Displaying publications 1 - 20 of 40 in total

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  1. Ghasemzadeh A, Jaafar HZ, Rahmat A
    Molecules, 2010 Jun 14;15(6):4324-33.
    PMID: 20657444 DOI: 10.3390/molecules15064324
    Ginger (Zingiber officinale Roscoe) is a well known and widely used herb, especially in Asia, which contains several interesting bioactive constituents and possesses health promoting properties. In this study, the antioxidant activities of methanol extracts from the leaves, stems and rhizomes of two Zingiber officinale varieties (Halia Bentong and Halia Bara) were assessed in an effort to compare and validate the medicinal potential of the subterranean part of the young ginger. The antioxidant activity and phenolic contents of the leaves as determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay and the total amounts of phenolics and flavonoids were higher than those of the rhizomes and stems. On the other hand, the ferric reducing/antioxidant potential (FRAP) activity of the rhizomes was higher than that of the leaves. At low concentration the values of the leaves' inhibition activity in both varieties were significantly higher than or comparable to those of the young rhizomes. Halia Bara had higher antioxidant activities as well as total contents of phenolic and flavonoid in comparison with Halia Bentong. This study validated the medicinal potential of the leaves and young rhizome of Zingiber officinale (Halia Bara) and the positive relationship between total phenolics content and antioxidant activities in Zingiber officinale.
  2. Ghasemzadeh A, Jaafar HZ, Rahmat A
    Molecules, 2010 Sep 03;15(9):6231-43.
    PMID: 20877219 DOI: 10.3390/molecules15096231
    Flavonoids make up one of the most pervasive groups of plant phenolics. Due to their importance in plants and human health, it would be useful to have a better understanding of flavonoid concentration and biological activities that could indicate their potentials as therapeutic agents, and also for predicting and controlling the quality of medicinal herbs. Ginger (Zingiber officinale Roscoe) is a famous and widely used herb, especially in Asia, that contains several interesting bioactive constituents and possesses health promoting properties. In this study, total flavonoids and some flavonoid components including quercetin, rutin, catechin, epicatechin, kaempferol and naringenin were extracted from the leaves and rhizomes of two varieties of Zingiber officinale (Halia Bentong and Halia Bara) at three different growth points (8, 12 and 16 weeks after planting), and analyzed by a high performance liquid chromatography (HPLC) method in order to determine the potential of the subterranean part of the young ginger. The results showed that Halia Bara had a higher content of flavonoids in the leaves and rhizomes as compared to Halia Bentong. In both varieties, the concentration of flavonoids in the leaves decreased (Halia Bentong, 42.3%; Halia Bara 36.7%), and in the rhizomes it increased (Halia Bentong 59.6%; Halia Bara 60.1%) as the growth period increased. Quercetin was abundant in both varieties. The antioxidant activity determined by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay showed high activities (65.7%) in the leaves of Halia Bara at 8 weeks after planting. Results suggested a good flavonoid content and antioxidant activity potential in ginger leaves at 8 weeks after planting. The leaves of these ginger varieties could be useful for both food flavourings and in traditional medicine.
  3. Ghasemzadeh A, Jaafar HZ, Rahmat A, Wahab PE, Halim MR
    Int J Mol Sci, 2010 Oct 12;11(10):3885-97.
    PMID: 21152306 DOI: 10.3390/ijms11103885
    Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale) is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m(-2)s(-1)) were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP), total flavonoids (TF) and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale). TF biosynthesis was highest in the Halia Bara variety under 310 μmol m(-2)s(-1) and TP was high in this variety under a light intensity of 790 μmol m(-2)s(-1). The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) assay in both of varieties, increased significantly (p ≤ 0.01) with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m(-2)s(-1). The ferric reducing (FRAP) activity of the rhizomes was higher than that of the leaves in 310 μmol m(-2)s(-1) of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents.
  4. Ghasemzadeh A, Jaafar HZ, Rahmat A
    Molecules, 2010 Nov 03;15(11):7907-22.
