Leopoldia comosa prevents metabolic disorders in rats with high-fat diet-induced obesity.

PURPOSE: Obesity is the main feature of a complex illness known as metabolic syndrome. Anti-obesogenic therapies are often associated with side effects and represent a high cost in conventional pharmacological approaches. New strategies based on natural remedies are under continuous investigation. Leopoldia comosa (L.) Parl. (L. comosa) is a spontaneous plant with diuretic, anti-inflammatory and antioxidant properties. Recently, a hypoglycemic activity mediated by inhibition of carbohydrate digestion has been identified. The aim of this study was to evaluate the effects of a diet supplemented with L. comosa extracts on a rat model of diet-induced obesity. METHODS: Leopoldia comosa bulb extracts were obtained using a dynamic extractor. Phytochemical properties and in vitro determination of the antioxidant activity and of the inhibitory effects on lipase and pancreatic amylase were performed. Rats were fed (12 weeks) a standard diet, or a high-fat diet (HFD), or an HFD plus L. comosa (20 or 60 mg/die) extracts. The metabolic and anthropometric parameters were recorded. RESULTS: Results indicated that L. comosa inhibited lipase and pancreatic amylase activities. In vivo data showed that the supplementation with both doses of L. comosa extracts counteracted the HFD-dependent effects. It reduced body weight, abdominal obesity and dyslipidemia, and improved glucose tolerance with a reduction of lipidic tissue hypertrophy and liver steatosis, as compared to HFD-fed rat. In liver, L. comosa reduced protein expression levels of PEPCK and G6Pase. CONCLUSION: We suggest that L. comosa extracts prevent obesity-dependent metabolic disorders. This paves the way for their therapeutic application as a natural anti-obesity drug.

GC-MS characterisation and biological activity of essential oils from different vegetative organs of Plectranthus barbatus and Plectranthus caninus cultivated in north Italy.

Essential oils (EOs) from the roots, stems and leaves of Plectranthus barbatus (A) and Plectranthus caninus (B), cultivated in north Italy, were obtained by steam distillation and chemically characterised by gas chromatography-mass spectrometry. The highest yields were obtained from roots (268.15 and 673.60 mg/kg from A and B), followed by leaves (64.34 and 26.65 mg/kg) and stems (19.76 and 18.63 mg/kg). A total of 128 structures were identified in A and 121 in B. Fe(++) chelating and antiradical activities (DPPH and ABTS) were evaluated: root and stem EOs showed the strongest activities, while EOs from leaves did not show relevant activities. All EOs were tested for their in vitro antimicrobial activity, showing optimal growth-inhibition in antibiogram (∅>35 mm) and MIC tests (32-64 µg/mL) against Candida albicans, while EOs from leaves of both species showed a good activity (25 < ∅ < 34 mm, MIC 64-128 µg/mL) against Escherichia coli.

An analytical and theoretical approach for the profiling of the antioxidant activity of essential oils: the case of Rosmarinus officinalis L.

The antioxidant constituents of essential oils (EOs) of Rosmarinus officinalis L. (α-pinene chemotype) were isolated at the flowering (A), post-flowering (B), and vegetative stages (C). GC-MS was used to analyze total chemical composition, Folin-Ciocalteau and Prussian blue methods for reducing substances. Radical scavenging capacity (DPPH test, IC(50) 36.78±0.38, 79.69±1.54, 111.94±2.56µL) and anti-lipoperoxidant activity (TBARS, IC(50) 0.42±0.04, 1.20±0.06µL, 4.07±0.05µL) differed widely in the three stages. Antioxidant activity, identified after silica gel fractionation chromatography, was closely related (R(2)=0.9959) to each EO's content of hydroxilated derivatives, (containing alcohols, phenols and 1,8 cineole): 15.26±0.12%, 7.22±0.06%, and 5.09±0.10% in EOs from A, B, and C. Modeling the C, H, O terpenes in a simulated phospholipid bilayer indicated that anti-lipoperoxidant activity depended on the stability and rapidity of their interactions with the membrane bilayer components, and their positioning over its surface.