New flavane gallates isolated from the leaves of Plicosepalus curviflorus and their hypoglycemic activity

Two new flavane gallates were isolated from the leaves of Plicosepalus curviflorus. The structure of the new compounds was established as 2S,3R-3,3′,4′,5,7-pentahydroxyflavane-5-O-gallate (1) and 2S,3R-3,3′,4′,5,5′,7-hexahydroxyflavane-4′,5-di-O-gallate (2), respectively. In addition, seven known compounds (−)-catechin (3), quercetin (4), lupeol (5), β-sitosterol (6), pomolic acid (7), β-sitosterol 3-O-β-d-glucopyranoside (8) and 4-methoxycinnamic acid (9) were reported for the first time from the genus Plicosepalus. Compounds 1, 2 and 3 were investigated for their hypoglycemic activity and showed significant hypoglycemic activity in Swiss Albino mice.     

New icetexane diterpenes with intestinal α-glucosidase inhibitory and free-radical scavenging activity isolated from Premna tomentosa roots

New icetexane diterpenes (1-2); 8, 11, 13-icetexatriene-10-hydroxy, 11, 12, 16-tri acetoxyl (1) and 8, 11, 13-icetexatriene-7, 10, 11-dihydroxy-12, 13-dihydrofuran (2) along with six known compounds namely acetoxy syranzaldehyde (3), syranzaldehyde (4), coniferaldehyde (5), lupeol (6), betulin (7), and 4-(4-methoxy phenyl)-2-butanone (8) were isolated from the roots of Premna tomentosa. The structures of compounds 1 and 2 were established by detailed spectral analysis using UV, IR, ¹H NMR, ¹³C NMR, 1D, 2D and Mass. The newly isolated compounds were screened for rat intestinal α-glucosidase inhibitory and free radical (DPPH) scavenging potentiality. The new icetexane diterpenes (1, 2) and compound 3 were found to have significant α-glucosidase inhibitory and also free radical scavenging (DPPH) activities.     

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.     

Occurrence of stilbene oligomers in Cyperus rhizomes

Investigation of the chemical constituents of Rhizoma Cyperi (Cyperus rotundus Linneus) resulted in the isolation of novel enantiomeric and meso-stilbene trimers [i.e., (+)- and (−)-(E)-cyperusphenol A (1, 2 respectively) and (E)-mesocyperusphenol A (3)], a trimer bearing a novel hexacyclic ring system [cyperusphenol B (5)], as well as known stilbenoids (cyperusphenols C (4) and D (6), scirpusins A (7) and B (8), and piceid (9)) and luteolin. HPLC was used for the optical resolution of 1 and 2 as well as for the identification of cooccurrence of enantiomers of 7. The structures of the isolates were established by spectroscopic analyses, including a detailed NMR spectroscopic investigation. The isolates were evaluated in terms of their antiproliferative activity employing the Jurkat cell line (human T-cell leukemia cells), while the IC₅₀ potencies of a racemate of 1 and 2, 3, 5, and 6 were estimated as 27.4, 40.5, 26.4, and 26.3 μM, respectively. The suppression of cell growth by 6 was due to the induction of apoptosis, which was characterized by nuclear changes and PARP-1 cleavage determined by western blotting. We also evaluated the free radical scavenging activity of the isolates.     

New coumarin glycosides from the leaves of Diospyros crassiflora (Hiern)

Two new 5-methylcoumarin glycosides named diosfeboside A (1) and B (2) and five known compounds namely kaempferol 3-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranoside (3), ursolic acid (4), betulinic acid (5), stigmasterol (6) and stigmasterol 3-O-β-d-glucopyranoside (7) were isolated from the leaves of Diospyros crassiflora (Hiern). Their structures were established through interpretation of 1 and 2D NMR, mass spectra analysis and comparison with reported data. In vitro cytotoxic activity of the new compounds against human carcinoma cell lines (HL-60, Bel-7402, BGC-823, and KB) was evaluated and no cytotoxicity was observed for each of them.     