    PMID: 21060298 DOI: 10.3390/molecules15117907
    Zingiber officinale Roscoe. (Family Zingiberaceae) is well known in Asia. The plant is widely cultivated in village gardens in the tropics for its medicinal properties and as a marketable spice in Malaysia. Ginger varieties are rich in physiologically active phenolics and flavonoids with a range of pharmacological activities. Experiments were conducted to determine the feasibility of increasing levels of flavonoids (quercetin, rutin, catechin, epicatechin, kaempferol, naringenin, fisetin and morin) and phenolic acid (gallic acid, vanillic acid, ferulic acid, tannic acid, cinnamic acid and salicylic acid), and antioxidant activities in different parts of Malaysian young ginger varieties (Halia Bentong and Halia Bara) with CO(2) enrichment in a controlled environment system. Both varieties showed an increase in phenolic compounds and flavonoids in response to CO(2) enrichment from 400 to 800 µmol mol-1 CO(2). These increases were greater in rhizomes compared to leaves. High performance liquid chromatography (HPLC) results showed that quercetin and gallic acid were the most abundant flavonoid and phenolic acid in Malaysian young ginger varieties. Under elevated CO(2) conditions, kaempferol and fisetin were among the flavonoid compounds, and gallic acid and vanillic acid were among the phenolic compounds whose levels increased in both varieties. As CO(2) concentration was increased from 400 to 800 µmol mol-1, free radical scavenging power (DPPH) increased about 30% in Halia Bentong and 21.4% in Halia Bara; and the rhizomes exhibited more enhanced free radical scavenging power, with 44.9% in Halia Bentong and 46.2% in Halia Bara. Leaves of both varieties also displayed good levels of flavonoid compounds and antioxidant activities. These results indicate that the yield and pharmaceutical quality of Malaysian young ginger varieties can be enhanced by controlled environment production and CO(2) enrichment.
  5. Ghasemzadeh A, Jaafar HZ, Rahmat A
    Int J Mol Sci, 2010 Nov 15;11(11):4539-55.
    PMID: 21151455 DOI: 10.3390/ijms11114539
    The relationship between phenolics and flavonoids synthesis/accumulation and photosynthesis rate was investigated for two Malaysian ginger (Zingiber officinale) varieties grown under four levels of glasshouse light intensity, namely 310, 460, 630 and 790 μmol m(-2)s(-1). High performance liquid chromatography (HPLC) was employed to identify and quantify the polyphenolic components. The results of HPLC analysis indicated that synthesis and partitioning of quercetin, rutin, catechin, epicatechin and naringenin were high in plants grown under 310 μmol m(-2)s(-1). The average value of flavonoids synthesis in leaves for both varieties increased (Halia Bentong 26.1%; Halia Bara 19.5%) when light intensity decreased. Photosynthetic rate and plant biomass increased in both varieties with increasing light intensity. More specifically, a high photosynthesis rate (12.25 μmol CO(2) m(-2)s(-1) in Halia Bara) and plant biomass (79.47 g in Halia Bentong) were observed at 790 μmol m(-2)s(-1). Furthermore, plants with the lowest rate of photosynthesis had highest flavonoids content. Previous studies have shown that quercetin inhibits and salicylic acid induces the electron transport rate in photosynthesis photosystems. In the current study, quercetin was an abundant flavonoid in both ginger varieties. Moreover, higher concentration of quercetin (1.12 mg/g dry weight) was found in Halia Bara leaves grown under 310 μmol m(-2)s(-1) with a low photosynthesis rate. Furthermore, a high content of salicylic acid (0.673 mg/g dry weight) was detected in Halia Bara leaves exposed under 790 μmol m(-2)s(-1) with a high photosynthesis rate. No salicylic acid was detected in gingers grown under 310 μmol m(-2)s(-1). Ginger is a semi-shade loving plant that does not require high light intensity for photosynthesis. Different photosynthesis rates at different light intensities may be related to the absence or presence of some flavonoid and phenolic compounds.
  6. Ghasemzadeh A, Jaafar HZ
    Int J Mol Sci, 2011 Feb 10;12(2):1101-14.
