Oleuropein and Verbascoside - Their Inhibition Effects on Carbonic Anhydrase and Molecular Docking Studies

Health Benefits of Olive Leaf: The Focus on Efficacy of Antiglycation Mechanisms

Olive leaves have been a therapeutic herbal agent for diseases for centuries. Olive leaves contain many health-beneficial nutrients and bioactive components. There is much evidence for the positive effects of the phenolic compounds they contain on health. The main active phenolic component in olive leaves is oleuropein, which can constitute 6%-9% of the leaf's dry matter and has been intensively studied for its promising results/effects on human health. In addition, olive leaf provides health benefits through bioactive components, such as secoiridoids, flavonoids, triterpenes, and lignans. The anti-inflammatory, antioxidant, anticancer, antidiabetic, and antihypertensive properties of bioactive components, especially oleuropein, are well known. In addition, various health benefits, such as neuroprotective effects and microbiota modulation, are also mentioned. In recent years, in vitro studies have shown that olive leaves and bioactive components from olive leaves may have antiglycation effects. Currently, it is thought that the components found in olive leaves have a direct or indirect antiglycation effect. It is thought that, their direct effects include reducing the interaction between sugars and amino acids, nucleic acids, and lipids and sequestering reactive dicarbonyl species, and their indirect effects include preventing the formation of advanced glycation end-products (AGEs) by reducing inflammation and oxidative stress. However, in vivo and clinical studies are needed to prove these mechanisms and understand how their metabolism works in the human body. This review examines the beneficial health effects of olive leaves and their potential antiglycation role.

Effect of the Mediterranean Diet (MeDi) on the Progression of Retinal Disease: A Narrative Review

Worldwide, the number of individuals suffering from visual impairment, as well as those affected by blindness, is about 600 million and it will further increase in the coming decades. These diseases also seriously affect the quality of life in working-age individuals. Beyond the characterization of metabolic, genetic, and environmental factors related to ocular pathologies, it is important to verify how lifestyle may participate in the induction of the molecular pathways underlying these diseases. On the other hand, scientific studies are also contributing to investigations as to whether lifestyle could intervene in modulating pathophysiological cellular responses, including the production of metabolites and neurohormonal factors, through the intake of natural compounds capable of interfering with molecular mechanisms that lead to ocular diseases. Nutraceuticals are promising in ameliorating pathophysiological complications of ocular disease such as inflammation and neurodegeneration. Moreover, it is important to characterize the nutritional patterns and/or natural compounds that may be beneficial against certain ocular diseases. The adherence to the Mediterranean diet (MeDi) is proposed as a promising intervention for the prevention and amelioration of several eye diseases. Several characteristic compounds and micronutrients of MeDi, including vitamins, carotenoids, flavonoids, and omega-3 fatty acids, are proposed as adjuvants against several ocular diseases. In this review, we focus on studies that analyze the effects of MeDi in ameliorating diabetic retinopathy, macular degeneration, and glaucoma. The analysis of knowledge in this field is requested in order to provide direction on recommendations for nutritional interventions aimed to prevent and ameliorate ocular diseases.

Wild and cultivated olive trees: Nutraceutical insights of extra virgin olive oils in cardiovascular and ocular diseases

Extra virgin olive oil (EVOO) from Olea europaea (cultivated olive tree) and the oil obtained from the wild olive variety or acebuche (ACE oil from Olea oleaster) contain an extraordinary number of bioactive molecules. These include oleic acid, sterols, tocopherols, triterpene compounds, and polyphenols. Both oils are known for their healthy properties and are considered to be a nutraceutical tool against cardiovascular diseases, including arterial hypertension, preeclampsia, and ocular diseases such as glaucoma or diabetic retinopathy. The benefits of EVOO and ACE oil stem from their anti-inflammatory, antioxidant, and anti-cancer properties. They also have potential as prebiotic compounds. In this update, we synthesise and illustrate the various characteristics and beneficial effects of olive oils from different varieties of olive trees, with special emphasis on Olea oleaster, also known as Olea europaea, L. var. sylvestris.

