Opuntia Ficus-indica Var Research Articles

Double-blind Randomized placebo-controlled Trials on controlling blood glucose level using the extract from <i>Opuntia ficus-indica</i> var. saboten

Objectives: The aim of this study was to evaluate the effects of Opuntia ficus-indica var. saboten extract on blood glucose regulation in both healthy individuals and those with impaired fasting glucose (IFG). Additionally, the study assessed the safety of <i>Opuntia</i> extract regarding liver and kidney function over a 12-week period.Methods: A double-blind, randomized, placebo-controlled clinical trial was conducted with 85 participants, including 47 healthy individuals and 38 individuals with impaired fasting glucose (IFG) or impaired glucose tolerance (IFG). Participants were randomly assigned to receive either Opuntia extract or a placebo for 12 weeks. Blood glucose control was evaluated using fasting blood glucose (FBS), oral glucose tolerance tests (OGTT), HbA1c, insulin, and C-peptide levels. Safety assessments included liver function tests (AST, ALT, <i>γ</i>-GTP, ALP) and kidney function tests (BUN, creatinine). Data were analyzed using independent and paired t-tests, with a significance level of p<0.05.Results: A total of 85 participants were initially enrolled, and after excluding 13 participants due to dropout, consent withdrawal, or protocol violations, the final statistical analysis was conducted with 72 participants. In the IFG group, Opuntia extract significantly reduced fasting blood glucose levels compared to the placebo group (p=0.010). Additionally, Opuntia extract reduced postprandial blood glucose levels at 120 minutes during the OGTT in healthy participants (p=0.047). No significant changes were observed in HbA1c, insulin, or C-peptide levels. Importantly, no adverse effects on liver or kidney function were detected in either group during the 12-week intervention.Conclusions: The administration of <i>Opuntia ficus-indica var. saboten</i> extract for 12 weeks demonstrated significant blood glucose-lowering effects in individuals with impaired glucose tolerance, without causing any liver or kidney toxicity. These findings suggest that <i>Opuntia</i> extract may be a safe and effective natural option for blood glucose regulation, particularly in pre-diabetic individuals. Further large-scale studies are recommended to confirm these results and explore its potential clinical applications.

Antioxidant and Anti-Inflammatory Effects of Opuntia Extracts on a Model of Diet-Induced Steatosis.

Oxidative stress and inflammation are widely recognised as factors that can initiate and facilitate the development of MAFLD. The aim of this study is to analyse the effect of low and high doses of Opuntia stricta var. dillenii peel extract (L-OD and H-OD, respectively) and Opuntia ficus-indica var. colorada pulp extract (L-OFI and H-OFI, respectively), which are rich in betalains and phenolic compounds, on oxidative stress, inflammation, DNA damage and apoptosis in rat livers with diet-induced steatosis. Steatotic diet led to increased final body and liver weight, serum transaminases, hepatic TG content, oxidative status and cell death. H-OFI treatment decreased serum AST levels, while L-OFI reduced hepatic TG accumulation. Oxidative stress was partially prevented with H-OD and H-OFI supplementation, and pro-inflammatory cytokines levels were especially improved with H-OFI treatment. Moreover, H-OFI appears to prevent DNA damage markers. Finally, H-OD and L-OFI supplementation down-regulated the apoptotic pathway. In conclusion, both H-OD and H-OFI supplementation were effective in regulating the progression to metabolic steatohepatitis, triggering different mechanisms of action.

Encapsulation of Indicaxanthin-Rich Opuntia Green Extracts by Double Emulsions for Improved Stability and Bioaccessibility.

