Isolation and Identification of Phytocompounds from Maytenus dhofarensis and Their Biological Potentials.

Maytenus dhofarensis Sebsebe (Celestraceae) is a naturally growing shrub in Oman. It is not a reputed medicinal plant in Oman, but it is regionally endemic and causes shivering attacks on goats that graze on it. The chemical investigation of the hexane and chloroform extracts of the fruits and stems of M. dhofarensis afforded dihydro-ß-agarofuran-type sesquiterpene pyridine alkaloid (1), lupanyl myristoate (2) and lignanolactone (3). Compounds (1-3) are new isolates from M. dhofarensis. The structures of these compounds were assigned through comprehensive IR, NMR, and ESI-MS analyses, and the relative configurations of compounds 1 and 3 were deduced from density function theory (DFT) calculations and NMR experiments. Compound 1 was assayed against the kinase enzyme and showed no inhibition activity for p38 alpha and delta at a 10 µM test concentration. Compound 3 inhibited the 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH) by 69.5%, compared to 70.9% and 78.0% for gallic acid and butylated hydroxyanisole, respectively, which were used as positive controls.

Pomegranate seed oil: Effect on 3-nitropropionic acid-induced neurotoxicity in PC12 cells and elucidation of unsaturated fatty acids composition.

BACKGROUND: Seed oils are used as cosmetics or topical treatment for wounds, allergy, dandruff, and other purposes. Natural antioxidants from plants were recently reported to delay the onset or progress of various neurodegenerative conditions. Over one thousand cultivars of Punica granatum (Punicaceae) are known and some are traditionally used to treat various ailments. AIM: The effect of pomegranate oil on 3-nitropropionic acid- (3-NP) induced cytotoxicity in rat pheochromocytoma (PC12) neuronal cells was analyzed in this study. Furthermore, the analysis of unsaturated fatty acid composition of the seed oil of pomegranate by gas chromatography-electron impact mass spectrometry (GC-MS) was done. RESULTS: GC-MS study showed the presence of 6,9-octadecadiynoic acid (C18:2(6,9)) as a major component (60%) as 4,4-dimethyloxazoline derivative. The total extractable oil with light petroleum ether by Soxhlet from the dry seed of P. granatum was 4-6%. The oil analyzed for 48.90 ±â€Š1.50 mg gallic acid equivalents/g of oil, and demonstrated radical-scavenging-linked antioxidant activities in various in vitro assays like the DPPH (2,2-diphenyl-l-picrylhydrazyl, % IP = 35.2 ± 0.9%), ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), % IP 2.2 ± 0.1%), and ß-carotene bleaching assay (% IP = 26 ± 3%), respectively, which could be due the possible role of one methylene interrupted diynoic acid system for its radical-scavenging/antioxidant properties of oil. The oil also reduced lipid peroxidation, suppressed reactive oxygen species, extracellular nitric oxide, lactate/pyruvate ratio, and lactase dehydrogenase generated by 3-NP- (100 mM) induced neurotoxicity in PC12 cells, and enhanced the levels of enzymatic and non-enzymatic antioxidants at 40 µg of gallic acid equivalents. CONCLUSION: The protective effect of pomegranate seed oil might be due to the ability of an oil to neutralize ROS or enhance the expression of antioxidant gene and the exact mechanism of action yet to be elucidated.

ent-Kaurene diterpenoids from Blepharispermum hirtum.

The twigs and leaves of Blepharispermum hirtum Oliver (Asteraceae) were investigated for their larvicidal and antimicrobial activity. Fractionation of the extracts of the twigs, directed by brine shrimp test and antibacterial activities, led to the isolation of compounds 1-4; two of which are new ent-kaurene diterpenoids, blepharispins A and B (1 and 2, resp.). The structures of compounds 1 and 2 were established from spectral data. The absolute configuration at C(15) in 1 was inferred from Mosher ester analysis and relative configurations were suggested by a NOESY experiment. Compound 4 was significantly larvicidal to newly hatched naupleii of Artemia salina L. (BST LC(50)=1.3 (3.7-0.0) microg/ml), but the blepharispins were not (BST LC(50) > 500 microg/ml). Nevertheless, compound 1 inhibited the growth of Staphylococcus aureus and Bacillus subtilis at a MIC value of 62.5 microg/ml. The significance of the bioactivity results and the presence of ent-kaurene diterpenoids in B. hirtum are discussed from biosynthetic and local utilization viewpoints.

Identification of the chemotypes of Ocimum forskolei and Ocimum basilicum by NMR spectroscopy.

