Afaf Mohammed Weli

Study of total phenol, flavonoids contents and phytochemical screening of various leaves crude extracts of locally grown Thymus vulgaris

OBJECTIVE To prepare various crude extracts using different polarities of solvent and to quantitatively evaluate their total phenol, flavonoids contents and phytochemical screening of Thymus vulgaris collected from Al Jabal Al Akhdar, Nizwa, Sultanate of Oman. METHODS The leave sample was extracted with methanol and evaporated. Then it was defatted with water and extracted with different polarities organic solvents with increasing polarities. The prepare hexane, chloroform, ethyl acetate, butanol and methanol crude extracts were used for their evaluation of total phenol, flavonoids contents and phytochemical screening study. The established conventional methods were used for quantitative determination of total phenol, flavonoids contents and phytochemical screening. RESULTS Phytochemical screening for various crude extracts were tested and shown positive result for flavonoids, saponins and steroids compounds. The result for total phenol content was the highest in butanol and the lowest in methanol crude extract whereas the total flavonoids contents was the highest in methanol and the lowest hexane crude extract. CONCLUSIONS The crude extracts from locally grown Thymus vulgaris showed high concentration of flavonoids and it could be used as antibiotics for different curable and uncurable diseases.

Identification and characterization of chemical compounds in different crude extracts from leaves of Omani neem

Abstract Azadirachta indica (neem) belonging to Meliaceae family is very important medicinal plant which is traditionally used to treat different diseases. The objective of this study was to evaluate in vitro antioxidant activity and characterize the chemical constituents in different crude extracts of the leaves of Azadirachta indica (neem) by using modern sensitive gas chromatography–mass spectrometry (GC–MS). The evaluation of antioxidant activity of different crude extracts was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) method. GC–MS analyses showed that majority of these identified compounds in various crude extracts contain normal hydrocarbons, phenolic compounds, terpeniods, alkaloids and glycosides. The high percentage of compounds that were identified in the crude extracts are chemically and biologically important. The evaluation of antioxidant capacity of different crude extracts was in the order of chloroform > butanol > ethyl acetate extract > hexane extract > methanol extract. The important chemical constituents were present in the leaf crude extracts of neem that can be endorsed to cultivation on a domestic plantation. The appropriate crude extracts for selective bioactive organic compounds can be chosen on the basis of GC–MS analysis. Therefore the identified good number of chemical compounds from various extracts of neem might have some ecological benefit for different aliments. Result from this study suggested that the chloroform crude extracts of neem could be used as a natural antioxidant.

Comparative study of total phenolics, flavonoids contents and evaluation of antioxidant and antimicrobial activities of different polarities fruits crude extracts of Datura metel L.

Abstract Objective To determine the total phenolics and flavonoids and to evaluate antioxidant and antimicrobial activities of different extracts from fruits of Datura metel (D. metel). Methods Different crude extracts from the fruits of D. metel were subjected to determination of total phenolics, flavonoids, antioxidant and antimicrobial activities by established methods. Resutls The total phenolics results showed that ethyl acetate extract was the most efficient (60.26%) compared to hexane, chloroform, butanol and methanol extracts which had phenolic contents of 50.08, 35.50, 52.54 and 26.49%, respectively. Almost similar results were obtained from the fruits crude extracts for total flavonoids and results found that methanol crude extract was the highest (1.71%) compared to other crude extracts. The antioxidant activity results showed that methanol extract acted the highest activity compared to other extracts and in the order of methanol>ethyl acetate>hexane>chloroform>butanol extract. All extracts were displayed moderate antibacterial potential against the tested bacteria such as Staphylococcus aureus, Escherichia coli and Pseudomonus aeruginosa in the range of 0%–10%. Conclusions The results of this present study clearly showed that the crude extracts of D. metel demenstrated antimicrobial and antioxidant activities and it may act as potential antioxidant sources for human biological system.

