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31.
Najeeb Ur Rehman Abdul Latif Khan Zahid Hassan Tania Shamim Rizvi Ahmed Al‐Harrasi Zabta Khan Shinwari Javid Hussain 《Helvetica chimica acta》2015,98(9):1240-1244
One new cyclopropyl‐triterpenoid ( 1 ), along with four known constituents including octacosan‐1‐ol ( 2 ), pentacosanoic acid ( 3 ), β‐sitosterol ( 4 ), and β‐sitosterol 3‐O‐β‐D ‐glucopyranoside ( 5 ) were isolated from the aerial parts of Ochradenus arabicus for the first time. These compounds were isolated by repeated column chromatography followed by further purification through recycling HPLC. The structure of the new secondary metabolite 1 was established on the basis of UV, IR, 1D‐ (1H‐ and 13C‐) and 2D‐NMR (HMBC and HSQC), and MS spectral data. The molecular mass was determined by HR‐MS, and hence the molecular formula was deduced. The configurations of stereogenic centers in the molecule were assigned by NOESY experiments, along with biogenetic considerations. The structures of the known compounds were confirmed by comparison of their physical and spectroscopic data with those reported in literature. 相似文献
32.
Glass fibers were characterized for physical and chemical changes before and after subjecting to aging under different environmental conditions. The conditions selected were: low temperature, outdoor atmosphere, indoor atmosphere, chemical environment, 95% humidity & water soaking treatment. The results show that glass fiber is a good candidate to resist sunlight, corrosive atmosphere, low temperature and shady atmosphere. The influence of prolonged time exposure to water caused a detrimental effect on the properties of the glass fiber. Hence, prolonged exposure to water should be avoided for the integrity of the glass fiber under study. 相似文献
33.
Najeeb Alam Khan Asmat Ara Muhammad Jamil 《Mathematical Methods in the Applied Sciences》2011,34(14):1733-1738
In this paper, we apply the new homotopy perturbation method to solve the Volterra's model for population growth of a species in a closed system. This technique is extended to give solution for nonlinear integro‐differential equation in which the integral term represents the total metabolism accumulated fromtime zero. The approximate analytical procedure only depends on two components. The newhomotopy perturbationmethodwas applied to nonlinear integro‐differential equations directly and by converting the problem into nonlinear ordinary differential equation. We also compare this method with some other numerical results and show that the present approach is less computational and is applicable for solving nonlinear integro‐differential equations and ordinary differential equations as well. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
34.
Aftab Alam Najeeb Ur Rehman Mohd Nazam Ansari Amber Hanif Palla 《Molecules (Basel, Switzerland)》2021,26(9)
The present study examined the chemical composition and antimicrobial and gastrointestinal activity of the essential oils of Elettaria cardamomum (L.) Maton harvested in India (EC-I) and Guatemala (EC-G). Monoterpenes were present in higher concentration in EC-I (83.24%) than in EC-G (73.03%), whereas sesquiterpenes were present in a higher concentration in EC-G (18.35%) than in EC-I (9.27%). Minimum inhibitory concentrations (MICs) of 0.5 and 0.25 mg/mL were demonstrated against Pseudomonas aeruginosa in EC-G and EC-I, respectively, whereas MICs of 1 and 0.5 mg/mL were demonstrated against Escherichia coli in EC-G and EC-I, respectively. The treatment with control had the highest kill-time potential, whereas the treatment with oils had shorter kill-time. EC-I was observed to be more potent in the castor oil-induced diarrhea model than EC-G. At 100 and 200 mg/kg, P.O., EC-I exhibited 40% and 80% protection, respectively, and EC-G exhibited 20% and 60% protection, respectively, in mice, whereas loperamide (10 mg/kg, i.p., positive control) exhibited 100% protection. In the in vitro experiments, EC-I inhibited both carbachol (CCh, 1 µM) and high K+ (80 mM)-induced contractions at significantly lower concentrations than EC-G. Thus, EC-I significantly inhibited P. aeruginosa and E. coli and exhibited more potent antidiarrheal and antispasmodic effects than EC-G. 相似文献
35.
