Asperuloside Enhances Taste Perception and Prevents Weight Gain in High-Fat Fed Mice.

Asperuloside is an iridoid glycoside found in many medicinal plants that has produced promising anti-obesity results in animal models. In previous studies, three months of asperuloside administration reduced food intake, body weight, and adipose masses in rats consuming a high fat diet (HFD). However, the mechanisms by which asperuloside exerts its anti-obesity properties were not clarified. Here, we investigated homeostatic and nutrient-sensing mechanisms regulating food intake in mice consuming HFD. We confirmed the anti-obesity properties of asperuloside and, importantly, we identified some mechanisms that could be responsible for its therapeutic effect. Asperuloside reduced body weight and food intake in mice consuming HFD by 10.5 and 12.8% respectively, with no effect on mice eating a standard chow diet. Fasting glucose and plasma insulin were also significantly reduced. Mechanistically, asperuloside significantly reduced hypothalamic mRNA ghrelin, leptin, and pro-opiomelanocortin in mice consuming HFD. The expression of fat lingual receptors (CD36, FFAR1-4), CB1R and sweet lingual receptors (TAS1R2-3) was increased almost 2-fold by the administration of asperuloside. Our findings suggest that asperuloside might exert its therapeutic effects by altering nutrient-sensing receptors in the oral cavity as well as hypothalamic receptors involved in food intake when mice are exposed to obesogenic diets. This signaling pathway is known to influence the subtle hypothalamic equilibrium between energy homeostasis and reward-induced overeating responses. The present pre-clinical study demonstrated that targeting the gustatory system through asperuloside administration could represent a promising and effective new anti-obesity strategy.

Distinct Drimane Chemotypes in Tasmanian Mountain Pepper (Tasmannia lanceolata): Differences in the Profiles of Pungent Leaf Phytochemicals Associated with Altitudinal Cline.

This study assesses whether the distinct altitudinal cline in leaf morphology (decreased leaf width and length with increased altitude) in Tasmanian mountain pepper (Tasmannia lanceolata) is associated with changes in the leaf chemistry of wild populations from different ecological landscapes and altitudes. The presence of distinct pungent drimane sesquiterpenoid chemotypes was identified: subalpine woodland and wet sclerophyll forest chemotypes. Isolation studies and analysis of extracts revealed that wet sclerophyll forest T. lanceolata populations featured polygodial as the principal terpenoid, with profiles similar to the commercial cultivars sampled. In contrast, the subalpine woodland populations contained the drimane sesquiterpenoids 1ß-acetoxy-9-deoxyisomuzigadial and 3ß-acetoxydrimenin and the conspicuous absence of the pungent principle polygodial.

Employing Pressurized Hot Water Extraction (PHWE) to Explore Natural Products Chemistry in the Undergraduate Laboratory.

A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products research has also found applications as an effective teaching tool. Specifically, this technique has been used to introduce second- and third-year undergraduates to aspects of natural products chemistry in the laboratory. In this report, two experiments are presented: the PHWE of eugenol and acetyleugenol from cloves and the PHWE of seselin and (+)-epoxysuberosin from the endemic Australian plant species Correa reflexa. By employing PHWE in these experiments, the crude clove extract, enriched in eugenol and acetyleugenol, was obtained in 4-9% w/w from cloves by second-year undergraduates and seselin and (+)-epoxysuberosin were isolated in yields of up to 1.1% w/w and 0.9% w/w from C. reflexa by third-year students. The former exercise was developed as a replacement for the traditional steam distillation experiment providing an introduction to extraction and separation techniques, while the latter activity featured guided-inquiry teaching methods in an effort to simulate natural products bioprospecting. This primarily derives from the rapid nature of this PHWE technique relative to traditional extraction methods that are often incompatible with the time constraints associated with undergraduate laboratory experiments. This rapid and practical PHWE method can be used to efficiently isolate various classes of organic molecules from a range of plant species. The complementary nature of this technique relative to more traditional methods has also been demonstrated previously.

Extraction of carboxylic acid-containing diterpenoids from Dodonaea viscosa via pressurised hot water extraction.

Pressurised hot water extraction (PHWE) was employed to effect the extraction of two carboxylic acid-containing ent-labdane diterpenoids from Dodonaea viscosa. The different extraction profile provided by PHWE in this case suggests that this recently developed method also has applications as a complementary tool for natural products extraction.