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.     

Bioactive phenolics from the fruits of Livistona chinensis

This study investigated the antioxidant and cytotoxic activity of the phenolics isolated from the fruits of Livistona chinensis. Four new compounds, 1-{ω-isoferul[6- (4-hydroxybutyl)pentadecanoic acid]}-glycerol (1), E-[6′-(5″-hydroxypentyl)tricosyl]-4-hydroxy-3-methoxycinnamate (2), 2-(3′-hydroxy-5′-methoxyphenyl)-3-hydroxylmethyl-7-methoxy-2,3-dihydrobenzofuran-5- carboxylic acid (3), 7-hydroxy-5,4′-dimethoxy-2-arylbenzofuran (4), together with eleven known phenolics (5-15), were isolated and identified. Among these compounds, 1-4, 5-O-caffeoylshikimic acid (5), caffeic acid (7), and 3-O-caffeoylshikimic acid (8) showed potent antioxidant activity. 1-5, and 8 showed potent antiproliferative activities with IC₅₀ values among 5-150 μM against HepG2 human liver cancer, HL-60 human myeloid leukemia, K562 human myeloid leukemia, and CNE-1 human nasopharyngeal carcinoma cell lines. On the basis of these findings, it could be proposed that the fruits of L. chinensis may serve as attractive mines of powerful anticancer and antioxidant agents for various purposes.     

Dammarane-type glycosides and long chain sesquiterpene glycosides from Gynostemma yixingense

A new dammarane-type glycoside and a new long chain sesquiterpene glycoside, along with nine known compounds 20(S)-ginsenoside Rh1 (3), 20(R)-ginsenoside Rh1 (4), ginsenoside F1 (5), amarantholidoside IV (6), ginsenoside Rc (7), 20(S)-ginsenoside Rg2 (8), 20(R)-ginsenoside Rg2 (9), ginsenoside Rd (10) and gypenoside XLVI (11) were isolated from Gynostemma yixingense. The structures of the new compounds were determined on the basis of spectroscopic analysis, including 1D-, 2D-NMR and ESI-MS techniques as well as by comparison of the spectral data with those of related compounds as 2α,3β,20(S)-trihydroxydammar-24-ene-3-O-[β-d-glucopyranosyl((1 → 2)-β-d-glucopyranosyl]-20-O-[β-d-xylopyranosyl((1 → 6)-β-d-glucopyranoside] (1) (2E,6E)-10-β-d-glucopyranosyl-1,10,11-trihydroxy-3,7,11-trimethyldodeca-2,6-diene (2).     

neo-Clerodane diterpenes from Ajuga decumbens and their inhibitory activities on LPS-induced NO production

A phytochemical investigation of the whole plants of Ajuga decumbens led to the isolation of three new (1, 2a, and 2b) and three known (3a−3c) neo-clerodane diterpenes. Their structures were elucidated by spectroscopic data analysis (IR, ESIMS, HR-ESIMS, 1D and 2D NMR), and the structure of 1 was confirmed by X-ray crystallography. The inhibitory activities on LPS-induced NO production of the six diterpenes were evaluated and compounds 2a, 2b, and 3a showed inhibitory effects.     

New norlignan derivatives from Curculigo capitulata

Two new norlignan derivatives, crassifoside I (1) and sinensigenin C (2), were isolated from the rhizomes of Curculigo capitulate, along with six known norlignan derivatives, 1,1-bis(3,4-dihydroxyphenyl)-1-(2-furan)-methane (3), crassifogenin B (4), crassifoside A (5), breviscaside A (6), crassifoside D (7), and curcapital (8). Their structures were elucidated on the basis of spectral evidence and comparisons with literature data. The ¹H and ¹³C NMR data of compound 3 was first assigned. Compounds 3–7 were isolated from this plant for the first time.     