Muddaser Shah Hazir Rahman Ajmal Khan Shabana Bibi Obaid Ullah Saeed Ullah Najeeb Ur Rehman Waheed Murad Ahmed Al-Harrasi 《Molecules (Basel, Switzerland)》2022,27(4)
The recent study investigated the in vitro anti-diabetic impact of the crude extract (MeOH) and subfractions ethyl acetate (EtOAc); chloroform; n-butanol; n-hexane; and aqueous fraction of S. edelbergii and processed the active EtOAc fraction for the identification of chemical constituents for the first time via ESI-LC-MS analysis through positive ionization mode (PIM) and negative ionization mode (NIM); the identified compounds were further validated through computational analysis via standard approaches. The crude extract and subfractions presented appreciable activity against the α-glucosidase inhibitory assay. However, the EtOAc fraction with IC50 = 0.14 ± 0.06 µg/mL revealed the maximum potential among the fractions used, followed by the MeOH and n-hexane extract with IC50 = 1.47 ± 0.14 and 2.18 ± 0.30 µg/mL, respectively. Moreover, the acarbose showed an IC50 = 377.26 ± 1.20 µg/ mL whereas the least inhibition was observed for the chloroform fraction, with an IC50 = 23.97 ± 0.14 µg/mL. Due to the significance of the EtOAc fraction, when profiled for its chemical constituents, it presented 16 compounds among which the flavonoid class was dominant, and offered eight compounds, of which six were identified in NIM, and two compounds in PIM. Moreover, five terpenoids were identified—three and two in NIM and PIM, respectively—as well as two alkaloids, both of which were detected in PIM. The EtOAc fraction also contained one phenol that was noticed in PIM. The detected flavonoids, terpenoids, alkaloids, and phenols are well-known for their diverse biomedical applications. The potent EtOAc fraction was submitted to computational analysis for further validation of α-glucosidase significance to profile the responsible compounds. The pharmacokinetic estimations and protein-ligand molecular docking results with the support of molecular dynamic simulation trajectories at 100 ns suggested that two bioactive compounds—dihydrocatalpol and leucosceptoside A—from the EtOAc fraction presented excellent drug-like properties and stable conformations; hence, these bioactive compounds could be potential inhibitors of alpha-glucosidase enzyme based on intermolecular interactions with significant residues, docking score, and binding free energy estimation. The stated findings reflect that S. edelbergii is a rich source of bioactive compounds offering potential cures for diabetes mellitus; in particular, dihydrocatalpol and leucosceptoside A could be excellent therapeutic options for the progress of novel drugs to overcome diabetes mellitus. 相似文献
36.
Najeeb Alam Khan Muhammad Ali Qureshi Tooba Hameed Saeed Akbar Saif Ullah 《理论物理通讯》2020,72(12):125004-70
In this paper, we propose an innovative chaotic system, combining fractional derivative and sine-hyperbolic nonlinearity with circuit execution. The study of this system is conducted via an analog circuit simulator, using two anti-parallel semiconductor diodes to provide hyperbolic sine nonlinearity, and to function as operational amplifiers. The multi-stability of the system is also enhanced with the help of multi-equilibrium points for distinct real orders of system. The system explores the generation of a four-wing attractor in different phases, both numerically and electronically. By changing the input parameters of the system, different graphs are generated for current flow in state, phase, and space, to confirm the precision of the fractional order derivatives. A reasonable simulation shows that the deliberate circuit provides effective chaos in terms of speed and accuracy, which is comensurate with the numerical simulation. This nonlinear chaotic behavior is utilized to encrypt sound (.wav), images (.jpg), and animated (.gif) data which are a major requirement for the security of communication systems. The proposed circuit performs chaos and cryptographic tasks with high-effective analog computation, and constitutes a novel approach to this area of research. 相似文献
37.
