This study aims to determine and compare antioxidant activity, total phenolics, flavonoids, and the relationship of phenolic and total flavonoids with the antioxidant activity of the three kratom ...variants. The ethanol extract of the third variant of kratom leaves was obtained by maceration. Through the antioxidant activity test using DPPH method, all three extracts showed strong antioxidant activity with IC50 values of 26.39, 30.25, and 30.59 μg/mL. The relationship of total phenolics and flavonoids with antioxidant activity was determined by the Pearson correlation test. Examination of total phenolic content using the Folin-Ciocalteu method with successive results for green, red, and white kratom are 6.11, 8.67, and 9.09 mg GAE/g extract. Examination of total flavonoid content using the colorimetric method for green, red, and white kratom were 0.86, 0.68, and 1.13 mg QE/g extract, respectively. The total phenolic content and antioxidant activity showed a correlation coefficient value of -0.32 (P0.05), and the total flavonoid content to antioxidant activity showed a correlation coefficient value of 0.81 (P0.05). Thus, all three variants of kratom have potency as natural antioxidants, but their total phenolic and flavonoid content does not influence their antioxidant activity.
Padas stone is one of the natural mineral containing 67.5% of SiO2 compounds. In this research, synthesis of nanosilica was carried out by sol-gel method asistanced by 2.45 GHz microwave radiations ...with low (10%), medium (50%) and high (100%) power at 30 and 60 minutes of contact times. It was analyzed by XRD, BET, FTIR spectrophotometry and SEM. The synthesized silica was then used as absorbent for total organic carbon (TOC) of palm oil waste. The results show that the synthesized silica was a mixture of cristobalite and quartz type minerals according to ICDD No. 00-003-0271 and 01-083-287. The surface area and silicon dioxide contains are 12.174 m2/g and 76.325% for silica without microwave assistance (SiO2-TPMW); 12.796 m2/gand 86.385% for silica with 30 minutes on 10% microwave assistance(SiO2 -MW 10A); 12.735 m2/gand 86.254% for silica with 60 minutes on 10% microwave assistance (MW 10B); 13,659 m2/gand 87.211% for MW 50A; 13,583 m2/g and 86.684% for MW 50B;7.883 m2/gand 57.527% for MW 100A; also 8.752 m2/g and 37.725% for MW 100B, respectively. The use of silica as an absorbent of TOC shows the effectiveness of 62.89% (TPMW); 63.68% (MW 10A); 62.96% (MW 10B); 65.25% (MW 50A); 64.61% (MW 50B); 62.37% (MW 100A) and 61.18% (MW 100B) from the initial TOC of 1520 mg/L. Keywords: synthesis, nanosilica, padas stone, total organic carbon, oil waste.
In this paper, we report for the first time thesimple method for detection of Hg(II) ion in anaqueousmedium using silver nanoparticles capped with 3-hydroxybenzoic acid. Silver nanoparticles capped ...with 3-hydroxybenzoic acid were preparedby reduction of the silver ion with 3-hydroxybenzoic acid and without surface functionalization. The formation of silver nanoparticles was characterized by a UV-Visible spectrophotometer. The yellowcolloid of prepared silver nanoparticles capped with 3-hydroxybenzoic acid showed a surface plasmon resonance peak at 420 nm. The ability of silver nanoparticles capped with 3-hydroxybenzoic acid in detection was tested by doing a reaction with several metal ions individually(Na(I), K(I), Cu(II), Zn(II), Ca(II), Mg(II), Hg(II), Mn(II), Ni(II), Pb(II), and Co(II)). It was foundthat silver nanoparticles capped with 3-hydroxybenzoic acid highly selective toHg(II) and then the prepared silver nanoparticles were developedfor detection of Hg(II) ion. Addition of 1 mL Hg(II) ion into 4mL the as-preparedsilver nanoparticles reducedthe peak of surface plasmon resonance spectra, andthe reduction of peak intensity was proportional to the concentration of Hg(II) ion. A goodlinear relationship (R2= 0.998) between absorbance at 420 nm and concentrationof Hg(II) over the range 1.0x10-3to 5.5x10-3M was obtained. Silver nanoparticles capped with 3-hydroxybenzoic acid were highly sensitive to Hg (II) ion with the detection limit down to 4.7x10-5M. Application the method to the real water sample showed the excellentresult with recovery ranged from 98 to 101%. The proposed method was found to be useful forthe colorimetric detection of Hg(II) ion in an aqueousmedium.
