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  1. Ghasemzadeh A, Karbalaii MT, Jaafar HZE, Rahmat A
    Chem Cent J, 2018 Feb 17;12(1):17.
    PMID: 29455357 DOI: 10.1186/s13065-018-0382-9
    BACKGROUND: In the recent years, the health benefits of the pigmented rice varieties have reported due to the presence of bioactive compounds. In this study, the phytochemical constituents (total phenolic, flavonoid and anthocyanin content) and individual phenolics and flavonoids of the extracts of sixteen genotypes of pigmented rice bran were evaluated using spectrophotometric and ultra-high performance liquid chromatography method. Antioxidative properties of the free and bound fractions were evaluated using nitric oxide and 1,1-diphenyl-2-picrylhydrazyl scavenging assays. Extracts were evaluated for antiproliferative activity against breast cancer cell lines (MCF-7 and MDA-MB-231) using the MTT assay.

    RESULTS: Signifficant diferences were observed in the concentrations of phytochemicals and biological activities among different pigmented rice brans. The highest phytochemical content was observed in black rice bran followed by red and brown rice bran. The concentration of free individual flavonoids and phenolic compounds were significantly higher than those of bound compounds except those of ferulic acid and p-coumaric acid. Highest antioxidant activities were observed in black rice bran, followed by red and brown rice bran extracts. Extracts of black rice bran exhibited potent antiproliferative activity, with half maximal inhibitory concentrations (IC50) of 148.6 and 119.2 mg/mL against MCF-7 and MDA-MB-231 cell lines, respectively, compared to the activity of the extracts of red rice bran (175.0 and 151.0 mg/mL, respectively) and brown rice bran (382.3 and 346.1 mg/mL, respectively).

    CONCLUSIONS: Black rice bran contains high levels of phytochemicals, and thus has potent pharmaceutical activity. This highlights opportunities for researcher to breed new genotypes of rice with higher nutritional values, which the food industry can use to develop new products that will compete in expanding functional food markets.