    PMID: 21541046 DOI: 10.3390/ijms12021101
    The effect of two different CO(2) concentrations (400 and 800 μmol mol(-1)) on the photosynthesis rate, primary and secondary metabolite syntheses and the antioxidant activities of the leaves, stems and rhizomes of two Zingiber officinale varieties (Halia Bentong and Halia Bara) were assessed in an effort to compare and validate the medicinal potential of the subterranean part of the young ginger. High photosynthesis rate (10.05 μmol CO(2) m(-2)s(-1) in Halia Bara) and plant biomass (83.4 g in Halia Bentong) were observed at 800 μmol mol(-1) CO(2). Stomatal conductance decreased and water use efficiency increased with elevated CO(2) concentration. Total flavonoids (TF), total phenolics (TP), total soluble carbohydrates (TSC), starch and plant biomass increased significantly (P ≤ 0.05) in all parts of the ginger varieties under elevated CO(2) (800 μmol mol(-1)). The order of the TF and TP increment in the parts of the plant was rhizomes > stems > leaves. More specifically, Halia Bara had a greater increase of TF (2.05 mg/g dry weight) and TP (14.31 mg/g dry weight) compared to Halia Bentong (TF: 1.42 mg/g dry weight; TP: 9.11 mg/g dry weight) in average over the whole plant. Furthermore, plants with the highest rate of photosynthesis had the highest TSC and phenolics content. Significant differences between treatments and species were observed for TF and TP production. Correlation coefficient showed that TSC and TP content are positively correlated in both varieties. The antioxidant activity, as determined by the ferric reducing/antioxidant potential (FRAP) activity, increased in young ginger grown under elevated CO(2). The FRAP values for the leaves, rhizomes and stems extracts of both varieties grown under two different CO(2) concentrations (400 and 800 μmol mol(-1)) were significantly lower than those of vitamin C (3107.28 μmol Fe (II)/g) and α-tocopherol (953 μmol Fe (II)/g), but higher than that of BHT (74.31 μmol Fe (II)/g). These results indicate that the plant biomass, primary and secondary metabolite synthesis, and following that, antioxidant activities of Malaysian young ginger varieties can be enhanced through controlled environment (CE) and CO(2) enrichment.
  7. Ghasemzadeh A, Jaafar HZ, Karimi E
    Int J Mol Sci, 2012 Nov 13;13(11):14828-44.
    PMID: 23203096 DOI: 10.3390/ijms131114828
    The effect of foliar application of salicylic acid (SA) at different concentrations (10-3 M and 10-5 M) was investigated on the production of secondary metabolites (flavonoids), chalcone synthase (CHS) activity, antioxidant activity and anticancer activity (against breast cancer cell lines MCF-7 and MDA-MB-231) in two varieties of Malaysian ginger, namely Halia Bentong and Halia Bara. The results of high performance liquid chromatography (HPLC) analysis showed that application of SA induced the synthesis of anthocyanin and fisetin in both varieties. Anthocyanin and fisetin were not detected in the control plants. Accordingly, the concentrations of some flavonoids (rutin and apigenin) decreased significantly in plants treated with different concentrations of SA. The present study showed that SA enhanced the chalcone synthase (CHS) enzyme activity (involving flavonoid synthesis) and recorded the highest activity value of 5.77 nkat /mg protein in Halia Bara with the 10-5 M SA treatment. As the SA concentration was decreased from 10-3 M to 10-5 M, the free radical scavenging power (FRAP) increased about 23% in Halia Bentong and 10.6% in Halia Bara. At a concentration of 350 μg mL-1, the DPPH antioxidant activity recorded the highest value of 58.30%-72.90% with the 10-5 M SA treatment followed by the 10-3 M SA (52.14%-63.66%) treatment. The lowest value was recorded in the untreated control plants (42.5%-46.7%). These results indicate that SA can act not only as an inducer but also as an inhibitor of secondary metabolites. Meanwhile, the highest anticancer activity against MCF-7 and MDA-MB-231 cell lines was observed for H. Bara extracts treated with 10-5 M SA with values of 61.53 and 59.88%, respectively. The results suggest that the high anticancer activity in these varieties may be related to the high concentration of potent anticancer components including fisetin and anthocyanin. The results thus indicate that the synthesis of flavonoids in ginger can be increased by foliar application of SA in a controlled environment and that the anticancer activity in young ginger extracts could be improved.
