Oleanolic Acid: Extraction, Characterization and Biological Activity

Bioactive components, pharmacological effects, and drug development of traditional herbal medicine Rubus chingii Hu (Fu-Pen-Zi)

Rubus chingii Hu (Chinese Raspberry), known as Fu-Pen-Zi in Chinese, a woody perennial plant of the genus Rubus in the Rosaceae family, has specific nutritional and medicinal values, which is considered food-medicine herb in China for thousands of years to treat impotence, premature ejaculation, enuresis, frequent urination, and other diseases. This review aims to summarize recent advances in the bioactive components, pharmacological effects, and drug development and utilization of Rubus chingii Hu, hoping to provide useful support for its further research and clinical application. The bioactive components in Rubus chingii Hu contain mainly terpenoids, flavonoids, alkaloids, phenolic acids, polysaccharides, and steroids. The main pharmacological effects are their anti-oxidant, anti-inflammatory, and anti-tumor capacity on human health. Rubus chingii Hu is a very valuable food-medicine herb. The development of Rubus chingii Hu-related drugs is relatively single, which is limited to traditional Chinese medicine and prescriptions. Therefore, it is vital to pay interest to Rubus chingii Hu and its bioactive components in the future and extend its scientific application.

Effects of oleanolic acid administration on renal NF-kB, IL-18, IL-6, YKL-40, and KIM-1 in experimental diabetic rats

Objectives

Neuropathy, retinopathy, and nephropathy, known as the triopathy of diabetes, are the consequences of microvascular complications of diabetes. The present study aimed to investigate the potential protective effects of oleanolic acid (OA) administration against diabetic nephropathy considering biochemical and histopathological parameters.

Materials and Methods

The rats with fasting blood glucose levels of 200 mg/dl and above were considered diabetic after induction of diabetes via injecting STZ. The other half of the rats were not injected with STZ (healthy rats). Both healthy and diabetic rats were then divided randomly into two subgroups to be administered with either OA (5 mg/kg) with 1 ml tap water by oral gavage or 1 ml tap water in the same route for 21 days. Serum urea-N, Ca, P, and Mg as well as renal tissue MDA, SOD, NF-κB, IL-6, IL-18, AMPK, YKL-40, and KIM-1 levels were measured.

Results

OA administration partially decreased levels of serum urea-N and P, as well as levels of renal tissue MDA and inflammation markers (NF-κB, IL-6, IL-18, YKL-40, and KIM-1) in the diabetic rats. It also partially increased serum Ca and renal tissue AMPK levels in diabetic rats. These positive effects were also seen in renal tissue histopathology.

Conclusion

OA treatment partially alleviated renal damage inflammatory and oxidative profiles in diabetic rats.

An Updated Systematic Review of Vaccinium myrtillus Leaves: Phytochemistry and Pharmacology

Bilberry leaves are used in many countries in traditional medicine for treating a wide variety of diseases. Due to the high therapeutic potential of Vaccinium myrtillus (VM) leaves, this review aims to present the latest knowledge on the phytochemical profile, as well as the therapeutic effects of this herbal drug. The review was conducted according to the Prisma guidelines, and the scientific databases were searched using combinations of the following keywords: "Vaccinium myrtillus", "leaves", "bilberry". Recent research was focused on the influence of abiotic factors on the phytochemical composition, and it seems that there are significant differences between the herbal drugs collected from different countries. The phytochemical composition is correlated with the broad spectrum of pharmacological effects. The paper outlines the potent antimicrobial activity of VM extracts against multidrug-resistant bacterial strains, and also the pathways that are modulated by the unique "cocktail" of phytoconstituents in different metabolic alterations. Reviewing the research articles published in the last 10 years, it seems that bilberry leaves have been slightly forgotten, although their phytochemical and pharmacological characteristics are unique.

