Displaying publications 41 - 60 of 102 in total

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  1. Identification and quantification of phenolic and flavonoid components in straw and seed husk of some rice varieties (Oryza sativa L.) and their antioxidant properties
    Karimi E, Mehrabanjoubani P, Keshavarzian M, Oskoueian E, Jaafar HZ, Abdolzadeh A
    J Sci Food Agric, 2014 Aug;94(11):2324-30.
    PMID: 24415452 DOI: 10.1002/jsfa.6567
    Plant foods are rich sources of bioactive compounds that can act as antioxidants to prevent heart disease, reduce inflammation, reduce the incidence of cancers and diabetes. This study aimed to determine the phenolics and flavonoids profiling in three varieties of rice straw and five varieties of the seed husk of Iranian rice using high-performance liquid chromatography (HPLC). Furthermore, the antioxidant activities of the extracts were evaluated by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and nitric oxide assays.
    Matched MeSH terms: Flavonoids/analysis
  2. Effect of extraction solvents and plant parts used on the antihyperlipidemic and antioxidant effects of Garcinia atroviridis: a comparative study
    Al-Mansoub MA, Asmawi MZ, Murugaiyah V
    J Sci Food Agric, 2014 Jun;94(8):1552-8.
    PMID: 24166055 DOI: 10.1002/jsfa.6456
    Garcinia atroviridis is a seasonal fruit plant found in many parts of South East Asia. The fruit rind is used in cooking and traditionally consumed for various reasons, including to lower blood cholesterol. A comparative study was undertaken to investigate the influence of extraction solvents and plant parts used on the lipid-lowering and antioxidant activities of Garcinia atroviridis.
    Matched MeSH terms: Flavonoids/analysis
  3. Chemical composition, antioxidant and antibacterial properties of the essential oils of Etlingera elatior and Cinnamomum pubescens Kochummen
    Abdelwahab SI, Zaman FQ, Mariod AA, Yaacob M, Abdelmageed AH, Khamis S
    J Sci Food Agric, 2010 Dec;90(15):2682-8.
    PMID: 20945508 DOI: 10.1002/jsfa.4140
    Plant essential oils are widely used as fragrances and flavours. Therefore, the essential oils from the leaves of Cinnamomum pubescens Kochummen (CP) and the whole plant of Etlingera elatior (EE) were investigated for their antioxidant, antibacterial and phytochemical properties.
    Matched MeSH terms: Flavonoids/analysis
  4. Comparison of partial least squares and random forests for evaluating relationship between phenolics and bioactivities of Neptunia oleracea
    Lee SY, Mediani A, Maulidiani M, Khatib A, Ismail IS, Zawawi N, et al.
    J Sci Food Agric, 2018 Jan;98(1):240-252.
    PMID: 28580581 DOI: 10.1002/jsfa.8462
    BACKGROUND: Neptunia oleracea is a plant consumed as a vegetable and which has been used as a folk remedy for several diseases. Herein, two regression models (partial least squares, PLS; and random forest, RF) in a metabolomics approach were compared and applied to the evaluation of the relationship between phenolics and bioactivities of N. oleracea. In addition, the effects of different extraction conditions on the phenolic constituents were assessed by pattern recognition analysis.

    RESULTS: Comparison of the PLS and RF showed that RF exhibited poorer generalization and hence poorer predictive performance. Both the regression coefficient of PLS and the variable importance of RF revealed that quercetin and kaempferol derivatives, caffeic acid and vitexin-2-O-rhamnoside were significant towards the tested bioactivities. Furthermore, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) results showed that sonication and absolute ethanol are the preferable extraction method and ethanol ratio, respectively, to produce N. oleracea extracts with high phenolic levels and therefore high DPPH scavenging and α-glucosidase inhibitory activities.

