Potential lipase inhibitors from Chinese medicinal herbs

Comparative Anti-Cancer and Anti-Inflammatory Activities of Essential Oils from the Bark and Flower of Magnolia officinalis Rehd. et Wils

This study was designed to compare the antioxidant, antitumor and anti-inflammatory effects of essential oils from the bark and flower of Magnolia officinalis Rehd. et Wils. Distillation extraction and steam distillation were used to extract EOs from the bark and flower. The results showed that the contents of EOs of SDE-F and SDE-B were much higher than that of SD-F and SD-B. EOs from the bark were rich in eudesmol (especially α-eudesmol) and exhibited a stronger antioxidant effect than the flower. The anti-tumor effects of SD-B and SD-F on HepG2 and MDA-MB-231 cells were better than that of SDE-B and SDE-F. The inhibitory rates of SD-B and SD-F on MDA-MB-231 cells were 59.21% and 48.27%, exceeding that of positive control 5-fluorouracil (47.04%) at 50 μg/mL. All four EOs exhibited excellent anti-inflammatory activities through the regulation of nitric oxide production and pro-inflammation cytokines in LPS-induced RAW 264.7 cells and they also remarkably suppressed the mRNA expressions of nitric oxide synthase, IL-6 and TNF-α at the concentration higher than that of positive control dexamethasone. These results indicated significant differences in the composition, and anti-inflammatory and anti-tumor activities of EOs extracted by different methods and provided a theoretical basis for their development and utilization.

Exploring the anti-obesity bioactive compounds of Thymelaea hirsuta and Ziziphus spina-christi through integration of lipase inhibition screening and molecular docking analysis

Activity-guided fractionation of the ethanolic extracts of Thymelaea hirsuta and Ziziphus spina-christi furnished eight compounds with pancreatic lipase inhibitory activity. Six compounds were isolated from the chloroform fraction of T. hirsuta. It is worth mentioning that this is the first report for the isolation of 5,7,4'-trihydroxy-8-methoxycarbonyl flavanol (2), daphnodorin G-3''-methyl ether (4) and daphnodorin G (5) from genus Thymelaea. Moreover, daphnoretin (1), neochamaejasmin A (3) and daphnodorin B (6) were also isolated from the chloroform fraction of the same plant. On the other hand, quercetin 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-galactopyranoside (7) and 3-O-[α-l-fucopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 3)-α-l-arabinopyranosyl] jujubogenin (christinin A) (8) were isolated from the n-butanol fraction of Z. spina-christi. Structure elucidation of the isolated compounds was carried out by detailed analysis of 1D and 2D spectral data. These compounds showed percentage inhibitions of 72% (1), 52% (2), 61.8% (3), 39% (4), 69.5% (5), 3.5% (6), 68% (7) and 75% (8) at the concentration of 250 μM and XP-G scores of lipase inhibition were 11.40 (1), 8.71 (2), 6.13 (3), 8.23 (4), 6.22 (5), 9.76 (6), 14.66 (7) and 12.00 (8). This is the first report of the isolation of lipase inhibitors from both plants T. hirsuta and Z. spina-christi. In addition to that, this might result in presenting the biscoumarin, daphnoretin, and the dammarane saponin, christinin A, as potent lipase inhibitors.

Methodologies for Assessing Pancreatic Lipase Catalytic Activity: A Review

Obesity is a disease of epidemic proportions with a concerning increasing trend. Regarded as one of the main sources of energy, lipids can also represent a big part of an unnecessary intake of calories and be, therefore, directly related to the problem of obesity. Pancreatic lipase is an enzyme that is essential in the absorption and digestion of dietary fats and has been explored as an alternative for the reduction of fat absorption and consequent weigh loss. Literature describes a great variability of methodologies and experimental conditions used in research to evaluate the in vitro inhibitory activity of compounds against pancreatic lipase. However, in an attempt to choose the best approach, it is necessary to know all the reaction conditions and understand how these can affect the enzymatic assay. The objective of this review is to understand and summarize the methodologies and respective experimental conditions that are mainly used to evaluate pancreatic lipase catalytic activity. 156 studies were included in this work and a detailed description of the most commonly used UV/Vis spectrophotometric and fluorimetric instrumental techniques are presented, including a discussion regarding the differences found in the parameters used in both techniques, namely enzyme, substrate, buffer solutions, kinetics conditions, temperature and pH. This works shows that both UV/Vis spectrophotometry and fluorimetry are useful instrumental techniques for the evaluation of pancreatic lipase catalytic activity, presenting several advantages and limitations, which make the choice of parameters and experimental conditions a crucial decision to obtain the most reliable results.

