Records of Natural Products Articles

Peshawaraquinone; a novel naphthoquinone (1) and a new indanone (2) were isolated from the stem heartwood of Heterophragma adenophyllum Seem. Their structures were elucidated using advance spectral techniques including X-ray crystallography for the compound 1.

To our knowledge this is the first report on the isolation of a flavonoid glycoside: quercetin 3-O-α-arabinopyranoside (5), two phenylbutanon glycosides: 4-(4'-O-[6''-O-galloyl-β-galactopyranosyl]-3'-hydroxyphenyl)-butan-2-on (8), 4-(3'-O-β-glucopyranosyl-4'-hydroxyphenyl)-butan-2-on (9), one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (10) and a steroid glycoside: sitosterol-3-O-(6''-O-butanoyl)-β-galactopyranoside (14) from the Cistus species (Cistaceae). Additional to these compounds three flavonol aglycones: kaempferol (1), quercetin (2), myricetin (3); three flavonoid glycosides; kaempferol 3-O-β-(6''-O-trans-p-coumaroyl)-glucopyranoside (4), quercetin 3-O-β-galactopyranoside (6), myricetin 3-O-β-galactopyranoside (7); one phloroglucinol glycoside: 1-O-β-glucopyranosyl-3,5-dimethoxybenzene (11); one steroid aglycone: β-sitosterol (12); one steroid glycoside: Sitosterol-3-O- β-glucopyranoside (13) were isolated from the aerial parts of the Cistus salviifolius L.. Their structures were identified using spectral methods (UV, IR, 1D- and 2D-NMR, and ESI-MS).

Investigation of EtOAc extract from the fermentation broth of the fungus Penicillium oxalicum led to the isolation of a xanthone, secalonic acid D, which showed good antitumor activity both in vivo and in vitro. The docking study revealed that secalonic acid D could block the active pocket of topoisomerase І with seven hydrogen bonds between secalonic acid D and ARG488, LYS532, ASP533.

Three new phragmalin-type limonoids, with isomeric D-lactone ring from C-16/C-17 to C-16/C-30, tabulalin K(1),L(2),M(3) were isolated from the stem barks of Chukrasia tabularis var. velutina during our ongoing research work in this area. Their structures were elucidated on HR-ESI-MS, 1H and 13C-NMR, HSQC, HMBC, and ROESY experiments.

In our screening for antitubercular leading compounds, an endophytic Streptomyces sp. YIM65484 was selected by biological assay. Four bioactive metabolites were isolated from this strain. Their structures were determined as (2E,4E)-5-(3-hydroxyphenyl)- penta-2,4- dienamide (1), ergosterol (2), ergosterol peroxide (3) and halolitoralin B (4) by spectral analysis. Compound 1 is a new phenylpentadienamide with its rarely encountered skeleton in natural products. Compounds 1-4 showed selectivity for anti-M. Tuberculosis activity in comparison with other antimicrobial activity. Compound 4 was first isolated from Streptomyces.

The principal constituent of the essential oil from the leaves of the Cordia verbenacea plants collected in Minas Gerais, Brazil had a GC retention time similar to that of α-bisabolol, a sesquiterpene alcohol with important biological properties. NMR analyses ( 1H, 13C, DEPT-135, COSY, HMQC and HMBC) comparing the purified compound with α-bisabolol compound revealed that the new alcohol is an isomer structural of α-bisabolol, due to change in relation to the position of the double bond and the methyl group present in the cyclic chain of these compounds.

