18-nor-Podocarpanes and podocarpanes from the Bark of Taiwania cryptomerioides

Seven nor- and podocarpane-type diterpenes were isolated from the bark of Taiwania cryptomerioides Hayata, including three 18-nor-podocarpanes: 18-nor-1beta,4alpha,14-trihydroxy-13-methoxy-8,11,13-podocarpatriene (1), 18-nor-1beta,4alpha,13,14-tetrahydroxy-8,11,13-podocarpatrien-7-one (2), 18-nor-1beta,4alpha,14-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (3), 1beta,14,19-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (4), 1beta,13,14,18-tetrahydroxy-8,11,13-podocarpatrien-7-one (5), 18-acetoxy-1beta,13,14-trihydroxy-8,11,13-podocarpatrien-7-one (6), and 1beta,14,18-trihydroxy-13-methoxy-8,11,13-podocarpatrien-7-one (7). Their structures were determined by application of 1D and 2D NMR spectroscopy and other techniques. Podocarpane-type diterpenes do not occur extensively in nature, and the presumed oxidative enzyme in this plant will be of interest to identify.     

Diterpene constituents of leaves from Juniperus brevifolia

The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3beta-hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta-8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported (13)C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other diterpenoid compounds.     

New neutral diterpenes from southern pine tall oil

Five new diterpene natural products isolated from southern pine (Pinus spp.) tall oil were characterized as 8(14),15-pimaradiene-3β,18-diol, 19-hydroxy-15,16-dinorlabd-8(17)-en-13-one, 8,13β-epoxy-14-labden-6α-ol, 8,11, 13-abietatriene-15,18-diol and 9,10-secoabieta-8,11,13-trien-18,10-olide.     

Rapid Identification of α-Glucosidase Inhibitors from Phlomis tuberosa by Sepbox Chromatography and Thin-Layer Chromatography Bioautography

Alpha-glucosidase inhibitors currently form an important basis for developing novel drugs for diabetes treatment. In our preliminary tests, the ethyl acetate fraction of Phlomis tuberosa extracts showed significant α-glucosidase inhibitory activity (IC₅₀ = 100 μg/mL). In the present study, a combined method using Sepbox chromatography and thin-layer chromatography (TLC) bioautography was developed to probe α-glucosidase inhibitors further. The ethyl acetate fraction of P. tuberosa extracts was separated into 150 individual subfractions within 20 h using Sepbox chromatography. Then, under the guidance of TLC bioautography, 20 compounds were successfully isolated from these fractions, including four new diterpenoids [14-hydroxyabieta-8,11,13-triene-11-carbaldehyde-18-oic-12-carboxy-13-(1-hydroxy-1-methylethyl)-lactone (1), 14-hydroxyabieta-8,11,13-triene-17-oic-12-carboxy-13-(1-hydroxy-1-methylethyl)-lactone (2), 14,16-dihydroxyabieta-8,11,13-triene-15,17-dioic acid (3), and phlomisol (15,16-eposy-8,13(16),14-labdatrien-19-ol) (4)], and 16 known compounds. Activity estimation indicated that 15 compounds showed more potent α-glucosidase inhibitory effects (with IC₅₀ values in the range 0.067–1.203 mM) than the positive control, acarbose (IC₅₀ = 3.72 ± 0.113 mM). This is the first report of separation of α-glucosidase inhibitors from P. tuberosa.     

Abietane diterpenoids from the root of Salvia phlomoides

From the root of Salvia phlomoides three new abietane diterpenoids, demethylcryptojaponol, 14-deoxycoleon U and salviphlomone, have been isolated, besides the previously known diterpenes 8,13-abietadiene, 8,11,13-abietatriene, royleanone, 7α-acetoxyroyleanone, taxodione, taxodone, cryptojaponol and sugiol. The structures of demethylcryptojaponol (11,12-dihydroxy-8,11,13-abietatrien-7-one), 14-deoxycoleon U (6,11,12-trihydroxy-5,8,11,13-abietatetraen-7-one) and salviphlomone (6α,7β-dihydroxy-8,13-abietadiene-11,12-dione) were established by chemical and spectroscopic means.     

A revised structure for the diterpene rosmanol

The diterpene rosmanol, previously isolated from Rosmarinus officinalis, has been isolated from the flowers of Salvia canariensis and its structure revised as 7α,11,12-trihydroxyabieta-8,11,13-trien-20-oic acid 20,6-lactone, on the basis of chemical evidence and an X-ray diffraction analysis.     

