Isobornyl Acetate Research Articles

Acute oral toxicity and genotoxicity assessment of the essential oil from Croton pulegiodorus Baill (Euphorbiaceae) leaves in mice

Essential oils obtained from Croton pulegiodorus leaf are renowned for their biological activities; however, data on their toxicity are limited. Therefore, this study aimed to evaluate the acute oral toxicity and genotoxicity of a C. pulegiodorus leaf essential oil (CPLEO). Chemical characterization of CPLEO was conducted by gas chromatography coupled to mass spectrometry (GC-MS). In vitro assay was performed to verify the hemolytic capacity of the oil in mice erythrocytes. Next, an acute oral toxicity study was conducted on female mice at CPLEO doses of 2000, 1000, 500, 250, 100, and 50 mg/kg. Hematological, biochemical, and histopathological markers were assessed in mice from groups were no death occurred. Relative consumption of water and food and the weight of animals and their organs were also recorded. Finally, a genotoxicity analysis was performed using the micronucleus and comet assays. The extraction yield of CPLEO was 1.149% and its major compounds were ascaridole (23.18%), eucalyptol (17.20%), camphor (14.20%), p-cymene (7.91%), α-terpineol (4.69%), and isobornyl acetate (4.57%). CPLEO showed a hemolytic effect only at high concentrations (185.5–1000 mg/mL). It showed acute oral toxicity in mice with a LD50 of 460.42 mg/kg. CPLEO (50–250 mg/kg) caused some significant changes in hematological and biochemical parameters. Histopathological evaluation indicated alterations in liver and kidneys but transaminases, urea and creatinine levels remained like the negative control. CPLEO administration impaired weight gain and reduced water and food consumption. Finally, it was not genotoxic by both comet and micronucleus tests. The results highlight the need for attention when choosing doses to evaluate the bioactivities of CPLEO.

GC-MS Characterization of Eupatorium odoratum (L.) Leaves Essential Oil and Evaluation of In vitro Antimicrobial and Antioxidant Activity

The leaves essential oil of Eupatorium odoratum (L.) obtained by the hydro-distillation method was light yellowish in colour, having pungent aromatic fragrance with the yield of 0.010%. Fifteen secondary metabolites were identified via the GC-MS analysis of the essential oil and tau-Cadinol (20.10%) was found to be the major secondary metabolite in the essential oil followed by α Bisabolol (15.33%), cis-muurola-4 (14) 5- diene (10.79%), Isobornyl acetate (6.40%), and Isocaryophyllene (5.39%). The antimicrobial efficacy was investigated via agar well diffusion technique and essential oil was most effective against P. aeruginosa with inhibition zone 22.00±0.57 mm, which was followed by E. coli (19.00±0.57 mm), S. aureus (18.33±0.33 mm), K. pneumoniae (16.50±0.33 mm), and S. pyogenes (11.00±0.33 mm). MIC and MBC values were observed lowest against P. aeruginosa, i.e. 3.12µl/ml and 6.24µl/ml, respectively. Antioxidant activity of essential oil was investigated by DPPH and H2O2 scavenging assay and IC50 value was found very low, i.e. 10.58µl/ml and 11.76µl/ml, respectively, so the essential oil was considered as a potential antioxidant agent. The results validate scientifically the traditional utilization of leaves essential oil of E. odoratum in traditional medicinal system and confirmed that it can be used as modern phytomedicines as an antimicrobial as well as antioxidant agent.

COMPONENT COMPOSITION OF ESSENTIAL OILS FROM LEAVES, INFLORESCENCES AND STEMS OF PEROVSKIA SCROPHULARIFOLIA GROWN IN UZBEKISTAN

Essential oils as secondary metabolites, promising sources of biologically active substances with pronounced antimicrobial, antifungal and antiviral effects, are of considerable interest for study and possible use in medicine, pharmaceuticals, and aromatherapy. We have studied the composition of the essential oil of an endemic species for the first time Perovskia scrophularifolia Bunge. (Lamiaceae = Labiatae). This species of plant is of considerable interest as a medicinal plant, which is widely used in folk medicine in Uzbekistan and neighboring countries. Studies of biologically active substances of this species did not concern the essential oil. During the period of mass flowering in the inflorescences of Perovskia scrophularifolia contains 0.65%, in leaves – 0.71% of essential oil. The stems of the plant contain essential oils in small quantities. The composition and content of the components of the studied samples were determined according to the data of gas chromatographic and chromate-mass-spectrometric analysis. 26 substances were identified in essential oils from leaves, 43 from inflorescences and 18 substances from stems. The main components of essential oils from leaves and inflorescences are 1,8-Cineol up to 19.3% and Isobornyl acetate – up to 15.9%. This species is a promising source of biologically active compounds with biological activity (including antibiotic).