Comparison of Phytochemical Profiles of Wild and Cultivated American Ginseng Using Metabolomics by Ultra-High Performance Liquid Chromatography-High-Resolution Mass Spectrometry

American ginseng (Panax quinquefolius L.) has been recognized as a valuable herb medicine, and ginsenosides are the most important components responsible for the health-beneficial effects. This study investigated the secondary metabolites responsible for the differentiation of wild and cultivated American ginsengs with ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS)-based metabolomic approach. An in-house ginsenoside library was developed to facilitate data processing and metabolite identification. Data visualization methods, such as heatmaps and volcano plots, were utilized to extract discriminated ion features. The results suggested that the ginsenoside profiles of wild and cultivated ginsengs were significantly different. The octillol (OT)-type ginsenosides were present in greater abundance and diversity in wild American ginsengs; however, a wider distribution of the protopanaxadiol (PPD)-and oleanolic acid (OA)-type ginsenosides were found in cultivated American ginseng. Based on the tentative identification and semi-quantification, the amounts of five ginsenosides (i.e., notoginsenoside H, glucoginsenoside Rf, notoginsenoside R1, pseudoginsenoside RT2, and ginsenoside Rc) were 2.3-54.5 fold greater in wild ginseng in comparison to those in their cultivated counterparts, and the content of six ginsenosides (chicusetsusaponin IVa, malonylginsenoside Rd, pseudoginsenoside Rc1, malonylfloralginsenoside Rd6, Ginsenoside Rd, and malonylginsenoside Rb1) was 2.6-14.4 fold greater in cultivated ginseng compared to wild ginseng. The results suggested that the in-house metabolite library can significantly reduce the complexity of the data processing for ginseng samples, and UHPLC-HRMS is effective and robust for identifying characteristic components (marker compounds) for distinguishing wild and cultivated American ginseng.

Multidirectional Characterization of Phytochemical Profile and Health-Promoting Effects of Ziziphora bungeana Juz. Extracts

Ziziphora species (Lamiaceae) have been used in traditional medicine as sedatives, antiseptics, carminatives, or expectorants. Despite their common applications in phytotherapy, there is still lack of evidence about the composition of their extracts and its impact on biological properties of the plants. The aim of this study was to evaluate the content of Ziziphora bungeana, a less studied species growing in Kazakhstan, using HPLC-ESI-QTOF-MS/MS instrumentation and to determine its antimicrobial, antioxidant, and cytotoxic activity together with inhibitory properties against tyrosinase and toxicity in erythrocyte lysis assay. Extracts from Z. bungeana were found to be sources of flavonoids, phenolic acids, organic acids, and terpenes that determined their antiradical activity. The minimum inhibitory concentrations of extracts were lower for Gram-positive bacteria (1.25-10 mg/mL) than for Gram-negative bacteria and fungi (5-20 mg/mL). The EC₅₀ value calculated for antiradical activity ranged between 15.00 ± 1.06 µg/mL and 13.21 ± 3.24 µg/mL for ABTS and DPPH assays, respectively. Z. bungeana extracts were found to decrease the activity of tyrosinase by 50% (at 200 µg/mL) similarly to kojic acid and were slightly cytotoxic for human melanoma A375 cell line (at 200 µg/mL) with no effect on HaCaT keratinocytes. In the end, Z. bungeana did not reveal toxic effects in hemolytic assay as compared to the positive control Triton X-100. The performed tests show potential application of the plant in the treatment of infectious diseases, disorders caused by free radicals, and skin problems.

Potential bioactive compounds and mechanisms of Fibraurea recisa Pierre for the treatment of Alzheimer's disease analyzed by network pharmacology and molecular docking prediction

Introduction

Heat-clearing and detoxifying Chinese medicines have been documented to have anti-Alzheimer's disease (AD) activities according to the accumulated clinical experience and pharmacological research results in recent decades. In this study, Fibraurea recisa Pierre (FRP), the classic type of Heat-clearing and detoxifying Chinese medicine, was selected as the object of research.

Methods

12 components with anti-AD activities were identified in FRP by a variety of methods, including silica gel column chromatography, multiple databases, and literature searches. Then, network pharmacology and molecular docking were adopted to systematically study the potential anti-AD mechanism of these compounds. Consequently, it was found that these 12 compounds could act on 235 anti-AD targets, of which AKT and other targets were the core targets. Meanwhile, among these 235 targets, 71 targets were identified to be significantly correlated with the pathology of amyloid beta (Aβ) and Tau.

Results and discussion

In view of the analysis results of the network of active ingredients and targets, it was observed that palmatine, berberine, and other alkaloids in FRP were the key active ingredients for the treatment of AD. Further, Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis revealed that the neuroactive ligand-receptor interaction pathway and PI3K-Akt signaling pathway were the most significant signaling pathways for FRP to play an anti-AD role. Findings in our study suggest that multiple primary active ingredients in FRP can play a multitarget anti-AD effect by regulating key physiological processes such as neurotransmitter transmission and anti-inflammation. Besides, key ingredients such as palmatine and berberine in FRP are expected to be excellent leading compounds of multitarget anti-AD drugs.