Ferulago macedonica Micevski & E. Mayer (Apiaceae), an endemic species from Macedonia, was evaluated for its essential oil composition and biological activity for the first time. The essential oil composition from inflorescence and aerial parts, analyzed by gas chromatography and gas chromatography–mass spectrometry (GC and GC-MS), indicated α-pinene (43.10% and 22.78%) and sabinene (26.73% and 15.46%) as the main components. The antioxidant activities of extracts was determinated spectrophotometrically using 2,2-diphenyl-1-picrylhydrazyl ( DPPH). The strongest activity had methanol extracts of inflorescence and aerial parts (IC 50=490 mg/mL and IC 50=630 mg/mL of solution, respectively). According to 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) test, the most effective were ethanol and methanol extracts of F. macedonicainflorescence (1.69 and 1.63 mg Vit.C/g dw). Total phenolic and flavonoid contents evaluation indicated that their amounts were ranged between 34.12-59.68 mg gallic acid (GA)/g dw for phenols and 9.08 - 23.73 mg quercetin hydrate (QE)/g dw for flavonoids. Antimicrobial activity of extracts and essential oils was investigated by micro-well dilution assay. Minimum inhibitory (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were defined. The methanol extract of inflorescence has shown to be the strongest in both, antibacterial ( MICs=4-8 mg/mL; MBCs=9-13 mg/mL ) and antifungal activity ( MICs=2-12 mg/mL; MFCs=6-18 mg/mL). Essential oil from inflorescence and aerial parts of F. macedonica manifested stronger inhibition on growth of pathogenic bacteria and fungy compared to tested extracts and positive standards.

Aerial parts of Nepeta hindostana (Roth) Haines collected from Gorakhpur Division, U. P., India possessed an essential oil in 0.42% yield. GC and GC-MS analysis of the oil revealed recognition of thirty three compounds, representing 91.0% (area percent) of the total oil composition. Oil was rich in sesquiterpene hydrocarbons, exhibited higher percentage of (E) β - farnesene (10.4%) followed by ageratochromene (9.7%), spiro [4.5] decan-1-one, 6-hydroxy (9.5%), b -caryophyllene (8.6%) and spiro [4.5] decan-6-ol, 6-methyl (8.2%). At 60 µL, oil showed 80.7% antioxidant activity by β-carotene bioassay (IC 50 = 8 µL) and 73.4% by DPPH free radical scavenging bioassay (IC 50 = 8.5 µL). Furthermore, the oil was tested for its antimicrobial activity in opposition to five plant and human pathogenic bacteria namely Bacillus subtilis, Erwinia herbicola, Escherichia coli, Pseudomonas putida, Salmonella typhi and six post-harvest fungi such as Aspergillus flavus Link., A. niger van Tieghem, A. ochraceus Wilhelm, A. terreus Thom, Fusarium nivale (Fries) Cesati and F. oxysporum Schlecht. The oil was found to be more efficacious for E. coli, Erw. herbicola and A. ochraceus.

Hydrodistilled essential oil from aerial parts of Marrubium anisodon (Lamiaceae) was analyzed by GC-FID and GC/MS. Thirty-nine components were characterized representing 87.9 % of the oil. (Z)- b -Farnesene (20.2 %), nonacosane (18.5%) and b -caryophyllene (13.3 %) were the main constituents.

The chemical composition of the essential oils from all parts of Pseudoscleropodium purum, Eurhynchium striatum and Eurhynchium angustirete were analysed by GC-FID-MS. Sixty-five, thirty-four and seven compounds, accounting for 99.7%, 97.3% and 99.9% of the oils, were identified and the main components were a - pinene (16.1%), 3-octanone (48.1%), and eicosane (28.6%), respectively. The essential oils were also tested against nine strains using a broth microdilution method and showed moderate antimicrobial activity with minimum inhibitory concentrations (MIC) ranging from 278.2 to 2225 µg/mL. All the mosses essential oils showed good antituberculosis activity against Mycobacterium smegmatis with MIC of 278.2-312.0 µg/mL.

A new aporphine alkaloid, 7-epi-duguetine (1) together with one known alkaloid, dicentrinone (2), and four known flavonoids, quercetin 3,7-dimethyl ether 3′ -O- α -L-rhamnopyranosyl-(1 g 2)-β-D-glucopyranoside (3), galangin 5-methyl ether (4), 5,7-dimethoxy-3-hydroxyflavone (5), and 3,5,7-trimethoxyflavone (6), were isolated from the leaves of Dasymaschalon acuminatum, a new plant species which has not been investigated phytochemically before. The structures of the isolated compounds were elucidated through extensive NMR spectroscopic analysis. All isolates were evaluated for antiplasmodial activity against Plasmodium falciparum strain K1 and 7- epi -duguetine was found to exhibit potent activity with an IC 50 of 0.385 m g/ml.

