Diterpenoids from the freshwater green algae Rhizoclonium hieroglyphicum with antibacterial activity

Three new isopimarane diterpenes 7β-hydroxy-19α-methylmalonyloxy-isopimara-8(14),15-diene (1), 7β-hydroxy-14-oxo-isopimara-8(9),15-dien-19oic acid (2), and 7β-hydroxy-14-oxo-19α-methylmalonyloxy-isopimara-9(11),15-diene (3) in addition to the known compounds isopimaric acid (4), 7oxo-13-epi-pimara-14,15-dien-18oic acid (5), 7oxo-13-epi-pimara-8,15-dien-18oic acid (6), and 6β-hydroxyisopimaric acid (7) were isolated from the hexane extract of Rhizoclonium hieroglyphicum. The structures of compounds 1-7 were established by 1D and 2D NMR techniques. The isolated diterpenoids were screened for antimicrobial activity against gram-positive and gram-negative bacteria and yeast strains.     

Microbial transformation of resibufogenin by Curvularia lunata AS 3.4381

In this paper, the microbial transformation of resibufogenin (1) by Curvularia lunata AS 3.4381 was investigated, and four transformed products were isolated and characterized as 3-epi-resibufogenin (2), 12α-hydroxy-3-epi-resibufogenin (3), 12-oxo-16β-hydroxy-3-epi-resibufogenin (4), and 12β,15-epoxy-3-epi-bufalin-14,15-ene (5). Among them, 4 and 5 are new compounds, and isomerization, hydroxylation, and oxidation reactions in microbial transformation process were observed. Additionally, the cytotoxicities of transformed products (2–5) were also investigated.     

Four new minor taxanes from cell cultures of Taxus chinensis

Four new minor taxanes (1–4) have been isolated from Ts-19 cell cultures of Taxus chinensis together with five known taxanes (5–9) by silica gel chromatography combined with semi-preparative HPLC chromatography. On the basis of the analyses of the chemical and spectroscopic (IR, MS, 1D, and 2D NMR) data, the structures of new compounds were elucidated as 5α-hydroxy-2α,10β-diacetoxy-14β-(3-hydroxy-2-methyl-butyryl)oxytaxa-4(20),11-diene (1), 2α,5α,10β-triacetoxy-14β-(2-hydroxy-propionyl)oxytaxa-4(20),11-diene (2), 2α,5α,10β-triacetoxy-14β-(2-hydroxy-3-methyl-butyryl)oxytaxa-4(20),11-diene (3), and 2α-benzoxy-4α,9α,10β,13α-tetraacetoxytax-11-ene (4), respectively. Compounds 1–5 were pharmacologically evaluated for their cytotoxicities against five human cancer cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780) and their reversing activity towards multi-drug resistance A549/taxol tumor cell line, and the results showed that all of the tested compounds exhibited very low cytotoxicities, while compound 4 possessed twice the reversing activity as that of verapamil at 10 μM.     

Triterpenoic acids of Prunella vulgaris var. lilacina and their cytotoxic activities In Vitro

