Weight-reducing effect of Acer truncatum Bunge may be related to the inhibition of fatty acid synthase

Acer truncatum leaves extract modulates gut microbiota, improves antioxidant capacity, and alleviates lipopolysaccharide-induced inflammation in broilers

This study investigated the appropriate way of dietary Acer truncatum leaves (ATL) addition, the effect of disease prevention and its mechanism of action. In experiment 1, 192 Arbor Acres broilers were assigned to 4 treatment groups, fed with basal diets containing 2% bran, replacing it with primary and fermented ATL, and additional 0.3% ATL extract to the basal diet for 42 d, respectively. In experiment 2, 144 broilers were assigned to 3 treatment groups for 21-d trial: (1) C-N group, basal diets, and injected with 0.9% (w/v) sterile saline; (2) C-L group, basal diets, and injected with lipopolysaccharide (LPS); (3) T-L group, ATL diets and injected with LPS. In experiment 1, ATL significantly decreased the index of abdominal fat at 42 d (P < 0.05). ATL extract had a better ability to improve antioxidant capacity and reduce inflammatory levels among all treatment groups, which significantly decreased the content of MDA in the liver and ileum mucosa at 21 d, and increased the expression of IL-10 and Occludin in jejunal mucosa at 42 d (P < 0.05). In experiment 2, ATL significantly increased the level of T-AOC in the liver, decreased the expression of NF-κB in the jejunal mucosa and ileum mucosa (P < 0.05), and restored LPS-induced the changed level of CAT in jejunal mucosa, the expression of IL-6, Claudin-1, and ZO-1 in jejunal mucosa and IL-1β in ileum mucosa (P < 0.05). Analysis of gut microbiota indicated that ATL enhanced the abundances of Bacteroidota and reduced the proportion of Firmicutes (P < 0.05), and the changed levels of T-AOC in body, IL-1β, IL-6, IL-10, and NF-κB in jejunum mucosa and propionic acid in cecal were associated with gut microbiota. Collectively, our data showed that the extract of ATL had a better antioxidant and anti-inflammatory effects than primality and fermented. Extraction of ATL modulated intestinal microbiota, and had a protective effect on oxidative stress, inflammation, and intestinal barrier function in broilers challenged with LPS.

Inhibitory Effect of Acer truncatum Bunge Seed Coat Extract on Fatty Acid Synthase, Differentiation and Lipid Accumulation in 3T3-L1 Adipocytes

Acer truncatum Bunge is now widely cultivated throughout the world. Fatty acid synthase (FAS) is a potential target in the treatment of both obesity and cancer. Only a few FAS inhibitors have been reported. In this study, the inhibitory effect of A. truncatum seed coat (ESA) on FAS and the inhibition mechanisms were investigated using a FAS activity assay and an enzyme kinetics study. The main chemicals of ESA were analyzed with UPLC-MS/MS. The effects of ESA on 3T3-L1 adipocyte differentiation and lipid accumulation were investigated using Oil red O staining. We first identified seven main compounds (quinic acid, malic acid, gentisic acid, procyanidin dimer, procyanidin trimer, catechin, and quercetin) from 50% ethanol extracts of seed coats of A. truncatum (ESAs), which were then found to inhibit 3T3-L1 adipocyte differentiation at the concentration of 50 μg/mL. ESA obviously reduced the visible triglyceride droplets accumulation, and dramatically decreased the number of the adipocytes at a comparatively high concentration. It is suggested that the effects are due to the inhibition of FAS by ESA; FAS activity is inhibited by ESA at a half inhibition concentration (IC₅₀) of 0.57 μg/mL, which is lower than that of classically known FAS inhibitors. Meanwhile, ESA displayed different inhibition kinetics and reacting sites for FAS. These results provide new clues for the development of novel products for obesity treatment and a scientific basis for the full use of byproducts for future industrial production of vegetable oil.

Acer truncatum Bunge: A comprehensive review on ethnobotany, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Acer truncatum Bunge is a multifunctional plant in northern China. It has traditionally been used to prevent cardiovascular and cerebrovascular diseases and treat skin trauma by different linguistic groups including Mongolian, Tibetan, and Korean. Although research has verified that A. truncatum contains a variety of active ingredients, especially nervonic acid, an important component in delaying brain aging, to date no review has been made to compile its traditional use, phytochemistry, and pharmacology.