Sorghum halepense (L.) Pers. is known as invasive weed in the world. In this paper we report three rare natural products from this weed. The compounds include a new rare natural product 2,2-dimethyl-5-(4-hydroxyphenyl)-4-oxazolidinone (1), and two other known mandelic acid derivatives, ethyl 4-hydroxymandelate (2) and 4-hydroxymandelamide (3). The structures of these compounds were elucidated by extensive spectroscopic analysis (MS, IR, 1H, 13C NMR and 2D NMR).

Aphytochemical investigation of Eugenia uniflora ’s leaf extract resulted in the isolation of eleven phenolic compounds: 2,3-di-O-galloyl- b - D -glucose (1), 1,2,3,4,6-penta-O-galloyl- b - D -glucose (2), gemin D (3), hippomanin A (4), oenothein B (5), eugeniflorin D 2 (6), camptothin A (7), afzelin (8), quercitrin (9), myricitrin, (10) and desmanthin-1 (11). These compounds were identified by spectroscopic methods including 1D- and 2D-NMR, UV, IR, and TOF/MS. Compounds 1, 2, 3, 4, 7, 8, 9, and 11 were isolated from this species for the first time. Ten isolates were evaluated for antioxidant activity by DPPH free radical and Oxygen Radical Absorbance Capacity (ORAC-Fluorecein) assay . Dimeric tannins, oenothein B (5), eugeniflorin D 2 (6), and camptothin A (7) showed a remarkable radical scavenging capacity.

A new amide, named ( 2E, 4E)-5-phenyl-N-(2-phenylethyl)-2,4-pentadienamide (1) , together with one known amide, N -2-phenylet hylcinnamide (2) and two known ceramides, 2-​hydroxy-​N-​[(1S,​2R,​3E)​-​2-​hydroxy-​1-​(hydroxymethyl)​-​3-​heptadecenyl]​-pentadecanamide (3), 1-O-(β-D-glucopyranosyl)-(2S,3R,4E,8E)-2-[(2R)-2-hydroxypentadecanoylamino]-4,8-octadecadiene-1,3-diol (4) were isolated from the stem bark of Illicium difengpi. The structures of the isolated compounds were elucidated by analyses of their 1H and 13C NMR, COSY, H S QC, HMBC spectr a and HR-ESI/MS mass spectrometric data. Anti-inflammatory assays with compounds 1‒4 were carried out, compounds 1 and 2 showed significant inhibitory effect on TNF- α release in LPS stimulated RAW 264.7 macrophages.

This study explored antidiabetic potential of eight known pure compounds, isolated from the bark of Rhododendron arboreum. Invitro studies of these compounds against α and β-glucosidases revealed them as very potent and selective inhibitors of α-glucosidase. Compound 7 (3-O-acetylursolic acid) was found to be the most potent inhibitor of α-glucosidase with 3.3±0.1µM IC 50 value which was many folds higher than standard inhibitor acarbose. Antiglycation studies of compounds showed that all compounds were also very active antiglycation agents. The studied biological properties of these compounds suggest that they are therapeutically interesting and important tools for treatment of diabetes.

A new lanostan-type triterpenoid with hydroperoxy group, toosendanin A (1), together with two known triterpenoids, meliastatin 3 (2) and ursolic acid (3), w ere isolated and identified from the stems of Melia toosendan. The structures of these compounds were elucidated by 1D- and 2D-NMR spectra and other spectroscopic studies. These compounds were assayed for the antibacterial activities against some hospital pathogenic bacteria. Toosendanin A (1) exhibited strong antibacterial activity against K. pneumoniae .