Opuntia ficus-indica var. Colorada fruit is an important source of indicaxanthin, a betalain with antioxidant, anti-inflammatory, and neuromodulatory potential, proven in both in vitro and in vivo models. Other betalains and phenolic compounds with bioactive activities have also been identified in Colorada fruit extracts. These compounds may degrade by their exposure to different environmental factors, so in the present research, two double emulsion systems (W1/O/W2) were elaborated using Tween 20 (TW) and sodium caseinate (SC) as surfactants to encapsulate Colorada fruit pulp extracts, with the aim of enhancing their stability during storage. Encapsulation efficiencies of up to 97.3 ± 2.7%, particle sizes between 236 ± 4 and 3373 ± 64 nm, and zeta potential values of up to ∣46.2∣ ± 0.3 mV were obtained. In addition, the evaluation of the in vitro gastro-intestinal stability and bioaccessibility of the main individual bioactives was carried out by standardized INFOGEST© protocol, obtaining the highest values for the encapsulated extract bioactives in comparison with the non-encapsulated extract (control). Especially, TW double emulsion showed bioaccessibility values of up to 82.8 ± 1.5% for the main bioactives (indicaxanthin, piscidic acid, and isorhamnetin glucoxyl-rhamnosyl-pentoside 2 (IG2)), indicating a promising potential for its use as a functional natural colorant ingredient.

Extensive profiling of three varieties of Opuntia spp. fruit for innovative food ingredients

Consumer interest in the use of natural ingredients is creating a growing trend in the food industry, leading to research into the development of natural products such as colorants, antimicrobials and antioxidant compounds. This work involves an extensive morphological (using physico-chemical assays), chemical (antioxidant activity assays) and microbiological (Gram-positive and negative strains) characterization of prickly peras (Opuntia ficus-indica (OFI) var. sanguigna, gialla and Opuntia engelmannii) fruits. Through chromatographic assays, these species have shown interesting contents of hydrophilic (sugars, organic acids and betalains) and lipophilic (tocopherols and fatty acids) compounds. While Opuntia engelmannii exhibited higher content of betacyanins and mucilage, OFI varieties sanguigna and gialla displayed greater organic acid content. The sanguigna variety also showed the highest α-tocopherol content. All this compounds could be the responsible of enhancing the bioactivity of this variety, which can be observed in its antimicrobial potential, tested in the studied strains too. Results revealed that Opuntia spp. could be used as a nutraceutical and/or food additive, maintaining and promoting health and life quality.

Antioxidant and Anti-Diabetic, Anti-Alzheimer Activities of Stem from Opuntia ficus-indica var. saboten Cultivated in Jeju at Harvest Time

Antioxidant and Anti-Diabetic, Anti-Alzheimer Activities of Stem from Opuntia ficus-indica var. saboten Cultivated in Jeju at Harvest Time

Hypoglycemic Effect of Opuntia ficus-indica var. saboten Is Due to Enhanced Peripheral Glucose Uptake through Activation of AMPK/p38 MAPK Pathway.

Opuntia ficus-indica var. saboten (OFS) has been used in traditional medicine for centuries to treat several illnesses, including diabetes. However, detailed mechanisms underlying hypoglycemic effects remain unclear. In this study, the mechanism underlying the hypoglycemic activity of OFS was evaluated using in vitro and in vivo systems. OFS treatment inhibited α-glucosidase activity and intestinal glucose absorption assessed by Na+-dependent glucose uptake using brush border membrane vesicles. AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle, and p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. In the present study, OFS dose-dependently increased glucose uptake in L6 muscle cells. The AMPK and p38 MAPK phosphorylations were stimulated by OFS, and inhibitors of AMPK (compound C) and p38 MAPK (SB203580) abolished the effects of OFS. Furthermore, OFS increased glucose transporter 4 (GLUT4) translocation to the plasma membrane. OFS administration (1 g/kg and 2 g/kg body weight) in db/db mice dose-dependently ameliorated hyperglycemia, hyperinsulinemia, and glucose tolerance. Insulin resistance assessed by homeostasis model assessment of insulin resistance and quantitative insulin sensitivity check index were also dose-dependently improved with OFS treatment. OFS administration improved pancreatic function through increased β-cell mass in db/db mice. These findings suggest that OFS acts by inhibiting glucose absorption from the intestine and enhancing glucose uptake from insulin-sensitive muscle cells through the AMPK/p38 MAPK signaling pathway.