Study on Synthesizing Isobornyl Acetate/Isoborneol from Camphene Using α-Hydroxyl Carboxylic Acid Composite Catalyst.

This study examined the preparation of isobornyl acetate/isoborneol from camphene using an α-hydroxyl carboxylic acid (HCA) composite catalyst. Through the study of the influencing factors, it was found that HCA and boric acid exhibited significant synergistic catalysis. Under optimal conditions, when tartaric acid-boric acid was used as the catalyst, the conversion of camphene and the gas chromatography (GC) content and selectivity of isobornyl acetate were 92.9%, 88.5%, and 95.3%, respectively. With the increase in the ratio of water to acetic acid, the GC content and selectivity of isobornol in the product increased, but the conversion of camphene decreased. The yield of isobornol was increased by adding ethyl acetate or titanium sulfate/zirconium sulfate to form a ternary composite catalyst. When a ternary complex of titanium sulfate, tartaric acid, and boric acid was used as the catalyst, the GC content of isobornol in the product reached 55.6%. Under solvent-free conditions, mandelic acid-boric acid could catalyze the hydration reaction of camphene, the GC content of isoborneol in the product reached 26.1%, and the selectivity of isoborneol was 55.9%. The HCA-boric acid composite catalyst can use aqueous acetic acid as a raw material, which is also beneficial for the reuse of the catalyst.

ГОМОГЕННО-КАТАЛИТИЧЕСКОЕ АЦЕТОКСИЛИРОВАНИЕ КАМФЕНА

The homogeneous catalytic reaction of camphene acetoxylation in the presence of palladium complexes with the predominant formation of isobornyl acetate was studied for the first time using chromatography-mass spectrometry. The reaction proceeds stoichiometrically, but can be converted to catalytic mode. Ways of formation of some accompanying products were shown and an explanation was found for the inhibition of the process during the accumulation of reaction products in the reaction zone. The obtained results were compared with the results of experiments under acid catalysis and it was shown that at a temperature of 75-80°C it is possible to achieve 99-100% conversion of the substrate with an 89% yield of isobornyl acetate.

Anti-Inflammatory Activities of Constituents from Cinnamomum insularimontanum Hayata Leaves and Their Mechanisms.

Cinnamomum insularimontanum is an endemic species of Taiwan. Although most Cinnamomum plants have significant biological activity, the bioactivity investment of C. insularimontanum is rare. Since inflammation plays an important role in many diseases, anti-inflammatory compounds can be developed into healthcare products. Therefore, we first conducted a study on the anti-inflammatory activity of C. insularimontanum leaves. First, we examined the antiinflammation activity of essential oil from C. insularimontanum leaves, and it revealed potent anti-inflammatory activity. A total of 23 volatile compounds were identified in C. insularimontanum leaves' essential oil by using GC/MS analysis. Among them were 1,8-cineole (35.94%), α-eudesmol (6.17%), pinene (7.55%), sabinene (5.06%), and isobornyl acetate (4.81%). According to previous studies, 1,8-cineole might be an anti-inflammation principal compound of C. insularimontanum leaves. Next, the ethanolic extracts of C. insularimontanum leaves also exhibited good anti-inflammatory activity. Two bioactive compounds, isoburmanol (F1) and burmanol (F2), were isolated from the ethyl acetate soluble fraction by using the bioactivity-guided separation protocol and spectroscopic analysis. F1 was obtained from C. insularimontanum for the first time, and F2 was isolated for the first time from natural resources. Both F1 and F2 could inhibit the production of nitric oxide (NO), and the IC50 values were 14.0 μM and 43.8 μM, RAW 264.7 cells after induction of lipopolysaccharide. Furthermore, F1 and F2 also revealed significant inhabitation effects on iNOS and COX-2 protein expression. The anti-inflammation activity of F1 and F2 was different from the common pathway of inhibiting NF-κB. Both of them could inhibit the production of NO and PGE2 by directly inhibiting the AP-1 (c-Jun) protein and then inhibiting the downstream iNOS and COX-2. Although both F1 and F2 possessed significant anti-inflammatory activity, the activity of F1 was better than F2. Through molecular docking simulation analysis, the results show that F1 and F2 interact with AP-1, inhibit the binding of AP-1 to DNA, and cause AP-1 to fail to transcribe the related factors of inflammation. The binding ability of AP-1 and F1 was stronger than F2, and that is the reason why F1 exhibited better activities in both downstream proteins and inflammatory cytokines. Based on the results obtained in this study, the essential oil and F1 and F2 isolated from C. insularimontanum leaves have good anti-inflammatory activities, and it is expected to be used as a reference for the development of medical care products in the future.

