Antioxidant and pancreatic lipase inhibitory effects of flavonoids from different citrus peel extracts: An in vitro study

Discovery of baicalein derivatives as novel inhibitors against human pancreatic lipase: Structure-activity relationships and inhibitory mechanisms

Human pancreatic lipase (hPL) is a vital digestive enzyme responsible for breaking down dietary fats in humans, inhibiting hPL is a feasible strategy for preventing and treating obesity. This study aims to investigate the structure-activity relationships (SARs) of flavonoids as hPL inhibitors, and to find potent hPL inhibitors from natural and synthetic flavonoids. In this work, the anti-hPL effects of forty-nine structurally diverse naturally occurring flavonoids were assessed and the SARs were summarized. The results demonstrated that the pyrogallol group on the A ring was a key moiety for hPL inhibition. Subsequently, a series of baicalein derivatives were synthesized, while 4'-amino baicalein (ABA) and 4'-pyrrolidine baicalein (PBA) were identified as novel potent hPL inhibitors (IC50 < 1 μM). Further investigations showed that scutellarein, ABA and PBA potently inhibited hPL in a non-competitive manner (Ki < 1 μM). Among all tested flavonoids, PBA showed the most potent anti-hPL effect in vitro, while this agent also exhibited favorable safety profiles, unique tissue distribution (high exposure level to intestinal system but low exposure levels to deep organs) and impressive in vivo effects for lowering blood triglyceride levels in mice. Collectively, this work uncovers the SARs of flavonoids against hPL, while a newly synthetic flavonoid (PBA) emerges as a potent hPL inhibitor with favorable safety profiles and impressive anti-hPL effects in vivo.

A narrative review on the mechanism of natural flavonoids in improving glucolipid metabolism disorders

Glucolipid metabolism disorder (GLMD) is a complex chronic disease characterized by glucose and lipid metabolism disorders with a complex and diverse etiology and rapidly increasing incidence. Many studies have identified the role of flavonoids in ameliorating GLMD, with mechanisms related to peroxisome proliferator-activated receptors, nuclear factor kappa-B, AMP-activated protein kinase, nuclear factor (erythroid-derived 2)-like 2, glucose transporter type 4, and phosphatidylinositol-3-kinase/protein kinase B pathway. However, a comprehensive summary of the flavonoid effects on GLMD is lacking. This study reviewed the roles and mechanisms of natural flavonoids with different structures in the treatment of GLMD reported globally in the past 5 years and provides a reference for developing flavonoids as drugs for treating GLMD.

Effects of different addition levels of CHM-JM113 on growth performance, antioxidant capacity, organ index, and intestinal health of AA broilers

The purpose of the present study was to investigate the effects of different levels of a Chinese herbal medicine formulation combined with JM113 (CHM-JM113) on growth performance, antioxidant capacity, organ index, and intestinal health of AA broilers. The AA broiler chicks were randomly allocated to 5 treatments as follows: a basic diet for the control group, the basic diet supplemented with 0.25% CHM-JM113, 0.5% CHM-JM113, 1% CHM-JM113 and 2% CHM-JM113 for the treatment group, respectively. The results showed that the addition of CHM-JM113 to the diet significantly reduced the mortality (p < 0.01) and improved the European Broiler Index (EBI) (p < 0.05), whereas it had no significance on growth performance of AA broilers (p > 0.05). Comparing the control group, 0.5 and 1% CHM-JM113 group significantly improved the organ index of liver, spleen and bursa (p < 0.05). In terms of intestinal morphology and structure, the addition of different levels of CHM-JM113 increased VH and VH/CD ratio, decreased CD in the small intestine compared to the control group, with 1 and 2% of the additive dose being more effective (p < 0.05). Chinese herbal medicine and probiotics as natural antioxidants also significantly increased the content of SOD in serum of 21-day-old broilers (p < 0.01), and significantly decreased the content of MDA in serum (p < 0.01). At 42 days of age, the addition of 1 and 2% CHM-JM113 significantly increased the content of SOD (p < 0.01) and significantly decreased the content of MDA in the organism (p < 0.01), accompanied by a significant increase in T-AOC and CAT content. In the study of the effect of CHM-JM113 on intestinal immunity, compared with the control group, we found that 1% or 2% CHM-JM113 had a better effect on the expression of occludin and claudin-1 in the intestinal segments of broilers (p < 0.05). For the expression of GATA-3, 0.5% CHM-JM113 may have a better effect (p < 0.05). CHM-JM113 may be used as an antibiotic alternative in broiler production.

Lemon Flavonoid Extract Eriomin Improves Pro/Antioxidant Status and Interferes with Cholesterol Metabolism without Affecting Serum Cholesterol Levels in Aged Rats

This study aimed to assess the antioxidant capacity of lemon flavonoid extract Eriomin® (LE) and its impact on cholesterol metabolism in the context of healthy aging. We orally treated 24-month-old male Wistar rats with an LE (40 mg/kg) suspended in 0.3 mL of sunflower oil. At the same time, control groups received an equal volume of sunflower oil (CON) or remained untreated (ICON) daily for 4 weeks. We examined LE's effects on superoxide dismutase and catalase- and glutathione-related enzyme activities, the concentration of lipid peroxides and protein carbonyls, total oxidant status (TOS) and antioxidant status (TAS), and oxidative stress index (OSI) in the liver, jejunum, and ileum. We also measured total cholesterol, its biosynthetic precursors (lanosterol, lathosterol, desmosterol), its degradation products (bile acid precursors) in the serum, liver, jejunum, and ileum, and serum phytosterols (intestinal absorption markers). LE reduced TOS, TAS, and OSI (p < 0.05) compared with control values, indicating its consistent antioxidant action in all examined organs. LE lowered hepatic desmosterol (p < 0.05) while also reducing 7α- and 24-hydroxycholesterol levels in the liver and ileum (p < 0.01). Serum cholesterol, hepatic gene expression, and the immunostaining intensity of CYP7A1 were unchanged. In conclusion, LE exerted non-enzymatic antioxidant effects and reduced cholesterol degradation, reducing its biosynthesis products, thereby maintaining serum cholesterol levels.

Inquiry lipaseoring the mechanism of pancreatic lipase inhibition by isovitexin based on multispectral method and enzyme inhibition assay

Isovitexin is a main natural flavonoid component in various plants. Currently, the inhibitory effect of isovitexin on pancreatic lipase (PL) and its mechanism have not been elucidated yet. In the present study, we investigated the inhibitory effect of isovitexin on PL, as well as its interaction mechanism, using enzyme inhibition methods, spectroscopic analysis, and molecular simulations. Results showed that isovitexin possessed significant PL inhibitory activity, with IC50 values of 0.26 ± 0.02 mM. The interaction between isovitexin and PL was dominated by static quenching, and mainly through hydrogen bonding and hydrophobic interaction forces. Analysis of fluorescence spectroscopy confirmed that isovitexin binding altered the conformation of the PL. Circular dichroism (CD) spectrum indicated that isovitexin altered the secondary structure of PL by decreasing the α-helix content and increasing the β-fold content. Molecular simulations further characterize the conformational changes produced by the interaction between isovitexin with PL. The performed study may provide a new insight into the inhibitory mechanism of isovitexin as a novel PL inhibitor.