    CONCLUSION: Both PLS and RF are useful regression models in metabolomics studies. This work provides insight into the performance of different multivariate data analysis tools and the effects of different extraction conditions on the extraction of desired phenolics from plants. © 2017 Society of Chemical Industry.

    Matched MeSH terms: Flavonoids/analysis
  5. Two-dimensional correlation infrared spectroscopy applied to analyzing and identifying the extracts of Baeckea frutescens medicinal materials
    Adib AM, Jamaludin F, Kiong LS, Hashim N, Abdullah Z
    J Pharm Biomed Anal, 2014 Aug 5;96:104-10.
    PMID: 24727283 DOI: 10.1016/j.jpba.2014.03.022
    Baeckea frutescens or locally known as Cucur atap is used as antibacterial, antidysentery, antipyretic and diuretic agent. In Malaysia and Indonesia, they are used as an ingredient of the traditional medicine given to mothers during confinement. A three-steps infra-red (IR) macro-fingerprinting method combining conventional IR spectra, and the secondary derivative spectra with two dimensional infrared correlation spectroscopy (2D-IR) have been proved to be effective methods to examine a complicated mixture such as herbal medicines. This study investigated the feasibility of employing multi-steps IR spectroscopy in order to study the main constituents of B. frutescens and its different extracts (extracted by chloroform, ethyl acetate, methanol and aqueous in turn). The findings indicated that FT-IR and 2D-IR can provide many holistic variation rules of chemical constituents. The structural information of the samples indicated that B. frutescens and its extracts contain a large amount of flavonoids, since some characteristic absorption peaks of flavonoids, such as ∼1600cm(-1), ∼1500cm(-1), ∼1450cm(-1), and ∼1270cm(-1) can be observed. The macroscopical fingerprint characters of FT-IR and 2D-IR spectra can not only provide the information of main chemical constituents in medicinal materials and their different extracts, but also compare the components differences among the similar samples. In conclusion, the multi-steps IR macro-fingerprint method is rapid, effective, visual and accurate for pharmaceutical research.
    Matched MeSH terms: Flavonoids/analysis
  6. Fulltext Chemical Composition, Oxidative Stability, and Antioxidant Activity of Allium ampeloprasum L. (Wild Leek) Seed Oil
    Nehdi IA, Sbihi HM, Tan CP, Al-Resayes SI, Rashid U, Al-Misned FA, et al.
    J Oleo Sci, 2020 May 02;69(5):413-421.
    PMID: 32281562 DOI: 10.5650/jos.ess19298
    Allium ampeloprasum L., commonly known as wild leek, is an edible vegetable that has been cultivated for centuries. However, no detailed studies have been undertaken to valorize A. ampeloprasum seed oil. This study aims to evaluate the physicochemical properties, chemical composition, and antioxidant activity of A. ampeloprasum seed oil. The seed oil content was found to be 18.20%. Gas chromatographymass spectrometry (GC-MS) showed that linoleic acid (71.65%) was the dominant acid, followed by oleic acid (14.11%) and palmitic acid (7.11%). A. ampeloprasum seed oil exhibited an oxidative stability of 5.22 h. Moreover, γ- and δ-tocotrienols were the major tocols present (79.56 and 52.08 mg/100 g oil, respectively). The total flavonoid content (16.64 µg CE /g oil) and total phenolic content (62.96 µg GAE /g oil) of the seed oil were also determined. The antioxidant capacity of the oil, as evaluated using the ABTS assay (136.30 µM TEAC/g oil), was found to be significant. These findings indicate that A. ampeloprasum seeds can be regarded as a new source of edible oil having health benefits and nutritional properties.
    Matched MeSH terms: Flavonoids/analysis
  7. Fulltext Recovery and Utilization of Palm Oil Mill Effluent Source as Value-Added Food Products
    Teh SS, Hock Ong AS, Mah SH
    J Oleo Sci, 2017;66(11):1183-1191.