Essential Oil Biodiversity of Achillea ligustica All. Obtained from Mainland and Island Populations.

Background: The genus Achillea is rich in essential oil (EO) with high chemical diversity. In this study, eight EO samples obtained from flowers and leaves of Achillea ligustica All. collected on the Mediterranean mainland and island locations were analyzed to evaluate their possible chemical diversity. Methods: Sixteen samples of EO were analyzed by GC-MS, leading to the identification of 95 compounds in the leaves and 86 compounds in the flowers; a statistical analysis was performed to determine the chemical polymorphism. Results: Monoterpenes, such as β-pinene, borneol, ɑ-terpineol and isobornyl acetate, were more abundant in the continental samples, while the insular samples were richer in 1,8-cineole. Fragranyl acetate and fragranol were detected in remarkable concentrations in sample 8. The fruits of sample 8 were then cultivated under controlled agronomic conditions, providing plants rich in these compounds (sample 9). The geographical variability influenced the EO compositions, with unique observed chemotypes and a high degree of diversity among samples collected in various areas (mainland or island). Statistical analyses did not reveal any pattern between the geographical provenience and the compositions. Conclusion: Samples were distributed based on the plant organ, confirming the already reported high degree of chemical polymorphism of this species. Sample 8 could be used as a source of fragranol and fragranyl acetate, with potential applications in the insecticidal and pheromone industries.

Chemical Composition of the Volatile Oil from Aerial Parts of Rosmarinus officinalis L. Growing in UAE

In the present study, the chemical composition of the volatile oil hydrodistilled from aerial parts of Rosmarinus officinalis L., growing in UAE, was determined by means of GC/FID and GC/MS analyses. The oil was characterised by dominant concentration of monoterpenes (91.7%), particularly the oxygenated fraction (64.4%), with 1,8-cineole (25.5%), a well-known compound for its medicinal and pharmaceutical values, as the principal component. Isobornyl acetate (15.7%), camphor (12.2%), α-pinene (11.7%), camphene (9.0%), and β-caryophyllene (4.9%) were also identified among the other major oil constituents. The predominant level of 1,8-cineole in the analysed oil could assign a 1,8-cineole chemotype to the studied Emirati rosemary species. Compared with plants growing in other countries, the obtained results revealed a characteristic - mainly quantitative - profile of the volatile oil of the investigated species.

Essential oil components in the seed masses of Amomum xanthioides and its related species from Southeast Asia and China.

Previously, to develop an objective identification method for Amomi Semen (AS), the nucleotide sequences of nrDNA ITS region and two cpDNA regions of nine Amomum taxa specimens from Southeast Asia and China were determined, and the generated phylogenetic tree showed six taxa specimens were divided into four groups. In this study, 51 crude drug samples of AS in Japanese markets were classified into four groups or species based on their ITS sequences. Approximately 67% of samples were derived from A. villosum var. xanthioides or A. xanthioides, A. villosum var. villosum and A. longiligulare prescribed in Japanese Pharmacopoeia, and the rest were mixed with A. uliginosum and A. microcarpum. Subsequently, the essential oil compositions of Amomum taxa specimens and AS samples were determined by GC-MS to characterize each group or species. Group 1(A. xanthioides) samples were characterized by containing higher amount of camphor(6) than bornyl acetate(9), and a specific germacrene D-4-ol; group 2(Chinese A. villosum var. villosum and var. xanthioides) by containing higher amount of 9 than 6, a specific isobornyl acetate; group 3(Laotian A. villosum var. villosum and A. longiligulare) by containing higher amount of 6 than 9, and a characteristic neointermedeol, except for A. longiligulare specimen from Hainan, China; group 4(A. uliginosum) by containing equivalent amount of 6 and 9, and the specific (E,E)-farnesyl acetate and (E,E)-farnesol. A. microcarpum samples were discriminated from the above groups by absence of 6 and 9, and with higher amount of (E)-nerolidol. There was a good correlation between genetic classification and chemical discrimination.