Total Content and Composition of Phenolic Compounds from Filipendula Genus Plants and Their Potential Health-Promoting Properties

This current article was dedicated to the determination of the composition of phenolic compounds in extracts of four species of the genus Filipendula in order to establish a connection between the composition of polyphenols and biological effects. A chemical analysis revealed that the composition of the extracts studied depended both on the plant species and its part (leaf or flower) and on the extractant used. All four species of Filipendula were rich sources of phenolic compounds and contained hydrolyzable tannins, condensed tannins, phenolic acids and their derivatives, and flavonoids. The activities included data on those that are most important for creating functional foods with Filipendula plant components: the influence on blood coagulation measured by prothrombin and activated partial thromboplastin time, and on the activity of the digestive enzymes (pancreatic amylase and lipase). It was established that plant species, their parts, and extraction methods contribute meaningfully to biological activity. The most prominent result is as follows: the plant organ determines the selective inhibition of either amylase or lipase; thus, the anticoagulant activities of F. camtschatica and F. stepposa hold promise for health-promoting food formulations associated with general metabolic disorders.

Influence of industrial blanching, cutting, and freezing treatments on in vitro gastrointestinal digestion stability of orange (Citrus sinensis L.) and lemon (Citrus limon L.) peel polyphenols

BACKGROUND

Citrus peels, which are often discarded as waste in the food-processing industry, are rich sources of polyphenols. The aim of the current study was to investigate the influence of an industrial freezing process along with blanching and cutting pretreatments on the in vitro gastrointestinal digestion stability of orange (Citrus sinensis L.) and lemon (Citrus limon L.) peel polyphenols. The major polyphenols were identified and quantified with ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) and high performance liquid chromatography-photodiode array detector (HPLC-PDA), respectively.

RESULTS

The results revealed that hesperidin and chlorogenic acid were the predominant flavonoid and phenolic acids in orange peels whereas, for lemon peels, eriocitrin and caffeic acid were the dominant flavonoid and phenolic acids, respectively. Blanching pretreatment enhanced the levels of major flavonoids in orange and lemon peels (by 39-82% and 54-146%, respectively) (P < 0.05) after in vitro gastrointestinal digestion. On the other hand, the application of cutting treatment after blanching significantly reduced the levels of flavonoids (23-62%) (P < 0.05); however, there was no statistically significant difference between the phenolic acid levels of cut and uncut citrus peels. Overall, the bioaccessibility of individual flavonoids and phenolic acids from frozen orange peels was generally slightly lower than that of untreated peels (9-34% and 9-49%, respectively). Nevertheless, frozen lemon peels contained higher bioaccessible flavonoids and phenolic acids in comparison with untreated peels (40-172% and 32-98%, respectively).

CONCLUSION

These results suggest that industrial freezing steps could largely preserve the bioaccessibility of polyphenols in orange and lemon peels. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Mandarin peel ethanolic extract attenuates diclofenac sodium induced hepatorenal toxicity in rats by mitigating oxidative stress and inflammation

Nonsteroidal anti-inflammatory drugs (NSAIDs) constitute approximately one-third of the global pharmaceutical market and are the first drugs of choice when treating fever and pain. Furthermore, among NSAIDs, the use of diclofenac sodium (DS) is preferred as it is a strong inhibitor of cyclooxygenase enzyme. However, despite its strong efficacy, DS is known for its potential to cause hepatorenal damage. Currently, to mitigate the adverse effects of certain drugs, medically effective agricultural products are often preferred as they are inexpensive, effective and safe. One such agricultural product-mandarin-is noteworthy for its high phenolic contents. The purpose of the present study was to assess the efficacy of mandarin peel ethanolic extract (MPEE) in protecting against hepatorenal damage induced by DS. Four groups (six/group) of adult male albino rats received oral administration of physiological saline (control group), DS (10 mg/kg body weight), MPEE (200 mg/kg body weight), and DS + MPEE for 7 days. Rats in the DS group showed increased serum levels of ALT, AST, ALP, BUN, CRE, and UA. Furthermore, the hepatic and renal tissue levels of MDA, TNF-α and IL-1β increased, whereas those of GSH, SOD, GP-x and IL-10 decreased (p < 0.05). Investigation of MPEE in terms of its effects on biochemical, oxidative and inflammatory parameters, it exerted protective and healing effects. Therefore, MPEE can be used to ameliorate DS-induced hepatorenal damage.

Selenizing chitooligosaccharide with site-selective modification to alleviate acute liver injury in vivo

Two selenized chitooligosaccharide (O-Se-COS and N,O-Se-COS) with different sites modification were synthesized to alleviate liver injury in vivo. Comparing to traditional COS, both selenized COS exhibited enhanced reducibility as well as antioxidant capacity in vitro. Furthermore, O-Se-COS demonstrated superior efficacy in reducing intracellular reactive oxygen species (ROS) and mitochondrial damage compared to N,O-Se-COS as its enhanced cellular uptake by the positive/negative charge interactions. Two mechanisms were proposed to explained these results: one is to enhance the enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), which effectively scavenge free radicals; the other is to down-regulate intracellular cytochrome P450 (CYP2E1) levels, inhibiting carbon tetrachloride (CCl4)-induced peroxidation damage. In vivo studies further demonstrated the effective alleviation of CCl4-induced liver injury by selenized COS, with therapeutic efficacy observed in the following order: O-Se-COS > N,O-Se-COS > COS. Finally, hemolysis and histological tests confirmed the biosafety of both selenized COS. Taken together, these finding demonstrated that selenium has the potential to improve the biological activity of COS, and precise selenylation was more conducive to achieving the synergistic effect where 1 + 1>2.

Antioxidant and anti-inflammatory activity through inhibition of NF-κB and sEH of some citrus peel and phytoconstituent characteristics

In Indonesia, there are many types of citrus where parts of the fruit, leaves, and peel can be utilized as food, drinks, spices, and medicine. This research aims to determine the phytochemical characteristics, antioxidant activities, and anti-inflammatory activity through inhibition of NF-κB and sEH, and the main phytoconstituents of three types of citrus fruits that are commonly used as herbs in Indonesia. The flesh and peel of Citrus amblycarpa/CAm, C. aurantiifolia/CAu, and C. hystrix/CH were extracted by Ultrasound-Assisted Extraction (UAE) with 70 % ethanol and then concentrated. All extracts were tested for total flavonoid content (TFC), total polyphenolic content (TPC), chemical constituents using LCMS, and DPPH radical scavenging activity. Molecular docking tests of 33 compounds containing CAm, CAu, and CH fruit peels from the literature study against NF-κB (Nuclear Factor Kappa Beta) and sEH (Soluble Epoxide Hydrolase) were also conducted. The TFC in fruit peels was 13.47-17.34 mg QE/g extract, and in flesh was 1.35-2.51 mg QE/g extract. The TPC in fruit peels was 4.28-6.3 mg GAE/g extract, and in flesh was 0.85-2.09 mg GAE/g extract. The IC50 values of antioxidant activity on fruit peel were 74.01-168.54 µg/mL; and flesh 185.62-2669 µg/mL. CAu peels provided the highest antioxidant activity and polyphenol content. The LC-MS/MS test on citrus peels shows the main chemical compounds: naringin (C27H32O14), naringenin (C15H12O5), hesperidin (C28H34O15), and hesperitin (C16H14O6). Molecular docking shows that naringin and neohesperidin predicted inhibit NF-κB, and hesperidin, neohesperidin, narirutin, naringin, apigenin, kaempferol, quercetin, rutin, eriocitrin, sinensetin, and vitamin A predicted can inhibit sEH enzyme. All citrus peel has stronger antioxidant activity and more flavonoids and phenolics than the flesh. Naringin and neohesperidin can inhibit NF-κB and sEH enzymes. The main flavonoid contents of the citrus peels and presumed to have activity are hesperidin and naringin. These flavonoids and their glycosides can be used as marker phytoconstituents in the quality assurance of pharmaceutical products.

