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    Antioxidative properties of the fruits of selected tomato (Lycopersicon esculentum Mill.) varieties
    Baltazar, Gleza Wae D. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-05)
    This study was conducted to compare the antioxidative properties of greenstage fruits of selected Lycopersicon esculentum Miller varieties (Diamante, Diamante Max, and Pidada) from Barangay Durog, Miagao, Iloilo. The fresh fruit samples were extracted with 95% ethanol. The crude extracts were concentrated using rotary evaporator. The antioxidant activity of the ethanolic fruit extracts was assayed for DPPH radical scavenging activity and the IC50 values were determined. The determination of the phenolic and flavonoid contents was done employing Folin- Ciocalteu method and aluminum chloride spectrophotometric method, respectively. The results show that the fruits of the studied L. esculentum varieties exhibit DPPH radical scavenging activity. The IC50 values, however, differ significantly among the varieties. The IC50 values for Diamante (24.22 ± 1.41 g/L) and Diamante Max (25.08 ± 0.45 g/L) are comparable but are significantly lower than Pidada (29.47 ± 1.33 g/L). These findings imply that Diamante and Diamante Max varieties have stronger antioxidative capacity than the Pidada variety. Moreover, the results indicate that the antioxidative property of L. esculentum is variety-dependent. The results of the determination of the total phenolic content, expressed in mg gallic acid equivalent (GAE) per g fresh sample, are in the order of 0.16 ± 0.02 mg GAE/g for Diamante > 0.15 ± 0.02 mg GAE/g for Diamante Max and Pidada. On the other hand, the results of the determination of the flavonoid content, expressed in μg quercetin equivalent (QE) per g fresh sample, are in the order of 6.31 ± 1.27 μg QE/g for Diamante >6.21 ± 0.88 μg QE/g for Diamante Max > 5.63 ± 0.94 pg QE/g for Pidada. No significant difference in the total phenolic and flavonoid contents was found among varieties. Nonetheless, the detection of phenolics and flavonoids, known antioxidants, supports the present results on the antioxidative property of the fruits of the L. esculentum varieties studied.
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    Antioxidant property of anthocyanin from malatinta (Phyllanthus reticulatus Poir.) fruits obtained by static and microwave-assisted extraction
    Baldonasa, RB Hera Angelica R. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Fresh fruits of Phyllanthus reticulatus Poir. were analyzed for anthocyanin by spectrophotometric method. The antioxidant activity using 1,1 -diphenyl-2-picrylhydrazyl (DPPH ) free radical scavenging activity (FRSA) and reducing power (RP) through FeCl3 assay were determined. The use of two extraction processes, namely, the static method and microwave-assisted extraction, using two extraction solvents, acidified methanol and aqueous ethanol (1:1) were compared. The total anthocyanin content (TAC) of P. reticulatus fruit was highest in extract using static method of extraction in acidified methanol solvent (279.94 ±17.31 mg/lOOg), comparable to levels found in plants rich in anthocyanins, (e.g., berries genotypes, grapes and red cabbages). In microwave-assisted extraction, TAC using acidified methanol was higher (278.01 ± 18.76 mg/lOOg) compared to using aqueous ethanol (210.96 ± 2.02 mg/100g). P. reticulatus fruits exhibited high antioxidant activity as revealed by its RP and DPPH FRSA results when compared to ascorbic acid. These findings highlight the usefulness of P. reticulatus as a source of anthocyanins with good antioxidant properties, which, in turn, gives importance to the undervalued and underutilized plant.
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    Phytochemical, antioxidant, and antibacterial analysis of essential oils from Zingiber officinale Roscoe(Ginger) and Curcuma long Linn.(Turmeric)
    Alviar, Joseph Noel G. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    This study was conducted to characterize and compare the phytochemistry, antibacterial and antioxidant activities of essential oils extracted from the rhizomes of Zingiber officinale Roscoe (ginger) and Curcuma longa Linn. (turmeric). Percent yields in the steam distillation of ginger and turmeric were 0.42±0.02% and 0.43± 0.02%, respectively. Qualitative phytochemical screening showed that both essential oils are positive for flavonoids, phenols, saponins, terpenoids, tannins, and quinones. Antibacterial activity was tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli using 100%, 75%, 50%, and 25% (v/v) essential oil in ethanol with positive control tetracycline and negative control ethanol. It was determined that C. longa did not have antibacterial activity against both bacteria while Z. officinale had “moderately inhibitory” to “strongly inhibitory” activity against S. aureus with zone of inhibition (ZOI) from 17.67±1.53 mm to 23.67±0.58 mm and “weakly inhibitory” to “moderately inhibitory” activity against E. coli (ZOI from 12.33±1.15 mm to 15.67±2.08 mm). The standard antibiotic tetracycline also showed “moderately inhibitory” activity against both S. aureus (ZOl = 19.00±0.89 mm) and E. coli (ZOI = 17.33±1.21 mm). Antioxidant activity was determined by DPPH free radical inhibition. Highest % DPPH free radical inhibition was exhibited by the standard antioxidant ascorbic acid (92.98%), followed by C. longa essential oil (88.74%), and Z. officinale (76.30%).
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    Antioxidant and antibacterial activities of bika (Ampelocissus martini panch) seed oil
    Angot, Rose Imee Lyn N. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Ampelocissus martini Planch, locally known as Bika, is a native tropical plant generally found in Southeast Asia. It is abundant in Panay Island, particularly in the provinces of Antique and Iloilo. Despite that the fruit is being consumed as food, used as medicine, and made into wine, very few scientific studies pertaining to Bika grape exist. Hence, this study focused on its antioxidant and antibacterial activities. The antioxidant activities were carried out through the % DPPH radical scavenging activity and reducing power method. Results show that the Bika seed oil has antioxidant activity. Its IC50 using DPPH assay is 23.63 ppm. Moreover, it also showed a significant antioxidant activity based on the results from the reducing power assay. Both results demonstrated that Bika grape seed oil have antioxidant activity. On the other hand, the mean zones of inhibition using disk diffusion assay was used to assess the antibacterial activity of Bika seed oil against Escherichia coh and Staphylococcus aureus. Only the antibiotic Gentamicin showed active antibacterial property, whereas the Bika seed oil showed little zone of inhibition, only goes to show that it has an inactive antibacterial property.