Chemical Composition, Antioxidant, Antimicrobial and Cytotoxic Activities of Essential Oil from Premna microphylla Turczaninow.

Premna microphylla Turczaninow, an erect shrub, was widely used in Chinese traditional medicine to treat dysentery, appendicitis, and infections. In this study, the essential oil from P. microphylla Turcz. was obtained by hydrodistillation and analyzed by GC (Gas Chromatography) and GC-MS (Gas Chromatography-Mass Spectrometer). Fifty-six compounds were identified in the oil which comprised about 97.2% of the total composition of the oil. Major components of the oil were blumenol C (49.7%), ß-cedrene (6.1%), limonene (3.8%), α-guaiene (3.3%), cryptone (3.1%), and α-cyperone (2.7%). Furthermore, we assessed the in vitro biological activities displayed by the oil obtained from the aerial parts of P. microphylla, namely the antioxidant, antimicrobial, and cytotoxic activities. The antioxidant activity of the essential oil was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. For this, the IC50 value was estimated to be 0.451 mg/mL. The essential oil of P. microphylla exhibited considerable antibacterial capacity against Escherichia coli with an MIC (Minimum Inhibitory Concentration) value of 0.15 mg/mL, along with noticeable antibacterial ability against Bacillus subtilis and Staphylococcus aureus with an MIC value of 0.27 mg/mL. However, the essential oil did not show significant activity against fungus. The oil was tested for its cytotoxic activity towards HepG2 (liver hepatocellular cells) and MCF-7 Cells (human breast adenocarcinoma cell line) using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay, and exerted cytotoxic activity with an IC50 of 0.072 and 0.188 mg/mL for 72 h. In conclusion, the essential oil from P. microphylla is an inexpensive but favorable resource with strong antibacterial capacity as well as cytotoxic activity. Thus, it has the potential for utilization in the cosmetics and pharmaceutical industries.

Analysis of the essential oil from Gaillardia pulchella Foug. and its antioxidant activity.

The essential oil from Gaillardia pulchella Foug. flowers was obtained by hydrodistillation and its chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Twenty-eight compounds representing 92.63% of the essential oil were identified, of which the most prominent were n-Hexadecanoic acid (26.90%), Phytol (7.58%) and Cyclopropaneoctanoic acid, 2-[[2-[(2-ethylcyclopropyl) methyl] cyclopropyl] methyl]-, methyl ester (6.73%). Meanwhile, antioxidant activity of the essential oil was tested. The essential oil showed certain antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) with an EC50 of 70.95 µg/ml. This is the first report on the essential oil of this particular species. Its bioactivities warrant further studies.

Sesquiterpenoids and other constituents from Senecio argunensis.

Three new sesquiterpenoids, isodauc-7(14)-en-6alpha,10beta-diol (1), 10beta-hydroxyisodauc-6-en-14-al (2), and (7S(*))-opposit-4(15)-en-1beta,7-diol (4), along with ten known compounds have been isolated from the aerial parts of Senecio argunensis. Their structures were established by means of detailed spectroscopic analysis including IR, HR-MS, and 1D NMR and 2D NMR data. The sesquiterpenoids were assayed against Escherichia coli, Staphylococcus aureus and Bacillus subtilis. Compounds 4 exhibited weak antibacterial activity against Escherichia coli and Bacillus subtilis.

Eudesmane sesquiterpenes and other constituents from Aster himalaicus.

From the whole plants of Aster himalaicus, a new eudesmane-type sesquiterpene, 1-oxoeudesm-11(13)-eno-12,8alpha-lactone, along with twelve known compounds, was isolated. The structures of all compounds have been elucidated on the basis of spectroscopic data, including IR, EI-MS, HR-ESI-MS, and 1D- and 2D-NMR data.