  8. Ghasemzadeh A, Jaafar HZ, Karimi E, Ibrahim MH
    BMC Complement Altern Med, 2012 Nov 23;12:229.
    PMID: 23176249 DOI: 10.1186/1472-6882-12-229
    BACKGROUND: The increase in atmospheric CO(2) concentration caused by climate change and agricultural practices is likely to affect biota by producing changes in plant growth, allocation and chemical composition. This study was conducted to evaluate the combined effect of the application of salicylic acid (SA, at two levels: 0 and 10-3 M) and CO(2) enrichment (at two levels: 400 and 800 μmol·mol-1) on the production and antioxidant activities of anthocyanin, flavonoids and isoflavonoids from two Malaysian ginger varieties, namely Halia Bentong and Halia Bara.

    METHODS: High-performance liquid chromatography (HPLC) with photodiode array detection and mass spectrometry was employed to identify and quantify the flavonoids and anthocyanins in the ginger extracts. The antioxidant activity of the leaf extracts was determined by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and thiobarbituric acid (TBA) assays. The substrate specificity of chalcone synthase, the key enzyme for flavonoid biosynthesis, was investigated using the chalcone synthase (CHS) assay.

    RESULTS: CO(2) levels of 800 μmol·mol-1 significantly increased anthocyanin, rutin, naringenin, myricetin, apigenin, fisetin and morin contents in ginger leaves. Meanwhile, the combined effect of SA and CO(2) enrichment enhanced anthocyanin and flavonoid production compared with single treatment effects. High anthocyanin content was observed in H Bara leaves treated with elevated CO(2) and SA. The highest chalcone synthase (CHS) activity was observed in plants treated with SA and CO(2) enrichment. Plants not treated with SA and kept under ambient CO(2) conditions showed the lowest CHS activity. The highest free radical scavenging activity corresponded to H Bara treated with SA under high CO(2) conditions, while the lowest activity corresponded to H Bentong without SA treatment and under atmospheric CO(2) levels. As the level of CO(2) increased, the DPPH activity increased. Higher TBA activity was also recorded in the extracts of H Bara treated with SA and grown under high CO(2) conditions.

    CONCLUSIONS: The biological activities of both ginger varieties were enhanced when the plants were treated with SA and grown under elevated CO(2) concentration. The increase in the production of anthocyanin and flavonoids in plants treated with SA could be attributed to the increase in CHS activity under high CO(2) levels.

  9. Ibrahim MH, Jaafar HZ, Karimi E, Ghasemzadeh A
    Int J Mol Sci, 2012;13(11):15321-42.
    PMID: 23203128 DOI: 10.3390/ijms131115321
    A randomized complete block design was used to characterize the relationship between production of total phenolics, flavonoids, ascorbic acid, carbohydrate content, leaf gas exchange, phenylalanine ammonia-lyase (PAL), soluble protein, invertase and antioxidant enzyme activities (ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) in Labisia pumila Benth var. alata under four levels of potassium fertilization experiments (0, 90, 180 and 270 kg K/ha) conducted for 12 weeks. It was found that the production of total phenolics, flavonoids, ascorbic acid and carbohydrate content was affected by the interaction between potassium fertilization and plant parts. As the potassium fertilization levels increased from 0 to 270 kg K/ha, the production of soluble protein and PAL activity increased steadily. At the highest potassium fertilization (270 kg K/ha) L. pumila exhibited significantly higher net photosynthesis (A), stomatal conductance (g(s)), intercellular CO(2) (C(i)), apparent quantum yield (ξ) and lower dark respiration rates (R(d)), compared to the other treatments. It was found that the production of total phenolics, flavonoids and ascorbic acid are also higher under 270 kg K/ha compared to 180, 90 and 0 kg K/ha. Furthermore, from the present study, the invertase activity was also found to be higher in 270 kg K/ha treatment. The antioxidant enzyme activities (APX, CAT and SOD) were lower under high potassium fertilization (270 kg K/ha) and have a significant negative correlation with total phenolics and flavonoid production. From this study, it was observed that the up-regulation of leaf gas exchange and downregulation of APX, CAT and SOD activities under high supplementation of potassium fertilizer enhanced the carbohydrate content that simultaneously increased the production of L. pumila secondary metabolites, thus increasing the health promoting effects of this plant.
