Characterisation of phenols and antioxidant and hypolipidaemic activities of Lethariella cladonioides

Antimicrobial and antioxidant activity of Evernia prunastri extracts and their isolates

Lichens are symbiotic organisms formed by a fungus and one or more photosynthetic partners which are usually alga or cyanobacterium. Their diverse and scarcely studied metabolites facilitate adaptability to extreme living conditions. We investigated Evernia prunastri (L.) Ach., a widely distributed lichen, for its antimicrobial and antioxidant potential. E. prunastri was sequentially extracted by hexane (Hex), dichloromethane (DCM) and acetonitrile (ACN) that were screened for their antioxidant and antimicrobial (against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans) activities. The Hex extract possessed the highest antioxidant capacity (87 mg ascorbic acid/g extract) corresponding to the highest content of phenols (73 mg gallic acid/g extract). The DCM and Hex extracts were both active against S. aureus (MICs of 4 and 21 µg/ml, respectively) but were less active against Gram-negative bacteria and yeast. The ACN extract exhibited activity on both S. aureus (MIC 14 µg/ml) and C. albicans (MIC 38 µg/ml) and was therefore further fractionated by silica gel column chromatography. The active compound of the most potent fraction was subsequently characterized by 1H and 13C-NMR spectroscopy and identified as evernic acid. Structural similarity analyses were performed between compounds from E. prunastri and known antibiotics from different classes. The structural similarity was not present. Antioxidant and antimicrobial activities of E. prunastri extracts originate from multiple chemical compounds; besides usnic acid, most notably evernic acid and derivatives thereof. Evernic acid and its derivatives represent possible candidates for a new class of antibiotics.

The crystal structure of 2-hydroxy-4-((2-hydroxy-4-methoxy-3,6-dimethylbenzoyl)oxy)-3,6-dimethylbenzoic acid–methanol (1/1), C20H24O8

C20H24O8, triclinic, P1̄ (no. 2), a = 4.6850(6) Å, b = 7.1895(2) Å, c = 29.1839(3) Å, α = 88.815(8)°, β = 86.346(8)°, γ = 80.052(9), V = 966.20(13) Å3, Z = 2, R gt(F) = 0.0785, wR ref(F 2) = 0.2235, T = 205 K.

The anti-obesity effect of Lethariella cladonioides in 3T3-L1 cells and obese mice

The aim of this study was to investigate whether a water extract of L. cladonioides (LC) has an anti-obesity effect in 3T3-L1 cells and obese mice. Treatment of differentiated 3T3-L1 adipocytes with LC caused a significant increase in glycerol release and reduced the protein expression of the adipogenic transcription factors, PPARγ and C/EBPα. In an animal model, obese mice were artificially induced by a high fat diet for 10 weeks. Experimental groups were treated with LC (100 mg/kg/day) by gavage for the next 10 weeks. At the end of experiment, the body weight of the LC group mice was reduced by 14.2% compared to the high fat diet (HFD) group. The treatment also decreased liver (31.0%), epididymal (18.0%) and retroperitoneal (19.3%) adipose tissue, and kidney (6.7%) weights, respectively, compared with those of the HFD group. LC prevented diet-induced increases in the serum level of TC (22.6%), TG (11.6%), and glucose (35.0%), respectively, compared with the HFD group. However, the HDL-C level was higher in the LC group (26.1%) than the HFD group. The results of this study thus suggest that LC suppressed lipid accumulation and expression of adipogenic transcription factors, and increased the amount of glycerol release. LC also indicated an anti-obese and anti-hyperlipidemic effect.