AIMS OF THE REVIEW

This review aimed to update the traditional uses, phytochemistry, and pharmacology of A. truncatum, which expect to provide theoretical support for the future utilization as well as highlight the further investigation of this important plant.

MATERIALS AND METHODS

The ethnobotanical, phytochemical, and pharmacological information related to A. truncatum from 1949 to March 2021 were collated by surveying the traditional medicinal books and ethnomedicinal publications and searching the online databases including Google Scholar, Sci Finder, Web of Science, Springer Link, PubMed, Wiley, China National Knowledge Infrastructure (CNKI), Baidu Scholar, and Wan Fang Database.

RESULTS

A. truncatum has traditionally been used for medicinal, edible and ornamental purposes in northern China for many centuries. Different parts of the plant including leaves, fruits and bark, are mainly used as herbal medicine to treat hyperpiesia, hyperlipidemia, bruises, back pain, etc. A total of 288 compounds in A. truncatum, including polyphenols, organic acids or lipids, and biological volatile organic compounds were isolated or identified by phytochemical studies. Pharmacological research showed that A. truncatum has various bioactivities such as acetylcholinesterase inhibition, antibacterial, antioxidant, antitumor, and fatty acid synthase inhibition effects.

CONCLUSION

A. truncatum has been used as a traditional herbal medicine for centuries in northern China. Polyphenols, organic acids, lipids and other compounds were isolated or identified from different parts of the plant. Most of the pharmacological activities of A. truncatum have been reported, which showed its potential in the development of new drugs or nutraceuticals. However, detailed information on the molecular mechanisms, metabolic activity, and toxicology of active components is limited. Further comprehensive research to evaluate the medicinal properties of A. truncatum will be necessary.

Acer okamotoanum inhibits adipocyte differentiation by the regulation of adipogenesis and lipolysis in 3T3‑L1 cells

Acer okamotoanum is reported to have various antioxidant, anti‑inflammatory and beneficial immune system effects. The anti‑adipocyte differentiation effects and mechanisms of the ethyl acetate (EtOAc) fraction of an A. okamotoanum extraction was investigated in 3T3‑L1 adipocyte cells. Treatment with differentiation inducers increased the level of triglycerides (TGs) in 3T3‑L1 adipocyte cells compared with an untreated control. However, the EtOAc fraction of A. okamotoanum significantly decreased TGs. Treatment with 1, 2.5 and 5 µg/ml showed weak activity, but TG production was inhibited at 10 µg/ml compared with the control. In addition, A. okamotoanum caused a significant downregulation of proteins related to adipogenesis, such as γ‑cytidine‑cytidine‑adenosine‑adenosine‑thymidine/enhancer binding protein‑α, ‑β and peroxisome proliferator‑activated receptor‑γ, compared with the untreated control. Furthermore, A. okamotoanum significantly upregulated lipolysis related protein, hormone‑sensitive lipase and the phosphorylation of adenosine monophosphate‑activated protein kinase (AMPK). Therefore, these results indicate that A. okamotoanum suppressed adipogenesis and increased lipolysis and the activation of AMPK, suggesting a protective role in adipocyte differentiation.

Metabolic Profiling of Different Parts of Acer truncatum from the Mongolian Plateau Using UPLC-QTOF-MS with Comparative Bioactivity Assays

Acer truncatum is an important ornamental, edible, and medicinal plant resource in China. Previous phytochemical research has focused on the leaf (AL) due to its long history as a tea for health. Other parts such as the branch (ABr), bark (ABa), fruit (AF), and root (AR) have drawn little attention regarding their metabolites and bioactivities. The strategy of an in-house chemical library combined with Progenesis QI informatics platform was applied to characterize the metabolites. A total of 98 compounds were characterized or tentatively identified, including 63 compounds reported from this species for the first time. Principal component analysis showed the close clustering of ABr, ABa, and AR, indicating that they share similar chemical components, while AL and AF clustered more distantly. By multiple orthogonal partial least-squares discriminant analyses (OPLS-DA), 52 compounds were identified as potential marker compounds differentiating these different plant parts. The variable influence on projection score from OPLS-DA revealed that catechin, procyanidins B2 or B3, and procyanidins C1 or C2 are the significant metabolites in ABa extracts, which likely contribute to its antioxidant and cytotoxic activities.