    PMID: 29093377 DOI: 10.5650/jos.ess17078
    The environmental impacts of palm oil mill effluent (POME) have been a concern due to the water pollution and greenhouse gases emissions. Thus, this study was conducted to recover the value-added products from POME source before being discharged. The samples, before (X) and after (Y) the pre-recovery system in the clarification tank were sampled and analysed and proximate analysis indicated that both samples are energy rich source of food due to high contents of fats and carbohydrates. GCMS analysis showed that the oil extracts contain predominantly palmitic, oleic, linoleic and stearic acids. Regiospecific analysis of oil extracts by quantitative 13C-NMR spectroscopy demonstrated that both oil extracts contain similar degree of saturation of fatty acids at sn-2 and sn-1,3 positions. The samples are rich in various phytonutrients, pro-vitamin A, vitamin E, squalene and phytosterols, thus contributing to exceptionally high total flavonoid contents and moderate antioxidant activities. Overall, samples X and Y are good alternative food sources, besides reducing the environmental impact of POME.
    Matched MeSH terms: Flavonoids/analysis
  8. Phytochemical profiles and antimicrobial activity of aromatic Malaysian herb extracts against food-borne pathogenic and food spoilage microorganisms
    Aziman N, Abdullah N, Noor ZM, Kamarudin WS, Zulkifli KS
    J Food Sci, 2014 Apr;79(4):M583-92.
    PMID: 24666004 DOI: 10.1111/1750-3841.12419
    Preliminary phytochemical and flavonoid compounds of aqueous and ethanolic extracts of 6 aromatic Malaysian herbs were screened and quantified using Reverse-Phase High Performance Liquid Chromatography (RP-HPLC). The herbal extracts were tested for their antimicrobial activity against 10 food-borne pathogenic and food spoilage microorganisms using disk diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of herbal extracts were determined. In the phytochemical screening process, both aqueous and ethanolic extracts of P. hydropiper exhibited presence of all 7 tested phytochemical compounds. Among all herbal extracts, the aqueous P. hydropiper and E. elatior extracts demonstrated the highest antibacterial activity against 7 tested Gram-positive and Gram-negative bacteria with diameter ranging from 7.0 to 18.5 mm and 6.5 to 19 mm, respectively. The MIC values for aqueous and ethanolic extracts ranged from 18.75 to 175 mg/mL and 0.391 to 200 mg/mL, respectively while the MBC/MFC values for aqueous and ethanolic extracts ranged from 25 to 200 mg/mL and 3.125 to 50 mg/mL, respectively. Major types of bioactive compounds in aqueous P. hydropiper and E. elatior extracts were identified using RP-HPLC instrument. Flavonoids found in these plants were epi-catechin, quercetin, and kaempferol. The ability of aqueous Persicaria hydropiper (L.) H. Gross and Etlingera elatior (Jack) R.M. Sm. extracts to inhibit the growth of bacteria is an indication of its broad spectrum antimicrobial potential. Hence these herbal extracts may be used as natural preservative to improve the safety and shelf-life of food and pharmaceutical products.
    Matched MeSH terms: Flavonoids/analysis
  9. Identification of bioactive candidate compounds responsible for oxidative challenge from hydro-ethanolic extract of Moringa oleifera leaves
    Karthivashan G, Tangestani Fard M, Arulselvan P, Abas F, Fakurazi S
    J Food Sci, 2013 Sep;78(9):C1368-75.