Antioxidative, Metabolic and Vascular Medicinal Potentials of Natural Products in the Non-Edible Wastes of Fruits Belonging to the Citrus and Prunus Genera: A Review

Diabetes mellitus and related metabolic and vascular impairments are notable health problems. Fruits and vegetables contain phenolics that are beneficial to metabolic and oxidative health and useful in preventing associated disease. Scientific evidence has shown that some bioactive phenolics are more abundant in the non-edible parts (especially the peels) of many fruits than in their respective edible tissues. Fruits belonging to the Citrus and Prunus genera are commonly consumed worldwide, including in South Africa, and their non-edible wastes (peel and seed) have been shown to have antioxidative, metabolic and vascular pharmacological potentials and medicinal phytochemistry. It is therefore imperative to evaluate the pharmacological actions and phytochemical properties of the non-edible wastes of these fruits and understand how they could potentially be of medicinal relevance in oxidative, metabolic and vascular diseases, including diabetes, oxidative stress, obesity, hypertension and related cardiovascular impairments. In the absence of a previous review that has concomitantly presented the medicinal potentials of fruits wastes from both genera, this review presents a critical analysis of previous and recent perspectives on the medicinal potential of the non-edible wastes from the selected Citrus and Prunus fruits in metabolic, vascular and oxidative health. This review further exposes the medicinal phytochemistry, while elucidating the underlying mechanisms through the fruit wastes potentiates their therapeutic effects. A literature search was carried out on "PubMed" to identify peer-reviewed published (mostly 2015 and beyond) studies reporting the antidiabetic, antioxidative, antihypertensive, anti-hyperlipidemic and anti-inflammatory properties of the non-edible parts of the selected fruits. The data of the selected studies were analyzed to understand the bioactive mechanisms, bioactive principles and toxicological profiles. The wastes (seed and peel) of the selected fruits had antioxidant, anti-obesogenic, antihypertensive, anti-inflammatory, antidiabetic and tissue protective potentials. Some phenolic acids and terpenes, as well as flavonoids and glycosides such as narirutin, nobiletin, hesperidin, naringin, naringenin, quercetin, rutin, diosmin, etc., were the possible bioactive principles. The peel and seed of the selected fruits belonging to the Citrus and Prunus genera are potential sources of bioactive compounds that could be of medicinal relevance for improving oxidative, metabolic and vascular health. However, there is a need for appropriate toxicological studies.

Chemical Constituents and α-Glucosidase Inhibitory, Antioxidant and Hepatoprotective Activities of Ampelopsis grossedentata

Ampelopsis grossedentata is a valuable medicinal and edible plant, which is often used as a traditional tea by the Tujia people in China. A. grossedentata has numerous biological activities and is now widely used in the pharmaceutical and food industries. In this study, two new flavonoids (1-2) and seventeen known compounds (3-19) were isolated and identified from the dried stems and leaves of A. grossedentata. These isolated compounds were characterized by various spectroscopic data including mass spectrometry and nuclear magnetic resonance spectroscopy. All isolates were assessed for their α-glucosidase inhibitory, antioxidant, and hepatoprotective activities, and their structure-activity relationships were further discussed. The results indicated that compound 1 exhibited effective inhibitory activity against α-glucosidase, with an IC50 value of 0.21 μM. In addition, compounds 1-2 demonstrated not only potent antioxidant activities but also superior hepatoprotective properties. The findings of this study could serve as a reference for the development of A. grossedentata-derived products or drugs aimed at realizing their antidiabetic, antioxidant, and hepatoprotective functions.

Research advances in citrus polyphenols: green extraction technologies, gut homeostasis regulation, and nano-targeted delivery system application

Citrus polyphenols can modulate gut microbiota and such bi-directional interaction that can yield metabolites such as short-chain fatty acids (SCFAs) to aid in gut homeostasis. Such interaction provides citrus polyphenols with powerful prebiotic potential, contributing to guts' health status and metabolic regulation. Citrus polyphenols encompass unique polymethoxy flavonoids imparting non-polar nature that improve their bioactivities and ability to penetrate the blood-brain barrier. Green extraction technology targeting recovery of these polyphenols has received increasing attention due to its advantages of high extraction yield, short extraction time, low solvent consumption, and environmental friendliness. However, the low bioavailability of citrus polyphenols limits their applications in extraction from citrus by-products. Meanwhile, nano-encapsulation technology may serve as a promising approach to improve citrus polyphenols' bioavailability. As citrus polyphenols encompass multiple hydroxyl groups, they are potential to interact with bio-macromolecules such as proteins and polysaccharides in nano-encapsulated systems that can improve their bioavailability. This multifaceted review provides a research basis for the green and efficient extraction techniques of citrus polyphenols, as well as integrated mechanisms for its anti-inflammation, alleviating metabolic syndrome, and regulating gut homeostasis, which is more capitalized upon using nano-delivery systems as discussed in that review to maximize their health and food applications.

Soluble polysaccharides decrease inhibitory activity of banana condensed tannins against porcine pancreatic lipase

The inhibition of soluble polysaccharides (SPs) (arabic gum, dextran and pectin from citrus) on the binding between banana condensed tannins (BCTs) and pancreatic lipase (PL) was studied from variant aspects. Molecular docking simulations predicted that BCTs strongly bound SPs and PL through non-covalent interactions. The experimental results showed that SPs reduced the inhibition of BCTs on PL, and the IC₅₀ value increased. However, the addition of SPs did not change the inhibitory type of BCTs on PL, which all were non-competitive inhibition. BCTs quenched PL fluorescence through static quenching mechanism and changed the secondary structure of PL. The addition of SPs alleviated the trending. The effect of SPs on the binding of BCTs-PL was mainly due to the strong non-covalent interaction between SPs and BCTs. This study emphasized that attention should be paid to the counteracting effects of polysaccharides and polyphenols in dietary intake to maximize their respective roles.

Research Progress of Immunomodulation on Anti-COVID-19 and the Effective Components from Traditional Chinese Medicine

SARS-CoV-2 has posed a threat to the health of people around the world because of its strong transmission and high virulence. Currently, there is no specific medicine for the treatment of COVID-19. However, for a wide variety of medicines used to treat COVID-19, traditional Chinese medicine (TCM) plays a major role. In this paper, the effective treatment of COVID-19 using TCM was consulted first, and several Chinese medicines that were frequently used apart from their huge role in treating it were found. Then, when exploring the active ingredients of these herbs, it was discovered that most of them contained flavonoids. Therefore, the structure and function of the potential active substances of flavonoids, including flavonols, flavonoids, and flavanes, respectively, are discussed in this paper. According to the screening data, these flavonoids can bind to the key proteins of SARS-CoV-2, 3CLpro, PLpro, and RdRp, respectively, or block the interface between the viral spike protein and ACE2 receptor, which could inhibit the proliferation of coronavirus and prevent the virus from entering human cells. Besides, the effects of flavonoids on the human body systems are expounded on in this paper, including the respiratory system, digestive system, and immune system, respectively. Normally, flavonoids boost the body's immune system. However, they can suppress the immune system when over immunized. Ultimately, this study hopes to provide a reference for the clinical drug treatment of COVID-19 patients, and more TCM can be put into the market accordingly, which is expected to promote the development of TCM on the international stage.

Antioxidants from different citrus peels provide protection against cancer

Cancer is one of the leading causes of death. Despite significant advancements in the discovery of medications for the treatment of cancer, these drugs are hindered by applicability and efficacy issues and frequently exhibit major side effects that can further impair patients 'quality of life. Therefore, the development of therapeutically sound anti-cancer medicines derived from natural products has gained prominence in the field of functional foods. Some of these compounds have shown efficacy in the prevention and treatment of cancer as well as low toxicity. Additionally, many recent studies have explored the recycling of agro-industrial waste to create bioactive chemicals. Citrus peels are produced in vast quantities in the food processing sector; due to their abundance of flavonoids, they may be inexpensive sources of protection against several cancers. Citrus is a common type of fruit that contains a variety of nutrients. In particular, the antioxidant chemicals found in citrus peel have been identified as potential cancer-fighting agents. Antioxidant substances such as flavonoids prevent the development of cancer by inhibiting the metastatic cascade, decreasing the mobility of cancer cells in the circulatory system, promoting apoptosis, and suppressing angiogenesis. To explore the most effective uses of citrus peel-derived antioxidants, this review presents background information, an overview of the role of citrus antioxidants in cancer therapy, and a discussion of the key underlying molecular mechanisms.