思茅松松香中的一个新二萜

从思茅松（Pinus kesiya var.langbianensis）的松香中分离得到一个新奇的松香烷二萜化合物——思茅松素,经现代波谱分析将其化学结构确定为13（14）-烯-8,12-环氧-1-松香酸（1）,同时分离得到5个已知化合物,分别为abiet-8,11,13-trien-15-hydroxy-18-oic acid（2）;pimarol（3a）;iso-pimarol（3b）;abiet-trien-18．oic acid（4）;15．hydroxy abietic acid（5）。     

Diterpenes from Salvia mellifera

Two new aromatic diterpenes have been obtained from the aerial part of Salvia mellifera and their structures identified, on the basis of spectral data and chemical correlations, as 11,12,20-trihydroxy-abieta-8,11,13-triene and 11,12,16-trihydroxy- abieta-8,11,13-trien-20-al. The known diterpenes, carnosic acid, carnosol, rosmanol, isorosmanol, galdosol, rosmadial, 9 (10 → 20)-abeo-abieta-8,11,13-triene-10β,11,12-triol (demethylsalvicanol)and salvicanol were also isolated from the same source. The absolute configuration of salvicanol was established by X-ray diffraction analysis of its 11-p-bromobenzoate derivative.     

Tricyclic diterpenes from the resin of Daemonorops draco and their activities on oxidative stress-induced mesenchymal stromal cells

A bioassay-guided chemical investigation of the resin exudates from Daemonorops draco (dragon’s blood, Palmaceae) has resulted in the isolation of two new trinorditerpenes, 7β-13-dihydroxypodocarpa-8,11,13-trien-15-oic acid (1) and 7α-13-dihydroxypodocarpa-8,11,13-trien-15-oic acid (2), along with ten previously described abietane diterpenes, 7β-15-dihydroxydehydroabietic acid (3), 7α-15-dihydroxydehydroabietic acid (4), 15-hydroxydehydroabietic acid (5), 7-oxodehydroabietic acid (6), dehydroabietic acid (7), 15-hydroxyabietic acid (8), 12α-hydroxyabietic acid (9), abietic acid (10), 7,13,15-abietatrien-18-oic acid (11), and cephasinene B (12). The structures of 1 and 2 were elucidated using spectroscopic techniques, including HR-ESIMS and 1D/2D NMR. The absolute configurations were determined by comparing the experimental electronic circular dichroism (ECD) spectra with the calculated ECD data based on time-dependent density functional theory. The bioactivity of the extracts, fractions, and isolated compounds was assessed in oxidative stress-induced mesenchymal stromal cells (MSCs). The crude extract and the hexanes, ethyl acetate, and aqueous fractions exhibited high potency against oxidative stress-induced apoptosis of MSCs. Among the isolated compounds, compounds 1 (3 μM) and 10 (100 μM) demonstrated good recovery of MSCs against oxidative stress.     

日本榧树果实的化学成分研究

本文研究了日本榧树果实的化学成分。原植物用甲醇提取后经硅胶柱色谱、制备薄层色谱和制备HPLC色谱进行分离纯化,从日本榧树果实中分离得到了4个化合物,用质谱、红外、紫外、核磁等波谱方法鉴定为18-羟基弥罗松酚（1）、kayadiol（2）、花柏酚（3）和落叶松脂素（4）,化合物1．3、4为首次从该植物果实中分离得到。用MTT法检测了化合物1～3的细胞毒性,在浓度100μmol／L时lisa细胞生存率分别为100．00％、26．30％和59．74％。     

Isolation and structure characterization of two new diterpenoids from Clerodendrum bungei

Two new diterpenoids, 3β-(β-d-glucopyranosyl)isopimara-7,15-diene-11α,12α-diol (1), and 16-O-β-d-glucopyranosyl-3β-20-epoxy-3-hydroxyabieta-8,11,13-triene (2), along with three known ones were isolated from the roots of Clerodendrum bungei. These compounds were purified, and their structures were elucidated by extensive spectroscopic analyses, especially 2D NMR experiments. All compounds were evaluated for cytotoxicity against several tumor cell lines.     

Diterpenoids from Premna integrifolia

Premna integrifolia is an important constituent of famous herbal formulation “Dashmula” of Indian Ayurvedic system of medicines. The plant is known to possess hypoglycaemic, anti-inflammatory, antiarthritic and broad-spectrum antimicrobial activities due to the presence of several diterpenoids and spermine alkaloids in its decoction. In order to develop chemical markers for quality assurance of this herb in Ayurvedic formulation, we report here the isolation of three novel diterpenoids from the root bark of P. integrifolia namely 1β,3α,8β-trihydroxy-pimara-15-ene (1), 6α,11,12,16-tetrahydroxy-7-oxo-abieta-8,11,13-triene (2) and 2α,19-dihydroxy-pimara-7,15-diene (3). 1,3-Dihydroxy and 2-hydroxy diterpenes belong to a limited number of families and their isolation is also interesting from chemotaxonomic point of view. These diterpenoids were also evaluated for antibacterial activity.     

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.     

Terpenoids from the seed of chamaecyparis pisifera: the structures of six diterpenoids

Six new diterpenes, 12-hydroxy-20-nor-abieta-1(10),2,8,11,13-pentaene, pisiferanol (10S,12-dihydroxy-9(10 → 20)-abeo-abieta-8,11,13-triene), pisiferadinol (20S-hydroxypisiferanol), 12-deoxypisiferanol, 1β-hydroxyisopisiferin (1R,12-dihydroxy-9(10 → 2O)abeo-abieta-8,10(20),11,13-tetraene), and the dimethylamine salt of O-methylpisiferic acid were isolated from the seed of Chamaecyparis pisifera. The structures of these diterpenes were established by spectral and chemical methods. In addition, 15 mono-, four sesqui- and nine diterpenes were identified.     