Najeeb Ur Rehman Hidayat Hussain Mohammed Khiat Samia Ahmed Al‐Riyami René Csuk Husain Yar Khan Ghulam Abbas Ghanim Salim Al‐Thani Ivan R. Green Ahmed Al‐Harrasi 《Helvetica chimica acta》2016,99(9):687-690
Two new C‐glucosyl chromones named aloeverasides A ( 1 ) and B ( 2 ) were isolated from the resin of Aloe vera (L.) Burm.f . The structures of the two new natural products were elucidated based on 1D‐ (1H‐ and 13C‐NMR) and 2D‐NMR (COSY, HSQC, and HMBC) spectroscopic techniques and mass spectrometry (ESI‐MS). Aloeverasides A ( 1 ) and B ( 2 ) were evaluated for their anticancer activity, and both induced a 76.4 and 70.5% growth inhibition of the breast cancer cell line (MDA‐MB‐231) at a concentration of 100 μm . Both compounds were also evaluated for their 1,1‐diphenyl‐2‐picryl‐hydrazyl antioxidant, urease enzyme, and α‐glucosidase enzyme inhibition activities. Aloeverasides A ( 1 ) and B ( 2 ) displayed good urease enzyme inhibition activities (62 and 55%, resp.), as well as antioxidant activity in which aloeveraside A ( 1 ) had a value of 60% inhibition, while aloeveraside B ( 2 ) demonstrated a more potent antioxidant activity with 80% inhibition. 相似文献
38.
ABSTRACT: BACKGROUND: Biotransformation offers chemo enzymatic system to modify the compounds into their novel analogues which are difficult to synthesize by chemical methods. This paper describes the biotransformational studies of ambrox, one of the most important components of natural Ambergris (wale sperm) with fungal and plant cell culture. RESULTS: Biotransformation of ()-ambrox (1) with a fungal cell culture of Macrophomina phaseolina and a plant cell suspension cultures of Peganum harmala yielded oxygenated products, 3beta- hydroxyambrox (2), 6beta-hydroxyambrox (3), 1alpha-hydroxy-3oxoambrox (4), 1alpha,3beta- dihydroxyambrox (5), 13,14,15,16-tetranorlabdane-3-oxo-8,12-diol (6), 3-oxoambrox (7), 2alpha- hydroxyambrox (8), 3beta-hydroxysclareolide (9), and 2alpha,3beta-dihydroxyambrox (10). Metabolite 4 was found to be new compound. These metabolites were structurally characterized on the basis of spectroscopic studies. CONCLUSION: Nine oxygenated metabolites of ()-ambrox (1) were obtained from Macrophomina phaseolina and Peganum harmala. Enzymatic system of screened organisms introduced hydroxyl and keto functionalities at various positions of compound 1 in a stereo- and regiocontrolled manner. 相似文献
39.
Hussain J Bukhari N Hussain H Rehman NU Hussain SM 《Natural product communications》2010,5(11):1785-1786
Phytochemical investigation of Nepeta distans Raul resulted in the isolation of a new phenolic compound, nepatanol (1), and eight known compounds, markhamioside F, netidiol, nepedinol, thymoquinone, eugenol, oleanolic acid, ursolic acid, and beta-sitosterol, which have been isolated for the first time from this source. Structures of all the isolates were established on the basis of MS, and 1D and 2D NMR spectral data and by comparison with reported data. 相似文献
40.
Javid Hussain Najeeb Ur Rehman Hidayat Hussain Liaqat Ali Ahmed Al‐Harrasi Viqar Uddin Ahmad 《Helvetica chimica acta》2011,94(11):2106-2110
The structure elucidation of two new phthalate derivatives named nepethalates A ( 1 ) and B ( 2 ) is reported. Both of these secondary metabolites were isolated from the MeOH extract of Nepeta clarkei. HR‐EI‐MS, IR and UV absorption spectrometry, and NMR experiments including COSY, HMQC, and HMBC were used for the determination of the structures and complete 1H‐ and 13C‐NMR assignments. 相似文献