  10. Ghasemzadeh A, Jaafar HZ
    Molecules, 2013 May 21;18(5):5965-79.
    PMID: 23698049 DOI: 10.3390/molecules18055965
    The effect of foliar salicylic acid (SA) applications (10⁻³ and 10⁻⁵ M) on activities of nitrate reductase, guaiacol peroxidase (POD), superoxide dismutases (SOD), catalase (CAT) and proline enzymes and physiological parameters was evaluated in two ginger varieties (Halia Bentong and Halia Bara) under greenhouse conditions. In both varieties, tested treatments generally enhanced photosynthetic rate and total dry weight. Photosynthetic rate increases were generally accompanied by increased or unchanged stomatal conductance levels, although intercellular CO₂ concentrations of treated plants were typically lower than in controls. Lower SA concentrations were generally more effective in enhancing photosynthetic rate and plant growth. Exogenous application of SA increased antioxidant enzyme activities and proline content; the greatest responses were obtained in plants sprayed with 10⁻⁵ M SA, with significant increases observed in CAT (20.1%), POD (45.2%), SOD (44.1%) and proline (43.1%) activities. Increased CAT activity in leaves is naturally expected to increase photosynthetic efficiency and thus net photosynthesis by maintaining a constant CO₂ supply. Our results support the idea that low SA concentrations (10⁻⁵ M) may induce nitrite reductase synthesis by mobilizing intracellular NO³⁻ and can provide protection to nitrite reductase degradation in vivo in the absence of NO³⁻. Observed positive correlations among proline, SOD, CAT and POD activities in the studied varieties suggest that increased SOD activity was accompanied by increases in CAT and POD activities because of the high demands of H₂O₂ quenching.
  11. Ibrahim MH, Jaafar HZ, Karimi E, Ghasemzadeh A
    Molecules, 2013 Sep 05;18(9):10973-88.
    PMID: 24013410 DOI: 10.3390/molecules180910973
    A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah) in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P₂O₅:10% K₂O) and inorganic fertilizer (NPK green; 15% N, 15% P₂O₅, 15% K₂O)] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic fertilizer enhanced the production of total phenolics, flavonoids, ascorbic acid, saponin and gluthathione content in L. pumila, compared to the use of inorganic fertilizer. The nitrate content was also reduced under organic fertilization. The application of nitrogen at 90 kg N/ha improved the production of secondary metabolites in Labisia pumila. Higher rates in excess of 90 kg N/ha reduced the level of secondary metabolites and antioxidant activity of this herb. The DPPH and FRAP activity was also highest at 90 kg N/ha. The results indicated that the use of chicken dung can enhance the production of secondary metabolites and improve antioxidant activity of this herb.
  12. Ghasemzadeh A, Jaafar HZ
    PMID: 24289290 DOI: 10.1186/1472-6882-13-341
    Phytochemicals and antioxidants from plant sources are of increasing interest to consumers because of their roles in the maintenance of human health. Most of the secondary metabolites of herbs are used in a number of pharmaceutical products.
  13. Ghasemzadeh A, Jaafar HZ, Karimi E, Ashkani S
    Molecules, 2014 Oct 16;19(10):16693-706.