Neuroprotective Effects of Quercetin 3-O-Methyl Ether, Quercetin and (±)-Dihydroquercetin in a Rat Model of Transient Focal Cerebral Ischemia

Stroke is the third leading cause of death in most industrialized countries, and the most important source of chronic disability, among which cerebral ischemic stroke represents about 85% of all. Ischemic stroke occurs by thrombotic or embolic blockade of an artery to the brain resulting in a deficiency in blood flow and causing a brain infarction. During ischemic stroke, diminished blood flow initiates a series of events such as inducing excessive release of excitatory amino acids and subsequent several receptor activations leading to elevated calcium influx that may result in damage to brain cells. Oxidative stress is one of the primary factors that exacerbate damage in cerebral ischemia. Moreover, the reactive oxygen species can create a secondary source of extensive cell injury and death since re-supply of oxygen to the brain through the reperfusion is relevant during the ischemic phase. Therefore, antioxidants that can scavenge oxygen free radicals have the therapeutic potential for the treatment of neuronal injury following ischemia and reperfusion. Many natural antioxidants are reported to reduce reactive oxygen species and protect neuronal cells in animal models of cerebral ischemia. Previously, we reported protective effects of quercetin 3O-methyl ether (1) and its related compounds (2, 3) isolated from Opuntia ficus-indica var. saboten against oxidative neuronal injuries induced in primary cultured rat cortical cells (Fig. 1). Quercetin (2) was found to inhibit H2O2or xanthine (X)/xanthine oxidase (XO)-induced oxidative neuronal cell injury with an estimated IC50 value of 4-5 μg/ mL. (+)-Dihydroquercetin (3) inhibited oxidative neuronal injuries concentration-dependently, but it was 2-3 fold less potent than 2. On the other hand, quercetin 3-O-methyl ether (1) potently inhibited H2O2and X/XO-induced neuronal injuries with IC50 values of 0.6 and 0.7 μg/mL, respectively, indicating that 1 appeared to be the most potent neuroprotectant among three flavonoids isolated from this plant. Recently, antioxidative activities in cell-free systems of 1 have also been reported. However, neuroprotective effects of 1 in ischemic animal models have not yet been reported. The present study, therefore, examined neuroprotective effects of 1 in a transient focal cerebral ischemic rat model and compared with those of related flavonoids 2 and (±)-3. The middle cerebral artery occlusion (MCAO) model has usually been used for assessing neuroprotective effects since most ischemic strokes occur in the territory of the middle cerebral artery. Transient focal cerebral ischemia was induced by occlusion of the right middle cerebral artery for 2 h with a silicone-coated 4-0 nylon monofilament in male Sprague-Dawley rats. The antioxidative flavonoids dissolved in 0.9% saline vehicle were administered intraperitoneally at a dose of 10 mg/kg 30 min after onset of ischemia. Infarct size and % edema were measured 24 h after onset of ischemia using a 2,3,5-triphenyltetrazolium chloride (TTC) staining method. Neurological scoring was performed 30 min and 24 h after MCAO. The neurobehavioral tests consisted of scoring the degree of left forelimb flexion (0 to 3), the duration of left forelimb flexion (0 to 4) and symmetry of movement/forepaw outstretching (0 to 3). Rats were scored on a ranking scale of 0 to 10, which reflects the cumulative score of the individual tests with a score of 10 reflecting normal behavior. Representative TTC staining is shown in Figure 2 to illustrate neuroprotective effects of 1, 2 and (±)3. Area stained red with TTC was considered normal, while area not stained red with TTC was considered infarcted.

Extracts of Edible and Medicinal Plants Damage Membranes of Vibrio cholerae

The use of natural compounds from plants can provide an alternative approach against food-borne pathogens. The mechanisms of action of most plant extracts with antimicrobial activity have been poorly studied. In this work, changes in membrane integrity, membrane potential, internal pH (pH(in)), and ATP synthesis were measured in Vibrio cholerae cells after exposure to extracts of edible and medicinal plants. A preliminary screen of methanolic, ethanolic, and aqueous extracts of medicinal and edible plants was performed. Minimal bactericidal concentrations (MBCs) were measured for extracts showing high antimicrobial activity. Our results indicate that methanolic extracts of basil (Ocimum basilicum L.), nopal cactus (Opuntia ficus-indica var. Villanueva L.), sweet acacia (Acacia farnesiana L.), and white sagebrush (Artemisia ludoviciana Nutt.) are the most active against V. cholera, with MBCs ranging from 0.5 to 3.0 mg/ml. Using four fluorogenic techniques, we studied the membrane integrity of V. cholerae cells after exposure to these four extracts. Extracts from these plants were able to disrupt the cell membranes of V. cholerae cells, causing increased membrane permeability, a clear decrease in cytoplasmic pH, cell membrane hyperpolarization, and a decrease in cellular ATP concentration in all strains tested. These four plant extracts could be studied as future alternatives to control V. cholerae contamination in foods and the diseases associated with this microorganism.