    PMID: 24024688 DOI: 10.1111/1750-3841.12233
    Free radicals trigger chain reaction and inflict damage to the cells and its components, which in turn ultimately interrupts their biological activities. To prevent free radical damage, together with an endogenous antioxidant system, an exogenous supply of antioxidant components to the body in the form of functional food or nutritional diet helps undeniably. Research conducted by the Natl. Inst. of Health claimed that Moringa oleifera Lam possess the highest antioxidant content among various natural food sources based on an oxygen radical absorbent capacity assay. In this study, a 90% (ethanol:distilled water--90:10) gradient solvent was identified as one of the best gradient solvents for the effectual extraction of bioactive components from M. oleifera leaves. This finding was confirmed by various antioxidant assays, including radical scavenging activity (that is, 1, 1-diphenyl-2-picrylhydrazyl, H(2)O(2), and NO radical scavenging assay) and total antioxidant capacity (that is, ferric reducing antioxidant power and molybdenum assay). High-performance liquid chromatography (HPLC) fingerprints of the 90% gradient extract visually showed few specific peaks, which on further analysis, using HPLC-DAD-ESI-MS, were identified as flavonoids and their derivatives. Despite commonly reported flavonoids, that is, kaempferol and quercetin, we report here for the 1st time the presence of multiflorin-B and apigenin in M. oleifera leaves. These findings might help researchers to further scrutinize this high activity exhibiting gradient extract and its bio-active candidates for fruitful clinical/translational investigations.
    Matched MeSH terms: Flavonoids/analysis
  10. Phenolic acid composition and antioxidant properties of Malaysian honeys
    Khalil MI, Alam N, Moniruzzaman M, Sulaiman SA, Gan SH
    J Food Sci, 2011 Aug;76(6):C921-8.
    PMID: 22417491 DOI: 10.1111/j.1750-3841.2011.02282.x
    The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities.
    Matched MeSH terms: Flavonoids/analysis
  11. Total phenolic compounds, flavonoids, and radical scavenging activity of 21 selected tropical plants
    Mustafa RA, Abdul Hamid A, Mohamed S, Bakar FA
    J Food Sci, 2010 Jan-Feb;75(1):C28-35.
    PMID: 20492146 DOI: 10.1111/j.1750-3841.2009.01401.x
    Free radical scavenging activity of 21 tropical plant extracts was evaluated using 1,1-diphenyl-2-picrylhydrazyl assay (DPPH). Total phenolic compounds and flavonoids were determined using Folin-Ciocalteu and HPLC, respectively. Results of the study revealed that all the plants tested exhibited excellent antioxidant activity with IC(50) in the range of 21.3 to 89.6 microg/mL. The most potent activity was demonstrated by Cosmos caudatus (21.3 microg/mL) and Piper betle (23.0 microg/mL) that are not significantly different than that of -tocopherol or BHA. L. inermis extract was found to consist of the highest concentration of phenolics, catechin, epicatechin, and naringenin. High content of quercetin, myricetin, and kaempferol were identified in Vitex negundo, Centella asiatica, and Sesbania grandiflora extracts, respectively. Luteolin and apigenin, on the other hand, were found in Premna cordifolia and Kaempferia galanga extracts. Strong correlation (R = 0.8613) between total phenolic compounds and total flavonoids (R = 0.8430) and that of antioxidant activity of the extracts were observed. The study revealed that phenolic, in particular flavonoids, may be the main contributors to the antioxidant activity exhibited by the plants.
    Matched MeSH terms: Flavonoids/analysis*
  12. Inhibitory effect of morinda citrifolia L. On lipoprotein lipase activity
    Pak-Dek MS, Abdul-Hamid A, Osman A, Soh CS
    J Food Sci, 2008 Oct;73(8):C595-8.
    PMID: 19019102 DOI: 10.1111/j.1750-3841.2008.00929.x
    Efficacy of Morinda citrifolia L. leaf (MLE) and fruit extracts (MFE) in inhibiting lipoprotein lipase (LPL) was determined in vitro. The result of the study showed that the highest inhibition on the LPL activity was exhibited by MLE (66%+/- 2.1%), which is significantly higher than that demonstrated by MFE (54.5%+/- 2.5%), green tea extract (GTE) (54.5%+/- 2.6%), and catechin (43.6%+/- 6.1%). Percent of LPL inhibition increase with concentration of the extracts. Quantitative analysis of the extracts revealed the presence of high levels of (+)-catechin at 63.5 +/- 17 and 53.7 +/- 5.7 mg/g in MLE and MFE, respectively, although not as high as that found in GTE (530.6 +/- 42 mg/g). Appreciable amount of epicatechin was found in all extracts tested, while rutin was only found in MLE and MFE. The study suggested that both leaf and fruit of M. citrifolia may be used as antiobesity agents in body weight management.
