New C20-gibberellin diterpene from the leaves of Schefflera sessiliflora De P. V.

From the leaves of Schefflera sessiliflora De P. V., one new C₂₀-gibberellin diterpene 2β,12β-dihydroxygibberellin (12β-hydroxy-GA₁₁₀ or 2β-hydroxy-GA₁₁₂) (1), together with three known compounds, trans-tiliroside (2), kaempferol 3-O-β-d-glucuronopyranoside (3), 5-p-trans-coumaroylquinic acid (4), was isolated for the first time from the genus Schefflera by various chromatography methods. Their structures were elucidated by IR, UV, HR-ESI-MS, NMR 1D and 2D experiments and comparison with previous reported data. The α-glucosidase inhibitory activity of all compounds was measured. The isolates (2, 3) showed better α-glucosidase inhibitory activity (IC₅₀ = 134.60, 147.10 μM, respectively) than the standard drug acarbose (IC₅₀ = 214.50 μM).     

A new butenolide cinnamate and other biological active chemical constituents from Polygonum glabrum

Phytochemical investigation of the methanol extract of the aerial parts of Polygonum glabrum afforded one new natural product ( ? )-2-methoxy-2-butenolide-3-cinnamate (1) along with six known compounds, β-hydroxyfriedalanol (2), 3-hydroxy-5-methoxystilbene (3), ( ? ) pinocembrin (4), sitosterol-(6′-O-palmitoyl)-3-O-β-d-glucopyranoside (5), ( ? ) pinocembrin-5-methyl ether (6) and sitosterol-3-O-β-d-glucopyranoside (7). Compound 1 showed promising in vitro anti-HIV-1 activity against primary isolates HIV-1_UG070 (X4, subtype D) and HIV-1_VB59 (R5, subtype C) assayed using TZM-bl cell line with IC₅₀ in the range of 15.68–22.43 μg/mL. The extract showed TI in the range of 19.19–27.37 with IC₅₀ in the range of 10.90–15.55 μg/mL. Compounds 1, 3 and 4 exhibited in vitro anti-mycobacterium activity against Mycobacterium tuberculosis H37Ra with IC₅₀ values of 1.43, 3.33 and 1.11 μg/mL in dormant phase and 2.27, 3.33 and 1.21 μg/mL in active phase, respectively. Compound 4 was found to be the most active antiproliferative with IC₅₀ values of 1.88–11.00 μg/mL against THP-1, A549, Panc-1, HeLa and MCF7 cell lines.     

Officinalioside,a new lignan glucoside from Borago officinalis L.

A new lignan glucoside, officinalioside (1), was isolated from n-BuOH fraction of the aerial parts of Borago officinalis L., together with four known compounds: actinidioionoside (2), roseoside (3), crotalionoside C (4) and kaempferol 3-O-β-D-galactopyranoside (5). The structure of the new compound was established by means of spectroscopic and chemical analyses. Compounds 1 and 2 showed a moderate DPPH radical scavenging activity (IC₅₀: 52.6 ± 1.70 and 41.3 ± 0.25 μM, respectively) comparable with that of the standard trolox (16.6 ± 2.2 μM) without any significant cytotoxicity towards human cell line A549 (IC₅₀ > 100 μM).     

Chemical and biological studies on Bridelia ferruginea grown in Nigeria

Phytochemical investigation of the methanolic extract of dried leaves of Bridelia ferruginea led to the isolation and identification of fourteen compounds (1–14): compound 1 [mixture of palmitic, stearic and oleic acids], stearyl monoester of 2-O-β-?-glucosylglycerol (2), 6β-hydroxy-(20R)-24-ethylcholest-4-en-3-one (3a), 6β-hydroxy-(20R)-24-ethylcholest-4,22-dien-3-one (3b), lutein (4), vomifoliol (5), corilagin (6), kaempferide-3-O-β-?-glucoside (7), myricetin (8), isomericitrin (9), isoquercetin (10), myricitrin (11), quercitrin (12), rutin (13), and β-sitosterol glucoside (14). The total extract exhibited moderate activity towards CB2 receptor and 90% inhibition against leishmanial pathogen Trypanosoma brucei. Compound 4 exhibited 73% displacement in CB2 receptor with IC₅₀ 56.47 μM, and 93% inhibition towards T. brucei with IC₅₀ 4.16 μM. Compound 11 showed 99% inhibition towards Escherichia coli with IC₅₀ 1.123 μM.     

