A new dimeric resveratrol from the roots of Shorea roxburghii

A new resveratrol dimer, roxburghiol A (1) together with eleven known compounds were isolated from the roots of Shorea roxburghii. Their structures were identified on the basis of spectroscopic evidence and physicochemical properties. All isolated compounds were evaluated for their cytotoxicity (KB and HeLa cells). Compounds 8 and 9 showed potent cytotoxicity against both KB and HeLa cell lines with IC₅₀ values of 6.5, 8.5 and 8.7, 10.1 μg/mL, respectively.     

Tabebuialdehydes A–C,cyclopentene dialdehyde derivatives from the roots of Tabebuia rosea

Two new cyclopentene dialdehydes, tabebuialdehydes A and B (1 and 2) and a new dihydrocyclopenta[c]furan monoaldehyde, tabebuialdehyde C (3), along with ten known compounds were isolated from the roots of Tabebuia rosea. The structures of all isolated compounds were elucidated through their physical properties and by the use of spectroscopic methods, as well as comparisons with previous literature data. Moreover, all isolated compounds were evaluated for their cytotoxicity (KB and HeLa cell lines). Compounds 6, 7 and 9 showed significant cytotoxicity against both KB and HeLa cells with IC₅₀ values of 1.35 and 1.15, 0.53 and 0.77, 1.79 and 0.73 μg/mL, respectively.     

Macrostachyols A-D, new oligostilbenoids from the roots of Gnetum macrostachyum

Four new oligostilbenes, macrostachyols A-D (1-4) along with six known stilbenoids (5-10), were isolated from the roots of Gnetum macrostachyum. These compounds were also evaluated for their cytotoxicity towards HeLa and KB cell lines. Only compound 4 showed the significant cytotoxicity to HeLa cells with IC₅₀ value of 4.13 μM.     

Sesquiterpenoids and norterpenoids from Vitex negundo

Chemical investigation on the seeds of Vitex negundo has afforded a new furan-containing sesquiterpenoid, negunfurol (1), a new norlabdane-type diterpenoid, negundoal (2), and two new norursane-type triterpenoids, negundonorins A (3) and B (4), together with two know compounds, 3-formyl-4,5-dimethyl-8-oxo-5H-6,7-dihydronaphtho[2,3-b]furan (5) and 3-epi-corosolic acid (6). Their structures and configurations were elucidated by detailed spectroscopic analyses on the basis of NMR, IR, and MS data. Compound 3 was strongly cytotoxic against ZR-75-30 cell line with IC₅₀ value of 0.56 ± 0.19 μg/mL, whereas compound 1 was most active against HL-60 cell line with IC₅₀ value of 0.94 ± 0.26 μg/mL.     

New diterpenoids and cytotoxic and anti-inflammatory diterpenoids from Amentotaxus formosana

Two new abietane diterpenoids, ramentoxide (1) and ramentoxidone (2) and a new icetexane diterpenoid, amentonone (3) were isolated from the barks of Amentotaxus formosana. The structures of 1-3 were determined by spectroscopic methods. Known compounds brevitaxin (4), and (+)-ferruginol (5) and ent-kaur-16-en-15-one (6) isolated from this plant revealed potent cytotoxic activity against human breast adenocarcinoma cells, MCF-7 cells with an IC₅₀ value of 0.08 ± 0.05 μg/mL, and significant anti-inflammatory activities, respectively.     

3-Prenyl luteolin,a new prenylated flavone with melanin biosynthesis inhibitory activity from wood of Artocarpus heterophyllus

In our efforts to find new whitening agent from natural resources, we focused on wood of Artocarpus heterophyllus which shows anti-melanogenesis activity. By activity-guided fractionation of A. heterophyllus wood extract, a new prenylated flavonoid, 3-prenyl luteolin (1) was isolated. The IC₅₀ of mushroom tyrosinase inhibitotry activity of 1 was 76.3 µM. The results of the comparison with that of luteolin showed the prenyl substituent at C-3 position of 1 play an important role for revealing tyrosinase inhibition. In melanin formation inhibition on B16 melanoma cells, IC₅₀ of 1 was 56.7 µM with less cytotoxicity.     