The column chromatographic separation of the MeOH extract from the aerial parts of Prunella vulgaris var. lilacina Nakai led to the isolation of fifteen triterpenoic acids (2–6, 9–13, 16–20), four flavonoids (14, 21–23), four phenolics (7, 8, 15, 24), and a diterpene (1). Their structures were determined by spectroscopic methods to be trans-phytol (1), oleanic acid (2) ursolic acid (3), 2α,3α,19α-trihydroxyurs-12en-28oic acid (4), 2α,3α-dihydroxyurs-12en-28oic acid (5), maslinic acid (6), caffeic acid (7), phydroxy cinnamic acid (8), 2α,3α,19α,23-tetrahydroxyurs-12en-28oic acid (9), 2α,3α,23-trihydroxyurs-12en-28oic acid (10), 2α,3β-dihydroxyurs-12en-28oic acid (11), 2α,3β,24-trihydroxyolea-12en-28oic acid (12), (12R, 13S)-2α,3α,24,trihydroxy-12,13-cyclo-taraxer-14-en-28oic acid (13), quercertin 3-O-β-D-glucopyranoside (14), rosmarinic acid (15), 2α,3α,24-trihydroxyurs-12,20(30)-dien-28oic acid (16), 2α,3α,24-trihydroxyolea-12en-28oic acid (17), 2α,3β,19α,24-tetrahydroxyurs-12en-28oic acid 28-O-Dglucopyranoside (18), 2α,3α,19α,24-tetrahydroxyurs-12en-28oic acid 28-O-D-glucopyranoside (19), prunvuloside A (20), kaempferol 3-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopranoside (21), kaempferol 3-O-β-D-glucopyranoside (22), quercertin 3-O-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside (23), and 2-hydroxy-3-(3’,4’-dihydroxyphenly)propanoic acid (24). Compounds 1, 8–12, 17, 21, 23, and 24 were isolated from this plant source for the first time. The isolated compounds were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT15 cells in vitro using the sulforhodamin B bioassay (SRB) method. Compound 3 exhibited moderate cytotoxic activity against A549, SK-OV-3, SK-MEL-2, and HCT15 cells, with ED₅₀ values of 3.71, 3.65, 13.62, and 5.44 μM, respectively.     

3α,19-Dihydroxyl-ent-pimara-8(14),15-diene,a new diterpenoid from the rhizomes of Ricinus communis

A new natural product, 3α,19-dihydroxyl-ent-pimara-8(14),15-diene (1), which possesses an α-orientation hydroxymethyl at C-4 and ?^8,14 groups, as well as eight known compounds, was isolated from the rhizomes of Ricinus communis. The structure of 1 was elucidated by extensive spectroscopic methods and its absolute configurations were confirmed by X-ray crystallographic analysis. The inhibitory rate of 1 against protein tyrosine phosphatase 1B (PTP1B) was 49.49% at the concentration of 6.58 × 10^?5 mol/L.     

Antioxidant and α-amylase inhibitory activities of extract and isolates from Zygogynum pancheri subsp. arrhantum

One new sesquiterpenoid (5R^*,8R^*,9R^*,10R^*)-cinnamolide (8), and seven known compounds, 5-hydroxy-7-methoxyflavonone (1), 8-hydroxy-3-(4′-hydroxyphenyl)-6,7-(2″,2″-dimethylchromene)-tetralone (2), 8-hydroxy-3-(3′,4′-dihydroxyphenyl)-6,7-(2″,2″-dimethylchromene)-tetralone (3), 1β-E-O-p-methoxycinnamoyl-bemadienolide (4), 1β-O-(E-cinnamoyl)-6α-hydroxy-9-epi-polygodial (5), 1β-O-(E-cinnamoyl)-6α-hydroxypolygodial (6), and 1β-O-E-cinnamoylpolygodial (7) were isolated from the ethyl acetate extract of barks of Zygogynum pancheri subsp. arrhantum (Winteraceae). The structures of these molecules were assigned predominantly based on spectral data. The structure of compound 8 was confirmed by X-ray crystallographic analysis. Compounds 2 and 3 exhibited significant antioxidant activity, whereas compounds 1 and 4–7 showed significant α-amylase inhibitory activity.     

Antioxidant compounds from the stem bark of Garcinia atroviridis

A new xanthone, namely garcinexanthone G (1), along with eight known compounds, stigmasta-5,22-dien-3β-ol (2), stigmasta-5,22-dien-3-O-β-glucopyranoside (3), 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide (4), 2,6-dimethoxy-p-benzoquinone (5), 1,3,5-trihydroxy-2-methoxyxanthone (6), 1,3,7-trihydroxyxanthone (7), kaempferol (8) and quercetin (9), were isolated from the stem bark of Garcinia atroviridis. Their structures were elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D), UV, IR, and mass spectrometry. All the isolated compounds were evaluated for their antioxidant properties based on the DPPH radical scavenging activities. Results showed that 1,3,7-trihydroxyxanthone and quercetin showed significant antioxidant activities with EC₅₀ values of 16.20 and 12.68 μg/ml, respectively, as compared to the control, ascorbic acid (7.4 μg/ml).     