Evaluation of honokiol, magnolol and of a library of new nitrogenated neolignans as pancreatic lipase inhibitors

Obesity is a complex disease defined as an excessive amount of body fat. It is considered a risk factor for several pathologies; therefore, there is an increasing interest in its treatment. Pancreatic lipase (PL) plays a key role in fat digestion, and its inhibition is a preliminary step in the search for anti-obesity agents. For this reason, many natural compounds and their derivatives are studied as new PL inhibitors. This study reports the synthesis of a library of new compounds inspired by two natural neolignans, honokiol (1) and magnolol (2) and bearing amino or nitro groups linked to a biphenyl core. The synthesis of unsymmetrically substituted biphenyls was achieved through an optimisation of the Suzuki-Miyaura cross-coupling reaction followed by the insertion of allyl chains, thus furnishing the O- and/or N-allyl derivatives, and finally, a sigmatropic rearrangement yielding in some cases, the C-allyl analogues. Magnolol, honokiol and the twenty-one synthesised biphenyls were evaluated for their in vitro inhibitory activity toward PL. Three compounds (15b, 16 and 17b) were more effective inhibitors than the natural neolignans (magnolol IC₅₀ = 158.7 µM and honokiol IC₅₀ = 115.5 µM) with IC₅₀ of 41-44 µM. Detailed studies through kinetics suggested better inhibitory activity of the synthetic analogues compared with the natural 1 and 2. Magnolol (K_i = 614.3 µM; K'_i of 140.9 µM) and the synthetic biphenyls 15b (K_i = 286.4 µM; K'_i = 36.6 µM) and 16 (K_i = 176.2 µM; K'_i = 6.4 µM) are mixed-type inhibitors, whereas honokiol (K_i = 674.8 µM) and 17b (K_i = 249 µM) are competitive inhibitors. Docking studies corroborated these findings, showing the best fitting for intermolecular interaction between biphenyl neolignans and PL. The above outcomes highlighted how the proposed structures could be considered interesting candidates for future studies for the development of more effective PL inhibitors.

Polyphenol-rich extract and fractions of Terminalia phaeocarpa Eichler possess hypoglycemic effect, reduce the release of cytokines, and inhibit lipase, α-glucosidase, and α-amilase enzymes

ETHNOPHARMACOLOGICAL RELEVANCE

species of Terminalia (Combretaceae) are used to treat diabetes and metabolic disorders in Asia, Africa, and America. Terminalia phaeocarpa Eichler is an endemic tree from Brazil, popularly known as capitão. This species is closely related to Terminalia argentea Mart., also vulgarly known as capitão, a native but not endemic tree. Due to their phenotype similarity, these species might eventually prove inseparable and they are indistinctly used by locals to treat diabetes, among other diseases. The potential antidiabetic effect of T. argentea has been previously reported, whereas the biological effects and chemical composition of T. phaeocarpa have never been addressed so far.

AIM OF THE STUDY

investigate the hypoglycaemic effect of an ethanol extract (EE) of T. phaeocarpa leaves and its ethyl acetate (FrEtOAc) and hydromethanolic (FrMEOH) fractions, in addition to their activity on the release of pro-inflammatory mediators and inhibition of lipase, α-amylase, and α-glucosidase enzymes. Additionally, it aimed to characterize the chemical composition of the extract and fractions, seeking to identify the compounds related to the biological activities.

MATERIALS AND METHODS

The effect on the release of TNF-α, IL-1β, and CCL-2 was evaluated in LPS-stimulated THP-1 cells (ATCC TIB-202). The inhibition of lipase, α-amylase, and α-glucosidase was tested in vitro, whereas the hypoglycemic effect was assayed in the oral starch tolerance test. The chemical composition was investigated by extensive UHPLC-DAD-ESI-MS/MS analyses.

