate (PC-3) cancer cells.     

Cordifolide A, a sulfur-containing clerodane diterpene glycoside from Tinospora cordifolia

Cordifolide A (1), a novel unprecedented sulfur-containing clerodane diterpene glycoside, together with other two new diterpene glycosides, cordifolides B (2) and C (3), and four known analogues, was isolated from a methanol-soluble extract of the stems of Tinospora cordifolia. The structures of the new compounds were determined on the basis of spectroscopic data interpretation, with that of cordifolide A (1) confirmed by a single-crystal X-ray crystallographic analysis. All isolates were evaluated for their in vitro immunomodulatory activity using mouse bone marrow-derived dentritic cells (BMDCs).     

Three new diterpenoids from Leonurus japonicus

Phytochemical investigation of the aerial parts of Leonurus japonicus led to the isolation of one unusual clerodane diterpenoid,leojaponin A(1),characterized by a C4–C7oxa-bridge,and two new labdane diterpenoids,leojaponins B(2) and C(3).The structures of these new compounds were determined based on extensive 1D and 2D NMR spectroscopic data.To the best of our knowledge,compound 1 is the first clerodane diterpenoid obtained from Leonurus.japonicus.All of them were evaluated for their cytotoxicity.     

Nepetanal and nepetanoate: a new diterpene aldehyde and a benzene derivative ester from Nepeta juncea

One new tricyclic clerodane type diterpene aldehyde nepetanal (1) and one new benzene derivative nepetanoate (2) have been isolated from a plant Nepeta juncea together with two known compounds oleanolic acid (3) and ursolic acid (4). The structures of the isolated compounds were elucidated by means of modern spectroscopic techniques and comparison with literature data. Copyright © 2009 John Wiley & Sons, Ltd.     

A new ent-clerodane diterpenoid from Crassocephalum bauchiense Huch. (Asteraceae)

A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3′,5-dihydroxy-4′,5′,6,7,8-pentamethoxyflavone (2) and 4′,5-dihydroxy-3′,5′,6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC₅₀ = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially ¹H and ¹³C NMR, ¹H–¹H COSY, NOESY, HMBC and HR-ESI-MS.     

Novel microbial transformations of sclareolide

Fungal catalysis of sclareolide (1) using Mucor plumbeus (ATCC 4740), Cunninghamella blakesleeana (ATCC 9245), Cunninghamella echinulata (ATCC 9244), Curvularia lunata (ATCC 12017) and Aspergillus niger (ATCC 1004), was performed. Cunninghamella blakesleeana (ATCC 9245) metabolized compound 1 to afford O(6)-sclareolide (2), 3beta,6alpha-dihydroxysclareolide (3), 9-hydroxysclareolide (4), along with three known metabolites, 1beta,3beta-dihydroxysclareolide (5), 3-oxosclareolide (6) and 3beta-hydroxysclareolide (7). Biotransformation experiments of compound 1 with Cunninghamella echinulata (ATCC 9244) also yielded two new compounds, 5-hydroxysclareolide (8), and 7beta-hydroxysclareolide (9) along with two known compounds 5 and 7. Spectroscopic methods were used to establish the structures of compounds 2-9. Compounds 2-9 exhibited modest acetylcholinesterase inhibitory activity.     

Splendidins A – C,Three New Clerodane Diterpenoids from Salvia splendens

Three new clerodane diterpenoids, splendidins A–C ( 1 – 3 , resp.), were isolated from Salvia splendens, together with six known ones. Their structures were elucidated by extensive spectroscopic analysis. Splendidin C ( 3 ) was the first diterpenoid glucoside reported from this plant. These compounds were evaluated for their cytotoxic activity; however, none of them were cytotoxic.     

A novel iridoid from Boschniakia rossica

A novel iridoid, (4R)-4-hydroxymethylboschnialactone (1), has been isolated from Boschniakia rossica, together with three previously known compounds, (24S)-3beta-hydroxy-24-ethylcholest-5-en-7-one (2), (24R)-3beta-hydroxy-24-ethylcholest-5-en-7-one (3) and methyl p-coumarate, using column chromatography. The structures of compounds were elucidated by spectroscopic methods.     

A new steroidal glycoside from the Ophiopogon japonicus Ker-Gawler (Liliaceae)

A new steroidal glycoside (1), (25R)-14α, 17α-hydroxyspirost-5-en-3β-yl 3-O-α-L-rhamnpyranosyl-(1 → 2)-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranoside, together with three known steroidal glycosides, (25R)-3β-hydroxyspirost-5-en-1β-yl-3-O-α-L-rhamnopyranosyl-(1 → 2)-O-β-D-xylopyranosyl-(1 → 3)-α-L-arabinopyranoside (2), Cixi-ophiopogon B (3) and Cixi-ophiopogon A (4), were obtained from the tuberous roots of Ophiopogon japonicus (Liliaceae). Compound 2 was isolated from the Ophiopogon genus for the first time. Their structures were identified on the basis of extensive mass and nuclear magnetic resonance spectroscopic analysis.     

Thrombin Inhibitory Constituents from Duranta repens

The C‐alkylated flavonoids 3,7,4′‐trihydroxy‐3′‐(4‐hydroxy‐3‐methylbutyl)‐5,6‐dimethoxyflavone ( 1 ), 3,7‐dihydroxy‐3′‐(4‐hydroxy‐3‐methylbutyl)‐5,6,4′‐trimethoxyflavone ( 2 ) and the trans‐clerodane diterpenoids 6β‐hydroxy‐15,16‐epoxy‐5β,8β,9β,10α‐cleroda‐3,13(16),14‐trien‐18‐oic acid ( 3 ) and 2β‐hydroxy‐15,16‐epoxy‐5β,8β,9β,10α‐cleroda‐3,13(16),14‐trien‐18‐oic acid ( 4 ) were isolated from Duranta repens. Their structures and the relative configuration of 3 and 4 were determined by spectroscopic methods (¹H‐ and ¹³C‐NMR, IR, and MS) and 2D‐NMR experiments. The known flavonoid 5 is also reported for the first time from this species. The compounds 1 , 3 , and 5 showed significant enzyme‐inhibitory activity against thrombin.