Three new diterpenoids from Aralia dumetorum

Three new diterpenoids, dumetoranes A (1) and B (2), melanocane B (3), together with four known ones including melanocane A (4), ent-15S,16-dihydroxypimar-8(14)-en-19-oic acid (5), ent-pimara-8(14),15-diene-19-oic acid (6), and ent-pimara-8(14),15-diene-19-ol (7) were obtained from the ethanol extract of the roots of Aralia dumetorum. Their structure elucidation was achieved by the methods of spectroscopic HRMS, IR, NMR, and by comparison with literature. The cytotoxicities of compounds 1–3 and 5 were assayed by in vitro MTT methods.     

Chemical constituents of Isodon nervosus and their cytotoxicity

Two new ent-kaurane diterpenoids, 6,20,15α-trihydroxy-6,7-seco-1α,7-olide-ent-kaur-16-ene (1) and 7β,12α-dihydroxy-6β,15β-diacetoxy-7α,20-epoxy-ent-kaur-2,16-dien-1-one (2), together with the six known compounds, were isolated from the aerial part of Isodon nervosus. The structures of the new compounds were determined by spectral methods (1D, 2D NMR, and MS). Six compounds were assayed for their cytotoxicity against HL60, SMMC-7721, and HeLa human cell lines. Compounds 5, 7, and 8 showed significant cytotoxicity.     

A new polyketide glycoside from the rhizospheric Clonostachys rogersoniana associated with Panax notoginseng

A new polyketide glycoside rogerson A (1), along with two known compounds, rogerson B (2) and (22E)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (3), was obtained from the solid fermentation of Clonostachys rogersoniana, which was isolated from the rhizosphere soil of Panax notoginseng. Rogerson B (2) was isolated for the first time from a natural source. Their structure was determined by extensive analyses of NMR and MS studies. Compounds 1 and 2 were tested for its cytotoxicity against five human cancer cell lines.     

Antibacterial sesquiterpene lactone glucoside from seed pods of Bauhinia retusa

From the seed pods of Bauhinia retusa, a new eudesmane sesquiterpene glucoside, 1-O-β-D-glucopyranosyl-9β,15-dihydroxy-5α,6βH-eudesma-3-ene-6α,12-olide (1), has been isolated together with three known compounds, 4′-hydroxy-7-methoxy flavane (2), β-sitosterol (3), and stigmasterol (4). The structures of isolated compounds were verified with the help of 1D, 2D NMR, and HR-ESI-MS spectroscopies. Compound 1 showed moderate antibacterial activity against Pseudomonas aeruginosa and Escherichia coli when a disc diffusion method is used.     

Biotransformation of oleanolic acid by Alternaria longipes and Penicillium adametzi

Microbial transformation of oleanolic acid (1) was carried out. Six transformed products (2–7) from 1 by Alternaria longipes and three transformed products (8–10) from 1 by Penicillium adametzi were isolated. Their structures were elucidated as 2α,3α,19α-trihydroxy-ursolic acid-28-O-β-d-glucopyranoside (2), 2α,3β,19α-trihydroxy-ursolic acid-28-O-β-d-glucopyranoside (3), oleanolic acid 28-O-β-d-glucopyranosyl ester (4), oleanolic acid-3-O-β-d-glucopyranoside (5), 3-O-(β-d-glucopyranosyl)-oleanolic acid-28-O-β-d-glucopyranoside (6), 2α,3β,19a-trihydroxy-oleanolic acid-28-O-β-d-glucopyranoside (7), 21β-hydroxyl oleanolic acid-28-O-β-d-glucopyranoside (8), 21β-hydroxyl oleanolic acid (9), and 7α,21β-dihydroxyl oleanolic acid (10) based on the extensive NMR studies. Among them, 10 was a new compound and compounds 5 and 8–10 had stronger cytotoxic activities against Hela cell lines than the substrate. At the same time, it was reported for the first time in this paper that the skeletons of compounds 2 and 3 were changed from oleanane to uranane and seven glycosidation products were obtained by biotransformation.     

