Farm Size and Productivity Revisited

The negative relationship between farm size and output per acre has been tested for Pakistan and it is concluded that the observed negative or positive correlations between land productivity and the farm size in the case of Pakistan are the result of over-aggregation. Land productivity curve is U-Shaped; the productivity is high on desperately small farms due to intensive labour and irrigation use and on largest farms due to capital-intensive inputs. The middle-level efficient entrepreneur farmer has so far failed to emerge

Characterization of leaves and flowers volatile constituents of Lantana camara growing in central region of Saudi Arabia

AbstractThe chemical components of essential oils derived from leaves and flowers of Lantana camara growing in Saudi Arabia are analyzed for the first time using gas chromatography techniques (GC–MS, GC–FID, Co-GC, LRI determination, and database and literature searches) on two different stationary phase columns (polar and nonpolar). This analysis led to the identification of total 163 compounds from leaves and flowers oils. 134 compounds were identified in the oil obtained from leaves of L. camara, whereas 127 compounds were identified in the oil obtained from flowers; these compounds account for 96.3% and 95.3% of the oil composition, respectively. The major components in the oil from leaves were cis-3-hexen-1-ol (11.3%), 1-octen-3-ol (8.7%), spathulenol (8.6%), caryophyllene oxide (7.5%) and 1-hexanol (5.8%). In contrast, the major compounds in the flowers oil were caryophyllene oxide (10.6%), β-caryophyllene (9.7%), spathulenol (8.6%), γ-cadinene (5.6%) and trans-β-farnesene (5.0%). To the best of our knowledge, cis-3-hexen-1-ol and 1-octen-3-ol that were identified as major components in this study have not been reported earlier from Lantana oils

Phytochemical analysis and bioactivity screening of three medicinal plants of Saudi Arabia

Purpose: To investigate the phytochemical analysis and bioactivity screening of some Asteraceae medicinal plants. Methods: The chemical constituents were isolated by column chromatography and elucidated using chemical and extensive spectroscopic methodologies including gas chromatoraphy-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), as well as 1D and 2D nuclear magnetic resonance (NMR). The plant extracts were obtained by solvent extraction method while hydrodistillation was used to isolate plant essential oils. Furthermore, cup-plate agar diffusion was applied for antimicrobial activity evaluation while minimum inhibitory concentration (MIC) was assessed by microdilution technique. Results: Centaurea pseudosinaica, Tripleurospermum auriculatum, and Koelpinia linearis afforded previously undescribed three coumarins (xanthotoxin, cirsimaritin, salvigenins) from C. pseudosinaica, one steroid (estradiol) and a pentacyclic triterpene (β-amyrin) from T. auriculatum and a coumarin (santin) from K. linearis in good yields. In addition, the plant extracts and oils exhibited remarkable bioactivities including antifungal, antibacterial and antipyretic etc. Conclusion: The results reveal the presence of bioactive phytomolecules from Asteraceae plant extracts and volatile oils from three Asteraceae plants. Keywords: C. pseudosinaica, T. auriculatum, K. linearis, Xanthotoxin, Salvigenin, Cirsimaritin, Santin, Estradiol, β-amyrin, Antimicrobial activit

Enzyme inhibition and antibacterial potential of 4-Hydroxycoumarin derivatives

The 4-Hydroxycoumarin derivatives are known to show a broad spectrum of pharmacological applications. In this paper we are reporting the synthesis of a new series of 4-Hydroxycoumarin derivatives synthesized through Knovenegal condensation; they were characterized by using UV-Vis, FT-IR, NMR spectroscopies. The synthesized compounds were evaluated for antibacterial activity against Staphylococcus aureus and Salmonella typhimurium strains. The compounds (2), (3) and (8) showed favorable antibacterial activity with zone of inhibitions 26.5± 0.84, 26.0 ± 0.56 and 26.0 ± 0.26 against Staphylococcus aureus (Gram-positive) respectively. However, the compounds (5) and (9) were found more active with 19.5 ± 0.59 and 19.5 ± 0.32 zone of inhibitions against Salmonella typhimurium (Gram-negative). Whereas, in urease inhibition assay, none of the synthesized derivatives showed significant anti-urease activity; although, in carbonic anhydrase-II inhibition assay, the compound (2) and (6) showed enzyme inhibition activity with IC50 values 263±0.3 and 456±0.1, respectively