Natural compounds targeting glycolysis as promising therapeutics for gastric cancer: A review

Gastric cancer, a common malignant disease, seriously endangers human health and life. The high mortality rate due to gastric cancer can be attributed to a lack of effective therapeutic drugs. Cancer cells utilize the glycolytic pathway to produce energy even under aerobic conditions, commonly referred to as the Warburg effect, which is a characteristic of gastric cancer. The identification of new targets based on the glycolytic pathway for the treatment of gastric cancer is a viable option, and accumulating evidence has shown that phytochemicals have extensive anti-glycolytic properties. We reviewed the effects and mechanisms of action of phytochemicals on aerobic glycolysis in gastric cancer cells. Phytochemicals can effectively inhibit aerobic glycolysis in gastric cancer cells, suppress cell proliferation and migration, and promote apoptosis, via the PI3K/Akt, c-Myc, p53, and other signaling pathways. These pathways affect the expressions of HIF-1α, HK2, LDH, and other glycolysis-related proteins. This review further assesses the potential of using plant-derived compounds for the treatment of gastric cancer and sheds insight into the development of new drugs.

Chemical constituents from Ficus sur Forssk (Moraceae)

Phytochemical investigation of the aerial roots of Ficus sur, a Cameroonian medicinal plant, resulted in a previously undescribed cerebroside, suroside (1), in addition to its aglycon congener suramide (2). Moreover, six known natural products including alpinumisoflavone (3), wighteone metabolite (4), oleanolic acid (5), β-sitosterol (6), β-sitosterol-3-O-β-D-glucopyranoside (7), and epi-ѱ-taraxastanolone (8) were identified. The structures of the previously undescribed compounds were determined by analysis of 1D and 2D-NMR (One and two dimensional nuclear magnetic resonance), mass spectrometry, chemical conversion, and by comparison of these data with those from the literature. Wighteone metabolite (4) exhibited a weak cytotoxic activity against the human HepG2 hepatocellular carcinoma cells with an IC50 value of 51.9 µM.

Microemulsions Enhance the In Vitro Antioxidant Activity of Oleanolic Acid in RAW 264.7 Cells

Oleanolic acid (OA) is the main triterpenic acid of olive leaves known for numerous pharmacological properties, including antioxidant activity. However, it is poorly soluble in water and consequently with low bioavailability, which limits its pharmacological application. Microemulsions (MEs) are dispersed systems consisting of two immiscible phases that promote rapid solubilization and absorption in the gastrointestinal tract. To improve both solubility and intestinal permeability of this molecule, OA has been formulated in two different microemulsions (ME-1 and ME-2). A solubility screening was carried out to select the ME components, and pseudoternary phase diagrams were constructed to evaluate the region of existence and select the appropriate amount of the constituents. ME-1 was prepared using Capmul PG-8/NF as the oily phase, and Transcutol and Tween 20 (7:3) as surfactants, while ME-2 contained Nigella oil and Isopropil myristate as the oily phase, and Transcutol HP and Cremophor EL (2:1) as surfactants. The OA solubility was increased by 1000-fold and 3000-fold in ME-1-OA and ME-2-OA, respectively. The MEs’ droplet size and the PdI were evaluated, and the stability was assessed for 8 weeks by monitoring chemical and physical parameters. The parallel artificial membrane permeability assay (PAMPA) also demonstrated an enhanced intestinal permeability of both OA formulations compared with free OA. The potential ability of both MEs to enhance the bioactivity of OA against LPS-induced oxidative stress in RAW 264.7 murine macrophages was also investigated. Overall, this study suggests that both MEs promote a bio-enhancement of the protective action of OA against the LPS-induced pro-oxidant stress in macrophages. Overall, this study suggests that MEs could be an interesting formulation to improve OA oral bioavailability with potential clinical applications.