Antidepressant-like Effect of Kaempferol and Quercitirin, Isolated from Opuntia ficus-indica var. saboten

Opuntia ficus-indica var. saboten. is widely cultivated in Jeju Island (South Korea) for use in manufacture of health foods. This study described antidepressant effect of two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. The expression of the hypothalamic POMC mRNA or plasma β-endorphin levels were increased by extract of Opuntia ficus-indica var. saboten or its flavoniods administered orally. In addition, antidepressant activity was studied using tail suspension test (TST), forced swimming test (FST) and rota-rod test in chronically restraint immobilization stress group in mice. After restraint stress (2 hrs/day for 14 days), animals were kept in cage for 14 days without any further stress, bet with drugs. Mice were fed with a diet supplemented for 14 days and during the behavioral test period with kaempferol or quercitrin (30 mg/kg/day). POMC mRNA or plasma β-endorphin level was increased by extract of Opuntia ficus-indica var. saboten and its flavoniods. In addition, immobility time in TST and FST was significantly reduced by kaempferol or quercitrin. In rota-rod test, the time of permanence was maintained to the semblance of control group in turning at 15 rpm. Our results suggest that two flavonoids (kaempferol and quercitrin) isolated from the Opuntia ficus-indica var. saboten. show a potent antidepressant effect.

The n-butanolic extract of Opuntia ficus-indica var. saboten enhances long-term memory in the passive avoidance task in mice

Opuntia ficus-indica var. saboten Makino (Cactaceae) is used to treat burns, edema, dyspepsia, and asthma in traditional medicine. The present study investigated the beneficial effects of the n-butanolic extract of O. ficus-indica var. saboten (BOF) on memory performance in mice and attempts to uncover the mechanisms underlying its action. Memory performance was assessed with the passive avoidance task, and western blotting and immunohistochemistry were used to measure changes in protein expression and cell survival. After the oral administration of BOF for 7 days, the latency time in the passive avoidance task was significantly increased relative to vehicle-treated controls ( P < 0.05). Western blotting revealed that the expression levels of brain-derived neurotrophic factor (BDNF), phosphorylated cAMP response element binding-protein (pCREB), and phosphorylated extracellular signal-regulated kinase (pERK) 1/2 were significantly increased in hippocampal tissue after 7 days of BOF administration ( P < 0.05). Doublecortin and 5-bromo-2-deoxyuridine immunostaining also revealed that BOF significantly enhanced the survival of immature neurons, but did not affect neuronal cell proliferation in the subgranular zone of the hippocampal dentate gyrus. These results suggest that the subchronic administration of BOF enhances long-term memory, and that this effect is partially mediated by ERK-CREB-BDNF signaling and the survival of immature neurons.

Inhibitory effect of glycoprotein isolated from Opuntia ficus-indica var. saboten MAKINO on activities of allergy-mediators in compound 48/80-stimulated mast cells