Chemical composition of essential oils and in vitro antioxidant activity of fresh and dry leaves crude extracts of medicinal plant of Lactuca Sativa L. native to Sultanate of Oman

OBJECTIVE To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L. (L. sativa). METHODS The essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L. sativa (lettuce) grown in Sultanate of Oman by hydro distillation method. The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity (DPPH) method. RESULTS About 20 chemical compounds of different concentration representing 83.07% and 79.88% respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves as α-pinene (5.11% and 4.05%), γ-cymene (2.07% and 1.92%), thymol (11.55% and 10.73%), durenol (52.00% and 49.79%), α-terpinene (1.66% and 1.34%), thymol acetate (0.99% and 0.67%), caryophyllene (2.11% and 1.98%), spathulenol (3.09% and 2.98%), camphene (4.11% and 3.65%), limonene (1.28% and 1.11%) representing these major chemical compounds. However, some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including β-pinene, α-terpinolene, linalool, 4-terpineol, α-terpineol, o-methylthymol, L-alloaromadendrene and viridiflorene. CONCLUSIONS The chemical constituents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes, sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons. Therefore, the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant, antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases.

Gas chromatography-mass spectrometry analysis of different organic crude extracts from the local medicinal plant of Thymus vulgaris L

OBJECTIVE To isolate and analyze the chemical composition in different crude extracts of from the leaves of locally grown of Thymus vulgaris L (T. vulgaris) by gas chromatography-mass spectrometry (GC-MS). METHODS The shade dried leaves powder was extracted with methanol by using Soxhlet extractor. Methanol crude extracts of T. vulgaris and the derived fractions of hexane, chloroform, ethyl acetate and butanol were obtained. RESULTS Qualitative analyses of various organic crude extracts of T. vulgaris by using GC-MS showed that there were different types of high and low molecular weight compounds. Most of the isolated and identified compounds by GC-MS in the crude extracts are basically biologically important. Further, the T. vulgaris leaf possessed certain characteristics that can be ascribed to cultivation on a domestic plantation. The crude extracts were prepared from the powder leaves of T. vulgaris for respective compounds can be chosen on the basis of above GC-MS analysis. CONCLUSIONS All the major compounds were identified and characterized by spectroscopic method in different organic crude extracts of T. vulgaris are biologically active molecules. Thus the identification of a good number of compounds in various crude extracts of T. vulgaris might have some ecological role.

Effect of different polarities leaves crude extracts of Omani juniperus excels on antioxidant, antimicrobial and cytotoxic activities and their biochemical screening

Objective To prepare different polarities leave crude extracts of Juniperus excels (J. excels) and to determine their phytochemical screening, antioxidant, antimicrobial and cytotoxic activities.

Gas chromatography–mass spectrometry analysis and total phenolic contents of various crude extracts from the fruits of Datura metel L.

Abstract Datura metel is considered as medicinal plants worldwide. Locally it is used as a traditional medicine due to its medicinal values. The objective of this present work is to identify the chemical ingredients and evaluation of total phenolics contents of different crude extracts from the locally grown D. metel. In vitro evaluation of total phenolics contents of different crude extracts was measured by established Folin–Ciocalteu reagents method. The identification of chemical ingredients was carried out in various crude extracts of D. metel by using sensitive gas chromatography–mass spectrometry (GC–MS). The results showed from different chromatogram that high percentage ingredients are high molecular weight ingredients such as polyphenolics and their derivatives, flavonoids, triterpeniods, hydrocarbons etc. The identified high percentage chemical ingredients present in the crude extracts are biologically active. The phenolic contents of crude extracts as gallic acid equivalents were found to be highest in chloroform followed by the order methanol > butanol > ethyl acetate > hexane extract. The identification of good number of chemical ingredients by spectrometry method in various crude extracts of D. metel fruits might have some ecological significance. In conclusion, chloroform crude extract contains highest phenolics content could be used as antibiotics.

