Chemical constituents and antioxidant activity of essential oil and organic extract from the peel and kernel parts of Citrus japonica Thunb. (kumquat) from Iran

The constituents of essential oils and organic extracts from peel and kernels of Citrus japonica were analysed by GC and GC/MS. The content of essential oil in peel and kernel was 1.1 and 0.8% based on dry weight. The essential oil of C. japonica peel and kernel was characterised by a higher amount of limonene (51.0 and 47.1%) and germacrene D (12.1 and 6.3%), and the hexane extracts of its peel and kernel were characterised by a higher amount of dodecanol-1(12.9 and 20.8%) and linolenic acid (13.1 and 16.3%), respectively. The antioxidant activities of oils were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results indicate that both oils from different parts of C. japonica possess considerable antioxidant activity. The fruit peel and kernel essential oil could thus be useful in the industries, chiefly in the food and pharmaceutical industries.     

Insecticidal and α-glucosidase inhibitory activities of chemical constituents from Viburnum fordiae Hance

The ethanolic extract of the stems of Viburnum fordiae Hance showed insecticidal and α-glucosidase inhibitory activities and then was fractionated by bioactivity-guided fractionation to obtain a rare C₁₃-norisoprenoid (1), together with a new phenolic glycoside (2), and seven known compounds, alangionoside C (3), pisumionoside (4), koaburaside (5), 3,5-dimethoxy-benzyl alcohol 4-O-β-d-glucopyranoside (6), 3,4,5-trimethoxybenzyl-β-d-glucopyranoside (7), arbutin (8), and salidroside (9). The previously undescribed compounds were elucidated as (3R,9R)-3-hydroxy-7,8-didehydro-β-ionyl 9-O-α-d-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1) and 2-(4-O-β-d-glucopyranosyl)syringylpropane-1,3-diol (2) by spectroscopic data (¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, HSQC-TOCSY, HRESIMS, IR and ORD) and chemical methods. Compound 1 showed potent insecticidal effect against Mythimna separata with LD₅₀ value of 140 μg g^?1. Compounds 2, 5, 6, 8 and 9 showed varying α-glucosidase inhibitory activity with IC₅₀ values ranging from 148.2 to 230.9 μM.     

Chemical constituents,anticancer, antimicrobial and antioxidant activities of essential oil from Anaphalis lacteal grown in Qinghai-Tibet Plateau

The chemical constituent of the essential oil from Anaphalis lacteal was determined; 31 compounds, representing 93.91% of the total oil, were identified by gas chromatography–mass spectrometry analysis. Three Gram-positive bacteria species, three Gram-negative bacteria species and four fungi were used to determine antimicrobial activity; the results revealed that the essential oil had a remarkable antimicrobial effect against bacteria and a susceptive effect against fungus. The oil also possessed more efficient free-radical scavenging activities than butylated hydroxytoluene (BHT) with 50% inhibitory concentration (IC₅₀) value 31 μg/mL (40 μg/mL for BHT). MTT assay illustrated that the oil expressed certain effect in inhibiting the growth of HeLa and Hep-6 cancer cells.