Variation of Yield and Chemical Composition of Essential Oil from Cupressus lusitanica Growing in Different Agro-ecological Zones of Rwanda

Chemical composition and essential oil contents among essential oil-bearing plants are mostly influenced by different factors including ecological features of habitat. In this study, variation in yield and chemical composition of essential oils (EOs) from the leaves of Cupressus lusitanica Mill. (Cupressaceae) in different regions of Rwanda was investigated. Extraction of essential oils from fresh leaves of C. lusitanica collected in March 2021 and April, 2021 from three different ecological zones of Rwanda, Buberuka highland zone (Burera), Central plateau zone (Huye) and Eastern savannah zone (Kayonza) was realized through steam distillation. The chemical compositions of distilled EOs were analyzed using both Fourier transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS), while their yields were determined by simple calculus. The average yields of the EOs were 0.27 ± 0.02, 0.34 ± 0.02 and 0.39 ± 0.01% (v/w) for Burera, Huye and Kayonza, respectively. Results of FT-IR analysis were confirmed by those of GC-MS analysis, and indicated the presence of different groups of compounds including aliphatic alkanes, carboxylic acids, alkenes, aldehydes, aromatics and ketones in the EOs. GC-MS results revealed that sabinene (20.84%), myrcene (19.63%), α-pinene (10.23%) and δ-3-carene (10.13%) were the dominant chemical constituents for EOs of C. lusitanica from Burera. Umbellulone (24.21%), δ-3-carene (16.76%), sabinene (10.54%) and α-pinene (8.21%) were the main constituents for EOs of C. lusitanica from Huye, while γ-terpinene (18.77%), umbellulone (18.16%), isobornyl acetate (9.972%), and myrcene (7.20%) were the major components of EOs of C. lusitanica from Kayonza. The current results demonstrated an intraspecific variation in content and chemical profile of C. lusitanica EOs from one geographical region to another. The observed variations are mostly due to the interactions of C. lusitanica species with climatic and environmental conditions of ecological habitat. However, it could also be the effects of various biotic factors, as well as maturity of plant and stage of plant growth. Further studies are needed to establish the influence of different geo-climatic and environmental factors on each single major component of C. lusitanica EOs.

Biosynthesis of Organic Nanocomposite Using Pistacia vera L. Hull: An Efficient Antimicrobial Agent.

Here presented a quick and easy synthesis of copper nanoparticles (CuNPs). Pistachio hull extract has been used as a reducing and stabilizing agent in the preparation of CuNPs. This biosynthesis is a kind of supporter of the environment because chemical agents were not used to making nanoparticles, and on the other hand, it prevents the release of pistachio waste in nature and its adverse effects on nature. The biosynthesized CuNPs and CuNPs/silver Schiff base nanocomposite (CSS NC) were characterized by UV-VIS spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). CuNP and CSS NC antimicrobial activity was examined by both well diffusion and determination MIC methods against four bacteria Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa and two fungi Aspergillus Niger and Candida albicans. CuNPs and CSS NC showed significant antimicrobial activity on the samples, preventing the growth of bacteria and fungi at very low concentrations. CuNPs and CSS NC had the greatest effect on Escherichia coli bacteria and Aspergillus niger fungi. Phenolic compounds are one of the most important antioxidants that are involved in various fields, including pharmacy. Pistacia vera hull is a rich source of phenolic compounds. In this study, the most phenolic compound in Pistacia vera hull is gallic acid and rutin, which has been identified by HPLC analysis. In this study, Pistacia vera hull essential oil analysis was performed by the GC-MS method, in which α-pinene, D-limonene, and isobornyl acetate compounds constitute the highest percentage of Pistacia vera hull essential oil.