Potential antioxidant, anticholinergic, antidiabetic and antiglaucoma activities and molecular docking of spiraeoside as a secondary metabolite of onion (Allium cepa)

Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative flavonoids in onion. Several antioxidant techniques were used in this investigation to assess the antioxidant capabilities of spiraeoside, including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging, N,N-dimethyl-p-phenylenediamine radical (DMPD•+) scavenging, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS•+) scavenging activities, cupric ions (Cu2+) reducing and potassium ferric cyanide reduction abilities. In contrast, the water-soluble α-tocopherol analogue trolox and the conventional antioxidants butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and α-tocopherol were utilized as the standards for evaluation. Spiraeoside scavenged the DPPH radicals an IC50 of 28.51 μg/mL (r2: 0.9705) meanwhile BHA, BHT, trolox, and α-tocopherol displayed IC50 of 10.10 μg/mL (r2: 0.9015), 25.95 μg/mL (r2: 0.9221), 7.059 μg/mL (r2: 0.9614) and 11.31 μg/mL (r2: 0.9642), accordingly. The results exhibited that spiraeoside had effects similar to BHT, but less potent than α-tocopherol, trolox and BHA. Also, inhibitory effects of spiraeoside were evaluated toward some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II) and α-glycosidase, which are related to a number of illnesses, such as Alzheimer's disease (AD), diabetes mellitus and glaucoma disorder. Spiraeoside exhibited IC50 values of 4.44 nM (r2: 0.9610), 7.88 nM (r2: 0.9784), 19.42 nM (r2: 0.9673) and 29.17 mM (r2: 0.9209), respectively against these enzymes. Enzyme inhibition abilities were compared to clinical used inhibitors including acetazolamide (for CA II), tacrine (for AChE and BChE) and acarbose (for α-glycosidase). Spiraeoside demonstrated effective antioxidant, anticholinergic, antidiabetic and antiglaucoma activities. With these properties, it has shown that Spiraeoside has the potential to be a medicine for some metabolic diseases.

Enzyme Inhibition and Antioxidant Activities of Asparagus officinalis L. and Analysis of Its Phytochemical Content by LC/MS/MS

In the study, water, ethanol, methanol, dichloromethane, and acetone extracts of Asparagus officinalis L. were obtained by maceration. DPPH⋅, ABTS⋅⁺ , FRAP, and CUPRAC methods determined the antioxidant capacities of all extracts. Moreover, the in vitro effects of extracts on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase (CA)-I, CA-II and α-Glycosidase were investigated. At a 10 μg/ml concentration, the extract with the highest Fe³⁺ reduction capacity was ethanol (AE), and the extract with the highest Cu²⁺ reduction capacity was acetone (AA). AE for AChE (IC₅₀ =21.19 μg/ml) and α-Glycosidase (IC₅₀ : 70.00 μg/ml), methanol (AM) for BChE (IC₅₀ =17.33 μg/ml), CA-I and II (IC₅₀ =79.65 and 36.09 μg/ml, respectively) showed the most potent inhibition effect. The content analysis of acetone extract was performed with LC/MS-MS, the first three phytochemicals found most were p-Coumaric acid, rutin, and 4-hydroxybenzoic acid (284.29±3.97, 135.39±8.19, and 102.06±5.51 μg analyte/g extract, respectively).

The pharmacokinetic property and pharmacological activity of acteoside: A review

Acteoside (AC), a phenylpropanoid glycoside isolated from many dicotyledonous plants, has been demonstrated various pharmacological activities, including anti-oxidation, anti-inflammation, anti-cancer, neuroprotection, cardiovascular protection, anti-diabetes, bone and cartilage protection, hepatoprotection, and anti-microorganism. However, AC has a poor bioavailability, which can be potentially improved by different strategies. The health-promoting characteristics of AC can be attributed to its mediation in many signaling pathways, such as MAPK, NF-κB, PI3K/AKT, TGFβ/Smad, and AMPK/mTOR. Interestingly, docking simulation study indicates that AC can be an effective candidate to inhibit the activity of SARS-CoV2 main protease and protect against COVID-19. Many clinical trials for AC have been investigated, and it shows great potentials in drug development.