The antifungal constituents from the seeds of Itoa orientalis

Three new phenolic constituents, itolide A (1), itolide B (2), itoside P (3), and 1D-3-deoxy-3-hydroxymethyl-myo-inositol (4), which is described herein for the first time as a natural product, were isolated along with four other known compounds (5 to 8) from the methanol extract of the seeds of Itoa orientalis Hemsl by the activity-guided fractionation. Their structures were determined by spectroscopic means. Compounds 1 to 8 exhibited antifungal activities against Sclerotium rolfsii with IC₅₀ values ranging from 60.12 to 240.00 μM and against Rhizoctonia solani with IC₅₀ values ranging from 45.34 to 233.14 μM, respectively, and compounds 1, 2, 5 exhibited cytotoxic activity against Tn5B1-4 insect cell line with EC₅₀ values of 203.68, 93.41 and 40.37 μM, respectively.     

Cytotoxic ceramides and glycerides from the roots of Livistona chinensis

A 70% ethanol extract of the roots of Livistona chinensis has been investigated, led to the isolation of 13 compounds, including a new ceramide, (2S,3S,4R,9Z)-2-[(2R)-2-hydroxytricosanoylamino]-9-octadecene-1,3,4-triol (2), a new glycosyl ceramide, 1-O-β-d-glucopyranosyl-(2S,3S,4R,9Z)-2-[(2R)-2-hydroxydocosanoylamino]-9-octadecene-1,3,4-triol (3), three new monoacylglycerols, 1-(34-hydroxytetratriacontanoyl)-sn-glycerol (9), 1-[nonadeca-(9Z,12Z)-dienoyl]-sn-glycerol (10), and 1-[12-hydroxypentatriaconta-(13E,15Z)-dienoyl]-sn-glycerol (11), a new diacylglycerol, 1-(heptadeca-6Z,9Z-dienoyl)-3-(octadeca-6Z,9Z,12Z-trienoyl)-sn-glycerol (12), as well as a new diacylglycerol aminoglycoside, 1-octadecanoyl-2-nonadecanoyl-3-O-(6-amino-6-deoxy)-β-d-glucopyranosyl-sn-glycerol (13). The structures of new compounds were elucidated, based on spectroscopic, zymologic and chemical methods. Among the compounds tested, compounds 3, 4 and 13 showed significantly antiproliferative effects against the human tumor cell lines (K562, HL-60, HepG2, and CNE-1) with the IC₅₀ of 10–65 μM. To our knowledge, this is first report of the occurrence of ceramides and acylglycerols in the genus Livistona.     

Antiproliferative steroidal glycosides from Digitalis ciliata

Two new compounds, a furostanol glycoside (1) and a pregnane glycoside (4), along with eight known compounds, belonging to the classes of spirostane (2,3), pregnane (5–7) and cardenolide (8–10) glycosides, were isolated from the seeds of Digitalis ciliata. Their structures were elucidated by 1D and 2D-NMR experiments as well as ESI-MS analysis. For the first time pregnane glycosides of the diginigenin series have been isolated from D. ciliata. The cytotoxic effects of compounds 1–10 on cell viability of several cancer cell lines, namely human breast cancer (MCF-7), human glioblastoma (T98G), human lung adenocarcinoma (A549), human colon carcinoma (HT-29), and human prostate cancer (PC-3) cell lines were evaluated. Compounds 1, 4, 7 and 8 showed antiproliferative effects against MCF-7, HT-29 and A549 cancer cells with IC₅₀ values ranging from 8.3 to 20 μM. The effects of compounds 1–10 on cell proliferation were evaluated on these three cancer cell lines by cell cycle analysis of DNA content using flow cytometry. Compounds 7, 8 and 10 induced significant changes in G₂/M cell cycle phase of all analyzed cells. The obtained results indicate that compounds 7, 8 and 10 are cytostatic compounds effective in reducing cell proliferation by inducing accumulation of the cells in the G₂/M phase of the cell cycle.     

New flavonol glycosides from Aconitum burnatii Gáyer and Aconitum variegatum L.