Screening of antimicrobial activity compound from steam bark of Shorea foxworthyi Sym by Thin Layer Chromatography-Bioautography method have been conducted. The result of this research can be base in ...elucidation of antimicrobial activity compounds from S. foxworthyi Sym. The first step was done in this research that is maceration of S. foxworthyi steam bark using methanol solvent. Fractination to methanol extract was done using n-hexane, chloroform, and ethyl acetate solvent, respectively. Phytochemical screening were done to methanol, chloroform, n-hexane, and ethyl acetate fractions. Screening of antimicrobial activity compound were done to polar fraction such as methanol, chloroform, and ethyl acetate fraction. The bacteria were used in this screening such as E. coli, S. aureus, S. thypii, and B. Subtilis. The extract was highest antimicrobial activity choosed to test by Thin Layer Chromatography-Bioautography. The result was showed that chloroform extract was had highest antimicrobial activity and the flavonoide of compaund was considered having antimicrobial activity. Keywords: antimicrobial, TLC-Bioautography, and Shorea foxworthyi Sym
Synthesis of 7-O-carboxymethyl-3',4'-dimethoxyisoflavone from 7-hydroxy-3',4'-dimethoxyisoflavone derived from eugenol had been done. 7-hydroxy-3',4'-dimethoxyisoflavone was first converted into ...7-O-ethoxycarbonylmethyl-3',4'-dimethoxyisoflavone via substitution of hydroxyl group at 7-O position by ethyl-2 chloro acetate through bimolecular nucleophilic substitution reaction (SN2). Hydrolysis of ester group of 7-O-ethoxycarbonylmethyl-3',4'-dimethoxyisoflavone using KOH produce 7-O-carboxymethyl-3',4'-dimethoxyisoflavone in 93.4% yield as a white solid with melting point of 155-159 °C.
Agarwood is a plant known for its aromatic resin, which is one of the most widely distributed species in Indonesia. This research was carried out in several stages, namely maceration, partitioning, ...Thin Layer Chromatography (TLC), and termites activity. The test was carried out for 3 days with variations in the concentration of 0% (negative control), 0.1%, 0.2%. 0.3%, 0.4%, 0.5% (w/v), and 0.25% fipronil reagent as positive controls. The crude extract yield of sapwood gaharu aloe acetone obtained was 23,4321% and the partition result of 233,789 grams of crude extract of acetone consisted of n-hexane fraction with a yield of 3.812%, chloroform fraction of 42.205%, and acetone fraction of 43.621%. The results of the phytochemical test showed that aloe vera sapwood contained alkaloid compounds, flavonoids, steroids, terpenoids, phenolics and saponins. GC-MS analysis of the n-hexane fraction showed the number of peaks as many as 55 peaks which may contain 55 compounds in the fraction. The compound with the highest % area was 4-Chloro-6-methoxy-2-methyl quinoline-8-amine (10.33%) followed by stigmasterol compound (5.94%). The results of the termite activity test showed that the most active fraction as an anti-termite was acetone fraction (LC50 0.082%) followed by chloroform fraction (LC50 0.134%), crude extract (LC50 0.144%) and n-hexane fraction (LC50 0.176%)
Synthesis of 5,7-dihydroxy-3',4'-dimethoxyisoflavone from eugenol as isolated product of clove leaves oil had been done. Eugenol was firstly converted into 3,4-dimethoxybenzyl cyanide via several ...stages of reaction. Hoeben-Hoesch reaction of 3,4-dimethoxybenzyl cyanide with phloroglucin produced 3,4-dimethoxybenzyl-2',4',6'-trihydroxyphenyl ketone (deoxybenzoin intermediate) in 58% yield. Eventually, cyclization of the intermediate with reagents of BF3.OEt2/DMF/POCl3 yielded 5,7-dihydroxy-3',4'-isoflavone in 88% yield.
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