A new phenolic compound with antioxidant activity from the branches and leaves of Pyrus pashia

The branches and leaves of Pyrus pashia are used to cure abdominal pain and diarrhoea in Chinese folk medicine. A new phenilic compound, 4-O-β-d-glucopyranosylbenzyl-benzoate ester (1), along with 21 known ones (2–22) were isolated from the branches and leaves of this plant. Compounds 2 and 3 displayed remarkable antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl radical (IC₅₀ = 13.26 ± 0.04 μM, 13.28 ± 0.11 μM, respectively), which were at the same grade as positive control rutin. The caffeoyl group in compounds 2 and 3 was supposed to play an important role in the antioxidant activities.     

New lipoxygenase and cholinesterase inhibitory sphingolipids from Carthamus oxyacantha

Two new sphingolipids: oxyacanthin A [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol; 1] and B [(2S,3S,4R)-2-{[(2R,5E)-2-hydroxyoctadec-5-enoyl]amino}hexaeicosane-1,3,4-triol-1-O-β-D-glucopyranoside; 2], together with 1-octacosanol, β-sitosterol, β-sitosterol 3-O-β-D-glucopyranoside and luteolin 7-O-β-glucopyranoside were isolated from the methanolic extract of the whole plant of Carthamus oxyacantha. Their structures were elucidated using ¹H and ¹³C NMR spectra and 2D NMR analyses (HMQC, HMBC and COSY) in combination with mass spectrometry (EI-MS, HR-EI-MS, FAB-MS and HR-FAB-MS) experiments and in comparison with the literature data of the related compounds. Both the compounds 1 and 2 showed inhibitory potential against lipoxygenase (LOX) in a concentration-dependent manner with IC₅₀ values 83.3 ± 1.3 and 245.7 ± 1.1 µM, whereas compound 2 showed inhibition against enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC₅₀ values 65.3 ± 0.1 and 93.6 ± 0.1 µM, respectively.     

Phytochemical analysis and antioxidant potential of the leaves of Garcinia travancorica Bedd.

Phytochemical analysis of the leaves of Garcinia travancorica, a hitherto uninvestigated endemic species to the Western Ghats of south India, resulted in isolation and characterisation of the polyisoprenylated benzophenones 7-epi-nemorosone (1) and garcinol (2) along with biflavonoids GB-1a (3), GB-1 (4), GB-2 (5), morelloflavone (6) and morelloflavone-7″-O-β-d-glycoside or fukugiside (7). The compounds were identified using various spectroscopic techniques, mainly through NMR and MS. The methanol extract and the biflavonoids 3, 4, 5 and 7 showed potential in vitro antioxidant activities. The IC₅₀ value of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of compound 7 was 8.34 ± 2.12 μg/mL, comparable to that of standard ascorbic acid (3.2 ± 0.50 μg/mL). In the superoxide radical scavenging assay, compound 7 gave IC₅₀ value of 6.95 ± 1.33 μg/mL close to standard ascorbic acid with IC₅₀ value of 5.8 ± 0.25 μg/mL. Validated HPTLC estimation revealed G. travancorica as a rich source of morelloflavone-7″-O-β-d-glycoside (7.12% dry wt. leaves).     

