Najeeb Ur Rehman

meta-Chloroperbenzoic acid (mCPBA): a versatile reagent in organic synthesis

The synthetic uses of different peroxides for organic synthesis have been widely studied. Among these peroxides, meta-chloroperbenzoic acid (mCPBA) is an efficient oxidizing reagent and have been used for many oxidative transformations. mCPBA is widely used for chemical transformations such as the oxidation of carbonyl compounds, iminoindolines, olefins, imines, alkanes, silyl enol ethers, N- and S-heterocycles, active methylene groups, fluoromethylated allylic bromides, cyclic acetals, N-substituted phthalimidines, selenides, furans and phosphates. The purpose of this review is to collect and discuss the synthetic applications of meta-chloroperbenzoic acid (mCPBA) over the past few decades.

Essential oil composition and nutrient analysis of selected medicinal plants in Sultanate of Oman

Objective To evaluate the nutrients and essential oils of five medicinal plants, Juniperus excelsa (J. excelsa), Dodonaea viscosa, Euryops pinifolius, Teucrium polium (T. polium), and Helianthemum lippii that were collected from Jabal Al Akhdar, Oman.

A fruitful decade from 2005 to 2014 for anthraquinone patents

Introduction: Anthraquinones are aromatic compounds whose structures are related to anthracene (parent structure: 9,10-dioxoanthracene) for which various methods for their synthesis have been developed. In the past decade (2005 – 2014), much work has been done regarding anthraquinone chemistry in order to discover new compounds related to this scaffold as anticancer, antibacterial, antidiabetic, antiviral, anti-HCV, antifibrotic, fungicidal and anti-inflammatory agents. Areas covered: This review covers the patents on therapeutic activities of anthraquinones and their derivatives in the years between 2005 and 2014. A large portion of the therapeutic applications that were reported in international patents will be presented and discussed. Although a large number of patents have been registered over the last decade, this review is focused on important patents related to cancer, inflammation, infectious diseases, diabetic conditions and hepatitis C. Expert opinion: The tricyclic planar ring system of anthraquinones displays a wide range of important pharmaceutical properties. By linking active anthraquinone analogs to other important pharmacophores or conjugates such as oximes, N-heterocycles, benzodiazepines or glycosyl ethers, their anticancer potential is enhanced. The ability of anthraquinone analogs to become more prominent as novel pharmaceutical agents may further be enhanced by fusing functionalized heterocyclic rings onto established anthraquinone cores.

Isolation and Bioactivities of the Flavonoids Morin and Morin-3-O-β-D-glucopyranoside from Acridocarpus orientalis—A Wild Arabian Medicinal Plant

Acridocarpus orientalis is an important medicinal plant for some of the locals of Arabian region. Very little is known about its phytochemical constituents. In the present study, we aimed to isolate bioactive chemicals from the crude methanolic extract of the aerial parts of A. orientalis. The extraction and isolation resulted in the purification of two flavonoids: morin (1) and morin-3-O-β-D-glucopyranoside (2). The structure elucidation was carried out by extensive analysis of spectroscopic data and comparison with the reported data for the known constituents. The pure isolates were subjected to various biological assays for their bioactivities. The compounds 1 and 2 were significantly active against the growth of various pathogenic fungi and phytotoxic against lettuce seed at higher concentrations. Furthermore, the free radical scavenging activities, anti-lipid peroxidation, and cytotoxic effects against HepG2, HT29, and HCT116 cancer cell lines were also assayed and the results are presented in this paper.

Analgesic, anti-inflammatory, and CNS depressant activities of new constituents of Nepeta clarkei

Two new pentacyclic triterpenes named kirmanoic acid (1) and kurramanoic acid (2) have been isolated from the chloroform-soluble portion of the whole plant of Nepeta clarkei Hook. The structures of the two new compounds were assigned on the basis of their ¹H and ¹³C NMR spectra including two-dimensional NMR techniques such as COSY, HMQC, and HMBC experiments. Kirmanoic acid (1) was investigated for analgesic, anti-inflammatory, and CNS depressant activities. Interestingly kirmanoic acid (1) showed strong analgesic activity than standard drug in acetic induced writhing and formalin tests. Similarly kirmanoic acid (1) also showed strong anti-inflammatory activity than its standard drug. The gross behavioral study of kirmanoic acid (1) revealed that it exhibited mild CNS stimulant and muscle relaxant in the mice. Compound 1 showed a slight increase in Locomotor activity and possesses the antidepressant effect.