    PMID: 25325154 DOI: 10.3390/molecules191016693
    The increase of atmospheric CO2 due to global climate change or horticultural practices has direct and indirect effects on food crop quality. One question that needs to be asked, is whether CO2 enrichment affects the nutritional quality of Malaysian young ginger plants. Responses of total carbohydrate, fructose, glucose, sucrose, protein, soluble amino acids and antinutrients to either ambient (400 μmol/mol) and elevated (800 μmol/mol) CO2 treatments were determined in the leaf and rhizome of two ginger varieties namely Halia Bentong and Halia Bara. Increasing of CO2 level from ambient to elevated resulted in increased content of total carbohydrate, sucrose, glucose, and fructose in the leaf and rhizome of ginger varieties. Sucrose was the major sugar followed by glucose and fructose in the leaf and rhizome extract of both varieties. Elevated CO2 resulted in a reduction of total protein content in the leaf (H. Bentong: 38.0%; H. Bara: 35.4%) and rhizome (H. Bentong: 29.0%; H. Bara: 46.2%). In addition, under CO2 enrichment, the concentration of amino acids increased by approximately 14.5% and 98.9% in H. Bentong and 12.0% and 110.3% in H. Bara leaf and rhizome, respectively. The antinutrient contents (cyanide and tannin) except phytic acid were influenced significantly (P ≤ 0.05) by CO2 concentration. Leaf extract of H. Bara exposed to elevated CO2 exhibited highest content of cyanide (336.1 mg HCN/kg DW), while, highest content of tannin (27.5 g/kg DW) and phytic acid (54.1 g/kg DW) were recorded from H.Bara rhizome grown under elevated CO2. These results demonstrate that the CO2 enrichment technique could improve content of some amino acids and antinutrients of ginger as a food crop by enhancing its nutritional and health-promoting properties.
  14. Ghasemzadeh A, Nasiri A, Jaafar HZ, Baghdadi A, Ahmad I
    Molecules, 2014 Oct 30;19(11):17632-48.
    PMID: 25361426 DOI: 10.3390/molecules191117632
    In the current study, changes in secondary metabolite synthesis and the pharmaceutical quality of sabah snake grass leaves and buds were considered in relation to plant age (1 month, 6 months, and 1 year old). The activity of the enzyme chalcone synthase (CHS, EC 2.3.1.74) was measured, as it is a key enzyme for flavonoid production. Significant differences in total flavonoid (TF) production were observed between the three plant growth periods and the different plant parts. The highest contents of TF (6.32 mg/g dry weight [DW]) and total phenolic (TP) (18.21 mg/g DW) were recorded in 6-month-old buds. Among the flavonoids isolated in this study the most important ones based on concentration were from high to low as follows: catechin > quercetin > kaempferol > luteolin. Production of phenolic acids increased from 1 to 6 months, but after 6 months up to 1 year of age, they decreased significantly. The highest contents of caffeic acid (0.307 mg/g DW) and gallic acid (5.96 mg/g DW) were recorded in 1-year and 6-month-old buds, respectively. The lowest and highest activity of CHS was recorded in 1-month and 6-month-old buds with values of 3.6 and 9.5 nkat/mg protein, respectively. These results indicate that the increment in flavonoids and phenolic acids in 6-month-old buds can be attributed to an increase in CHS activity. The highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity was observed in the extract of 1-year-old buds followed by 6-month-old buds, with 50% of free radical scavenging (IC50) values of 64.6 and 73.5 µg/mL, respectively. Interestingly, a ferric reducing antioxidant power (FRAP) assay showed a higher activity in 6-month-old buds (488 μM of Fe(II)/g) than in 1-year-old buds (453 μM of Fe(II)/g), in contrast to the DPPH result. Significant correlations (p < 0.05) were observed between CHS enzyme activity and FRAP activity, TF, catechin, and kaempferol content. Extracts of 6-month-old bud exhibited a significant in vitro anticancer activity against HeLa cancer cells with IC50 value of 56.8 µg/mL. These results indicate that early harvesting of snake grass (6-month-old) may yield increased concentrations of secondary metabolites, which are potent antioxidant compounds.