A new triterpenoid saponin from Gleditsia sinensis and its antiproliferative activity

Chemical investigation of the anomalous fruits of Gleditsia sinensis led to the isolation and identification of a new triterpenoid saponin, 3-O-β-D-xylopyranosyl-(1 → 2)-α-L-arabinopyranosyl-(1 → 6)-β-D-glucopyranosyl oleanolic acid 28-O-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyrano--syl-(1 → 4)-β-D-xylopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 3)-β-D-glucopyranosyl ester (1), along with other nine known compounds (2–10). All the isolates from this species were reported for the first time. The structure of Compound 1 was determined by a detailed analysis using various analytical techniques, including 1D and 2D NMR. In vitro antiproliferative activities of Compound 1 on MCF-7 and Hep-G2 tumor cell lines were evaluated. IC₅₀ values against the two cell lines were 9.5 and 11.6 μM, respectively.     

A new alkylbenzoquinone from Embelia rowlandii Gilg. (Myrsinaceae)

A new alkylbenzoquinone named embeliquinone (1) together with five known compounds, lupeol (2), 3-O-[6′-O-palmitoyl-β-d-glucosyl]-spinasta-7,22(23)-diene (3), quercetin (4), (2S,3S,4R,8E)-2-[(2′R)-2′-hydroxy-heneicosanoylamino]-heneicosane-1,3,4-triol-8-ene (5), and β-sitosterol-3-O-β-d-glucopyranoside (6) were isolated from the MeOH leaf extract of Embelia rowlandii by using repeated open column chromatography techniques. The structure of the new compound was characterized by analyses of 1D- and 2D-NMR, and MS data. Embeliquinone (1) had moderate anti-cell proliferation activity against A549 cell line with the IC₅₀ value of 21.8 μM. In addition, 1 exhibited weak antibacterial activities against Klebsiella pneumoniae and Staphylococcus aureus with an MIC value of 206.0 μM in both cases.     

Two new eudesmane-type glucopyranosides from the fruits of Daucus carota L.

Two new eudesmane-type glucopyranosides have been isolated from the fruits of Daucus carota L. On the basis of their spectroscopic and chemical evidence, the new compounds were elucidated as daucucarotol-10-O-β-d-glucopyranoside (1) and decahydro-7-[(2-O-β-d-glucopyranosyl)-isopropyl]-1β,4aα-dimethyl-(1α,4α,8aβ)-naphthalenetriol (2). Compounds 1 and 2 showed moderate antitumour activity against human ECA-109 and gave IC₅₀ values of 23.22 and 26.76 μM, respectively.     

Synthesis and antiproliferative activity of (1R,2R)-N1-(2-butyl)-1,2-cyclohexanediamine platinum(II) complexes with malonate derivatives

Three new platinum(II) complexes of (1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine with malonate derivatives as leaving groups have been synthesized and spectrally characterized. They were tested in vitro against four human cancer cell lines. [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](2-ethylmalonato-O,O′)platinum(II) turned out to be more active (IC₅₀ = 4.65 μM) than oxaliplatin (IC₅₀ = 6.55 μM) against the MCF-7 cell line and is superior to its parent complex, [(1R,2R)-N¹-(2-butyl)-1,2-cyclohexanediamine-N,N′](malonato-O,O′)platinum(II). In addition, agarose gel electrophoresis study revealed that the interaction of the complex with pET22b plasmid DNA had a different behavior from that of cisplatin or oxaliplatin.     

Calaxanthones A-C,three new xanthones from the roots of Calophyllum calaba and the cytotoxicity

Three new xanthones, named calaxanthones A-C (1–3), along with 17 known xanthones (4–20) were isolated from the roots of Calophyllum calaba. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against five cancer cell lines (KB, HeLa S-3, HT-29, MCF-7 and HepG-2). Compound 3 showed potent cytotoxicity against all the five cancer cell lines with IC₅₀ values in the range of 0.82–5.04 μM. Furthermore, compound 6 showed potent cytotoxicity against KB, HeLa S-3 and HepG2 cells with IC₅₀ values of 7.06, 5.27 and 9.64 μM, respectively. Additionally, compound 7 showed potent cytotoxicity against KB cell with an IC₅₀ value of 4.62 μM.     