The present study was performed to investigate the anti-allergy potentials of glycoprotein (90 kDa) isolated from Opuntia ficus-indica var. saboten MAKINO (OFI glycoprotein) in vivo (ICR mice) and in vitro (RBL-2H3 cells). At first, to know whether the OFI glycoprotein has an inhibitory ability for allergy in vivo, we evaluated the activities of allergy-related factors such as histamine and β-hexosaminidase release, lactate dehydrogenase (LDH), and interleukin 4 (IL-4) in compound 48/80 (8 ml/kg BW)-treated ICR mice. After that, we studied to found the effect for anti-allergy in vitro such as nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS), extracellular signal-regulated kinase (ERK) 1/2, arachidonic acid, and cyclooxygenase-2 (COX-2) in compound 48/80 (5 μg/ml)-treated RBL-2H3 cells. Our results showed that the OFI glycoprotein (5 mg/kg) inhibited histamine and β-hexosaminidase release, lactate dehydrogenase (LDH), and interleukin 4 (IL-4) in mice serum. Also OFI glycoprotein (25 μg/ml) has suppressive effects on the expression of MAPK (ERK1/2), and on protein expression of anti-allergic proteins (iNOS and COX-2). Thus, we speculate that the OFI glycoprotein is an example of natural compound that blocks anti-allergic signal transduction pathways.

복분자와 백련초가 첨가된 닭가슴살 면류 개발

기능성 면류제조를 위해 사용된 복분자와 백련초의 기능성을 평가한 결과 total polyphenol 함량을 측정한 결과 전반적으로 70% ethanol 추출물보다는 열수 추출물의 total polyphenol 함량이 높았으며 그 중 시료 농도 1,000 ppm에서 복분자 열수 추출물이 150.25 ㎎%로 가장 높은 함량을 나타내었다. 전자공여능도 열수 추출물이 DPPH에 대한 전자공여능이 높은 것으로 나타났는데, 시료 농도 1,000 ppm에서 복분자 열수 추출물이 69.36%로 가장 높게 나타났다. 닭가슴살, transglutaminase, 활성글루텐, 복분자, 백련초 등을 첨가하여 조리면의 품질 특성을 조사하였다. 면 익는 시간은 CB가 304초로 가장 짧았고, NCB가 779초로 가장 오래 걸렸다. 수분 흡수율은 CB가 146.3%로 가장 높았고 NCB가 61.5%로 가장 낮았다. 부피 증가율은 CB가 246.3%로 가장 높았고, NCB는 161.5%로 가장 낮았다. 국물의 탁도는 조리중 고형분의 손실 정도를 나타내는 지표로서 CB가 0.421로 가장 높았고, NCBT가 0.240으로 가장 낮았다. 물성을 측정한 결과 전반적으로 transglutaminase를 첨가한 처리구에서 hardness, cohesivness, springness 및 gumminess가 높은 물성을 나타내었다. 관능평가 결과 color는 모든 시료에서 4.0 이상으로 나타내었고, flavor는 모든 시료군에서 전반적으로 2.6～2.8로 낮은 관능검사 결과를 나타내었다. Chewiness는 CB와 NCB보다 CBT와 NCBT가 높게 나타났었고, overall acceptability는 transglutaminase 첨가구가 높게 나타났다. Chewiness 항목의 평가가 높았던 시료가 overall acceptability에서 높은 평가를 받은 것은 소비자들이 면을 먹을 때 쫄깃한 것을 선호하는 것으로 판단된다.