  15. Ghasemzadeh A, Jaafar HZ, Karimi E, Rahmat A
    PMID: 25169626 DOI: 10.1186/1472-6882-14-318
    Extraction prior to component analysis is the primary step in the recovery and isolation of bioactive phytochemicals from plant materials.
  16. Ghasemzadeh A, Jaafar HZ
    ScientificWorldJournal, 2014;2014:523120.
    PMID: 25147852 DOI: 10.1155/2014/523120
    Response surface methodology was applied to optimization of the conditions for reflux extraction of Pandan (Pandanus amaryllifolius Roxb.) in order to achieve a high content of total flavonoids (TF), total phenolics (TP), and high antioxidant capacity (AC) in the extracts. Central composite experimental design with three factors and three levels was employed to consider the effects of the operation parameters, including the methanol concentration (MC, 40%-80%), extraction temperature (ET, 40-70°C), and liquid-to-solid ratio (LS ratio, 20-40 mL/g) on the properties of the extracts. Response surface plots showed that increasing these operation parameters induced the responses significantly. The TF content and AC could be maximized when the extraction conditions (MC, ET, and LS ratio) were 78.8%, 69.5°C, and 32.4 mL/g, respectively, whereas the TP content was optimal when these variables were 75.1%, 70°C, and 31.8 mL/g, respectively. Under these optimum conditions, the experimental TF and TP content and AC were 1.78, 6.601 mg/g DW, and 87.38%, respectively. The optimized model was validated by a comparison of the predicted and experimental values. The experimental values were found to be in agreement with the predicted values, indicating the suitability of the model for optimizing the conditions for the reflux extraction of Pandan.
  17. Ibrahim MH, Jaafar HZ, Karimi E, Ghasemzadeh A
    ScientificWorldJournal, 2014;2014:360290.
    PMID: 24683336 DOI: 10.1155/2014/360290
    A split plot 3 by 4 experiment was designed to investigate and distinguish the relationships among production of secondary metabolites, soluble sugar, phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity, leaf gas exchange, chlorophyll content, antioxidant activity (DPPH), and lipid peroxidation under three levels of CO2 (400, 800, and 1200 μ mol/mol) and four levels of light intensity (225, 500, 625, and 900 μ mol/m(2)/s) over 15 weeks in Labisia pumila. The production of plant secondary metabolites, sugar, chlorophyll content, antioxidant activity, and malondialdehyde content was influenced by the interactions between CO2 and irradiance. The highest accumulation of secondary metabolites, sugar, maliondialdehyde, and DPPH activity was observed under CO2 at 1200 μ mol/mol + light intensity at 225 μ mol/m(2)/s. Meanwhile, at 400 μ mol/mol CO2 + 900 μ mol/m(2)/s light intensity the production of chlorophyll and maliondialdehyde content was the highest. As CO2 levels increased from 400 to 1200 μ mol/mol the photosynthesis, stomatal conductance, f v /f m (maximum efficiency of photosystem II), and PAL activity were enhanced. The production of secondary metabolites displayed a significant negative relationship with maliondialdehyde indicating lowered oxidative stress under high CO2 and low irradiance improved the production of plant secondary metabolites that simultaneously enhanced the antioxidant activity (DPPH), thus improving the medicinal value of Labisia pumila under this condition.
  18. Mojani, M.S., Ghasemzadeh, A., Rahmat, A., Loh, S.P., Ramasamy, R.
    MyJurnal
    In current work, the nutritional composition, bioactive compounds, total phenolic contents and anti-oxidant activity of young Malaysian ginger rhizome were investigated. Proximate analysis and high performance liquid chromatography (HPLC) recruited to determine nutritional composition and bioactive compounds. The total flavonoid (TF) and total phenolic contents (TPC) of ginger rhizome were determined by aluminium chloride calorimetric assay and Folin-Ciocalteau reagent, respectively. 2,2’-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method were used to measure antioxidant capacity. The rhizome contained high moisture content and low level of carbohydrate and energy. 6-gingerol was the most abundant component in the selected ginger, and total flavonoid and phenolic content were reported to be 3.66±0.45 mg gallic acid/g and 10.22±0.87 mg quercetin/g of dry weight of rhizome, respectively. The rhizome also showed lower antioxidant activity than controls, with the IC 50 value of 46.5 vs. 15.5 for α-tocopherol and 22 for BHT. The results of this study predicted that the young ginger rhizome originated from Malaysia may exhibit anti-oxidative and anti-inflammatory potentials due to high levels of gingerols, total flavonoid and phenolic compounds and antioxidant capacity.