Anti-Inflammatory Effects of Aralia elata Extract Against Dextran Sodium Sulfate-Induced Colitis in Mice and Raw 264.7 Macrophage Cells Exposed to Lipopolysaccharide: First Report

Aralia elata (AE) is an anti-inflammatory, polyphenolic containing medicinal plant. However, little is known about AE and its application to ulcerative colitis (UC). This study aimed to confirm AE extract's antioxidant and anti-inflammatory effects in vivo and in vitro. The in vitro antioxidant activity was evaluated by measuring total polyphenol and flavonoid content in AE extract. AE extract (10 000 mg/L) contained 186.8 mg GAE/g polyphenol and 81.9 mg QE/g flavonoid. Mice were divided into 6 groups, including control, which received normal saline, and treatment groups, which received dextran sodium sulfate (DSS) with or without AE extract (250, 500, and 1000 mg/kg). RAW 264.7 macrophage cells were divided into 2 groups: control and treatment. RAW 264.7 macrophage cells treated with sterile double distilled water, 1 mg/L lipopolysaccharide (LPS), and AE extracts (25, 50, 75, 100 µg/mL) were used to assess the cytotoxicity and anti-inflammatory activity. High-performance liquid chromatography, enzyme-linked immunosorbent assay (ELISA) kits, and histology were employed to analyze the AE extract contents, nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6, as oxidative stress markers. In addition, the disease activity index (DAI) and cytotoxicity were determined in mice and cells, respectively. High-performance liquid chromatography analysis revealed that AE extract is rich in chlorogenic acid (96 ± 0.01 mg/g). DSS increased the DAI and levels of TNF-α, IL-1β, and immune cell infiltration compared with those of the control animals. Furthermore, LPS eventually reduced cell viability and increased the levels of NO, TNF-α, IL-1β, and IL-6 in contrast to control cells. After treatment, a noticeable reduction was observed in the levels of DAI, NO, TNF-α, IL-1β, and IL-6 compared to those without AE treatments. Overall, AE extract is safe and had anti-inflammatory properties. Therefore, AE extract can be considered a potential pre-treatment supplement for UC.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part I)

Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids (asiatic acid, oleanolic acid, and ursolic acid), corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value.

Lipophilic Bioactive Compounds Transported in Triglyceride-Rich Lipoproteins Modulate Microglial Inflammatory Response

Microglial cells can contribute to Alzheimer’s disease by triggering an inflammatory response that leads to neuronal death. In addition, the presence of amyloid-β in the brain is consistent with alterations in the blood–brain barrier integrity and triglyceride-rich lipoproteins (TRL) permeation. In the present work, we used lab-made TRL as carriers of lipophilic bioactive compounds that are commonly present in dietary oils, namely oleanolic acid (OA), α-tocopherol (AT) and β-sitosterol (BS), to assess their ability to modulate the inflammatory response of microglial BV-2 cells. We show that treatment with lab-made TRL increases the release and gene-expression of IL-1β, IL-6, and TNF-α, as well as NO and iNOS in microglia. On the other hand, TRL revealed bioactive compounds α-tocopherol and β-sitosterol as suitable carriers for oleanolic acid. The inclusion of these biomolecules in TRL reduced the release of proinflammatory cytokines. The inclusion of these biomolecules in TRL reduced the release of proinflammatory cytokines. AT reduced IL-6 release by 72%, OA reduced TNF-α release by approximately 50%, and all three biomolecules together (M) reduced IL-1β release by 35% and TNF-α release by more than 70%. In addition, NO generation was reduced, with the inclusion of OA by 45%, BS by 80% and the presence of M by 88%. Finally, a recovery of the basal glutathione content was observed with the inclusion of OA and M in the TRL. Our results open the way to exploiting the neuro-pharmacological potential of these lipophilic bioactive compounds through their delivery to the brain as part of TRL.

Dao-Chi Powder Ameliorates Pancreatitis-Induced Intestinal and Cardiac Injuries via Regulating the Nrf2-HO-1-HMGB1 Signaling Pathway in Rats