    Matched MeSH terms: Flavonoids/analysis
  13. Garlic flavonoids alleviate H2 O2 induced oxidative damage in L02 cells and induced apoptosis in HepG2 cells by Bcl-2/Caspase pathway
    Gao X, Yanan J, Santhanam RK, Wang Y, Lu Y, Zhang M, et al.
    J Food Sci, 2021 Feb;86(2):366-375.
    PMID: 33448034 DOI: 10.1111/1750-3841.15599
    Liver damage is a common liver disorder, which could induce liver cancer. Oral antioxidant is one of the effective treatments to prevent and alleviate liver damage. In this study, three flavonoids namely myricetin, isoquercitrin, and isorhamnetin were isolated and identified from Laba garlic. The isolated compounds were investigated on the protective effects against H2 O2 -induced oxidative damages in hepatic L02 cells and apoptosis inducing mechanism in hepatic cancer cells HepG2 by using MTT assay, flow cytometry and western blotting analysis. Myricetin, isoquercitrin, and isorhamnetin showed proliferation inhibition on HepG2 cells with IC50 value of 44.32 ± 0.213 µM, 49.68 ± 0.192 µM, and 54.32 ± 0.176 µM, respectively. While they showed low toxicity on normal cell lines L02. They could significantly alleviate the oxidative damage towards L02 cells (P < 0.05), via inhibiting the morphological changes in mitochondria and upholding the integrity of mitochondrial structure and function. The fluorescence intensity of L02 cells pre-treated with myricetin, isoquercitrin, and isorhamnetin (100 µM) was 89.23 ± 1.26%, 89.35 ± 1.43% and 88.97 ± 0.79%, respectively. Moreover, the flavonoids could induce apoptosis in HepG2 cells via Bcl-2/Caspase pathways, where it could up-regulate the expression of Bax and down-regulate the expression of Bcl-2, Bcl-xL, pro-Caspase-3, and pro-Caspase-9 proteins in a dose dependent manner. Overall, the results suggested that the flavonoids from Laba garlic might be a promising candidate for the treatment of various liver disorders. PRACTICAL APPLICATION: Flavonoids from Laba garlic showed selective toxicity towards HepG2 cells in comparison to L02 cells via regulating Bcl-2/caspase pathway. Additionally, the isolated flavonoids expressively barred the oxidative damage induced by H2 O2 in L02 cells. These results suggested that the flavonoids from laba garlic could be a promising agent towards the development of functional foods.
    Matched MeSH terms: Flavonoids/analysis
  14. Approach to preserve phenolics in Thunbergia laurifolia leaves by different drying treatments
    Oh HKF, Siow LF, Lim YY
    J Food Biochem, 2019 07;43(7):e12856.
    PMID: 31353691 DOI: 10.1111/jfbc.12856
    Different drying methods and blanching were investigated as to their effects on antioxidant and oxidase activities of Thunbergia laurifolia leaves. Results showed that oven-drying had the highest degradation of total phenolic content (TPC) and antioxidant activity at >85%, while freeze-drying had the lowest at <20%. However, inactivation of oxidase enzymes by blanching at 100°C resulted in a lesser decrease in TPC for oven-drying at 50 and 100°C (51% and 65%, respectively), indicating the importance of inactivating the oxidase enzymes for lower degradation of phenolics on drying. The high-performance liquid chromatography analysis showed that its major antioxidant, rosmarinic acid, degraded tremendously in the presence of oxidase enzymes, but only degraded slightly upon inactivation of oxidase enzymes. Hence, this work showed that by controlling the enzymatic activity, the preservation of phenolics with specific bioactivity in herbal tea leaves can be achieved. PRACTICAL APPLICATIONS: Thunbergia laurifolia leaves have been frequently consumed in the form of a tea or pill due to its medicinal properties. Processing of fresh herbal plant leaves by drying is required to preserve antioxidant phenolic compounds and quality of the plant leaves. Although the drying effects on the antioxidant properties have been studied, the factors that cause the change in properties have not been investigated in-depth. Controlling the factors that affect the phenolic content can help to preserve the beneficial antioxidants when processing the leaves by drying. The result of this study will be of relevance and beneficial to the herbal tea industry.