Six flavonol glycosides, compounds 1-3 from A. burnatii Gáyer and 4-6 from A. variegatum L., were obtained from their methanol extracts of aerial parts. The identified structures were quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-p-coumaroyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (1), quercetin 3-O-β-d-glucopyranoside-7-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (2), quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-caffeoyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (3), kaempferol 3-O-β-d-galactopyranoside-7-O-α-l-arabinopyranoside (4), quercetin 3-O-β-d-glucopyranoside (5), and kaempferol 3-O-β-d-glucopyranoside (6). Compounds 1, 2 and 4 were isolated for the first time. The antioxidant potential of the methanol extracts and pure compounds was tested with different assays.     

Antidiarrhoeal activity of carbazole alkaloids from Murraya koenigii Spreng (Rutaceae) seeds

The bioassay guided fractionation of the n-hexane extract of the seeds of Murraya koenigii Spreng (Rutaceae) resulted in the isolation of three bioactive carbazole alkaloids, kurryam (I), koenimbine (II) and koenine (III). The structures of the compounds were confirmed from their ¹H-, ¹³C-, and 2D-NMR spectral data. Of the three compounds (I) and (II) exhibited significant inhibitory activity against castor oil-induced diarrhoea and PGE₂-induced enteropooling in rats. The compounds also produced a significant reduction in gastrointestinal motility in the charcoal meal test in Wister rats.     

Phenolic glycosides from Dodecadenia grandiflora and their glucose-6-phosphatase inhibitory activity

Phytochemical investigation of Dodecadenia grandiflora leaves led to the isolation and identification of three phenolic glycosides, designated 1-[(4′-O-(E)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (1), 1-[(6′-O-(E)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (2) and 1-[O-β-d-glucopyranosyl(1→2)-β-d-glucopyranosyl]-oxy-2-phenol (3), along with nine known compounds. Compounds 1, 2, 5 and 9 exhibited significant glucose-6-phosphatase inhibitory activity (63.7, 66.9, 82.9 and 85.4%) with IC₅₀ values of 88.5, 81.0, 51 and 50 μM respectively. On the basis of biological results, a structure–activity relationship has been discussed.     

A new 9-nor-atractylodin from Atractylodes lancea and the antibacterial activity of the atractylodin derivatives

A new compound, namely, 9-nor-atractylodin (1) and one known atractylodin (2) were isolated from the rhizomes of Atractylodes lancea. The structural modifications of atractylodin were carried out and a series of atractylodin derivatives (3-10) were obtained. The antibacterial activities of 1-10 were examined against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Candida albicans. Compounds 4 and 8, which contained the α, β-unsaturated carbonyl fragment, were found to be active against E. coli and S. aureus.     

New spirobenzofuranoid dibenzocyclooctadiene lignans from Kadsura oblongifolia

Two new spirobenzofuranoid dibenzocyclooctadiene lignans, kadsulignans O (1) and P (2) were isolated from the stems of Kadsura oblongifolia, together with five known same type lignans, kadsulignans C (3), E (4), F (5), G (6), and heteroclitin J (7). Their structures were elucidated on the basis of spectral evidences and comparisons with literatures. Compounds 3-7 were isolated from this plant for the first time.     

Trichalasins C and D from the plant endophytic fungus Trichoderma gamsii

Two new cytochalasans, trichalasins C (1) and D (2) together with known cytochalasans aspochalasins D (3), M (4) and P (5) were isolated from one endophytic fungus Trichoderma gamsii inhabiting in traditional medicinal plant Panax notoginseng (BurK.) F.H.Chen. The structures for the new compounds 1 and 2 were determined by NMR and HRESIMS, and their relative configurations were established by analysis of coupling constants and NOESY correlations. Compound 3 displaying inhibitory activity with EC₅₀ value 5.72 μM, whereas the EC₅₀ values for compounds 1, 2 and 4, 5 are more than 40 μM.