The genus Pluchea : Phytochemistry, traditional uses and biological activities

In this review, literature data on phytochemical and biological investigations on the genus Pluchea are compiled. Pluchea is a genus of flowering plants in the Asteraceae family and comprises ca. 80 species distributed mainly in Northern and Southern America, Africa, Asia, and Australia. Sesquiterpenoids and flavonoids are the main constituents of this genus. Compounds isolated from plants of the Pluchea genus display a variety of biological properties, viz., anticancer, antileishmanial, immunosuppressive, antioxidant, anti‐acetylcholinesterase, antimicrobial, trypanocidal, hepatoprotective, cytotoxic, larvicidal, anti‐ulcer, anti‐inflammatory, and antinociceptive activities.

Analgesic effects of crude extracts and fractions of Omani frankincense obtained from traditional medicinal plant Boswellia sacra on animal models.

OBJECTIVE To investigate the analgesic effect of Boswellia sacra (B. sacra), which could support the Omani traditional uses of frankincense for muscle, stomach, and arthritis pain. METHODS The crude extract, the essential oils and various sub-fractions of the crude methanol extract (each 300 mg/kg of the body weight of the animal) obtained from the resin of B. sacra were administered orally, and were evaluated for their analgesic activities by using two well known models of pain in mice, viz. acetic acid induced writhing test and formalin induced pain test in mice. RESULTS Of 13 samples, almost all of them were effective at an orally administered dose of 300 mg/kg of the body weight. The acetic acid induced writhes were inhibited in all the three phases with comparable values to the standard drug aspirin (300 mg/kg of body weight) with inhibition of 67.6% in phase I, 66.8% in phase II, and 37.9% in phase III. At the same time, all the tested samples were found effective in both the early and the late phases of formalin test. In formalin test, most of the tested samples showed more inhibitory effects as compared to the standard drug aspirin (300 mg/kg of body weight), which showed 36.2% and 29.6% inhibition in early and late phases respectively. Among the tested samples, the most significant inhibition was produced by Shabi frankincense oil (57.5% in early phase, and 55.6% in late phase). Interestingly, the extracts showed comparable percentage of inhibition to the oil and found in the following order: 60% chloroform/n-hexane sub-fraction (55.3% in early phase, and 66.7% in late phase), and 70% chloroform/n-hexane sub-fraction (59.6% in early phase, and 63.0% in late phase). CONCLUSIONS The present study provided the scientific justification about the analgesic properties of the essential oils, extract, and various sub-fractions obtained from the resin of B. sacra, thus validating its use in traditional folk medicines and other products; and hence supporting the development in the analgesic properties of bioactive natural substances.

Determination of sucrose in date fruits (Phoenix dactylifera L.) growing in the Sultanate of Oman by NIR spectroscopy and multivariate calibration

A Near Infrared (NIR) spectroscopic method combined with multivariate calibration was developed for the determination of the amount of sucrose in date fruits growing in the Sultanate of Oman. In this study two groups of samples were used: one group of 48 sucrose standard solutions in the concentration range from 0.01% to 50% (w/v) and another group of 54 date fruit samples of 18 different varieties. The sucrose standard samples were split in two sets, i.e. one training set of 31 samples and one test set of 17 samples. All samples were measured with a NIR spectrophotometer in the wavelength range from 700 to 2500 nm. The spectra collected were preprocessed using baseline correction and Savitzky-Golay 1st derivative. Partial least-squares regression (PLSR) was used to build the regression model with the training set of 31 samples. This model was then validated by using random leave-one-out cross-validation. Later, the PLS regression model was externally validated by using the test set of 17 samples of known sucrose concentration. The root mean squared error of prediction (RMSEP) was found to be of 1.5%, which shows a good prediction ability of the model. Finally, the PLS model was applied to the spectra of 54 date fruit samples to quantify their sucrose amount. It was found that the Khalas, Barnia Nizwi, Ajwa Almadina, Maan, and Khunizi varieties contain high amounts of sucrose, i.e. ranging from 36% to 60%, while Naghal, Fardh, Nashu and Qash Tabaq varieties contain the least amount of sucrose, ranging from 3.5% to 8.1%.