RESULTS

The extract and derived fractions reduced TNF-α (EE pIC₅₀ = 4.58 ± 0.01; FrEtOAc pIC₅₀ = 4.69 ± 0.01; FrMeOH pIC₅₀ = 4.54 ± 0.02) and IL-1β (EE pIC₅₀ = 4.86 ± 0.02; FrEtOAc pIC₅₀ = 4.86 ± 0.02; FrMeOH pIC₅₀ = 4.75 ± 0.01) release by LPS-stimulated THP-1 cells in a concentration-dependent manner, whereas the inhibitory effect on CCL-2 release did not reach a clear linear relationship for the tested concentrations. The extract and fractions also inhibited in vitro the activity of lipase (EE pIC₅₀ = 3.97 ± 0.12; FrEtOAc pIC₅₀ = 3.87 ± 0.04; FrMeOH pIC₅₀ = 3.67 ± 0.14), α-amylase (EE pIC₅₀ = 4.46 ± 0.27; FrEtOAc pIC₅₀ = 5.47 ± 0.27; FrMeOH pIC₅₀ = 4.26 ± 0.22), and α-glucosidase (EE pIC₅₀ = 5.46 ± 0.05; FrEtOAc pIC₅₀ = 5.79 ± 0.11; FrMeOH pIC₅₀ = 5.74 ± 0.05). The pIC₅₀ values of the test samples were lower than those obtained with orlistat (7.59 ± 0.08) and acarbose (6.04 ± 0.37 and 7.63 ± 0.04) employed as the positive controls respectively in the lipase, α-amylase, and α-glucosidase assays. When assayed in the oral starch tolerance test, the extract and fractions also reduced animal glycaemia. UHPLC-DAD-ESI-MS/MS analyses of the extract and fractions led to the identification of 38 phenolic compounds, mainly phenolic acids, ellagitannins and flavonoids, among others, all of them first-time described for the species.

CONCLUSION

Based on our findings, T. phaeocarpa has hypoglycaemic activity and polyphenols are the probable bioactive compounds, which support the ethnomedical use of the species.

Effect of Panax notoginseng Saponins and Major Anti-Obesity Components on Weight Loss

The prevalence of individuals who are overweight or obese is rising rapidly globally. Currently, majority of drugs used to treat obesity are ineffective or are accompanied by obvious side effects; hence, the options are very limited. Therefore, it is necessary to find more effective and safer anti-obesity drugs. It has been proven in vivo and in vitro that the active ingredient notoginsenosides isolated from traditional Chinese medicine Panax notoginseng (Burk.) F. H. Chen exhibits anti-obesity effects. Notoginsenosides can treat obesity by reducing lipid synthesis, inhibiting adipogenesis, promoting white adipose tissue browning, increasing energy consumption, and improving insulin sensitivity. Although notoginsenosides are potential drugs for the treatment of obesity, their effects and mechanisms have not been analyzed in depth. In this review, the anti-obesity potential and mechanism of action of notoginsenosides were analyzed; thus laying emphasis on the timely prevention and treatment of obesity.

Plant Extracts and Reactive Oxygen Species as Two Counteracting Agents with Anti- and Pro-Obesity Properties

Obesity is a complex disease of great public health significance worldwide: It entails several complications including diabetes mellitus type 2, cardiovascular dysfunction and hypertension, and its prevalence is increasing around the world. The pathogenesis of obesity is closely related to reactive oxygen species. The role of reactive oxygen species as regulatory factors in mitochondrial activity in obese subjects, molecules taking part in inflammation processes linked to excessive size and number of adipocytes, and as agents governing the energy balance in hypothalamus neurons has been examined. Phytotherapy is the traditional form of treating health problems using plant-derived medications. Some plant extracts are known to act as anti-obesity agents and have been screened in in vitro models based on the inhibition of lipid accumulation in 3T3-L1 cells and activity of pancreatic lipase methods and in in vivo high-fat diet-induced obesity rat/mouse models and human models. Plant products may be a good natural alternative for weight management and a source of numerous biologically-active chemicals, including antioxidant polyphenols that can counteract the oxidative stress associated with obesity. This review presents polyphenols as natural complementary therapy, and a good nutritional strategy, for treating obesity without serious side effects.