Coumarins and alkaloids from the roots of Toddalia asiatica

The EtOAc and MeOH extracts of the roots of Toddalia asiatica Lam. were investigated for the roots’ chemical constituents. Two new compounds including 2′R-acetoxytoddanol (1) and 8S-10-O-demethylbocconoline (3) as well as 15 known compounds were isolated. Compound 10 showed strong cytotoxicity against KB cells with an IC₅₀ value of 2.60 μg/mL, which is nearly equal to the ellipticine standard, but showed no activity against Vero cells. Alkaloid 3 displayed weak cytotoxicity against the KB cell line with an IC₅₀ value of 21.69 μg/mL.     

Structure activity relationship of bergenin,p-hydroxybenzoyl bergenin, 11-O-galloylbergenin as potent antioxidant and urease inhibitor isolated from Bergenia ligulata

Ethanol extract of the aerial parts of Bergenia ligulata was subjected to solvent–solvent separation followed by various chromatographic techniques that lead to isolation of bergenine (1), p-hydroxybenzoyl bergenin (2), 11-O-galloylbergenin (3) and methyl gallate (4) as major constituents. Ethyl acetate fraction showed a dose-dependent urease inhibitory pattern with IC₅₀ value of 54μg/mL. Structures of compounds 1 and 3 were established by XRD and 2, 4 by NMR. All these compounds were subjected to DPPH scavenging activity, reducing power assay and urease inhibitory activity. The EC₅₀ 7.45 ± 0.2 μg/mL and 5.39 ± 0.28 μg/mL values in terms of antioxidant and reducing power, respectively, were less for 3. Compounds 1–3 showed moderate to significant urease inhibitory potential with IC₅₀ 57.1 ± 0.7, IC₅₀ 48.4 ± 0.3 and 38.6 ± 1.5. Antioxidant activities and urease inhibitory potential were investigated and compound 3 was found to be the most active.     

Glycosides of ursane-type triterpenoid,benzophenone, and iridoid from Vangueria agrestis (Fadogia agrestis) and their anti-infective activities

Abstract

Four ursane-type triterpenoid glycosides (1-4), two benzophenone glycosides (5 and 6), and one iridoid glucoside (7) were isolated and characterized from the dried roots of Vangueria agrestis. Compounds 1 (3-O-[α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyl]pomolic acid 28-O-β-D-glucopyranosyl ester) and 5 (2-O-[β-D-apiofuranosyl-(1→6)-β-D-glucopyranosyl]-6,4′-dihydroxy-4-methoxy benzophenone) were found to be new metabolites. The identity of all compounds has been accomplished, primarily, based on 1 D and 2 D NMR and HRESMS analysis. Compounds 6 and 2, showed inhibitory effect against Trypanosoma brucei with IC₅₀ 22.3 µM for 6 and IC₅₀ 11.1 µM, IC₉₀ 12.3 µM for 2.     

Antioxidative sulphated polygalactans from marine macroalgae as angiotensin-I converting enzyme inhibitors

Antioxidant and antihypertensive potential of the sulphated polygalactans isolated from the marine macroalgae Kappaphycus alvarezii and Gracilaria opuntia were assessed by utilising different in vitro systems. The galactans isolated from K. alvarezii possessed significantly greater antioxidative properties as determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH IC₉₀ 0.97 mg/mL) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS^.+ IC₉₀ 0.72 mg/mL) scavenging activities than those isolated from G. opuntia (DPPH IC₉₀ 1.2 mg/mL and ABTS 0.86 mg/mL). The sulphated polygalactan →4)-4-O-sulphonato-(2-O-methyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-methyl)-α-D-galactopyranan from K. alvarezii showed greater angiotensin-I-converting enzyme (ACE) inhibitory activity (IC₅₀ 0.02 μg/mL) than →3)-4-O-sulphonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulphonato)-α-D-galactopyranosyl-(1→3)-4-O-sulphonato-(6-O-acetyl)-β-D-xylosyl-(1→3)-4-O-sulphonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulphonato)-α-D-galactopyranan motif extracted from G. opuntia (IC₅₀ 0.70 μg/mL). Structure activity correlation studies displayed that the ACE inhibitory properties of titled polygalactans were directly proportional to their electronic properties and inversely with the steric and hydrophobic characteristics. Putative ACE inhibitory mechanism of action of sulphated galactans from marine macroalgae corroborated the structure bioactivity correlation analysis.     