Microbial transformation of acetyl-11-keto-boswellic acid by Cunninghamella elegans

Microbial biotransformation of acetyl-11-keto-boswellic acid by Cunninghamella elegans AS 3.1207 was carried out, and totally four transformed products were isolated. On the basis of the extensive spectral data, their structures were characterized as 7β-hydroxy-11-keto-boswellic acid (1), 7β,30-dihydroxy-11-keto-boswellic acid (2), 7β,16α-dihydroxy-3-acetyl-11-keto-boswellic acid (3), and 7β,15α,21β-trihydroxy-3-acetyl-11-keto-boswellic acid (4), respectively. Among them, products 1 and 2 are the new compounds.     

A new ganoderic acid from Ganoderma lucidum mycelia

A new ganoderic acid (GA), 7-O-ethyl ganoderic acid O (GA-O) (1), together with two known compounds, GA-T (2) and GA-Me (3), was isolated and purified from fermented mycelia of Ganoderma lucidum. The structure of the new triterpenoid was elucidated on the basis of the interpretation of extensive spectroscopic data (HR-MS, IR, UV, 1D and 2D NMR) as 3α,15α,22-triacetoxy-7α-ethoxy-5α-lanost-8,24E-dien-26-oic acid. The new compound was found to contain a rare ethoxyl group at C-7. In addition, its cytotoxicity against 95D and HeLa human cancer cell lines was also evaluated.     

Cholinesterase and BACE1 inhibitory diterpenoids from <Emphasis Type="Italic">Aralia cordata</Emphasis>

Fourteen diterpenes were isolated from the n-hexane fraction of the roots of Aralia cordata (syn. = A. continentalis). Through spectroscopy, the chemical structures were determined as: ent-pimara-8(14),15-diene-19-oic acid (1); ent-kaur-16-en-19-oic-acid (2); 18-nor-ent-pimara-8(14),15-diene-4β-ol (3); 18-nor-ent-kaur-16-ene-4β-ol (4); ent-pimara-8(14),15-diene-19-ol (5); 7α-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (6); 7β-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (7); ent-pimar-15-en-8α,19-diol (8); 7-oxo-ent-pimara-8(14),15-diene-19-oic acid (9); 16α-hydroxy-17-isovaleroyloxy-ent-kauran-19-oic acid (10); 17-hydroxy-ent-kaur-15-en-19-oic acid (11); 15α,16α-epoxy-17-hydroxy-ent-kauran-19-oic acid (12); 16α,17-dihydroxy-ent-kauran-19-oic acid (13); and 16α-methoxy-17-hydroxy-ent-kauran-19-oic acid (14). Compounds 4, 5, 8, 12, and 14 were first isolated from this plant. The anti-Alzheimer and antioxidant effects of ent-pimarane-type diterpenes 1, 3, 5, 8, and 9, as well as ent-kaurane-type diterpenes 2, 4, and 10∼13, were evaluated via β-site amyloid precursor protein cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), peroxynitrite (ONOO⁻), and nitric oxide (NO·) assays. Of the compounds tested, 8 exerted the most effective BChE inhibition with an IC₅₀ value of 7.58 μM, followed by 3, 13, 11, 2, and 10. Compounds 9∼11 exhibited good BACE1 inhibitory activities with IC₅₀ values of 18.58∼24.10 μM. However, 11 showed marginal AChE inhibitory effect, and all compounds tested showed no scavenging activities on ONOO⁻ and NO· at a concentration of 100 μM.     