    Matched MeSH terms: Flavonoids/analysis
  15. Pharmacological mechanisms underlying the vascular activities of Loranthus ferrugineus Roxb. in rat thoracic aorta
    Ameer OZ, Salman IM, Siddiqui MJ, Yam MF, Sriramaneni RN, Mohamed AJ, et al.
    J Ethnopharmacol, 2010 Jan 8;127(1):19-25.
    PMID: 19808083 DOI: 10.1016/j.jep.2009.09.057
    The present study was aimed to investigate the pharmacological basis for the use of Loranthus ferrugineus in hypertension.
    Matched MeSH terms: Flavonoids/analysis
  16. Dillenia suffruticosa exhibited antioxidant and cytotoxic activity through induction of apoptosis and G2/M cell cycle arrest
    Armania N, Yazan LS, Musa SN, Ismail IS, Foo JB, Chan KW, et al.
    J Ethnopharmacol, 2013 Mar 27;146(2):525-35.
    PMID: 23353897 DOI: 10.1016/j.jep.2013.01.017
    Dillenia suffruticosa (Family: Dilleniaceae) locally known as Simpoh air has been reported to be used traditionally to treat cancerous growth. Therefore, the present study was attempted to investigate the antioxidant and cytotoxic properties of different parts (root, flower, fruit and leaf) of D. suffruticosa extracts.
    Matched MeSH terms: Flavonoids/analysis
  17. A new phytochemical survey of Malaysia. V. Preliminary screening and plant chemical studies
    Teo LE, Pachiaper G, Chan KC, Hadi HA, Weber JF, Deverre JR, et al.
    J Ethnopharmacol, 1990 Feb;28(1):63-101.
    PMID: 2314111
    A large phytochemical survey of the flora of the Malaysian Peninsula and Sabah is described, covering the systematic search for alkaloids, and partly, for saponins and flavonoids. Details of some chemical studies are reported. This emphasizes the great interest of such a study.
    Matched MeSH terms: Flavonoids/analysis
  18. Assessment of antioxidant activity in Victorian marine algal extracts using high performance thin-layer chromatography and multivariate analysis
    Agatonovic-Kustrin S, Morton DW, Ristivojević P
    J Chromatogr A, 2016 Oct 14;1468:228-235.
    PMID: 27670751 DOI: 10.1016/j.chroma.2016.09.041
    The aim of this study was to develop and validate a rapid and simple high performance thin layer chromatographic (HPTLC) method to screen for antioxidant activity in algal samples. 16 algal species were collected from local Victorian beaches. Fucoxanthin, one of the most abundant marine carotenoids was quantified directly from the HPTLC plates before derivatization, while derivatization either with 2,2-diphenyl-1-picrylhydrazyl (DPPH) or ferric chloride (FeCl3) was used to analyze antioxidants in marine algae, based on their ability to scavenge non biological stable free radical (DPPH) or to chelate iron ions. Principal component analysis of obtained HPTLC fingerprints has classified algae species into 5 groups according to their chemical/antioxidant profiles. The investigated brown algae samples were found to be rich in non-and moderate-polar compounds and phenolic compounds with antioxidant activity. Most of the phenolic iron chelators also have shown free radical scavenging activity. Strong positive and significant correlations between total phenolic content and DPPH radical scavenging activity showed that, phenolic compounds, including flavonoids are the main contributors of antioxidant activity in these species. The results suggest that certain brown algae possess significantly higher antioxidant potential when compared to red or green algae and could be considered for future applications in medicine, dietary supplements, cosmetics or food industries. Cystophora monilifera extract was found to have the highest antioxidant concentration, followed by Zonaria angustata, Cystophora pectinate, Codium fragile, and Cystophora pectinata. Fucoxanthin was found mainly in the brown algae species. The proposed methods provide an edge in terms of screening for antioxidants and quantification of antioxidant constituents in complex mixtures. The current application also demonstrates flexibility and versatility of a standard HPTLC system in the drug discovery. Proposed methods could be used for the bioassay-guided isolation of unknown natural antioxidants and subsequent identification if combined with spectroscopic identification.