Bioconversion of conjugated linoleic acid by Lactobacillus plantarum CGMCC8198 supplemented with Acer truncatum bunge seeds oil

Conjugated linoleic acid (CLA) isomers, c9, t11-CLA and t10, c12-CLA, have been proved to exhibit excellent biomedical properties for potential use in anti-cancer applications and in reducing obesity. Acer truncatum Bunge (ATB), which is rich in unsaturated fatty acids, including oleic acid, linoleic acid, and nervonic acid, is a new resource for edible oil. In the present study, we developed a new method for producing two CLA isomers from ATB-seed oil by fermentation using Lactobacillus plantarum CGMCC8198 (LP8198), a novel probiotics strain. Polymerase chain reaction results showed that there was a conserved linoleate isomerase (LIase) gene in LP8198, and its transcription could be induced by ATB-seed oil. Analyses by gas chromatography-mass spectrometry showed that the concentration of c9, t11-CLA and t10, c12-CLA in ATB-seed oil could be increased by about 9- and 2.25-fold, respectively, after being fermented by LP8198.

Response Surface Methodology Optimization of Ultrasonic-Assisted Extraction of Acer Truncatum Leaves for Maximal Phenolic Yield and Antioxidant Activity

This study is the first to report the use of response surface methodology to improve phenolic yield and antioxidant activity of Acer truncatum leaves extracts (ATLs) obtained by ultrasonic-assisted extraction. The phenolic composition in ATLs extracted under the optimized conditions were characterized by UPLC-QTOF-MS/MS. Solvent and extraction time were selected based on preliminary experiments, and a four-factors-three-levels central composite design was conducted to optimize solvent concentration (X₁), material-to-liquid ratio (X₂), ultrasonic temperature (X₃) and power (X₄) for an optimal total phenol yield (Y₁) and DPPH• antioxidant activity (Y₂). The results showed that the optimal combination was ethanol:water (v:v) 66.21%, material-to-liquid ratio 1:15.31 g/mL, ultrasonic bath temperature 60 °C, power 267.30 W, and time 30 min with three extractions, giving a maximal total phenol yield of 7593.62 mg gallic acid equivalent/100 g d.w. and a maximal DPPH• antioxidant activity of 74,241.61 μmol Trolox equivalent/100 g d.w. Furthermore, 22 phenolics were first identified in ATL extract obtained under the optimized conditions, indicating that gallates, gallotannins, quercetin, myricetin and chlorogenic acid derivatives were the main phenolic components in ATL. What's more, a gallotannins pathway existing in ATL from gallic acid to penta-O-galloylglucoside was proposed. All these results provide practical information aiming at full utilization of phenolics in ATL, together with fundamental knowledge for further research.

Traditional uses, phytochemistry, and pharmacology of the genus Acer (maple): A review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Acer (Aceraceae), commonly known as maple, comprises approximately 129 species that primarily grow in the northern hemisphere, especially in the temperate regions of East Asia, eastern North America, and Europe. These plants have been traditionally used to treat a wide range of diseases in East Asia and North America. Moreover, clinical studies have shown that medicinal plants belonging to Acer are highly effective in the treatment of rheumatism, bruises, hepatic disorders, eye disease, and pain, and in detoxification. This review provides a systematic and constructive overview of the traditional uses, chemical constituents, and pharmacological activities of plants of the genus Acer.

MATERIAL AND METHODS

This review is based on a literature study of scientific journals and books from libraries and electronic sources such as SciFinder, ScienceDirect, Springer, PubMed, CNKI, Google Scholar, Baidu Scholar, and Web of Science. The literature in this review related to chemical constituents and pharmacological activities dates from 1922 to the end of October 2015. Furthermore, ethnopharmacological information on this genus was obtained from libraries and herbaria in China and USA.