Classification of Pericarpium Citri Reticulatae (Chenpi) age using surface-enhanced Raman spectroscopy

Pericarpium Citri Reticulatae (PCR) is used in food and medical herbal formula, and its quality is determined by its age. Raman spectroscopy is a laser technology for molecular fingerprinting. The feasibility of using surface-enhanced Raman spectroscopy (SERS) to determine the PCR age was investigated. The Raman peaks were acquired using a Raman spectrometer with a 785 nm diode laser and were analyzed using principal component analysis (PCA) followed by linear discriminant analysis (PCA-LDA). There were six major peaks at 600, 730, 990, 1370, 1607, and 1742 cm^-1 in the SERS spectra, and their intensity, especially the peak at 1607 cm^-1, was inversely correlated with the PCR age. The different ages of PCR could be correctly classified with over 90 % accuracy by using PCA-LDA based on the SERS spectra. In conclusion, a Raman spectrometer may be used as a novel method to identify the age of PCR products.

Role of flavonoids in controlling obesity: molecular targets and mechanisms

Obesity presents a major health challenge that increases the risk of several non-communicable illnesses, such as but not limited to diabetes, hypertension, cardiovascular diseases, musculoskeletal and neurological disorders, sleep disorders, and cancers. Accounting for nearly 8% of global deaths (4.7 million) in 2017, obesity leads to diminishing quality of life and a higher premature mortality rate among affected individuals. Although essentially dubbed as a modifiable and preventable health concern, prevention, and treatment strategies against obesity, such as calorie intake restriction and increasing calorie burning, have gained little long-term success. In this manuscript, we detail the pathophysiology of obesity as a multifactorial, oxidative stress-dependent inflammatory disease. Current anti-obesity treatment strategies, and the effect of flavonoid-based therapeutic interventions on digestion and absorption, macronutrient metabolism, inflammation and oxidative stress and gut microbiota has been evaluated. The use of several naturally occurring flavonoids to prevent and treat obesity with a long-term efficacy, is also described.

Comparative study on secondary metabolites from different citrus varieties in the production area of Zhejiang

To investigate the distribution pattern of bioactive components and their correlations between citrus varieties, we thoroughly analyzed secondary metabolites (including flavonoids, phenolic acids, carotenoids, and limonoids) in the peel and pulp of 11 citrus varieties from the production area of Zhejiang. Citrus peels accumulated metabolites far more than the pulp, and the accumulation varied significantly between species. Flavonoids were the most abundant compounds, followed by phenolic acids, with carotenoids and limonoids being far less abundant than the first two, but limonoids were more abundant than carotenoids. Hesperidin was the main flavonoid in most varieties, but cocktail grapefruit and Changshanhuyou contained naringin, with Ponkan having the most abundant polymethoxylated flavones (PMFs). The major components of phenolic acids, carotenoids, and limonoids were ferulic acid, β-cryptoxanthin, and limonin, respectively. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) indicated that these components were mostly correlated with each other, and these citrus varieties could be categorized into four groups by pulp and three groups by peel. The obtained results filled the data gap for secondary metabolites from local citrus and could provide data references for citrus resource utilization, selection and breeding of superior varieties, and other research.

Molecular structures, chemical descriptors, and pancreatic lipase (1LPB) inhibition by natural products: a DFT investigation and molecular docking prediction

Density functional theory (DFT) calculations and molecular docking have been carried out on natural products containing eugenol, gingerol, ascorbic acid, oleurpoein, piperine, hesperidin, quercetin, Luteolin, and curcumin in order to predict their biological activities and to analyze their pancreatic lipase inhibition. The biological activity predictions are based on the global and local chemical descriptors, namely, HOMO-LUMO gaps, chemical hardness, chemical potential, electrophilicity, dipole moment, and Fukui functions. Our findings show that the studied compounds can be divided into two groups based on the chemical descriptors; the first group is composed of eugenol, gingerol, ascorbic acid, and oleuropein and the second one is composed of piperine, hesperidin, quercetin, Luteolin, and curcumin depending on the HOMO-LUMO gaps and electrophilicity values predicting best reactivity for the second group than the first one. The frontier orbitals offer a deeper insight concerning the electron donor and electron acceptor capabilities, whereas the local descriptors resulting from Fukui functions put emphasis on the active sites of different candidate ligands. The molecular docking was performed in order to compare and identify the inhibition activity of the natural candidate ligands against pancreatic lipase which were compared to that of synthesized ones. The molecular docking results revealed that the Luteolin compound has the best binding affinity of -8.56 kcal/mol due to their unique molecular structure and the position of -OH aromatic substituents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11224-023-02176-2.

Screening and identification of lipase inhibitors extracted from Dioscorea nipponica Makino by UV-vis and HPLC coupled to UPLC-Q-TOF-MS/MS

Dioscoreae nipponica Makino (D. nipponica) as the rhizome of dioscoreaceae rich in steroidal saponins, has been reported to have the hypolipidemic effects etc. However, it is still unclear which exact active components are primary responsible for the beneficial effects. This study was conducted to fish out the lipase inhibitors from D. nipponica, and evaluate the inhibitory activity on porcine pancreatic lipase (PPL) through in vitro kinetic assay using p-nitrophenyl palmitate as substrate. Accordingly, the ethanolic extract was subjected to D101 macroporous resin purification for spectrophotometric screening, high performance liquid chromatography (HPLC) separation and structural characterization by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Through orlistat validation, the PPL inhibitory activity and IC₅₀ value of the extract were respectively 68.34 ± 1.47 % and 107.05 μg/mL under the optimized inhibition conditions. From 6 steroidal saponins identified, the inhibitory components named the protodioscin, protogracillin, dioscin and gracillin were fished out by grouping separation and HPLC analysis. Furthermore, dioscin and gracillin with the parent structure of diogenin were confirmed as the major inhibitors by virtue of stability tests based on transformation of protodioscin and protogracillin. Finally, the inhibitory mechanism of the major inhibitors toward PPL was further clarified by kinetic analysis and molecular docking analysis. The proposed method not only revealed the PPL inhibitory components in D. nipponica, but also provided an effective approach to hierarchical screening of PPL inhibitors from natural plants.

Exploring the binding effects and inhibiting mechanism of hyperoside to lipase using multi-spectroscopic approaches, isothermal titration calorimetry, inhibition kinetics and molecular dynamics

Hyperoside (HYP) is a flavonoid with various physiological activities. The present study examined the interaction mechanism between HYP and lipase using multi-spectrum and computer-aided techniques. Results demonstrated that the force type of HYP on lipase was mainly hydrogen bond, hydrophobic interaction force, and van der Waals force, and HYP had an excellent binding affinity with lipase at 1.576 × 10⁵ M^-1. HYP dose-dependently inhibited lipase in the inhibition experiment, and its IC₅₀ value was 1.92 × 10^-3 M. Moreover, the results suggested that HYP could inhibit the activity by binding to essential groups. Conformational studies indicated that the conformation and microenvironment of lipase were slightly changed after the addition of HYP. Computational simulations further confirmed the structural relationships of HYP to lipase. The interaction between HYP and lipase can provide ideas for the development of functional foods related to weight loss. The results of this study help comprehend the pathological significance of HYP in biological systems, as well as its mechanism.

