Laceioside, a new cycloartane saponin from Astragalus tephrosioides Boiss. var. lacei (Ali) Kirchoff.

Phytochemical investigation of the aerial parts of Astragalus tephrosioides Boiss. var. lacei (Ali) Kirchoff. (Family Fabaceae) resulted in the isolation of a new cycloartane glycoside laceioside (1). The structure of the previously undescribed compound 1 was established as 16ß-acetyloxy-3- O-ß-d-glucopyranosyloxy-cycloartan-11α,24ξ, 25-triol. The structure elucidation of compound 1 was based primarily on 1D and 2D-NMR techniques including 1H and 13CNMR spectra, DEPT and by 2D COSY, HSQC and HMBC experiments.

The isolation, purification and biological activity of a novel antibacterial compound produced by Pseudomonas stutzeri.

A novel compound designated zafrin [4beta-methyl-5, 6, 7, 8 tetrahydro-1 (4beta-H)-phenanthrenone] was isolated from a crude extract of a marine bacterium identified as Pseudomonas stutzeri. Zafrin showed strong antibacterial activity against both Gram-positive and Gram-negative bacteria. The compound was purified and its structure was elucidated by spectroscopic methods including 1H-nuclear magnetic resonance (NMR), 13C-NMR, 1D-NMR and 2D-NMR spectroscopy. It could be demonstrated that a purified solution of zafrin was active against several human pathogens, including Staphylococcus aureus, and Salmonella typhi. By contrast, zafrin did not inhibit the growth of eukaryotic organisms Candida albicans and Schizosaccharomyces pombe. The minimal inhibitory concentration for Gram-positive bacteria ranged from 50 to 75 microg mL(-1) and varied between 75 and 125 microg mL(-1) for Gram-negative bacteria. Zafrin lysed Bacillus subtilis cells grown in an osmotically protected medium, suggesting that it does not act upon the cell wall. Further investigation using B. subtilis indicated that the compound is bactericidal and is likely to target the cell membrane.

Isolation, purification, structural elucidation and antimicrobial activities of kocumarin, a novel antibiotic isolated from actinobacterium Kocuria marina CMG S2 associated with the brown seaweed Pelvetia canaliculata.

AIMS: Screening of seaweed-associated bacteria capable of producing antimicrobials. METHODS AND RESULTS: Fifteen microbial strains, associated to the brown seaweed Pelvetia canaliculata (Linnaeus) attached to the rocks of Sonmiani Beach (Karachi, Pakistan), were screened. Crude extract filtrates of CMG S2 strain grew on Zobell marine agar (ZMA) had the most remarkable antimicrobial activity. Based on its phenotypic aspects (e.g. Gram-positive, microccoid form), biochemical characteristics (e.g. halotolerance) and genetic analyses, CMG S2 is identified as a putatively new Kocuria marina type strain belonging to the actinobacteria's class and micrococcaceae family. Thereby, the nucleotide sequence analysis of its full-length 16S ribosomal ribonucleic acid (rRNA) gene (GenBank accession number EU073966.1) displayed highest identity (i.e. 99%) and score (2630) with K. marina KMM 3905. Phylogenic trees analysis using the neighbor-joining method showed closest evolutionary distance of CMG S2 with KMM 3905 strain and K. carniphila (DC2201) specie. Interestingly, a unique ultraviolet (UV)-bioactive compound was purified from CMG S2 crude extracts by flash silica gel column and thin-layer chromatography (TLC) techniques. Its chemical structure was unraveled as 4-[(Z)-2 phenyl ethenyl] benzoic acid (PEBA, later named kocumarin) by nuclear magnetic resonance (NMR) spectroscopy techniques. Importantly, kocumarin demonstrated prominent and rapid growth inhibition against all tested fungi and pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA), with a minimal fungal inhibitory concentration (MFC) of 15-25µg/mL and a minimal (bacterial) inhibitory concentration (MIC) of 10-15µg/mL. SIGNIFICANCE AND IMPACT OF THE STUDY: Kocumarin represents a new promising natural antibiotic for in vivo and environmental applications.