Amiodarone, lidocaine, magnesium or placebo in shock refractory ventricular arrhythmia: A Bayesian network meta-analysis

ABSTRACT Recent evidence challenges, the superiority of amiodarone, compared to other anti‐arrhythmic medications, as the agent of choice in pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF). We conducted Bayesian network and traditional meta‐analyses to investigate the relative efficacies of amiodarone, lidocaine, magnesium (MgSO4) and placebo as treatments for pulseless VT or VF. Eleven studies [5200 patients, 7 randomized trials (4, 611 patients) and 4 non‐randomized studies (589 patients)], were included in this meta‐analysis. The search was conducted, from 1981 to February 2017, using MEDLINE, EMBASE and The Cochrane Library. Estimates were reported as odds ratio (OR) with 95% Credible Interval (CrI). Markov chain Monte Carlo (MCMC) modeling was used to estimate the relative ranking probability of each treatment group based on surface under cumulative ranking curve (SUCRA). Bayesian analysis demonstrated that lidocaine had superior effects on survival to hospital discharge, compared to amiodarone (OR, 2.18, 95% Cr.I 1.26–3.13), MgSO4 (OR, 2.03, 95% Cr.I 0.74–4.82) and placebo (OR, 2.42, 95% Cr.I 1.39–3.54). There were no statistical differences among treatment groups regarding survival to hospital admission/24 h (hrs) and return of spontaneous circulation (ROSC). Probability analysis revealed that lidocaine was the most effective therapy for survival to hospital discharge (SUCRA, 97%). We conclude that lidocaine may be the most effective anti‐arrhythmic agent for survival to hospital discharge in patients with pulseless VT or VF. HighlightsBoth the American Heart Association and the European Resuscitation Council guidelines suggest amiodarone as first‐line anti‐arrhythmic therapy in shock refractory ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), with lidocaine as an alternative if amiodarone is unavailable.Recent reports have raised concerns regarding the superiority of amiodarone as the agent of choice for shockable cardiac arrest.These observations mandate re‐evaluation of evidence on effective anti‐arrhythmic therapy in shock refractory VT and VF.We performed traditional and Bayesian analyses to compare amiodarone, lidocaine, magnesium and placebo in shockable cardiac rhythms to update the evidence.

Exploring the Potentials of Lysinibacillus sphaericus ZA9 for Plant Growth Promotion and Biocontrol Activities against Phytopathogenic Fungi

There is an ongoing hunt for biologically active compounds that can combat phytopathogenic fungi and improve plant growth without causing any hazards to the environment. Consequently the present study aims at deciphering the plant growth promotion and antifungal capability of Lysinibacillus sphaericus ZA9. The bacterium was previously isolated and identified in our laboratory from maize rhizosphere using 16S rRNA gene sequencing. The test bacterium L. sphaericus ZA9 was found to produce high quantity of IAA (697 μg/ mL); siderophores (195.79 μg/ mL), HCN and hydrolytic enzyme as compared to the reference strain Bacillus sphaericus Z2-7. The bacterium was also capable of solubilizing silicates (Si), phosphates (P), and potassium (K). The bacterium enhanced the seedling vigor and germination of seeds pretreated with it and promoted the shoot length of both cucumber and tomato seeds in greenhouse experiment. L. sphaericus ZA9 and its cell free culture supernatant showed varied antagonistic behavior against Alternaria alternata, Curvularia lunata, Aspergillus sp., Sclerotinia sp., Bipolaris spicifera, Trichophyton sp. Fermentation broth culture of L. sphaericus ZA9 was then used to isolate antifungal metabolites by silica column chromatography. Identification and determination of antifungal compounds was carried out by Thin-layer chromatography (TLC) followed by NMR spectroscopy. Two compounds were isolated and identified as 2-pentyl-4-quinolinecarboxylic acid (C15H17NO2) which is a quinoline alkaloid and 1- methylcyclohexene which is a cycloalkene. Compound 1; 2-Penthyl-4-quinolinecarboxylic acid was found to be highly antagonistic against most of the fungi tested as compared to the bacterium itself. Its activity was comparable to that of fungicide Benlate, while compound 2; 1- methylcyclohexene did not show any antifungal activity.