Verbascoside potentiates the effect of tyrosine kinase inhibitors on the induction of apoptosis and oxidative stress via the Abl-mediated MAPK signalling pathway in chronic myeloid leukaemia

Verbascoside (Verb) may exhibit potential antitumour activities in leukaemia. The present study investigated the effect of Verb, in combination with imatinib (IM), dasatinib (Das), lipopolysaccharide (LPS) and TNF, on cell survival, Abl expression, apoptosis, oxidative stress and the MAPK pathway in chronic myeloid leukaemia (CML) cells. Cell viability was determined using the WST-8 assay in K562 and R-K562 cells treated with Verb and/or IM, Das, LPS and TNF. Apoptosis and DNA damage in CML cells was detected by caspase-3 and comet analysis. The protein levels of Abl (Phospho-Tyr412), and total/phosphorylated p38, JNK and ERK in CML cells were analysed using a Colorimetric Cell-Based Assay. Oxidative stress was examined using total antioxidant and oxidant status assays. Treatment with Verb and/or tyrosine kinase inhibitors (TKIs), LPS and TNF resulted in a significant decrease in the Tyr-412 phosphorylation of Abl in K562 and R-K562 cells. In addition, cotreatment with Verb and IM or Das additively induced apoptosis by activating caspase-3 levels in both cell lines. Activation of p38 and JNK can result in growth arrest and cell death, whereas ERK stimulation results in cell division and differentiation. The present study demonstrated that cotreatment with Verb and TKIs suppressed phosphorylated-ERK1/2, whereas the levels of phosphorylated-p-38 and phosphorylated-JNK were significantly elevated by Verb and/or IM, Das, LPS and TNF, thus suggesting that Abl and Src inhibition could be involved in the effects of Verb on MAPK signalling in R-K562 cells. Furthermore, Verb elevated reactive oxygen species levels additively with TKIs in both cell lines by increasing the oxidant capacity and decreasing the antioxidant capacity. In conclusion, anti-leukemic mechanisms of Verb may be mediated by Abl protein and regulation of its downstream p38-MAPK/JNK pathway, caspase-3 and oxidative stress in CML cells.

Screening of Carbonic Anhydrase, Acetylcholinesterase, Butyrylcholinesterase, and α-Glycosidase Enzyme Inhibition Effects and Antioxidant Activity of Coumestrol

Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in plants. In this study, antiglaucoma, antidiabetic, anticholinergic, and antioxidant effects of Coumestrol were evaluated and compared with standards. To determine the antioxidant activity of coumestrol, several methods-namely N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD•+)-scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS•+)-scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•)-scavenging activity, potassium ferric cyanide reduction ability, and cupric ion (Cu2+)-reducing activity-were performed. Butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants for comparison. Coumestrol scavenged the DPPH radical with an IC50 value of 25.95 μg/mL (r2: 0.9005) while BHA, BHT, Trolox, and α-Tocopherol demonstrated IC50 values of 10.10, 25.95, 7.059, and 11.31 μg/mL, respectively. When these results evaluated, Coumestrol had similar DPPH•-scavenging effect to BHT and lower better than Trolox, BHA and α-tocopherol. In addition, the inhibition effects of Coumestrol were tested against the metabolic enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which are associated with some global diseases such as Alzheimer's disease (AD), glaucoma, and diabetes. Coumestrol exhibited Ki values of 10.25 ± 1.94, 5.99 ± 1.79, 25.41 ± 1.10, and 30.56 ± 3.36 nM towards these enzymes, respectively.