Aroma Profile, Chemical Composition and Antiproliferative Activity of the Hydrodistilled Essential Oil of a Rare Salvia Species (Salvia greggii)

The present study deals with the gas chromatography/mass spectrometry (GC/ MS) analysis of the aroma profile of different aerial organs obtained by solid-phase microextraction (SPME) and that of the hydro distilled essential oil of the fresh leaves and flowers of Salvia greggii A. Gray grown in Jordan. Oxygenated sesquiterpenes dominated the hydrodistilled oils of the leaves and flowers with guaiol (35.60 % and 31.92 %, respectively) and patchouli alcohol (16.30 % and 16.88 %, respectively) as the main constituents. Alpha-pinene, camphene, limonene, and γ-terpinene were detected as the major hydrocarbon monoterpenes and 1,8-cineol, camphor, and isobornyl acetate as the major oxygenated monoterpenes. The antiproliferative activity of the leaf essential oil was screened on MCF-7 and HCT116 cell lines. The essential oil exhibited a promising dosedependent inhibition of cell growth with low IC50’s (MCF-7: 35.35 μg/mL; HCT116: 23.57 μg/mL) with a high safety profile against the normal Vero cell line compared to the positive control Doxorubicin.

Thermodynamic and Kinetic Study on the Catalysis of Isobornyl Acetate by a Cation Exchange Resin an Intensified Fixed-Bed Reactor

Esterification Thermodynamic and Kinetic on acetic acid with camphene was studied systematically in an intensified fixed bed reactor at 303-323 K with anhydrous NKC-9 resin. The catalyst loading, initial molar ratio, temperature, and catalyst reusability were studied and optimized. The method of UNIFAC was applied to calculate the activity coefficient of each component for correcting the nonideality of the solution. Reaction enthalpy, entropy, and Gibbs free energy were calculated. The kinetics of camphene esterification was studied by pseudo-homogeneous model (PH model), and the fitting effect was good, which provided experimental reference and theoretical basis for the industrial production of isobornyl acetate.

Molecular Docking of Compounds in the Essential Oil of Ocimum gratissimum Leaf against PIM-1 Kinase of Escherichia coli

The activity of the phytochemical compounds in the essential oil of Ocimum gratissimum against PIM-1 kinase of Escherichia coli was studied using computer simulation. The essential oil was extracted by hydrodistillation, and the components identified using a gas chromatography-flame ionization detector (GC-FID) instrument. The quantity of the compounds in the essential oil was in the order isobornyl acetate (64.3 %) > Octamethylhexadecan-1-ol (12.2 %) > nonadecanal (11.5 %) > decanal (8.7 %) > undecanal (2.8 %) > α-selinene (0.5 %) > drimenin (< 0.1 %). The results from the in silico studies showed that α-selinene had good binding affinity on the PIM-1 kinase target and therefore, could be a promising drug candidate for prostate cancer.

Phytochemical investigation of saponifiable matter & volatile oils and antibacterial activity of Moluccella laevis L., family Lamiaceae (Labiatae)

Abstract The current study was aimed to evaluate some parts of Moluccella laevis viz., phytochemical and antibacterial. Regarding to GC/MS of the saponifiable matters of petroleum ether fraction of total ethanolic extract of the aerial parts (TEE), the main recognized unsaturated fatty acids were methyl linolenate (25.58%) and methyl linoleate (15.87%). Whereas, the major saturated fatty acids were, palmitic (25.4%) followed by stearic acid (10.48). A comparative analysis of the volatile constituents of M. laevis flowers and leaves was performed by Head Space GC/MS. The volatile mixtures of both plant parts displayed comparable amounts of hydrocarbons and oxygenated compounds, with a noticeable greater contribution of the latter in the leaves.Besides, a-pinene (40.84%), chrysanthenyl acetate (17.89%) and isobornyl acetate (10.64%), were identified as the major volatile components in the flowers. While, isobornyl acetate (35.09%) was characterized as the major constituent followed by, 2-methyl-4-butanolide (22.12%), 1-heptene oxide (7.47%) and benzoic acid, methyl ester (4.05%) of the volatile oil composition of the leaves. Moreover, this study included the antibacterial activity of TEE and its different fractions against Gram positive and negative bacteria. TEE exhibited MIC values of 326 476, and 541 µg/mL against E. coli, K. pneumonia and P. aeruginosa, respectively, while the aqueous fraction showed MICs of 410, 633, 748 and 10713 µg/mL against P. aeruginosa, K. pneumonia, E. coli and S. aureus, respectively. Finally, the EtOAc fraction displayed MICs 449, 541 and 1085 µg/mL against K. pneumonia, E. coli and P. aeruginosa, respectively.