Dao-Chi powder (DCP) has been widely used in the treatment of inflammatory diseases in the clinical practice of traditional Chinese medicine, but has not been used in acute pancreatitis (AP). This study aimed to evaluate the effect of DCP on severe AP (SAP) and SAP-associated intestinal and cardiac injuries. To this end, an SAP animal model was established by retrograde injection of 3.5% taurocholic acid sodium salt into the biliopancreatic ducts of rats. Intragastric DCP (9.6 g/kg.BW) was administered 12 h after modeling. The pancreas, duodenum, colon, heart and blood samples were collected 36 h after the operation for histological and biochemical detection. The tissue distributions of the DCP components were determined and compared between the sham and the SAP groups. Moreover, molecular docking analysis was employed to investigate the interactions between the potential active components of DCP and its targets (Nrf2, HO-1, and HMGB1). Consequently, DCP treatment decreased the serum levels of amylase and the markers of gastrointestinal and cardiac injury, further alleviating the pathological damage in the pancreas, duodenum, colon, and heart of rats with SAP. Mechanistically, DCP rebalanced the pro-/anti-inflammatory cytokines and inhibited MPO activity and MDA levels in these tissues. Furthermore, Western blot and RT-PCR results showed that DCP intervention enhanced the expression of Nrf2 and HO-1 in the duodenum and colon of rats with SAP, while inhibiting the expression of HMGB1 in the duodenum and heart. HPLC-MS/MS analysis revealed that SAP promoted the distribution of ajugol and oleanolic acid to the duodenum, whereas it inhibited the distribution of liquiritigenin to the heart and ajugol to the colon. Molecular docking analysis confirmed that the six screened components of DCP had relatively good binding affinity with Nrf2, HO-1, and HMGB1. Among these, oleanolic acid had the highest affinity for HO-1. Altogether, DCP could alleviated SAP-induced intestinal and cardiac injuries via inhibiting the inflammatory responses and oxidative stress partially through regulating the Nrf2/HO-1/HMGB1 signaling pathway, thereby providing additional supportive evidence for the clinical treatment of SAP.

Antiaging Mechanism of Natural Compounds: Effects on Autophagy and Oxidative Stress

Aging is a natural biological process that manifests as the progressive loss of function in cells, tissues, and organs. Because mechanisms that are meant to promote cellular longevity tend to decrease in effectiveness with age, it is no surprise that aging presents as a major risk factor for many diseases such as cardiovascular disease, neurodegenerative disorders, cancer, and diabetes. Oxidative stress, an imbalance between the intracellular antioxidant and overproduction of reactive oxygen species, is known to promote the aging process. Autophagy, a major pathway for protein turnover, is considered as one of the hallmarks of aging. Given the progressive physiologic degeneration and increased risk for disease that accompanies aging, many studies have attempted to discover new compounds that may aid in the reversal of the aging process. Here, we summarize the antiaging mechanism of natural or naturally derived synthetic compounds involving oxidative stress and autophagy. These compounds include: 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) derivatives (synthetic triterpenoids derived from naturally occurring oleanolic acid), caffeic acid phenethyl ester (CAPE, the active ingredient in honey bee propolis), xanthohumol (a prenylated flavonoid identified in the hops plant), guggulsterone (a plant steroid found in the resin of the guggul plant), resveratrol (a natural phenol abundantly found in grape), and sulforaphane (a sulfur-containing compound found in cruciferous vegetables).

Solubility and Permeability Enhancement of Oleanolic Acid by Solid Dispersion in Poloxamers and γ-CD

Oleanolic acid (OA) is a pentacyclic triterpenoid widely found in the Oleaceae family, and it represents 3.5% of the dry weight of olive leaves. OA has many pharmacological activities, such as hepatoprotection, anti-inflammatory, anti-oxidant, anti-diabetic, anti-tumor, and anti-microbic activities. Its therapeutic application is limited by its poor water solubility, bioavailability, and permeability. In this study, solid dispersions (SDs) were developed to overcome these OA limitations. Solubility studies were conducted to evaluate different hydrophilic polymers, drug-to-polymer ratios, and preparation methods. Poloxamer 188, Poloxamer 407, and γ-CD exhibited the highest increases in terms of OA solubility, regardless of the method of preparation. Binary systems were characterized using differential scanning calorimetry (DSC), X-ray diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). In addition, pure compounds and SDs were analyzed using scanning electron microscopy (SEM) in order to observe both the morphology and the particle surface. In vitro dissolution studies were performed for P407, P188, and γ-CD SDs. Preparation using the solvent evaporation method (SEM) produced the highest increase in the dissolution profiles of all three polymers with respect to the OA solution. Finally, the effect of SDs on OA permeability was evaluated with an in vitro parallel artificial membrane permeability assay (PAMPA). The formulation improved passive permeation across the simulated barrier due to OA increased solubility. The dissolution and PAMPA results indicate that the amorphization of OA by SD preparation could be a useful method to enhance its oral absorption, and it is also applicable on an industrial scale.