  2. Ghasemzadeh A, Jaafar HZE, Baghdadi A, Tayebi-Meigooni A
    Molecules, 2018 07 05;23(7).
    PMID: 29976903 DOI: 10.3390/molecules23071646
    Gingerols and shogaols are compounds found in ginger (Zingiber officinale Roscoe); shogaols are found in lower concentration than gingerols but exhibit higher biological activities. This work studied the effects of different drying methods including open sun drying (OSD) solar tunnel drying (STD) and hot air drying (HAD) with various temperature on the formation of six main active compounds in ginger rhizomes, namely 6-, 8-, and 10-gingerols and 6-, 8-, and 10-shogaols, as well as essential oil content. Antioxidant and antimicrobial activity of dried ginger was also evaluated. High performance liquid chromatography (HPLC) analysis showed that after HAD with variable temperature (120, 150 and 180 °C), contents of 6-, 8-, and 10-gingerols decreased, while contents of 6-, 8-, and 10-shogaol increased. High formation of 6-, 8-, and 10-shogaol contents were observed in HAD (at 150 °C for 6 h) followed by STD and OSD, respectively. OSD exhibited high content of essential oil followed by STD and HAD method. Ginger-treated with HAD exhibited the highest DPPH (IC50 of 57.8 mg/g DW) and FRAP (493.8 µM of Fe(II)/g DM) activity, compared to STD and OSD method. HAD ginger exhibited potent antimicrobial activity with lower minimum inhibition concentration (MIC) value against bacteria strains followed by STD and OSD, respectively. Ginger extracts showed more potent antimicrobial activity against Gram positive bacteria than Gram negative bacteria strains. Result of this study confirmed that conversion of gingerols to shogaols was significantly affected by different drying temperature and time. HAD at 150 °C for 6 h, provides a method for enhancing shogaols content in ginger rhizomes with improving antioxidant and antimicrobial activities.
  3. Ghasemzadeh A, Jaafar HZE, Baghdadi A, Tayebi-Meigooni A
    Molecules, 2018 Jul 25;23(8).
    PMID: 30044450 DOI: 10.3390/molecules23081852
    Since α-mangostin in mangosteen fruits was reported to be the main compound able to provide natural antioxidants, the microwave-assisted extraction process to obtain high-quality α-mangostin from mangosteen pericarp (Garcinia mangostana L.) was optimized using a central composite design and response surface methodology. The parameters examined included extraction time, microwave power, and solvent percentage. The antioxidant and antimicrobial activity of optimized and non-optimized extracts was evaluated. Ethyl acetate as a green solvent exhibited the highest concentration of α-mangostin, followed by dichloromethane, ethanol, and water. The highest α-mangostin concentration in mangosteen pericarp of 121.01 mg/g dry matter (DM) was predicted at 3.16 min, 189.20 W, and 72.40% (v/v). The verification of experimental results under these optimized conditions showed that the α-mangostin value for the mangosteen pericarp was 120.68 mg/g DM. The predicted models were successfully developed to extract α-mangostin from the mangosteen pericarp. No significant differences were observed between the predicted and the experimental α-mangostin values, indicating that the developed models are accurate. The analysis of the extracts for secondary metabolites showed that the total phenolic content (TPC) and total flavonoid content (TFC) increased significantly in the optimized extracts (OE) compared to the non-optimized extracts (NOE). Additionally, trans-ferulic acid and catechin were abundant among the compounds identified. In addition, the optimized extract of mangosteen pericarp with its higher α-mangostin and secondary metabolite concentrations exhibited higher antioxidant activities with half maximal inhibitory concentration (IC50) values of 20.64 µg/mL compared to those of the NOE (28.50 µg/mL). The OE exhibited the highest antibacterial activity, particularly against Gram-positive bacteria. In this study, the microwave-assisted extraction process of α-mangostin from mangosteen pericarp was successfully optimized, indicating the accuracy of the models developed, which will be usable in a larger-scale extraction process.
  4. Ghasemzadeh A, Jaafar HZE, Bukhori MFM, Rahmat MH, Rahmat A
    Chem Cent J, 2018 Feb 07;12(1):12.
    PMID: 29417254 DOI: 10.1186/s13065-018-0377-6
    BACKGROUND: Parkia speciosa seeds are a common ingredient in Malay cuisine with traditional interest because of its medicinal importance and content of health-promoting phytochemicals. This study evaluated the phytochemical constituents and biological activities (antioxidant and antibacterial activities) of Parkia speciosa Hassk seeds collected from three different regions of Malaysia (Perak, Negeri Sembilan and Johor). Phytochemical constituents (total flavonoid and total phenolic) were measured using the spectrophotometric method, and individual flavonoids and phenolic acids were identified using ultra-high-performance liquid chromatography. Ferric reducing antioxidant potential (FRAP) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay we used in order to evaluation of antioxidant activities. Disc diffusion method was employed for the evaluation of antibacterial activity of extracts against Gram-positive and Gram-negative bacterial strains.

    RESULTS: The primary screening of phytochemicals showed that P. speciosa seeds contain alkaloids, terpenoids, flavonoids, and phenolics. Samples collected from Perak contained the highest levels of the phytochemical constituents, with highest DPPH and FRAP activity followed by Negeri sembilan and Johor. From the identified compounds, quercetin and gallic acid were identified as the most abundant compounds. Seeds collected from the Perak location exhibited potent antibacterial activity, against both Gram-positive and Gram-negative bacteria strains. Staphylococcus aureus and Bacillus subtilis were recorded as the bacterial strains most sensitive to P. speciosa seed extracts. Correlation analysis showed that flavonoid compounds are responsible for the antioxidant activities of the P. speciosa seeds studied, while antibacterial activity showed a high correlation with the levels of gallic acid.

    CONCLUSIONS: Parkia speciosa seed grown in Perak exhibit the highest concentrations of phytochemicals, as well as the highest biological activity. It may also be recommended for the food industry to use seeds from this area for their products, which are going to compete in the expanding functional food markets.

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