Digestive and gastroprotective effects of Achillea erba-rotta subsp. moschata (Wulfen) I.Richardson (syn. A. moschata Wulfen) (Asteraceae): From traditional uses to preclinical studies

ETHNOPHARMACOLOGICAL RELEVANCE

Achillea erba-rotta subsp. moschata (Wulfen) I.Richardson (syn. A. moschata Wulfen) (Asteraceae) is an alpine endemic plant whose aerial parts are harvested by the locals mainly for the digestive properties. Despite its widespread use, few studies have been conducted to date to verify its bioactivity.

AIM OF THE STUDY

The purpose of the work was to meet the tradition confirming with experimental data the popular belief that the consumption of this species offers beneficial effects to the gastrointestinal system.

MATERIALS AND METHODS

Using Soxhlet apparatus, the dried aerial parts of A. erba-rotta subsp. moschata were successively extracted with petroleum ether (PET), dichloromethane (DCM) and methanol (MeOH). The essential oil (EO) was obtained by hydrodistillation using a Clevenger apparatus while infusion (AE) was prepared following the traditional local recipe. Their chemical characterization was performed by various techniques including SPME-GC/MS, GC/MS and HPLC/MS-MS. An in vitro biological screening was carried out. The influence of AE on lipid digestion was monitored by titration of free fatty acids (FFA) during pancreatic lipase activity with the pH-stat method. For all extracts and EO, the anti-Helicobacter pylori activity was assessed by the broth microdilution method, the influence on cell viability was evaluated against NCI-N87, OE21 and Caco-2 cell lines and a preliminary toxicity evaluation was done using Brine Shrimp lethality (BSL) assay. The anti-inflammatory potential was evidenced by interleukin IL-1- induced IL8 expression on Caco-2 cells.

RESULTS

AE increased by 15% the FFA releasing compared to the pancreatic lipase alone. PET, DCM and MeOH extracts as well as AE and EO were considered active against the growth of both antimicrobial susceptible and resistant strains of H. pylori with MIC values starting from 16 μg/mL. PET and DCM (IC₅₀ = 89 μg/mL and 96 μg/mL, respectively, against Caco-2 cell line) extracts showed the high effect on cell viability while the EO reduced in 50% of cell viability at 1.48 μL/mL (NCI-N87 cells), 1.42 μL/mL (OE21 cells), and 3.44 μL/mL (Caco-2 cells) corroborating the BSL results. In different degrees, all extracts and EO inhibited the IL-1β-stimulated IL-8 production in Caco-2 cells.

CONCLUSIONS

The obtained data are encouraging and provide a scientific basis for the traditional use of A. erba-rotta subsp. moschata as a digestive agent although they need to be further corroborated by studies involving the investigation of both the in vivo activities and the role of the compounds detected in the extracts.

Evaluation of the impact of hydrogen-rich water on the quality attribute notes of butter

The effects of washing raw butter with hydrogen-rich water (HRW), prepared with hydrogen (H₂) and/or magnesium (Mg), on butter quality were investigated in this research paper. During the washing process, titratable acidity (TA) decreased by 12% for all washed samples. During the storage period, TA increased by 28% and 93% (control), 14% and 58% (H₂), and 10% and 66% (Mg) for the 60^th and 90^th days, respectively. Peroxide value (mEq O₂/kg) increased to 2.76 and 8.83 (control), 1.92 and 7.25 (H₂), and 2.02 and 8.12 (Mg) for the 60^th and 90^th days. HRW samples showed the lowest acid degree value (ADV) and the highest color notes (L*, C*, and h). The HRW treatment of raw butter has shown improving effects on the product without any harmful residuals in the final product or the environment.

The flavonoid profiles in the pulp of different pomelo (Citrus grandis L. Osbeck) and grapefruit (Citrus paradisi Mcfad) cultivars and their in vitro bioactivity

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Fourteen flavonoid compounds were detected in pomelo and grapefruit pulp.

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The flavonoid profiles in pomelo and grapefruit pulp had varietal difference.

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Flavonoids of pomelo and grapefruit showed strong cellular antioxidant activity.

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Flavonoids of pomelo and grapefruit are good inhibitors of pancreatic lipase.

Previous results indicated that the flavonoid profiles might have varietal differences in pomelo, but detailed information is unknown. We previously isolated 4 new flavonoids, cigranoside C, D, E, F, in Citrus grandis Shatianyu pulp. However, their distribution in different pomelo cultivars remains to be explored. Therefore, the flavonoid profiles and in vitro bioactivity of the pulp from 5 pomelo and 1 grapefruit cultivars commonly consumed in China were investigated. Fourteen flavonoids were identified, cigranoside C, D, E were detected in these pomelo and grapefruit. Naringin and cigranoside C were the major flavonoids in grapefruit, Guanximiyu-W, Guanximiyu-R and Liangpingyu, while melitidin and rhoifolin was the predominant flavonoid in Shatianyu and Yuhuanyu, respectively. Pomelo and grapefruit showed strong antioxidant activity, and were potent inhibitors of pancreatic lipase with IC₅₀ values of 11.4–72.6 mg fruit/mL except Shatianyu. Thus, pomelo and grapefruit are natural antioxidants and possess anti-obesity potential.

In vitro determination of anti-lipidemic, anti-inflammatory, and anti-oxidant properties and proximate composition of range of millet types and sorghum varieties in Sri Lanka

Methanolic extracts of whole grains of five millet types and two sorghum varieties were evaluated for anti-lipidemic, anti-inflammatory, and a range of anti-oxidant properties in vitro (n = 3 each). Furthermore, proximate composition (n = 3 each) was also studied. Results showed significant differences (P &lt; 0.05) among the selected samples for studied parameters. Pancreatic lipase and cholesterol esterase inhibitory activities of selected samples (2 mg/ml) ranged from 21.16 ± 1.58 to 66.65 ± 3.30 and 17.43 ± 0.60 to 52.09 ± 1.61%, respectively. Nitric oxide inhibitory activity of selected samples (2 mg/ml) ranged from −1.17 ± 0.32 to 13.56 ± 0.93%. Total polyphenolic content (TPC), total flavonoid content (TFC), and total proanthocyanidin content (TPAC) were in the range of 0.19 ± 0.01–12.50 ± 0.87 mg gallic acid equivalents/g, 0.05 ± 0.00–1.57 ± 0.01 mg quercetin equivalents/g, and 0.35 ± 0.01–12.87 ± 0.25 mg cyaniding equivalents/g of samples, respectively. Ferric reducing anti-oxidant power, oxygen radical absorbance capacity, ferrous ion chelating activity, and ABTS and DPPH anti-oxidant properties ranged from 0.15 ± 0.00 to 4.56 ± 0.03 mg of Trolox equivalents (TEs)/g, 0.19 ± 0.01 to 8.50 ± 0.72 mg of TEs/g, 0.13 ± 0.00 to 0.79 ± 0.03 mg EDTA equivalents/g, 0.22 ± 0.00 to 25.57 ± 0.35 mg of TEs/g, and 0.07 ± 0.00 to 22.97 ± 0.83 mg of TEs/g of samples, respectively. Among the studied samples, pigmented sweet sorghum exhibited the highest activities for all the tested parameters. The observed activities were moderate compared to the reference standards used. The highest values for proximate composition parameters tested varied with the different samples studied. In conclusion, the consumption of especially pigmented millet and sorghum in Sri Lanka may play an important role in the prevention and management of oxidative stress–associated chronic diseases. This is the first study to report pancreatic lipase and cholesterol esterase inhibitory activities of any millet types and sorghum varieties in Sri Lanka and the first report of cholesterol esterase inhibitory activity of millet and sorghum the world over.