In vivo evaluation of analgesic, anti-inflammatory, and neuropharmacological activities of the chemical constituent from Nepeta clarkei.

The plant species of genus Nepeta are used to treat various human diseases and for ornamental purposes as well. Nepethalate B (1) was isolated as a result of phytochemical investigations of Nepeta clarkei and was subjected in the present study for investigation of analgesic, anti-inflammatory, and central nervous system (CNS) depressant activities. The percentage inhibition in phase I of the acetic acid induced writhing test of compound 1 (dose of 0.1, 0.2 and 0.4 mg/kg of body weight) was 53.3, 58.0 and 86.7% respectively. These results were found significantly higher (P < 0.01) as compared to the negative control. Moreover, the percentage inhibitions of three phases for 0.1, 0.2 and 0.4 mg/kg were higher than the values obtained for Aspirin (positive control). In formalin test, the percentage pain inhibition between 0 and 5 min (early phase) was 68.0, 25.5, and 75.5% for 0.1, 0.2 and 0.4 mg/kg intra-peritoneal doses of compound 1 respectively. In case of late phase (20-30 min) it was 63.0, 66.7 and 48.1%, respectively. In comparison to aspirin, overall percentage inhibition of compound 1 was significantly higher in early and late phases. Interestingly, at all doses compound 1 showed more potent anti-inflammatory effects in terms of intensity and duration as compared to aspirin. The gross behavioral study of nepethalate B (1) was also carried out and the results revealed that it exhibited CNS depression in the mice and showed a prominent decrease in locomotor activity.

A new glucuronolactone glycoside phoenixoside B from the seeds of Phoenix dactylifera.

A new glucuronolactone glycoside, phoenixoside B (1), has been isolated from the n-butanol soluble fraction of seeds of Phoenix dactylifera. The structure was characterized as 1-(1'-ethyl-beta-D-glucosyl)-4,5-diethyl-[alpha-D-glucofuranourono-6,3-lactone] on the basis of 1D and 2D-NMR spectroscopy and high-resolution mass spectrometry.

A new monodesmosidic triterpenoid saponin from the leaves of Pometia pinnata.

Phytochemical investigation of the leaves of Pometia pinnata resulted in the isolation of a new triterpenoid saponin (1), together with a known compound, kaemferol 3-O-alpha-L-rhamnopyranoside (2). The structure of 1 was established as 3-O-[alpha-L-arabinofuranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-hederagenin. The structure elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR techniques, including 1H and 13C NMR spectra, DEPT, and by 2D COSY, HMQC, HMBC and TOCSY experiments.

Two new antioxidant bergenin derivatives from the stem of Rivea hypocrateriformis.

Two new bergenin derivatives, named rivebergenin A and B (1, and 2), together with two known compounds, bergenin (3) and norbergenin (4) were isolated from the stem of Rivea hypocrateriformis (Desr.) Choisy. The structures of the new compound have been assigned from (1)H and (13)C NMR spectra, DEPT, and by 2D COSY, HMQC, and HMBC experiments. Compounds 1-4 showed the strong antioxidant activity.

A new triterpenoid saponin from the stem bark of Pometia pinnata.

Phytochemical investigation of the stem bark of Pometia pinnata resulted in the isolation of a new triterpenoidal saponin. The structure of the new compound, pometin (1), was established as 3-O-[beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-glucopyranosyl]-oleanolic acid based on 1D and 2D-NMR analysis including COSY, 2D J-resolved, HMQC, HMBC correlations and chemical transformations.

Saponins from the seeds of Achras sapota.

A new pentacyclic triterpenoid saponin (2) along with one known was isolated from the cotyledons of Achras sapota. Their structures were determined with the help of (1)H NMR, (13)C NMR and MS spectral data. The isolated compounds were named as 3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl protobassic acid (1) and 3-O-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-16alpha-hydroxy protobassic acid (2). Compound 2 showed antibacterial activity against Gram positive and negative bacteria.