New diterpenes from Chamaecyparis pisifera

Three new diterpenes, pisiferin, 15-hydroxyferruginol, and O-methyl pisiferic acid have been isolated and the presence of 12-hydroxyabieta-8,11,13-trien-20-al has been confirmed in studies of the leaves of Chamaecyparis pisifera. The structure of pisiferin, a phenolic diterpene with a new carbon skeleton, has been determined by chemical degradation. The presence of diterpenes of the ferruginol type in the leaves of four varieties of C. pisifera has been examined.     

Abietane diterpenoids from Clerodendrum mandarinorum

From the stem of Clerodendrum mandarinorum Diels (Verbenaceae), three new abietane derivatives, mandarones A, B and C, have been isolated. The structures were characterized as (5R,10S)-12-hydroxy-8,11,13-abietatriene-37-dione (mandarone A), (16 S)-12,16-epoxy-11,14-dihydroxy-17(15→16)-abeo-abieta-5,8,11,13-tetraene-7-one (mandarone B) and 12,16-epoxy-11,14-dihydroxy-17(15→16)-abeo-abieta-2,5,8,11,13,15-hexaene-7-one (mandarone C) on the basis of spectral analysis. Mandarones B and C possess a rearranged abietane skeleton which contains a 17(15→16)-abeo-abietane framework.     

Anti-inflammatory abietane diterpenoids from the seeds of Podocarpus nagi

In searching for naturally occurring anti-inflammatory agents, three new abietane-type diterpenoids, named 16-hydroxylambertic acid (1), 7-oxo-18-hydroxyferruginol (2), and 5α,12-dihydroxy-6-oxa-abieta-8,11,13-trien-7-one (3), were isolated from the seeds of Podocarpus nagi, together with three known compounds. The structures of the new compounds were elucidated by extensive analysis of NMR and HR-ESIMS data. All the new compounds were tested for nitric oxide (NO) inhibitory activities on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 1 significantly inhibited NO production with IC₅₀ value of 5.38 ± 0.17 μM, and suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner, which were mediated through inhibiting the mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation.     

Abietane diterpenoids from suspension cultured cells of Torreya nucifera var. radicans

Three abietane diterpenoids were isolated from the suspension cultured cells of Torreya nucifera var. radicans along with four known abietane diterpenoids. Based on spectroscopic evidence, the structures of the three were elucidated as (3S,5R,10S)-7-oxo-12-methoxyabieta-8,11,13-triene-3,11-diol, (3S,5R,10S)-7-oxo-12-methoxyabieta-8,11,13-triene-3,11,14-triol and (5R,10S)-3-oxo-7R,12-dimethoxyabieta-8,11,13-trien-11-ol, respectively.     

Antibacterial profiling of abietane-type diterpenoids

Abietic and dehydroabietic acid are interesting diterpenes with a highly diverse repertoire of associated bioactivities. They have, among others, shown antibacterial and antifungal activity, potentially valuable in the struggle against the increasing antimicrobial resistance and imminent antibiotic shortage. In this paper, we describe the synthesis of a set of 9 abietic and dehydroabietic acid derivatives containing amino acid side chains and their in vitro antimicrobial profiling against a panel of human pathogenic microbial strains. Furthermore, their in vitro cytotoxicity against mammalian cells was evaluated. The experimental results showed that the most promising compound was 10 [methyl N-(abiet-8,11,13-trien-18-yl)-d-serinate], with an MIC₉₀ of 60 μg/mL against Staphylococcus aureus ATCC 25923, and 8 μg/mL against methicillin-resistant S. aureus, Staphylococcus epidermidis and Streptococcus mitis. The IC₅₀ value for compound 10 against Balb/c 3T3 cells was 45 μg/mL.     

Antifungal rosane diterpenes and other constituents of Hugonia castaneifolia

The rosane diterpenoids hugorosenone [3beta-hydroxyrosa-1(10),15-dien-2-one], 18-hydroxyhugorosenone and 18-hydroxy-3-deoxyhugorosenone, and 12-hydroxy-13-methylpodocarpa-8,11,13-trien-3-one were isolated as antifungal constituents of H. castaneifolia Engl. root bark, together with the previously reported di-podocarpanoids hugonone A and hugonone B that were weakly active, and 1(10),15-rosadiene-2beta,3beta-diol (hugorosenol), 4alpha-methoxyhimachal-10-en-5beta-ol (hugonianene B) and 2-hydroxyhenpentacont-2-enal, and the known compounds tetracosyl-(E)-ferrulate and caryophyllene oxide, all of which were inactive. Hugorosenone also exhibited activity against Anopheles gambiae mosquito larvae. Structural determination was achieved based on spectroscopic data.