Value-Added Utilization of Citrus Peels in Improving Functional Properties and Probiotic Viability of Acidophilus-bifidus-thermophilus (ABT)-Type Synbiotic Yoghurt during Cold Storage

Citrus peel, a fruit-processing waste, is a substantial source of naturally occurring health-promoting compounds, including polyphenols, and has great potential as a dietary supplement for enhancing the functional properties of food. The present work aimed to investigate the effects of sour orange (SO), sweet orange (SWO), and lemon (LO) peels on the typical physiochemical, antioxidant, antibacterial, and probiotic properties of synbiotic yoghurt fermented by acidophilus-bifidus-thermophilus (ABT)-type cultures during cold storage (0−28 days). High-performance liquid chromatography-diode array detection (HPLC-DAD) analysis showed that the total phenolic content in the SO peel were more than 2-fold higher than that in the SWO and LO peel. The predominant phenolic compounds were myricetin (2.10 mg/g dry weight) and o-coumaric acid (1.13 mg/g) in SO peel, benzoic acid (0.81 mg/g) and naringin (0.72 mg/g) in SWO peel, and benzoic acid (0.76 mg/g) and quercetin (0.36 mg/g) in LO peel. Only 0.5% (w/w) of citrus peel addition did not reduce the overall acceptance of ABT synbiotic yoghurt but led to increased acidity and decreased moisture during cold storage (14 and 28 days). Additionally, compared to control samples without citrus peel addition, supplementation with citrus peels improved the antioxidant property of the ABT synbiotic yoghurt. ABT milks with SO and SWO peel addition had significantly stronger DPPH radical scavenging activities than that with LO peel addition (p < 0.05). Antibacterial analysis of ABT synbiotic yoghurt with citrus peel addition showed that the diameters of inhibition zones against S. aureus, B. subtilis, and E. coli increased by 0.6−1.9 mm relative to the control groups, suggesting the enhancement of antibacterial activities by citrus peels. The viabilities of probiotic starter cultures (L. acidophilus, S. thermophilus, and Bifidobacterial sp.) were also enhanced by the incorporation of citrus peels in synbiotic yoghurt during cold storage. Hence, our results suggest that citrus peels, especially SO and SWO peels, could be recommended as a promising multifunctional additive for the development of probiotic and synbiotic yoghurt with enhanced antioxidant and antibacterial properties, as well as probiotic viability.

Comparison of characterization and antioxidant activity of different citrus peel pectins

Pectins obtained from citrus peel of different cultivars and growth regions were compared based on physicochemical properties and antioxidant activity in vitro. The physicochemical features were elucidated using Fourier transform infrared (FT-IR), molecular weight distribution, monosaccharide composition, thermal behaviors and flow behaviors. Results showed that the different cultivars and growing areas have significant effects on the properties of citrus peel pectins (CPPs). Citrus peel pectins extracted by acetic acid were highly heterogeneous polysaccharides with broad molecular weight distributions and had high proportions of the RG-I domain. Among the 10 kinds of citrus peel pectins, Shatangju (CPP-6) and Xuecheng (CPP-7) own superior antioxidant biological activity and Dahongpao (CPP-3) and Buzhihuo (CPP-9) had excellent functional properties (thermal stability and viscosity). According to the correlation analysis, molecular weight, galacturonic acid content and degree of methyl-esterification were beneficial to increase the thermal stability and viscosity of citrus peel pectins, while the rhamnose content, rhamnogalacturonan I region and lower molecular weight can improve citrus peel pectins antioxidant activity. Our findings suggest that CPP-6 and CPP-7 may be useful as a potential natural antioxidant in pharmaceutical and cosmetic industries. Meanwhile, CPP-3 has great application potential in high temperature food and CPP-9 can be used as a thickener or stabilizer in the food industry.

Flavonoids from Lycium barbarum leaves attenuate obesity through modulating glycolipid levels, oxidative stress, and gut bacterial composition in high-fat diet-fed mice

Traditional herbal therapy made from Lycium barbarum leaves has been said to be effective in treating metabolic diseases, while its exact processes are yet unknown. Natural flavonoids are considered as a secure and reliable method for treating obesity. We thus made an effort to investigate the processes by which flavonoids from L. barbarum leaves (LBLF) reduce obesity. To assess the effectiveness of the intervention following intragastric injection of various dosages of LBLF (50, 100, and 200 mg/kg⋅bw), obese model mice developed via a high-fat diet were utilized. Treatment for LBLF may decrease body weight gain, Lee’s index, serum lipids levels, oxidative stress levels, and hepatic lipids levels. It may also enhance fecal lipids excretion and improve glucose tolerance. Additionally, LBLF therapy significantly restored gut dysfunction brought on by a high-fat diet by boosting gut bacterial diversities and altering the composition of the gut bacterial community by elevating probiotics and reducing harmful bacteria.

Chemical profiling, quantitation, and bioactivities of Du-Zhong tea

Du-Zhong tea is a health beverage produced from Eucommia ulmoides leaves (EUL) as raw materials using traditional tea processing and Chinese herbal pieces processing methods. To evaluate the differences between tender leaves and mature leaves of Du-Zhong tea, UPLC-Q-TOF MS was used to analyze the constituents in EUL collected in April and August. A total of 52 compounds, including iridoids, phenylpropanoids, flavonoids, lignans, and other types of compounds were identified. The contents of nine ingredients in the tender and mature leaves of E. ulmoides were determined by HPLC-DAD analysis. The results show that the average contents of the compounds in tender leaves were significantly higher than those in mature leaves. Lastly, the antioxidant and antipancreatic lipase activities of commercial Du-Zhong tea made by leaves of different maturity were evaluated. Du-Zhong tea with d-grade exhibited relatively higher antioxidant, while C-grade exhibited greater lipase inhibitory activities.

Highly clean recovery of natural antioxidants from lemon peels: Lactic acid-based automatic solvent extraction

INTRODUCTION

Food industry generates large amounts of waste by-products rich in natural antioxidants. On the other hand, application of advanced processes for the recovery of these fine chemicals is another popular topic of recent years.

OBJECTIVE

The purpose of this study is to propose a green extraction method by application of deep eutectic solvent-based automated solvent extraction (AMSE) from lemon peels.

METHODS

The primary polyphenols (hesperidin, naringin, and p-coumaric acid) and the total polyphenols of the lemon peel extract were quantified and used as response for the optimisation of the AMSE conditions. The Box-Behnken design type of the response surface method (RSM) was chosen for optimisation study. Scavenging activity of the lemon peel extract against 2,2-diphenyl-1-picrylhydrazil (DPPH) free radical was also measured in vitro.

RESULTS

The optimum conditions for the highest total phenolic (7.47 mg-gallic acid equivalent [GAE]/g-lemon peel [LP]), naringin (5.05 mg/g-LP), p-coumaric acid (3.27 mg/g-LP), and hesperidin (0.07 mg/g-LP) yields were obtained by 1.5 h of extraction time, 46% water (v/v), and 5 g of peel. The antioxidant activity changed between 37.31% and 94.10% in the peels.

CONCLUSIONS

Extraction time was the most effective process factor for the total phenolic and p-coumaric acid yields, while water addition was statistically very important (p < 0.0001) for the naringin and hesperidin yields in the current AMSE system. The second-order models generated for the selected systems represent the data satisfyingly based on the high coefficients of determination (> 0.99), statistically significant p-values (<0.0001), coefficient of variation values (< 10%), and non-significant lack-of-fit values (p > 0.05).