    Matched MeSH terms: Flavonoids/analysis
  19. RP-HPLC method for the quantitative analysis of naturally occurring flavonoids in leaves of Blumea balsamifera DC
    Nessa F, Ismail Z, Karupiah S, Mohamed N
    J Chromatogr Sci, 2005 Sep;43(8):416-20.
    PMID: 16212782
    A selective and sensitive reversed-phase (RP) high-performance liquid chromatographic method is developed for the quantitative analysis of five naturally occurring flavonoids of Blumea balsamifera DC, namely dihydroquercetin-7,4'-dimethyl ether (DQDE), blumeatin (BL), quercetin (QN), 5,7,3',5'-tetrahydroxyflavanone (THFE), and dihydroquercetin-4'-methyl ether (DQME). These compounds have been isolated using various chromatographic methods. The five compounds are completely separated within 35 min using an RP C18, Nucleosil column and with an isocratic methanol-0.5% phosphoric acid (50:50, v/v) mobile phase at the flow rate of 0.9 mL/min. The separation of the compounds is monitored at 285 nm using UV detection. Identifications of specific flavonoids are made by comparing their retention times with those of the standards. Reproducibility of the method is good, with coefficients of variation of 1.48% for DQME, 2.25% for THFE, 2.31% for QN, 2.23% for DQDE, and 1.51% for BL. The average recoveries of pure flavonoids upon addition to lyophilized powder and subsequent extraction are 99.8% for DQME, 99.9% for THFE, 100.0% for BL, 100.6% for DQDE, and 97.4% for QN.
    Matched MeSH terms: Flavonoids/analysis*
  20. Identification and quantification of phenolic compounds in bambangan (Mangifera pajang Kort.) peels and their free radical scavenging activity
    Hassan FA, Ismail A, Abdulhamid A, Azlan A
    J Agric Food Chem, 2011 Sep 14;59(17):9102-11.
    PMID: 21800901 DOI: 10.1021/jf201270n
    Phenolic compounds and antioxidant capacity of acidified methanolic extract prepared from fully ripe bambangan (Mangifera pajang K.) peel cultivated in Sarawak, Malaysia, were analyzed. The total phenolic content (98.3 mg GAE/g) of bambangan peel powder (BPP) was determined by the Folin-Ciocalteu method. BPP showed a strong potency of antioxidant activity and was consistent with that of BHT and vitamin C as confirmed by the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and FRAP (ferric-reducing antioxidant power) assays. Gallic acid, p-coumaric acid, ellagic acid, protocatechuic acid, and mangiferin were the major compounds among the 16 phenolics that have been identified and quantified in M. pajang peels with 20.9, 12.7, 7.3, 5.4, and 4.8 mg/g BPP, respectively. Peak identities were confirmed by comparing their retention times, UV-vis absorption spectra, and mass spectra with authentic standards. The 16 phenolic compounds identified in M. pajang K. using HPLC-DAD and TSQ-ESI-MS are reported here for the first time.
    Matched MeSH terms: Flavonoids/analysis
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