  19. Ghasemzadeh A, Jaafar HZ, Rahmat A, Devarajan T
    PMID: 24693327 DOI: 10.1155/2014/873803
    In this study, we investigated some bioactive compounds and pharmaceutical qualities of curry leaf (Murraya koenigii L.) extracts from three different locations in Malaysia. The highest TF and total phenolic (TP) contents were observed in the extracts from Kelantan (3.771 and 14.371 mg/g DW), followed by Selangor (3.146 and 12.272 mg/g DW) and Johor (2.801 and 12.02 mg/g DW), respectively. High quercetin (0.350 mg/g DW), catechin (0.325 mg/g DW), epicatechin (0.678 mg/g DW), naringin (0.203 mg/g DW), and myricetin (0.703 mg/g DW) levels were observed in the extracts from Kelantan, while the highest rutin content (0.082 mg/g DW) was detected in the leaves from Selangor. The curry leaf extract from Kelantan exhibited higher concentration of gallic acid (0.933 mg/g DW) than that from Selangor (0.904 mg/g DW) and Johor (0.813 mg/g DW). Among the studied samples, the ones from Kelantan exhibited the highest radical scavenging activity (DPPH, 66.41%) and ferric reduction activity potential (FRAP, 644.25  μ m of Fe(II)/g) followed by those from Selangor (60.237% and 598.37  μ m of Fe(II)/g) and Johor (50.76% and 563.42  μ m of Fe(II)/g), respectively. A preliminary screening showed that the curry leaf extracts from all the locations exhibited significant anticarcinogenic effects inhibiting the growth of breast cancer cell line (MDA-MB-231) and maximum inhibition of MDA-MB-231 cell was observed with the curry leaf extract from Kelantan. Based on these results, it is concluded that Malaysian curry leaf collected from the North (Kelantan) might be potential source of potent natural antioxidant and beneficial chemopreventive agents.
  20. Ghasemzadeh A, Jaafar HZ, Juraimi AS, Tayebi-Meigooni A
    Molecules, 2015 Jun 11;20(6):10822-38.
    PMID: 26111171 DOI: 10.3390/molecules200610822
    Secondary metabolite contents (total phenolic, flavonoid, tocopherol, and tocotrienol) and antioxidant activities of Hashemi rice bran extracts obtained by ultrasound-assisted and traditional solvent (ethanol and 50:50 (v/v) ethanol-water) extraction techniques were compared. Phenolic and, flavonoid compounds were identified using ultra-high performance liquid chromatography and method validation was performed. Significant differences (p < 0.05) were observed among the different extraction techniques upon comparison of phytochemical contents and antioxidant activities. The extracts obtained using the ethanol-water (50:50 v/v) ultrasonic technique showed the highest amounts of total phenolics (288.40 mg/100 g dry material (DM)), total flavonoids (156.20 mg/100 g DM), and total tocotrienols (56.23 mg/100 g DM), and the highest antioxidant activity (84.21% 1,1-diphenyl-2-picrylhydrazyl (DPPH), 65.27% β-carotene-linoleic bleaching and 82.20% nitric oxide scavenging activity). Secondary metabolite contents and antioxidant activities of the rice bran extracts varied depending of the extraction method used, and according to their effectiveness, these were organized in a decreasing order as follows: ethanol-water (50:50 v/v) ultrasonic, ethanol-water (50:50 v/v) maceration, ethanol ultrasonic and ethanol maceration methods. Ferulic, gallic and chlorogenic acids were the most abundant phenolic compounds in rice bran extracts. The phytochemical constituents of Hashemi rice bran and its antioxidant properties provides insights into its potential application to promote health.
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