The chemotypes of Ocimum forskolei Benth and Ocimum basilicum L. growing wild in Oman have been established by (13)C-NMR analyses of the vegetative and floral oils of the plants. The chemotypes, estragole for O. forskolei and linalool for O. basilicum, suggested by (13)C-NMR fingerprinting were also confirmed by GC-FID and GC/MS analyses. The oil of O. forskolei demonstrated better activities against bacteria and dermatophytes. The significance of the presence of estragole and linalool in the volatile oils of plants whose fragrances are traditionally inhaled, added to food, or rubbed on the skin are discussed.

Production of phenylacetic acid derivatives and 4-epiradicinol in culture by Curvularia lunata.

Phenylacetic acid derivatives, methyl 2-acetyl-3,5-dihydroxyphenylacetate (1) and methyl 2-acetyl-5-hydroxy-3-methoxyphenylacetate (3); curvulin or ethyl 2-acetyl-3,5-dihydroxyphenylacetate (4), a known metabolite of Curvularia siddiqui, and 4-epiradicinol (5) have been isolated from the culture mycelia of Curvularia lunata grown on YMG, a medium consisting of yeast, malt extract and glucose. Compounds 1, 3 and 4 lack antimicrobial and antioxidant activity, but 4-epiradicinol (5) inhibited the growth of Escherichia coli, Staphylococcus aureus, Salmonella choleraesuis and Bacillus subtilis. The structures of compounds 1, 3-5 were determined by analyses of IR, MS, 1D and 2D NMR data, assisted by chemical shift comparison to related and model compounds. The relative stereochemistry of the vicinal diol in 5 was determined from the 1H NMR signals for the methyl protons of the resulting cyclic acetonide prepared from 5.

Chemical composition, antibacterial and antifungal activities of the essential oil of Haplophyllum tuberculatum from Oman.

The chemical composition of the essential oil of Haplophyllum tuberculatum (Forsskal) A. Juss (Rutaceae) was analyzed by gas chromatography-mass spectral (GC-MS) and 13C NMR spectroscopy. Thirty compounds, constituting about 99.7% of the total oil, were identified. The most abundant oil components are beta-phellandrene (23.3%), limonene (12.6%), (Z)-beta-ocimene (12.3%), beta-caryophyllene (11.6%), myrcene (11.3%), and alpha-phellandrene (10.9%). Ten microlitres (25 mg) of pure oil partially inhibited the growth of Escherichia coli, Salmonella choleraesuis, and Bacillus subtilis to the same extent as 0.10 microg of gentamycin sulfate. The oil also affected the mycelial growth of Curvularia lunata and Fusarium oxysporium in a dose-dependent manner but had no effect on the germination of their spores.

Muscanone: a 3-O-(1", 8", 14"-trimethylhexadecanyl)naringenin from Commiphora wightii.

A new antifungal flavanone, muscanone (1), was isolated along with known naringenin (2) from Commiphora wightii (Arn.) Bhandari (Burseraceae) by directing the fractionation of an EtOH extract of the air-dried trunk of C. wightii with microbial sensitivity assay. The structures of 1 and 2 were determined from EIMS, HREIMS, DEPT, 1H-1H COSY, HSQC and HMBC spectral data. Muscanone (1) was identified as 3-O-(1", 8",14"-trimethylhexadecanyl)naringenin and was found to be active against Candida albicans. The isolation, structure elucidation, NMR spectral assignments, and bioactivities of 1 and 2 are reported.

Monoacylglycerol from Punica granatum seed oil.

The seeds of Punica granatum, known as hap roman in the Arabian Peninsula, are commonly eaten as a dessert. As part of an ongoing project to find nonnutritional natural products which have health benefits, or that can be exploited to protect crops, the chloroform-soluble extract of the fermented seeds of P. granatum was found to be rich in 1-O-trans,cis,trans-9,11,13-octadecatrienoyl glycerol (1). The seed oil is not lethal to brine shrimp larvae. 1-O-isopentyl-3-O-octadec-2-enoyl glycerol (2) and the known cis-9-octadecenoic, octadecanoic, and eicosanoic acids were also detected in small amounts in the seed oil by LC and MS. The structure of 1 was determined from NMR and MS spectral data.

New sesquiterpenes from Pluchea arabica.

Two new sesquiterpenes, godotol A (1) and godotol B (2), were isolated from Pluchea arabica. Their structures were determined by analysis of NMR data. The absolute configurations of 1 and 2 were established by Mosher ester methodology. The godotols displayed weak activity against bacteria and the brine shrimp larvae. They were also inactive in the DPPH antioxidant assay.