Two new sesquiterpene polyol esters from the root barks of Celastrus angulatus

Angulatin F (1) and angulatin I (2), two new sesquiterpene polyol esters, were isolated from the root barks of Celastrus angulatus, together with six known compounds 1β,2β-diacetoxy-4α,6α-dihydroxy-8α-isobutanoyloxy-9β-benzoyloxy-15-(α-methyl) butanoyloxy-β-dihydroagrofuran (3), angulatin A (4), angulatin B (5), celangulatin E (6), 1β,2β,15-triacetoxy-4α,6α-dihydroxy-8α-isobutanoyloxy-9β-benzoyloxy-β-dihydroagrofuran (7), and celangulin I (8). The structures of 1 and 2 were elucidated as 1β,2β,6α,15-tetraacetoxy-4α-hydroxy-8β,9α-difuroyloxy-β-dihydroagrofuran and 1β,2β,6α,8β,15-pentaacetoxy-4α-hydroxy-9β-furoyloxy-β-dihydroagrofuran by spectroscopic means.     

Two novel sesquiterpenoids from Ainsliaea fragrans Champ.

A new sesquiterpene lactone, 3β-O-β-d-glucopyranosyl-8α-hydroxy-11α,13-dihydrozaluzanin C (1), and a novel trinorguaiane-type sesquiterpene, 4β,10α-dimethyl-1β,5α-bicycle[3,5,0]dec-6-en-4α,10β-diol (2), together with three known compounds, glucozaluzanin C (3), 11α,13-dihydrozaluzanin C (4), and 8α-hydroxy-11α,13-dihydrozaluzanin C (5), were isolated from the whole plant of Ainsliaea fragrans Champ. The structures of 1 and 2 were elucidated on the basis of detailed spectral analysis. Structures of the known compounds were identified by comparison of its spectral data with those values in the literature.     

Four lanostane-type triterpenes from the fruiting bodies of mushroom Laetiporus sulphureus var. miniatus

Two new 3,4-seco-lanostane-type triterpenes, named as 15α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid (1), 5α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid 3-methyl ester (2), and one new lanostane triterpene 15α-acetoxylhydroxytrametenolic acid (3) together with a known one versisponic acid D (4) were isolated from the fruiting bodies of Laetiporus sulphureus var. miniatus. Their structures were determined on the basis of extensive spectroscopic methods and comparison with reported data. All four compounds were evaluated for their cytotoxicities against five human cancer cell lines; however, none exhibited inhibitory effects.     

Cytotoxic,radical scavenging and antimicrobial activities of sesquiterpenoids from the Tahitian liverwort <Emphasis Type="Italic">Mastigophora diclados</Emphasis> (Brid.) Nees (Mastigophoraceae)

A drimane, (+)-drimenol (1), five known herbertanes, (−)-α-herbertenol (2), (−)-herbertenediol (3), mastigophorene A (4), (−)-mastigophorene C (5) and (−)-mastigophorene D (6), a pimarane, (−)-e nt-pimara-8(14),15-dien-19-oic acid (7), and two eudesmanolides, (−)-diplophyllolide A (8) and (−)-diplophyllin (9) were isolated from the Tahitian Mastigophora diclados (Brid.) Nees. Herbertane sesquiterpenes (2, 3, 5 and 6) showed cytotoxicity against HL-60 and KB cell lines, radical scavenging activity and antimicrobial activity against Bacillus subtilis. (−)-Diplophyllolide A (8) also exhibited cytotoxicity against HL-60 and KB cell lines.     

A tirucallane and two pairs of tetranortriterpene 23-epimers from the Thai mangrove Xylocarpus moluccensis

A new tirucallane, 3β-hydroxy-3-decarbonyl-24-epi-piscidinol A (1), and two new pairs of tetranortriterpene 23-epimers, named thaimoluccepimers A (2) and B (3), were isolated from the seeds of a Thai mangrove, Xylocarpus moluccensis. The structures of these compounds were elucidated by HRESIMS and NMR spectroscopic analysis.