손바닥 선인장 분말로부터 추출된 항균물질의 특성

본 연구자들은 동<TEX>${\cdot}$</TEX>서양에서 오랫동안 민간요법으로 사용되어져 왔고, 문헌에도 약리적인 작용이 기록되어 있는 Opuntia ficus-indica var. Saboten Makino (손바닥 선인장, 백년초) 줄기 분말을 사용하여 항균생리활성 물질을 규명하고자 하였다. 줄기 분말을 황산으로 가수분해 처리한 후 메탄올, 메틸클로라이드, 에탄올 등의 용매로 추출하였다. 용매추출물 가운데 methylene chloride 추출물의 경우 가장 탁월한 항균활성을 나타내었다. 항균활성을 나타내는 생리활성 물질을 분리 분석하기 위하여 조제용 TLC를 이용하여 산 가수분해 추출물로부터 7개의 분획물을 분리하였다. 7개 분획물 가운데 가장 광범위한 항균활성을 나타내는 유효 분획물로 분리된 것을 MBT-01108이라 명명하였다. 산가수분해로 추출된 분획물 MBT-01108을 구조 분석한 결과 항균 활성을 나타내는 화합물이 levulinic acid임을 밝혀냈다. Opuntia ficus-indica var. Saboten Makino로부터 분리된 levulinic acid는 식품 또는 화장품의 천연 보존제로써 사용가능하리라 판단되며, 또한, 세균성 질병예방, 여드름, 노화 예방, 미백 화장품 성분, 그리고 항생제로도 사용 가능한 물질임을 밝혀냈다. In order to discover physiologically active substance, we investigated a powder obtained by processing of Opuntia ficus-indica var. saboten Makino trunk. The powder was treated by sulfuric acid and then extracted by several solvents such as methanol, methylene chloride, ethanol etc. Among them, the best antimicrobial activity was showed by methylene chloride extract. To identify materials exhibiting physiological activation, the acid hydrolyzed extract was separated by 7 fractions through preparative silica gel TLC. The effective fraction exhibiting the best broad antimicrobial activity was identified, named as MBT-01108. From structural analysis of the products extracted to acid hydrolysis, a compound exhibiting the antimicrobial activities is identified to levulinic acid. Levulinic acid isolated from Opuntia ficus-indica var. saboten Makino may be applicable as a natural preservative of food or cosmetic and for prevention of bacterial diseases, an ingredient of acne, ageing and whitening cosmetics and an antimicrobial agent.

백년초열매 분말 첨가 컵케이크의 품질특성

본 연구에서는 백년초 분말의 1, 3, 5% 첨가가 항산화성 및 컵케이크의 품질과 관능적 기호도, 저장성에 어떠한 영향을 주는지 확인하여 제품화의 최적조건 및 기능성 식품 소재로서의 이용가능성을 조사하였다. 백년초 분말의 각 농도에 대한 전자공여능 실험결과 백년초 분말의 농도가 증가함에 따라 항산화 활성이 증가하였다. 백년초 분말과 백년초 분말을 첨가한 컵케이크에서의 미생물 분석 결과 효모, 곰팡이, 대장균군은 검출되지 않았고 일반세균은 백년초 분말에서 4.41 log CFU/g로 나타났고 컵케이크에서는 검출한계(10² CFU/g) 이하로 나타났다. 컵케이크의 수분함량은 백년초 분말을 첨가한 구가 첨가하지 않은 구보다 높았으나 유의적인 차이는 없었다(p＜0.05). 색도는 첨가량이 증가할수록 crust와 crumb에서 명도와 황색도가 감소하고 적색도는 증가하였다. 물성은 백년초의 첨가 및 저장기간의 증가에 따라 견고성(hardness), 검성(gumminess), 씹힘성(chewiness)이 증가하였고 응집성(cohesiveness), 탄력성(springiness)은 감소하였다. 관능검사 결과 대조군 및 1% 백년초 분말 첨가 컵케이크가 색, 향, 맛, 조직감, 전체적인 기호도면에서 높은 점수를 받았다. 이러한 결과로 볼 때 백년초 분말을 컵케이크에 첨가하였을 때 항산화효과를 기대할 수 있으나 저장성에는 큰 영향을 미치지 않을 것으로 사료되었고, 컵케이크의 품질 및 관능특성, 기능성을 고려할 때 1% 첨가구가 최적조건일 것으로 판단되었다.

Synthesis and Antioxidant Activity of 3‐Methoxyflavones.

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Glycoprotein (90 kDa) Isolated from Opuntia ficus-indica var. saboten MAKINO Lowers Plasma Lipid Level through Scavenging of Intracellular Radicals in Triton WR-1339-Induced Mice

The Opuntia ficus-indica var. saboten MAKINO (OFI) has been traditionally used as health food and herbal agent in folk medicine in Korea. In this study, we investigated whether the OFI glycoprotein has antioxidative activity and hypolipidemic effect on Triton WR-1339-induced A/J mice. The OFI glycoprotein inhibits the production of reactive oxygen species (ROS) generated by glucose/glucose oxidase (G/GO) in BNL CL.2 cells. With its antioxidative property, the mice were orally administered in the OFI glycoprotein [50 mg/kg body weight (BW)] for two weeks. Our finding resulted in a significant decrease of plasma lipid levels in Triton WR-1339-treated mice such as total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL). Indeed, mice which induced by Triton WR-1339 were significantly increased the levels of TC, TG and LDL, whereas the high-density lipoprotein (HDL) level obviously decreased. However, the values were reversed at pretreatment with OFI glycoprotein in Triton WR-1339-treated mice. The data also showed that pretreatment with OFI glycoprotein resulted in decrease of thiobarbituric acid-reactive substances (TBARS) level and in increase of nitric oxide (NO) amount in presence of Triton WR-1339-treated mice, while the activities of antioxidant enzyme [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] were augmented. Therefore, we speculate that the OFI glycoprotein would be effective in lowering of plasma lipid levels.