Citrus Peel Flavonoid Extracts: Health-Beneficial Bioactivities and Regulation of Intestinal Microecology in vitro

Citrus peel and its extracts are rich in flavonoids, which are beneficial to human health. In this study, the extraction, component analysis, biological activity and intestinal microbiota regulation of citrus peel flavonoid extracts (CPFEs) were investigated. CPFEs from 14 Chinese cultivars were purified by ultrasound-assisted extraction and XAD-16 macroporous resin. The total flavonoid content of lemon was greatest at 103.48 ± 0.68 mg/g dry weight (DW) by NaNO2-Al(NO3)3-NaOH spectrophotometry. Using high-performance liquid chromatography–diode array detection, the highest concentrations of naringin, hesperidin and eriocitrin were found in grapefruit (52.03 ± 0.51 mg/g DW), chachiensis (43.02 ± 0.37 mg/g DW) and lemon (27.72 ± 0.47 mg/g DW), respectively. Nobiletin was the most polymethoxylflavone in chachiensis at 16.91 ± 0.14 mg/g DW. CPFEs from chachiensis and grapefruit had better antioxidant activity, α-glucosidase inhibitory and sodium glycocholate binding ability. In addition, chachiensis and grapefruit CPFEs had positive effects on intestinal microecology, as evidenced by a significant increase in the relative abundance of Bifidobacterium spp., and production of short-chain fatty acids, especially acetic acid, by a simulated human intestinal model. Collectively, our results highlight the biological function of CPFEs as prebiotic agents, indicating their potential use in food and biomedical applications.

Proanthocyanidins as the main pancreatic lipase inhibitors in chokeberry fruits

Pancreatic lipase inhibitors are recognized as important in strategies for the management of overweight and obesity. The phytocompounds in chokeberry fruit show multidirectional pro-health effects, including anti-obesity activity. The aims of this study were to fractionate and identify the phenolic compounds of chokeberry fruit phenolic-rich extract that are active as pancreatic lipase inhibitors. Phenolic compounds were fractionated using Sephadex LH-20 resin, followed by polyphenol profile analysis using chromatographic and spectrophotometric methods, while pancreatic inhibitory activity was determined using 4-methylumbelliferyl oleate and emulsified triolein as enzyme substrates. Among the six fractions isolated from extract, two fractions rich in highly polymerized proanthocyanidins showed the greatest ability to inhibit pancreatic lipase activity. In comparison, fractions containing mainly low-molecular-weight phenolic compounds, such as phenolic acids, flavonols and anthocyanins, were 11-64 times less active. The most active fraction showed a mixed mode of pancreatic lipase inhibition, as determined by Lineweaver-Burk plot analysis, and exhibited a cumulative effect with orlistat. This study shows that black chokeberry polyphenols, particularly highly polymerized procyanidins, can effectively inhibit pancreatic lipase activity determined by in vitro methods.

Inhibitory Effect of Lotus Leaf-Enriched Flavonoid Extract on the Growth of HT-29 Colon Cancer Cells through the Expression of PI3K-Related Molecules

Objectives

Lotus leaf is rich in flavonoids, and this study is aimed at examining the inhibitory effect of lotus leaf-enriched flavonoid extract (LLEFE) on HT-29 colon cancer cells through phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) expression regulation.

Methods

Lotus leaves were extracted by ethanol and purified using FL-3 macroporous resin to create the LLEFE. HT-29 colon cancer cells were tested using various methods: their proliferation was observed by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, their survival status was observed by fluorescence staining, their oxidative stress level was observed by biochemical kits, and their mRNA expression was determined by quantitative polymerase chain reaction (qPCR) assay. Additionally, the composition of the flavonoids in lotus leaf was determined by HPLC.

Results

The results showed that the proliferation of NCM460 normal human colon cells was not affected by 0–500 μg/mL LLEFE but the proliferation of HT-29 human colon cancer cells decreased. LLEFE increased the LDH level in an HT-29 colon cancer cell culture medium; also increased the superoxide dismutase (SOD), catalase (CAT) activities, and glutathione (GSH) level in HT-29 cells; and decreased the malondialdehyde (MDA) level. Further experimental results showed that LLEFE upregulated the expression of SOD1, CAT, and GSH mRNA and downregulated the expression of PI3K, Akt, and mammalian target of rapamycin (mTOR) in HT-29 cells. The high-performance liquid chromatography (HPLC) results showed that kaempferin, hyperoside, astragaloside, phloridzin, and quercetin were the main chemical constituents of lotus leaf.

Conclusion

Lotus leaves contain functional flavonoids that inhibit the proliferation of HT-29 colon cancer cells and regulate the expression of PI3K/Akt through five important chemicals.

Online Extraction–DPPH–HPLC-DAD-QTOF-MS System for Efficient Screening and Identification of Antioxidants from Citrus aurantium L. Var. amara (Rutaceae): Integrating Sample Preparation and Antioxidants Profiling

The lack of a direct connection between solid edible or medical natural products and bioactive compound profiling is a bottleneck in natural product research and quality control. Here, a novel integrated system, online extraction (OLE)–2,2′-diphenyl-1-picrylhydrazyl (DPPH)–HPLC−DAD−QTOF-MS, was fabricated to extract, screen, and identify antioxidants from the whole fruit of Citrus aurantium L. var. amara (CAVA, Rutaceae) simply, rapidly, and efficiently. The system consumes less sample (1.0 mg of CAVA powder) and requires a shorter analytical time (45 min for sample extraction, antioxidants screening, separation, and identification). Eight antioxidant flavonoids were screened and identified, and six available flavanones were sensitively, precisely, and accurately quantified. Two major flavanone glycosides, naringin (50.37 ± 0.43 mg/g) and neohesperidin (38.20 ± 0.27 mg/g), exhibit potent DPPH scavenging activities with IC₅₀ values of 111.9 ± 10.06 and 178.55 ± 11.28 μg/mL. A minor flavanone aglycone, hesperitin (0.73 ± 0.06 mg/g), presents stronger DPPH scavenging activity (IC₅₀, 39.07 ± 2.51 μg/mL). Furthermore, density functional theory calculations demonstrated their electron transport ability and chemical reactivity, which confirmed the screened results. The results indicate that the developed OLE–DPPH–HPLC−DAD−QTOF-MS system provides new perspectives for analysis of antioxidants from complex natural products, which also contribute to the quality evaluation of CAVA.

Chlorophyll Inhibits the Digestion of Soybean Oil in Simulated Human Gastrointestinal System

Nowadays, much available processed and highly palatable food such as cream products and fried and convenient food, which usually showed a high energy density, had caused an increase in the intake of dietary lipids, further leading to significant growth in the prevalence of obesity. Chlorophyll, widespread in fruits and vegetables, was proven to have beneficial effects on alleviating obesity. This study investigated the effects of chlorophyll on the digestive characteristics of lipids under in vitro simulated adult and infant gastrointestinal systems. Chlorophyll decreased the release rate of free fatty acid (FFA) during in vitro adult and infant intestinal digestion by 69.2% and 60.0%, respectively. Meanwhile, after gastrointestinal digestion, chlorophyll changed the FFA composition of soybean oil emulsion and increased the particle size of oil droplets. Interestingly, with the addition of chlorophyll, the activity of pancreatic lipase was inhibited during digestion, which may be related to pheophytin (a derivative of chlorophyll after gastric digestion). Therefore, the results obtained from isothermal titration calorimetry and molecular docking further elucidated that pheophytin could bind to pancreatic lipase with a strong affinity of (4.38 ± 0.76) × 10⁷ M^-1 (K_a), while the binding site was amino acid residue Trp253. The investigation not only explained why chlorophyll inhibited digestive enzyme activity to reduce lipids digestion but also provided exciting opportunities for developing novel chlorophyll-based healthy products for dietary application in preventing obesity.