Developing Brønsted–Lewis acids bifunctionalized ionic liquids based heteropolyacid hybrid as high-efficient solid acids in esterification and biomass conversion

A class of Brønsted–Lewis acid bifunctionalized ionic liquids based heteropolyacid hybrid (BLA-ILs-HPA) solid acids were developed by combining the double sulfonic groups grafted, ionic liquids based heteropolyacid hybrid with Lewis acidic centers (M = Zn, Co, Fe, Ni, Cu). The prepared BLA-ILs-HPA show both Brønsted and Lewis acidic sites with extremely-high acid strength and enhanced stabilities, as determined by FT-IR, Py-IR, TG, XPS and 31P solid state NMR results. BLA-ILs-HPA were successfully applied in esterification camphene with acetic acid to produce isobornyl acetate, and dehydration of glucose to produce 5-hydrozymethylfural. BLA-ILs-HPA show enhanced catalytic activities in comparison with various acid catalysts. The effects of reaction temperatures, initial reactant molar ratio, catalyst dosage, and reaction time were studied in detail. The optimal reaction conditions were obtained, and the experimental data was successfully correlated by a pseudohomogeneous (PH) reaction kinetic model in the temperature range of 313.15–333.15 K. The calculated values obtained by the reaction kinetic model were in good agreement with the experimental data. Moreover, as a heterogeneous reaction catalyst, BLA-ILs-HPA can be recovered by simple treatment. After six times cycling, the decreasing in the catalytic activity of BLA-ILs-HPA could not be observed significantly, suggesting their good reusability.

Content of basil essential oil on a loam texture soil under water regimes and different harvest stages

The essential oil of basil (Ocimum basilicum L.) has high economic value and is produced in the plant by secondary metabolism. Its quantity and composition tend to vary as a response of the plant to stress situations due to changes in the environment and phenological phase. This work aimed to evaluate the development, the chemical composition, content, and the yield of essential oil of basil rich in Linalool, as a function of the soil water tensions and the harvest stages, in a loam texture soil. The experiment was carried out in a greenhouse and consisted of three harvest times (BF - beginning of flowering, FF - full flowering, and EF - end of flowering) and five values of soil water tension to define when to irrigate (20, 30, 40, 50, and 60 kPa), totalizing 15 treatments. The irrigation in the soil water tension of 60 kPa generated a reduction in the content and the yield of essential oils compared with 20 kPa, only in the FF harvest stage. However, it did not modify the composition of the essential oil. Regardless of the soil water tension to define irrigation, the highest levels and yields of essential oil were found in the EF harvest stage. Harvest stages did not change the composition of the essential oil or the content of Linalool. In turn, the contents of the components Cineol, Camphor, ∝-Terpeneol, and Isobornyl acetate increased with the harvesting period from BF to EF. Eugenol had the opposite trend, reducing the content from BF to EF. Linalool, a component in greater proportion in essential oil, showed a higher content in soil water tensions up to 50 kPa, decreasing only by 60 kPa. In loam textured soils, it is recommended that basil producers, who aim to extract Linalool, irrigate when the soil water tension reaches up to 50 kPa, with the harvest at any stage of flowering.

Chemical Composition of Syzygium cumini (L.) Skeels Leaf Essential Oil with Respect to its Uses from North East Region of India

Syzygium cumini (L.) Skeels (Jambolan) is a widespread summer fruit plant, well-known for various therapeutic uses such as anti-diabetic, antimicrobial, antioxidant properties. The fruit helps to convert starch into energy which helps in regulating blood sugar levels and possesses a low glycemic index. The present study is aimed to estimate the chemical composition of the essential oil of leaves of Syzygium cumini through GC/MS. The essential oil was extracted by hydrodistillation using a Clevenger apparatus which was further analyzed through GC/MS. The GC/MS analysis identified twenty-five components with a total area percentage of 95.66 %. The major identified components were τ-cadinol (21.44 %) and tau-muurolol (12.01 %). The compounds of intermediate concentration were globulol (7.98 %), caryophyllene (6.69 %), δ-cadinene (6.56%) and α-pinene (6.32 %). While β-eudesmol (4.42 %), β-pinene (4.32 %), γ-cadinene (3.87 %), camphene (2.98 %), α-terpinenol (2.72 %), camphor (2.23 %), humulene 6,7-epoxide (2.17 %), cubeban-11-ol (1.98 %), α-muurolene (1.81 %), epicubenol (1.43 %), α-copaene (1.26 %), viridiflorene (1.02 %), β-guanine (0.65 %), β-bourbonene (0.23 %), terpinen-4-ol (0.13 %), endo-borneol (0.12 %), levoverbenone (0.12 %) and isobornyl acetate (0.12 %) were the compounds present in minor concentrations. Among the identified compounds there were monoterpene hydrocarbons (13.62 %), bicyclic-monoterpenoid (0.36 %), terpenoid ketones (2.23 %), monocyclic monoterpenoid alkene alcohol (2.85 %), non-oxygenated sesquiterpenes (25.17 %) and oxygenated sesquiterpenes (51.43 %). The present investigation also discusses the applications of various components found in S. cumini leaf essential oil and a comparative view on the essential oil composition of the leaves of the plant was reported earlier.