Synthesis and Antioxidant Activity of 3-Methoxyflavones

It is becoming increasingly apparent that the overproduction of reactive oxygen species may overwhelm the protective antioxidative defense mechanisms resulting in oxidative tissue injury. Reactive oxygen species have been implicated in several different diseases including ischemia, inflammation and cancer. Fortunately, plants contain a wide variety of free radical scavenging molecules such as flavonoids, anthocyanins, carotenoids, dietary glutathione, vitamins and endogenous metabolites. Such natural products are rich in antioxidant activities. Recently, important biological property of natural flavonoids was suggested mainly due to their antioxidant activity elicited by scavenging oxygen radicals and inhibiting peroxidation. Also, the antioxidant activity of the flavonoids varies considerably depending on the backbone structures and functional groups. In the course of searching for neuroprotective agents, we recently identified quercetin 3-O-methyl ether (1b, R1, R3, R4 = H, R2 = OH) as a potent antioxidant from Opuntia ficus-indica var. saboten. Quercetin 3-O-methyl ether also exhibited potent neuroprotective effects on the oxidative injuries to neuronal cells. For the purpose of the development of neuroprotective agents for therapeutic use, we needed to modify the structure or substitute suitable groups in the structure of 1b to improve physicochemical properties or enhance antioxidant activities. Therefore, we synthesized a series of 3-methoxyflavones (1c-g) and examined their antioxidant activities to elucidate a suitable position for modification (Figure 1). To investigate briefly the influence of substituents of 3-methoxyflavones on antioxidant activity, we methylated the C-5 or C-7 hydroxyl group at A-ring of the chromone backbone or introduced mono-, di-, and trihydroxyl groups at B-ring.

Neuroprotective effects of antioxidative flavonoids, quercetin, (+)-dihydroquercetin and quercetin 3-methyl ether, isolated from Opuntia ficus-indica var. saboten

The flavonoids quercetin, (+)-dihydroquercetin, and quercetin 3-methyl ether were isolated from the ethyl acetate fractions of the fruits and stems of Opuntia ficus-indica var. saboten. In the present study, we evaluated their protective effects against oxidative neuronal injuries induced in primary cultured rat cortical cells and their antioxidant activities by using three different cell-free bioassays. Quercetin was found to inhibit H 2O 2- or xanthine (X)/xanthine oxidase (XO)-induced oxidative neuronal cell injury, with an estimated IC 50 of 4–5 μg/ml. However, it was no more protective at concentrations of 30 μg/ml and above. (+)-Dihydroquercetin concentration-dependently inhibited oxidative neuronal injuries, but it was less potent than quercetin. On the other hand, quercetin 3-methyl ether potently and dramatically inhibited H 2O 2- and X/XO-induced neuronal injuries, with IC 50 values of 0.6 and 0.7 μg/ml, respectively. All three principles markedly inhibited lipid peroxidation and scavenged 1,1-diphenyl-2-picrylhydrazyl free radicals. In addition, quercetin and quercetin 3-methyl ether were shown to inhibit XO activity in vitro, with respective IC 50 values of 10.67 and 42.01 μg/ml. These results indicate that quercetin, (+)-dihydroquercetin, and quercetin 3-methyl ether are the active antioxidant principles in the fruits and stems of Opuntia ficus-indica var. saboten exhibiting neuroprotective actions against the oxidative injuries induced in cortical cell cultures. Furthermore, quercetin 3-methyl ether appears to be the most potent neuroprotectant of the three flavonoids isolated from this plant.