Chemical constituents from Delphinium chrysotrichum and their biological activity

A new diterpene alkaloid named delphatisine C (1) has been isolated from aerial parts of Delphinium chrysotrichum along with three known norditerpenoid alkaloids delpheline (2), delbrunine (3), and delectinine (4). Their structures were characterized on the basis of their spectral data. All of them were determined by SRB assay for their cytotoxicity, and compound (1) showed significant cytotoxic activities (IC₅₀ = 2.36 μmol/L) against the A549 cell line.     

Prenylated phloroglucinol derivatives from Hypericum sampsonii

Six new acylphloroglucinol derivatives, sampsonols A-F (1–6), were isolated from the petroleum ether extract of the aerial parts of Hypericum sampsonii. The structures and relative configurations of sampsonols A-F were elucidated by extensive spectroscopic analyses. All these compounds were tested for their in vitro cytotoxic and anti-inflammatory activities. Sampsonols A and B (1 and 2) showed significant cytotoxicity against four human tumor cell lines with IC₅₀ values in the range of 13–28 μM, whereas sampsonols C and F (3 and 6) showed potent inhibitory activities against LPS-induced NO production in RAW 264.7 macrophages with IC₅₀ values of 27.3 and 29.3 μM, respectively.     

Phenylpropionic acid derivates from the bark of Cerbera manghas

Two new phenylpropionic acid derivates, cerberic acids A (1) and B (2), were isolated from the bark of Cerbera manghas. Their structures were established on the basis of spectroscopic methods including IR, ESI-FT-ICR-MS, 1D and 2D NMR. Primary bioassays showed that compound 1 possessed weak cytotoxic activity against HepG2, MCF-7, and HeLa cell lines with IC₅₀ values of 44.7, 52.3, 48.7 μg/ml, respectively.     

Cyclic bisdesmosides from Actinostemma lobatum MAXIM (Cucurbitaceae) and their in vitro cytotoxicity

Two new cyclic bisdesmosides elucidated as lobatoside L (1) and lobatoside M (2) and four known cyclic bisdesmosides (3-6) were isolated from Actinostemma lobatum MAXIM (Cucurbitaceae). Their structures were determined on the basis of spectroscopic analyses including IR, HR-FAB-MS, TOCSY, 1D- and 2D-NMR experiments and chemical reactions. The inhibitory effects of the six compounds on human cancer cell growth (including esophageal squamous carcinoma cell line ECA109, lung cancer cell line A549 and gastric cancer cell line MGC-803) were determined using the MTT assay. The results revealed that the six compounds exhibited cytotoxicity against all the cell lines tested, and compounds 1, 3 and 5 showed significant activities in a dose dependent manner against all the cell lines, especially for compound 1 and 5, the IC₅₀ values for ECA-109 cells were 8.25 μM and 3.71 μM. The results demonstrated that compounds 1 and 5's activities are 2- and 4-fold that of cisplatin.     

Polyketides with antimicrobial activity from the solid culture of an endolichenic fungus Ulocladium sp

Two new polyketides, 7-hydroxy-3, 5-dimethyl-isochromen-1-one (1) and 6-hydroxy-8-methoxy-3a-methyl-3a,9b-dihydro-3H-furo[3,2-c]isochromene-2,5-dione (2), along with eleven known compounds, 5′-methoxy-6-methyl-biphenyl-3,4,3′-triol (3), 7-hydroxy-3-(2-hydroxy-propyl)-5-methyl-isochromen-1-one (4), rubralactone (5), isoaltenuene (6), altenuene (7), dihydroaltenuenes A (8), altenusin (9), alterlactone (10), 6-O-methylnorlichexanthone (11), norlichexanthone (12), and griseoxanthone C (13) were isolated from the culture of the endolichenic fungus Ulocladium sp. Compound 2 was obtained as a racemate with an unprecedented chemical skeleton. The NMR data assignments for 3 and 4 were achieved for the first time. Compounds 1-13 were screened for their antimicrobial and radical scavenging activities. Compound 1 showed some antifungal activity against Candida albicans SC 5314 with IC₅₀ of 97.93 ± 1.12 μM. Compounds 11-13 showed strong activity against Bacillus subtilis with IC₅₀ in the range of 1-5 μM. Compound 12 significantly inhibited the growth of methicillin-resistant Staphylococcus aureus with IC₅₀ of 20.95 ± 1.56 μM. Compounds 9 and 10 showed strong radical scavenging activity in comparison with vitamin C. The plausible biosynthetic pathways for compounds 1, 2, and 4-8 were discussed.     