Evaluation of antioxidant and antimicrobial potential of different leaves crude extracts of Omani Ficus carica against food borne pathogenic bacteria

Abstract Objective To prepare different polarities crude extract from the leaves of Ficus carica and to evaluate their antioxidant and antimicrobial potential against food borne pathogenic bacterial strains. Methods The dried leaves were macerated in absolute ethanol for one week. The ethanol was evaporated and the crude extract was defatted with ethanol-water. The defatted hydro alcoholic crude extract was successively extracted with hexane, chloroform and ethyl acetate. The antioxidant potential was determined against 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Evaluation of antimicrobial potential of different crude extracts against selected Gram positive and Gram negative bacteria by agar disc diffusion method. Results The total extraction yield was 2.2%. The highest extraction yield was in chloroform and the lowest in hexane. The antioxidant results were found in the order of hydro alcoholic>ethyl acetate>hexane>chloroform. Hydro alcoholic crude extract and its derived fractions display moderate antimicrobial potential against the selected bacterial strains such as Staphylococcus aureus, Escheichia coli and Pseudomonas, in the range of 0%–13%. Conclusions It is concluded that the hydro alcoholic and ethyl acetate crude extracts of Ficus carica possess very good antioxidant and antimicrobial potential.

Constituents of the essential oil from different brands of Syzigium caryophyllatum L by gas chromatography–mass spectrometry

Objective: The aim of this present study was to isolate and analyze the chemical composition of essential oils from two different imported brands of Syzigium caryophyllatum (clove) samples using gas chromatography-mass spectrometry (GC-MS). Methods: The two essential oils were isolated by hydrodistillation from two different brands of Syzigium caryophyllatum (clove) such as Guzal and Shahi clove samples using Clevenger type apparatus. Results: Eleven chemical components were identified in the essential oil isolated from Guzal clove imported from Indonesia. The isolated components representing 99.03% of the Guzal clove oil were identified as eugenol (51.51%), caryophyllene (36.20%), 毩- caryophyllene (4.26%), acetyleugenol (2.64%), carvacrol (2.42%), 毩-cubebene (0.77%) and thymol (0.42%) were the major components with some other minor components isolated from the same. About twenty two components representing 99.73% were identified within the essential oil isolated from the Shahi brand clove which was imported from India with the main components being eugenol (46.53%), caryophyllene (43.03%), 毩-caryophyllene (4.61%), aceteugenol (2.54%), copaene (0.80%), 毩-farnesene (0.72%), germacrene (0.43%) and 毮-cadinene (0.27%). Conclusions: Both the isolated essential oils were found to be rich in eugenol and caryophyllene. The clove essential oil from Guzal and Shahi was found to be comparable in terms of its eugenol and caryophyllene contents. According to the above findings, it is suggested that both brands of clove are of similar quality.

Composition of essential oil of Omani Juniperus excelsa fruit and antimicrobial activity against foodborne pathogenic bacteria

Abstract Juniperus excelas is an important flowering medicinal plant belonging to the Cupressaceae family. Essential oil was obtained from fresh fruit of J. excelas by hydro-distillation in a Clevenger apparatus and analysed by gas chromatography–mass spectrometry (GC–MS). The chemical constituents of the essential oil were identified by their mass spectra, retention time and retention indices. The yield was 0.27%. We identified 48 chemical compounds accounting for 89.74% of the composition. The major chemical components were α-terpinene (23.85%), limonene (23.42%), fenchene (6.57%), camphene (6%), δ-3-carene (4.17%), 4-terpineol (2.93%), germacrene B (2.21%), myrcene (1.96%), α-pinene (1.77%), β-pinene (1.53%) and abietatriene (1.13%). The antimicrobial activity of the essential oil of J. excelas was determined against one Gram-positive and two Gram-negative foodborne pathogenic bacteria, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. No activity was detected.