Seasonal changes in eastern hemlock (Tsuga canadensis) foliar chemistry

Eastern hemlock (Tsuga canadensis (L.) Carrière) is an eastern North American conifer threatened by the invasive hemlock woolly adelgid (Adelges tsugae Annand). Changes in foliar terpenes and phenolics were evaluated in new (current-year growth) and mature (1-year-old growth) hemlock needles during the growing season and into plant dormancy. From April through September, foliar concentrations of nonvolatile soluble phenolics, condensed tannins, lignin, mono- and sesquiterpenes, α-pinene, camphene, isobornyl acetate, and diterpene resin were quantified. After September, additional analyses of metabolites that continued to differ significantly between new and mature foliage were carried out. Total soluble phenolic and condensed tannin concentrations in new foliage remained low relative to those of mature foliage throughout the growing season and converged in December. Lignin concentration in new foliage converged with that of mature foliage by July. Concentrations of α-pinene, camphene, isobornyl acetate, and diterpene resin in new foliage converged with those of mature foliage within 1 month of budbreak. The convergence of terpene concentrations in new and mature foliage suggests that these metabolites may play a role in herbivore defense during the peak growing season. Conversely, soluble phenolics, including condensed tannins, may defend foliage from herbivory outside of the spring growth period.

Anti-oxidant and Anti-microbial Activities of Silver Nanoparticles of Essential Oil Extracts from Leaves of Zanthoxylum ovalifolium

Aim: The present study was aimed to synthesis and characterization of silver nanoparticles (AgNPs) using Zanthoxylum ovalifolium leaf essential oil extracts and to screen the anti-oxidant and antimicrobial potential of the same.
 Place and Duration of Study: The studies were carried out at Department of Botany, AVK College for Women, Hassan and Department of Biochemistry, Aurora’s Degree & PG College, Hyderabad from July 2017 to June 2018
 Methodology: The essential oil from leaves of Zanthoxylum ovalifolium was obtained by hydrodistillation and analyzed by GC and GC-MS. Synthesis of silver nanoparticles of essential oil extract was carried out and characterized by using UV-VIS spectroscopy and transmission electron microscopy (TEM). The total phenolic and flavonoid contents were estimated in all the extracts. Furthermore, all the extracts were evaluated for anti-microbial activity against two gram-positive and two gram-negative bacteria and four pathogenic fungi using agar disc diffusion technique. Subsequently the minimum inhibitory concentration (MIC) was also determined.
 Results: The major compounds identified were Limonene, isofenchol, Geijerene, isothujanol, Borneol, dihydrocarveol, isobornyl acetate, pregeijerene, b-elemene, trans-caryophyllene and Germacrene D. The TEM analysis of nanoparticles synthesized showed a size of 8 to 14 nm with a lmax of 450nm. All the extracts were evaluated for in vitro anti-oxidant activity where the AgNP of essential oil extract showed maximum activity of 89.61% and 84.92% respectively for both DPPH free radical scavenging and Hydrogen peroxide free radical scavenging assays at a concentration of 100µg/ml. Among all the bacteria tested, B. subtilis was most susceptible at 100µg/ml with zone of inhibition of 22.5mm. While among all the fungi tested, A. niger inhibited more effectively by the AgNP of essential oil extract at 100µg/ml with a zone of inhibition of 16.2mm.
 Conclusion: The results obtained were remarkable suggesting that AgNP of essential oil extract possess excellent anti-oxidant and anti-microbial activity and can be an alternative bio-friendly source for various pharmaceutical industries.