BF3-Et2O-Mediated One-Pot Synthesis of Acetylchromans from Polyhydroxyacetophenones and Isoprene/Allyl Alcohol

A convenient one-pot method has been developed for the synthesis of substituted acetylchromans involving the condensation of polyhydroxyacetophenone with isoprene and long chain allylic alcohol (phytol) in the presence of borontrifluoride etherate (BF₃-Et₂O).     

Chemical composition and anti-inflammatory activities of the essential oils from Acacia mearnsii de Wild

The volatile oils of the leaves and the stem bark of Acacia mearnsii de Wild obtained by hydro-distillation were analysed by gas chromatography–mass spectrometry. A total of 20, 38, 29 and 38 components accounted for 93.8%, 92.1%, 78.5% and 90.9% of the total oils of the fresh, dry leaves and fresh, dry stem bark, respectively. The major components of the oil were octadecyl alcohol (25.5%) and phytol (10.5%); cis-verbenol (29.5%); phytol (10.1%) and phytol (23.4%) for the fresh leaves, dried leaves, fresh stem, dry stem bark, respectively. Oral administration of essential oils at a dose of 2% showed significant (p < 0.05) anti-inflammatory properties in the albumin-induced test model in rats. Oils from the fresh leaves and dry stems inhibited inflammation beyond 4 h post treatment. The potent anti-inflammatory activity of essential oils of A. mearnsii hereby confirmed its traditional use in treating various inflammatory diseases.     

植醇对牧草中脂肪酸测定的干扰及其消除

通过对牧草脂肪酸的测定,分析气相色谱法直接碱催化甲酯化、碱皂化三氟化硼催化甲酯化2种前处理方法中植醇的干扰情况,优化碱皂化三氟化硼催化的试验条件。实验结果表明,在2种前处理方法中,植醇对牧草脂肪酸的测定均产生干扰,其中直接碱催化甲酯化法干扰较重。80℃是碱皂化三氟化硼催化甲酯化处理牧草的最优水浴温度,能完全去除植醇,且80℃时,脂肪酸的甲酯化效率最高。在添加量为100、500 mg/kg 2种水平中,5种脂肪酸甲酯的平均回收率在87.5%~94.1%之间,相对标准偏差(RSD)在2.0%~5.1%之间。改进的方法能消除植醇的干扰,其准确度和精密度能满足牧草脂肪酸测定要求。     

Phytochemical screening and chemical variability in volatile oils of aerial parts of Morinda morindoides

Morinda morindoides is an important Liberian traditional medicine for the treatment of malaria, fever, worms etc. The plant was subjected to integrated approaches including phytochemical screening and gas chromatography mass spectrometry (GC–MS) analyses. Phytochemical investigation of the powdered plant revealed the presence of phenolics, tannins, flavonoids, saponins, terpenes, steroidal compounds and volatile oil. Steam distillation followed by GC–MS resulted in the identification of 47 volatiles in its aerial parts: 28 were in common including various bioactive volatiles. Major constituents of leaves were phytol (43.63%), palmitic acid (8.55%) and geranyl linalool (6.95%) and stem were palmitic acid (14.95%), eicosane (9.67%) and phytol (9.31%), and hence, a significant difference in the percentage composition of aerial parts was observed. To study seasonal changes, similarity analysis was carried out by calculating correlation coefficient (r) and vector angle cosine (z) that were more than 0.91 for stem-to-stem and leaf-to-leaf batches indicating considerable consistency.     

Chemical composition and evaluation of the antimicrobial activity of the essential oil from leaves of Eugenia platysema

This study describes the qualitative and quantitative chemical composition and evaluates the antibacterial activity of essential oil from Eugenia platysema leaves. Analysis by GC–FID and GC–MS allowed the identification of 22 compounds. Different from the other species of the Eugenia genus, the major compound found in the essential oil was the diterpene phytol (66.05%), being this the first report of the presence of this compound in the essential oils from Eugenia genus. The sesquiterpene elixene was the second most concentrated compound in the studied essential oil (9.16%). The essential oil from E. platysema was tested for its antibacterial activity against cell-walled bacteria and mollicute strains of clinical interest using the microdilution broth assay. The results showed that the essential oil of E. platysema was inactive until 1000 μg mL^?1 against tested bacteria.     

Volatile oil analysis of aerial parts of Boerhavia coccinea (Mill.)

Volatile oil of the aerial part of Boerhavia coccinea was obtained by Clevenger-type apparatus, the chemical components were analysed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC–MS). Twenty constituents were recognised in the oil which accounted for 98.05% of it. This was characterised by high level of ethers (29.85%), while most dominant compound was phytol (24.02%). The essential oil of B. coccinea mainly consisted ethers and alcohols, which is being reported for the first time.