The phenylpropanoids of Aster flaccidus

Aster flaccidus bge has been used as traditional medicine in northwestern China. Two new phenylpropanoids (1–2) including one lignan: (7′R, 8S)-9′-lariciresinol-(α-methyl)-butanoate (1), 5,9-dimethoxyl-7-(α-methyl)-butanoxyl-phenyl-2E-propenol-(α-methyl)-butanoate (2) isolated from the chloroform extract of the root of Aster flaccidus bge were identified by means of extensive spectroscopic studies: 1D and 2D NMR spectra as well as HRMS analysis. They have not obvious anti-HIV-1 therapeutic activity (TI = 1.0–1.1) compared with AZT (TI = 55,556) as the result of the determination of their in vitro anti-HIV-1 activity while compound 2 displays strong antitumor activity against BEL 7402 (human liver carcinoma) with cisplatin as a positive control and the effect increases with the measuring-time going on (24 h, IC₅₀: 106.67 ± 8.47 µM — 72 h, IC₅₀: 50.51 ± 6.11 µM).     

Novel indole C-glycosides from Isatis indigotica and their potential cytotoxic activity

Two novel indole C-glycosides, which were the first reported alkaloids C-glycosides from Isatis indigotica, together with five known alkaloids were isolated. The novel alkaloids were elucidated to be indole-3-acetonitrile-4-methoxy-2-C-β-D-glucopyranoside (1) and N-methoxy-indole-3-acetonitrile-2-C-β-D-glucopyranoside (2) on the basis of spectroscopic analysis. 1 exhibited significant cytotoxic activities against human myeloid leukemia HL-60 and human liver cancer HepG2 cells with the IC₅₀ of 1.3 ± 0.1 and 2.1 ± 0.3 μM, respectively. 2 showed potential cytotoxic activities against HL-60 and human myeloid leukemia Mata cells with the IC₅₀ of 5.1 ± 0.4 and 12.1 ± 0.8 μM, respectively.     

Polyprenylated isoflavanone and isoflavonoids from Ormosia henryi and their cytotoxicity and anti-oxidation activity

A rare naturally-occurring polyprenylated isoflavanone, designated ormosinol (1), and a new isoflavonoid glycoside, named ormosinoside (2), along with 21 known compounds were isolated from the root bark of Ormosia henryi Prain. The structures of compounds 1 and 2 were determined as 5,7,2′,4′-tetrahydroxyl-6,8,5′-tri-(γ,γ-dimethylallyl)isoflavanone and isoprunetin-7-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranoside on the basis of a combination of 1D-, 2D-NMR and mass spectroscopic measurements. Compound 1 showed significant anti-oxidation activity against DPPH radicals (IC₅₀ 28.5 μM) and cancer cell line (A549, LAC, and HepG2) growth inhibitory activity with IC₅₀ ranging from 4.25 to 7.09 μM, while compound 2 found to be inactive to both testing systems.     

Antiparasitic antioxidant phenylpropanoids and iridoid glycosides from Tecoma mollis

A radical scavenging guided phytochemical study on the stem bark of Tecoma mollis afforded seven active phenylpropanoid glycosides (1–7), including a new one (4), and one iridoid (8). The structures of the isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Compounds (1–7) displayed promising antioxidant activity (DPPH assay) in relation to ascorbic acid (positive control). The antimicrobial activity for compounds (1–8) was evaluated against five bacterial and five fungal strains. The isolated compounds exhibited nonselective weak to moderate antimicrobial activity. The highest antileishmanial activity against Leishmania donovani was observed for compound (7) with an IC₅₀ value of 6.71 μg/ml, using pentamidine and amphotericin B as drug controls. Compound (5) exhibited moderate antimalarial activity (45% inhibition) against chloroquine sensitive (D6) clones of Plasmodium falciparum.     