RESULTS

In traditional medicine, 40 species, 11 subspecies, and one varieta of the genus Acer are known to exhibit a broad spectrum of biological activities. To date, 331 compounds have been identified from 34 species of the genus Acer, including flavonoids, tannins, phenylpropanoids, diarylheptanoids, terpenoids, benzoic acid derivatives, and several other types of compounds, such as phenylethanoid glycosides and alkaloids. Preliminary pharmacological studies have shown that the extracts and compounds isolated from this genus exhibit a broad spectrum of biological activities such as antioxidant, antitumor, anti-inflammatory, antidiabetic, hepatoprotective, and antiobesity activities, as well as promoting osteoblast differentiation. To date, reports on the toxicity of Acer species to humans are very limited, and the major safety concern of these plants is in the veterinary field.

CONCLUSIONS

Based on our systematic review, Acer species can be used to treat rheumatism, hepatic disorders, eye disease, pain, etc. effectively. Some indications from ethnomedicine have been validated by pharmacological activities, such as the anti-inflammatory and hepatoprotective activities of the species. The available literature showed that most of the activities of these species can be attributed to flavonoids and tannins. To ensure the safety and efficacy in clinical practice in the future, studies identifying active molecules and clarifying their pharmacological mechanisms as well as toxicity are needed.

Inhibition of Rat 5α-Reductase Activity and Testosterone-Induced Sebum Synthesis in Hamster Sebocytes by an Extract of Quercus acutissima Cortex

Objective. Bokusoku (BK) is an extract from the Quercus cortex used in folk medicine for treatment of skin disorders and convergence, and is present in jumihaidokuto, a traditional Japanese medicine that is prescribed for purulent skin diseases like acne vulgaris. The excess of sebum production induced by androgen is involved in the development of acne. Our aim is to examine whether BK and its constituents inhibit testosterone metabolism and testosterone-induced sebum synthesis. Methods. Measurements of 5α-reductase activity and lipogenesis were performed using rat liver microsomes and hamster sebocytes, respectively. Results. BK dose-dependently reduced the conversion of testosterone to a more active androgen, dihydrotestosterone in a 5α-reductase enzymatic reaction. Twenty polyphenols in BK categorized as gallotannin, ellagitannin, and flavonoid were identified by LC-MS/MS. Nine polyphenols with gallate group, tetragalloyl glucose, pentagalloyl glucose, eugeniin, 1-desgalloyl eugeniin, casuarinin, castalagin, stenophyllanin C, (−)-epicatechin gallate, and (−)-epigallocatechin gallate, inhibited testosterone metabolism. In particular, pentagalloyl glucose showed the strongest activity. BK and pentagalloyl glucose suppressed testosterone-induced lipogenesis, whereas they weakly inhibited the lipogenic action of insulin. Conclusions. BK inhibited androgen-related pathogenesis of acne, testosterone conversion, and sebum synthesis, partially through 5α-reductase inhibition, and has potential to be a useful agent in the therapeutic strategy of acne.

Role of the Ah receptor in homeostatic control of fatty acid synthesis in the liver

We have previously demonstrated a role for the aryl hydrocarbon receptor (AHR) in the attenuation of the cholesterol biosynthesis pathway. This regulation did not require that the AHR binds to its cognate response element. Based on these observations and other reports depicting a role for AHR in lipid metabolism, we chose to investigate the involvement of the receptor in the regulation of the fatty acid synthesis pathway in mice and humans. For this purpose, C57BL/6J, liver-specific transgenic DRE-binding mutant AhR (A78D-AhrTtr CreAlb Ahrfx/fx) and CreAlb Ahrfx/fx mice were treated with an AHR ligand, and hepatic mRNA expression levels of key fatty acid genes (e.g., Acaca, Fasn, Scd1) were measured. The basal levels of those genes were also compared between C57BL6/J and hepatic AHR-deficient mice, as well as between Ahb and Ahd congenic mice. To extend these results to humans, fatty acid gene expression in human cells were compared with AHR-silenced cells. In addition, primary human hepatocytes were treated with an AHR ligand to assess alterations in gene expression and fatty acid synthesis. These studies indicated that the AHR constitutively attenuates the expression of key fatty acid synthesis genes in the absence of binding to its cognate response element. In addition, activation of AHR led to further repression of the expression of these genes and a decrease in overall fatty acid synthesis and secretion in human hepatocytes. Based on our results, we can conclude that increased AHR activity represses fatty acid synthesis, suggesting it may be a future therapeutic target.