Anti-tumour-promoting and thermal-induced protein denaturation inhibitory activities of β-sitosterol and lupeol isolated from Diospyros lotus L.

In this study, the anti-tumour-promoting and thermal-induced protein denaturation inhibitory activities of β-sitosterol (1) and lupeol (2), isolated from Diospyros lotus L., were explored. Compound 1 showed a marked concentration-dependent inhibition against 12-O-tetradecanoylphorbol-13-acetate (20 ng/32 pmol)-induced Epstein–Barr virus early antigen activation in Raji cells with IC₅₀ of 270 μg/ml, without significant toxicity (70% viability). Compound 2 showed significant anti-tumour-promoting effect with IC₅₀ of 412 μg/ml, without significant toxicity (60% viability). In heat-induced protein denaturation assay, compound 1 exhibited a concentration-dependent attenuation with a maximum effect of 73.5% at 500 μg/ml with EC₅₀ of 117 μg/ml, while compound 2 exhibited a maximum effect of 59.2% at 500 μg/ml with EC₅₀ of 355 μg/ml. Moreover, in silico docking studies against the phosphoinositide 3-kinase enzyme also show the inhibitory potency of these compounds. In short, both the compounds exhibited a marked anti-tumour-promoting and potent inhibitory effect on thermal-induced protein denaturation.     

A new proline-containing flavonol glycoside from Caragana leucophloea Pojark

One new proline-containing flavonol glycoside, namely kaempferol-3-O-methyl-7-O-β-d-glucopyranosyl-8-(1-methyleneproline)-4′-O-β-d-glucopyranoside (1), together with 15 known flavonoids, 3-O-methylkaempferol (2), 3-O-methylquercetin (3), quercetin (4), kaempferol (5), apigenin (6), rhamnazin (7), astragalin (8), alquds (9), quercitrin (10), rutin (11), isoquercitrin (12), apigetrin (13), myricitrin (14), hesperidin (15) and calycosin-7-O-β-d-glucopyranoside (16) were isolated from the aerial parts of Caragana leucophloea Pojark. (Leguminosae). Their structures were determined on the basis of spectroscopic analyses and by comparison with literature data. Compounds 2–4 revealed a strong antimicrobial activity with minimum inhibitory concentration values of 12.5–150 μg/mL and median inhibitory concentration (IC₅₀) values of 7.42–76.61 μg/mL. Compounds 3, 4, 6–8, 10–12 and 14 showed strong antioxidant activity. Compounds 2–7 exhibited moderate antinematodal activity on Caenorhabditis elegans with IC₅₀ values of 40.51–68.05 μg/mL.     

Triterpenoid saponins from the buds of Lonicera similis

Four new lupane triterpenoid saponins, along with one known lupane and eight hederagenin saponins, were isolated from the EtOH extract of the buds of Lonicera similis Hemsl. The structures of the new compounds were established as 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside A, 1), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl 23-hydroxybetulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside B, 2), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl ester (lonisimilioside C, 3) and 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl betulinic acid 28-O-β-D-glucopyranosyl ester (lonisimilioside D, 4), respectively. The cytotoxic activities of the isolates against human cancer cell lines HepG2, MCF-7 and A-549 were evaluated. Only the monodesmosidic saponin with a free carboxyl group at C-28 (12) exhibited significant cytotoxicities against HepG2, MCF-7 and A-549 cell lines with the IC₅₀ values of 8.98 ± 0.19, 12.48 ± 0.45 and 11.62 ± 0.54 μM, respectively. Furthermore, Hoechst fluorescence 33342 staining was used to demonstrate that 12 could induce HepG2 and A-549 cells apoptosis significantly.     

Antiplasmodial prenylated flavanonols from Tephrosia subtriflora

The CH₂Cl₂/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC₅₀ values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC₅₀ > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC₅₀ 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC₅₀ 16.9 μM).