Cytotoxic prenylated flavonoids from Morus alba

A phytochemical fractionation of the methanol extract of the Morus alba leaves led to the isolation of eleven flavonoids (1–11). The structure of the new 3′-geranyl-3-prenyl-2′,4′,5,7-tetrahydroxyflavone (1) was elucidated by means of spectroscopic methods. The cytotoxicity of the isolated compounds against human cervical carcinoma HeLa, human breast carcinoma MCF-7, and human hepatocarcinoma Hep3B cells was evaluated. Of note, morusin (9) was the most potent with an IC₅₀ value of 0.64 μM against HeLa cells.     

Mushroom tyrosinase inhibitors from Aloe barbadensis Miller

Two new chromones, 5-((S)-2′-oxo-4′-hydroxypentyl)-2-(β-glucopyranosyl-oxy-methyl)chromone (1) and 5-((S)-2′-oxo-4′-hydroxypentyl)-2-methoxychromone (2), together with four known analogues, 8-C-glucosyl-7-O-methyl-(S)-aloesol (3), isoaloeresin D (4), 8-C-glucosyl-(R)-aloesol (5), and aloesin (6) were isolated from the aqueous extract of Aloe barbadensis Miller. Their structures were determined on the basis of spectroscopic evidences (1-D and 2-D NMR, HRMS, UV, and IR data), chemical methods and the literature data. The Mosher's method was applied to establish the absolute configuration of compounds 1 and 2. The inhibitory effects of these chromones on the activity of mushroom tyrosinase were examined, and compound 6 was identified as a noncompetitive tyrosinase inhibitor with an IC₅₀ value of 108.62 μg·mL^− 1.     

Chemical constituents of the Vietnamese liverwort Porella densifolia

From the ether extract of Porella densifolia, the first liverwort collected and chemically investigated in Vietnam, a kaurane diterpenoid, ent-kauren-15-one (1) and two sesquiterpene norpinguisone (2) and norpinguisone methyl ester (3) have been purified. Their structures were elucidated by spectroscopic analysis. In addition, an X-ray crystal structure of norpinguisone was obtained, allowing to determine its stereochemistry. Furthermore, the inhibitory activity of nitric oxide (NO) production in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) of compounds 1–3 was examined with their IC₅₀ values of 69.4, 45.5 and 1.68 μM, respectively.     

Antioxidant flavonoids from Epimedium wushanense

Two new flavonoids, wushanicaritin (1) and wushankaempferol (2), along with 24 known flavonoids were isolated from the whole herb of Epimedium wushanense T.S. Ying (Berberidaceae). On the basis of NMR and ESI-MS spectroscopic analysis, structures of compounds 1 and 2 were elucidated as 8-γ-hydroxy-γ,γ-dimethylpropyl-3,5,7-trihydroxy-4′- methoxyflavone and kaempferol 3-O-α-l-[2,3-di-O-β-d-(6-E-p-coumaroyl) glucopyranosyl]-rhamnopyranosyl-7-O-α-l-rhamnopyranoside, respectively. DPPH radical scavenging activity tests indicated that 1 (IC₅₀ 35.3 μM) exhibited antioxidant activity comparable to Vitamin C (IC₅₀ 32.0 μM), while 2 (IC₅₀ 443.7 μM) showed weak activity.     

A new dilactone from the seeds of Gaultheria yunnanensis

Gaultheriadiolide (1), a new compound, together with the known dauosterol (2), ginkgetin (3), myricetin (4), 6-ethyl-5-hydroxy-2,7-dimethoxy-1,4-naphthoquinone (5), ursolic acid (6), methyl salicylate 2-O-β-d-xylosyl(1→6)β-d-glucopyranoside (7), and methyl salicylate 2-O-β-d-glucopyranoside (8) were isolated from Gaultheria yunnanensis. The structure was elucidated on the basic of spectral analysis, especially 1D and 2D NMR. Primary bioassays showed that compound 1 had medium cytotoxic activity against HEp-2 and HepG2 Cells, with IC₅₀ of 23.337 μM and 29.4497 μM, respectively.