Characterization, Antioxidant Activities, and Pancreatic Lipase Inhibitory Effect of Extract From the Edible Insect Polyrhachis vicina

Oxidative stress and obesity are critical risk factors for metabolic syndrome. The consumption of functional food ingredients can a viable strategy to alleviate oxidative stress and obesity. In this study, the hydro-ethanolic extract of the edible insect Polyrhachis vicina was prepared and its bioactive components were characterized. The total polyphenol contents, total flavonoid contents, antioxidant and pancreatic lipase (PL) inhibitory activities of the extract were determined in vitro. In total, 60 bioactive components were tentatively identified in the P. vicina extract. Polyphenols and fatty acids were further quantified using LC-MS and GC-MS, respectively. P. vicina extract possessed excellent antioxidant and PL inhibition activities. Salicylic acid, gallic acid, liquiritigenin, and naringenin, which were the major polyphenols in the P. vicina extract, interacted with PL through hydrogen bonding, hydrophilic or hydrophobic and pi-cation interactions. Thus, P. vicina extract can be used as a nutraceutical to alleviate oxidative stress-induced disease and manage obesity.

Discovery and Characterization of the Naturally Occurring Inhibitors Against Human Pancreatic Lipase in Ampelopsis grossedentata

Pancreatic lipase (PL) inhibitor therapy has been validated as an efficacious way for preventing and treating obesity and overweight. In the past few decades, porcine PL (pPL) is widely used as the enzyme source for screening the PL inhibitors, which generates a wide range of pPL inhibitors. By contrast, the efficacious inhibitors against human PL (hPL) are rarely reported. This study aims to discover the naturally occurring hPL inhibitors from edible herbal medicines (HMs) and to characterize the inhibitory mechanisms of the newly identified hPL inhibitors. Following the screening of the inhibition potentials of more than 100 HMs against hPL, Ampelopsis grossedentata extract (AGE) displayed the most potent hPL inhibition activity. After that, the major constituents in AGE were identified and purified, while their anti-hPL effects were assayed in vitro. The results clearly showed that two abundant constituents in AGE (dihydromyricetin and iso-dihydromyricetin) were moderate hPL inhibitors, while myricetin and quercetin were strong hPL inhibitors [half-maximal inhibitory concentration (IC50) values were around 1.5 μM]. Inhibition kinetic analyses demonstrated that myricetin and quercetin potently inhibited hPL-catalyzed near-infrared fluorogenic substrate of human pancreatic lipase (DDAO-ol) hydrolysis in a non-competitive inhibition manner, with Ki values of 2.04 and 2.33 μM, respectively. Molecular dynamics simulations indicated that myricetin and quercetin could stably bind on an allosteric site of hPL. Collectively, this study reveals the key anti-obesity constituents in AGE and elucidates their inhibitory mechanisms against hPL, which offers convincing evidence to support the anti-obesity and lipid-lowering effects of this edible herb.

The edible seaweed Laminaria japonica contains cholesterol analogues that inhibit lipid peroxidation and cyclooxygenase enzymes

In this study, 5 sterols were isolated and purified from Laminaria japonica, commonly known as edible brown seaweed, and their structures were identified based on detailed chemical methods and spectroscopic analyses. Spectroscopic analyses characterized 5 sterols as 29-Hydroperoxy-stigmasta-5,24(28)-dien-3β-ol, saringosterol (24-vinyl-cholest-5-ene-3β,24-diol), 24-methylenecholesterol, fucosterol (stigmasta-5,24-diene-3β-ol), and 24-Hydroperoxy-24-vinyl-cholesterol. The bioactivities of these sterols were tested using lipid peroxidation (LPO) and cyclooxygenase (COX-1 and -2) enzyme inhibitory assays. Fucosterol exhibited the highest COX-1 and -2 enzyme inhibitory activities at 59 and 47%, respectively. Saringosterol, 24-methylenecholesterol and fucosterol showed higher LPO inhibitory activity at >50% than the other compounds. In addition, the results of molecular docking revealed that the 5 sterols were located in different pocket of COX-1 and -2 and fucosterol with tetracyclic skeletons and olefin methine achieved the highest binding energy (-7.85 and -9.02 kcal/mol) through hydrophobic interactions and hydrogen bond. Our results confirm the presence of 5 sterols in L. japonica and its significant anti-inflammatory and antioxidant activity.

Bioactive Compounds of Citrus Fruits: A Review of Composition and Health Benefits of Carotenoids, Flavonoids, Limonoids, and Terpenes

The increased consumption of fruits, vegetables, and whole grains contributes to the reduced risk of many diseases related to metabolic syndrome, including neurodegenerative diseases, cardiovascular disease (CVD), diabetes, and cancer. Citrus, the genus Citrus L., is one of the most important fruit crops, rich in carotenoids, flavonoids, terpenes, limonoids, and many other bioactive compounds of nutritional and nutraceutical value. Moreover, polymethoxylated flavones (PMFs), a unique class of bioactive flavonoids, abundantly occur in citrus fruits. In addition, citrus essential oil, rich in limonoids and terpenes, is an economically important product due to its potent antioxidant, antimicrobial, and flavoring properties. Mechanistic, observational, and intervention studies have demonstrated the health benefits of citrus bioactives in minimizing the risk of metabolic syndrome. This review provides a comprehensive view of the composition of carotenoids, flavonoids, terpenes, and limonoids of citrus fruits and their associated health benefits.

Aged Pericarpium Citri Reticulatae ‘Chachi’ Attenuates Oxidative Damage Induced by tert-Butyl Hydroperoxide (t-BHP) in HepG2 Cells

This study investigated the protective effects of aged Pericarpium Citri Reticulatae ‘Chachi’ (PCR-C) on tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in HepG2 cells. According to HPLC analysis, PCR-C aged 10 years (PCR-C10) had the highest flavonoids content, especially polymethoxyflavones (PMFs), compared with the fresh peel of Citrus reticulata cv. ‘Chachiensis’ and PCR-C aged 1, 3, and 5 years. Then, flavonoids-rich PCR-C samples and non-flavonoids-rich PCR-C samples (NF) were prepared by extracting and purifying PCR-C of different aging periods, for further cell experiments. Pretreatment with flavonoids-rich PCR-C samples (particularly PCR-C10) considerably reversed t-BHP-induced oxidative damage in HepG2 cells by improving cell viability, increasing SOD activity and GSH levels and reducing the overproduction of ROS and MDA. Correlation analysis further indicated that the accumulation of PMFs, mainly 5,6,7,4′-tetramethoxyflavone and nobiletin, was the main reason that PCR-C10 maintained the redox balance in HepG2 cells. These findings provided direct evidence for the cellular antioxidant activity of aged PCR-C and a guide for PCR-C’s classification, authentication and rational use.

Binding mechanism of lipase with Lentinus edodes mycelia polysaccharide by multi-spectroscopic methods

It is an effective strategy to avoid obesity by inhibiting the activity of lipase. In this study, the binding mechanism of lipase and Lentinus edodes mycelia polysaccharide (LMP) were explored with multi-spectral methods, for example, three-dimensional (3D) fluorescence, Fourier-transformed infrared (FT-IR), and Raman spectra. At 290 K, the binding constant was 2.44 × 10⁵  L/mol, there was only one binding site between LMP and lipase. Static quenching was the quenching mechanism. The major forces were hydrogen bonding and van der Waals force. The binding of LMP to lipase impacted the microenvironment around tyrosine and tryptophan residues. The polarity around these residues was decreased and hydrophobicity was enhanced. This study not only revealed the binding mechanism of LMP on lipase but also provided scientific evidence for expanding the application of LMP in functional food industries.