The composition of the essential oil and aqueous distillate of Origanum vulgare L. growing in Saudi Arabia and evaluation of their antibacterial activity

The essential oil and aqueous distillate composition of Origanum vulgare L. were analyzed by GC/MS. Sixty-seven different components were detected in both oils. Sixty-four components were characterized for the oil derived from the aerial parts, whereas thirty-three components in the volatile oil from the aqueous distillates of O. vulgare L., representing 99.8% and 98.5% of the oils, respectively. The main components of the volatile oil from the aerial parts of O. vulgare L. were carvacrol (70.2 ± 1.37%), c-terpinene (5.6 ± 0.11%), p-cymene (4.5 ± 0.42 %), trans-sabinene hydrate (3.8 ± 0.07%), and thymol (2.2 ± 0.12%). In comparison, the main compounds of the volatile oil of the O. vulgare L. aqueous distillates were carvacrol (92.5 ± 0.97 %), thymol (2.5 ± 0.09%), and terpinen-4-ol (1.0 ± 0.03%). The antibacterial activity of both oils, along with that of the purified major component, carvacrol, against Gram-positive and Gramnegative strains was assessed. The results revealed that all three samples showed significant antibacterial activity against all tested strains. The IC50 values of the oils derived from the aerial parts and aqueous distillates of O. vulgare L. against the tested strains was in the range of 107–383 mg�mL1 , whereas, the IC50 value of carvacrol was in the range of 53–151 mg�mL1 . The data suggest that carvacrol, a major component of both oils, possesses the highest antibacterial activity of all th

Asymmetric lithiantion/borylation of primary carbamates and applications towards the allylation of aldehydes and the Prins cyclisation

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Chelation-Assisted Substrate-Controlled Asymmetric Lithiation-Allylboration of Chiral Carbamate 1,2,4-Butanetriol Acetonide

The lithiation of 2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethyl diisopropylcarbamate (1) is achieved freely by sec-butyllithium in diethylether with high lk-diastereoselectivity: the bicyclic chelate complexes 3a and 3b are reacted with electrophiles to form optically active precursors 4a and 4b with >95% diastereoselectivity. In addition, tertiary diamines can undergo an external complexation in contest with the internal oxygen ligand, leading to improved stereoselectivities. The further reactions of lithiated carbamates with trans alkenyl-9-BBN derivatives after 1,2 metallate rearrangements, gave the key intermediate α-substituted allylic boranes 7. Subsequent allylboration of aldehydes gave (Z)-anti-homoallylic alcohols 8 in good yield and excellent d.r

Evaluation of Matricaria aurea Extracts as Effective Anti-Corrosive Agent for Mild Steel in 1.0 M HCl and Isolation of Their Active Ingredients

Plant extracts have shown promising corrosion inhibitive actions for different metals in diverse corrosive climate. In numerous studies, it has been demonstrated that corrosion inhibitive features of plant extracts are due to the presence of complex mixtures of phytomolecules in their composition. However, rare efforts have been made to identify those phytomolecules accountable for the activity of the extracts. Therefore, in this paper, several Matricaria aurea extracts were prepared and assessed for their anticorrosive actions for mild steel (MS) in corrosive media (1.0 M HCl). Among the tested extracts, the methanolic extract showing the utmost anticorrosive activity was selected and processed further to identify its active phytomolecules, which led to the identification of a novel green corrosion inhibitor, MAB (Apigetrin). Furthermore, the anticorrosive properties of MAB on MS were evaluated comprehensively involving gravimetric, linear polarization, Tafel plots, EIS, and techniques like SEM and EDS. These findings expose that MAB performs like a mixed-type inhibitor and conforms the isotherm of Langmuir adsorption model. Moreover, the MS surface via SEM techniques exhibits a remarkable advanced surface of the MS plate in the company of MAB. The outcome of results through electrochemical analysis and weight loss methods were in good consonance, which depicts remarkable inhibition properties of the novel green inhibitor MAB