Hwa-Jin Suh

Isolation and Characterization of a Defensin-Like Peptide (Coprisin) from the Dung Beetle, Copris tripartitus

The antibacterial activity of immune-related peptides, identified by a differential gene expression analysis, was investigated to suggest novel antibacterial peptides. A cDNA encoding a defensin-like peptide, Coprisin, was isolated from bacteria-immunized dung beetle, Copris tripartitus, by using differential dot blot hybridization. Northern blot analysis showed that Coprisin mRNA was up-regulated from 4 hours after bacteria injection and its expression level was reached a peak at 16 hours. The deduced amino acid sequence of Coprisin was composed of 80 amino acids with a predicted molecular weight of 8.6 kDa and a pI of 8.7. The amino acid sequence of mature Coprisin was found to be 79.1% and 67.4% identical to those of defensin-like peptides of Anomala cuprea and Allomyrina dichotoma, respectively. We also investigated active sequences of Coprisin by using amino acid modification. The result showed that the 9-mer peptide, LLCIALRKK-NH2, exhibited potent antibacterial activities against Escherichia coli and Staphylococcus aureus.

Antioxidant activity of various solvent extracts from Allomyrina dichotoma (Arthropoda: Insecta) larvae.

This study was under taken to evaluate the antioxidant properties of larvae extracts of Allomyrina dichotoma. The antioxidant activities of various larvae extracts of water, methanol, ethyl-acetate, chloroform, and hexane were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion radical and singlet oxygen ((1)O(2)). The methanolic larvae extracts displayed the greatest effect in DPPH radical scavenging assay, but the reducing activity of larvae extracts was weaker in the superoxide anion radical assay. However, methanol (ME) and chloroform extracts (CE) could be compared to ascorbic acid in (1)O(2) quenching ability. ME (the concentration of 50% (1)O(2) quenching, QC(50)=0.080mg/ml) and CE (QC(50)=0.051mg/ml) extracts had 1.7, 2.7 times better efficiency than ascorbic acid (QC(50)=0.138mg/ml), respectively. Also the extracts were found to protect biological systems in Escherichia coli and lactate dehydrogenase against detrimental effects of (1)O(2) of type II photosensitization in vitro. The ability of larvae extracts to scavenge free radicals could significantly change contents of GA equivalent, an important factor for the potency of antioxidant capacity. The results suggest that our study may contribute to the development of new bioactive products with potential applications to reduce oxidative stress in living organisms involving reactive oxygen species as well as play a vital role in insect organisms against oxidative damage of undesirable conditions.

Determination of singlet oxygen quenching and protection of biological systems by various extracts from seed of Rumex crispus L.

The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect and total phenolic contents were evaluated for the screening of singlet oxygen ((1)O(2)) quenching efficacy of various seed extracts from Rumex crispus L. The butanol and ethyl-acetate extracts displayed remarkable effect of DPPH as compared to positive control ascorbic acid. The concentrations (QC(50)) of butanol and ethyl-acetate extracts required to exert 50% reducing effect on (1)O(2) were found to be 116 and 82 μg mL(-1), respectively. Both extracts were also found to protect the in vitro biological system from the detrimental effect of (1)O(2) on type II photosensitization in Escherichia coli, red blood cell, lactate dehydrogenase and histidine. Among all the tested extracts, the ethyl-acetate and butanol extracts contained higher amount of total phenolic contents. The results suggest that our study may contribute to the development of new bioactive products with potential applications to reduce photo-produced oxidative stress involving reactive oxygen species in living organisms.

Antioxidant activity of aqueous methanol extracts of Protaetia brevitarsis Lewis (Coleoptera: Scarabaedia) at different growth stages

In this study, we evaluate the antioxidant properties of the various extracts of Protaetia brevitarsis Lewis (Coleoptera: Scarabaedia) at different growth stages. The antioxidant activities of six different extracts from larvae, pupae and imago were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and singlet oxygen ( ). The larval methanol extracts (LME) and imago methanol extracts (IME) displayed the greatest effect in DPPH and ABTS radical scavenging assay, but the activity of water extracts was weaker in the all tested assays. However, LME and IME could be compared to ascorbic acid in quenching ability (the effective concentrations of 50% quenching: EC50 0.174, 0.149 and 0.177 mg mL−1, respectively). The antioxidant ability of the extracts to scavenge free radicals could significantly change the contents of gallic acid equivalent, an important factor based on the value of R 2. The results suggest that our study may contribute to the development of new bioactive products with potential applications to reduce oxidative stress as well as play a vital role in protecting insect organisms against oxidative damage caused by undesirable conditions.

Antioxidant and Antiobesity Activity of Natural Color Resources

This study investigated the antioxidant and antiobesity activity of extract powders from the following natural color resources: Polygonum indigo, Black locust, Cochineal, Catechu, Grape, Tesu flower, Henna, Chrysanthemum, Sandalwood Red, Himalayan Rhubarb, and Madder. Total phenol content was the highest in Catechu extract, at 348.25 mg/g. DPPH, ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) were also higher in Catechu extract. Bleaching inhibition activity in the β-carotene linoleic acid system was the highest in Black locust extract, as was α-Glucosidase inhibition activity. α-Amylase inhibition activity was the highest in Catechu extract. Trypsin inhibition activity of Black locust extract was greater than 60%, and αchymotrypsin inhibition activity of Catechu extract was greater than 40%. Lipase inhibition activity was the highest Black locust extract, at 52.73%. Viability of 3T3-L1 cells was not affected by treatment with extracts at concentrations of 1.25~25 μg/ml. Lipid accumulation in the 3T3-L1 cells was the lowest following treatment with Catechu extract, at 55.8%, and this extract also inhibited adipocyte differentiation. These results suggest that the Catechu and Black locust extracts have high antioxidant and antiobesity activities and can be useful ingredients in functional foods.This study investigated the antioxidant and antiobesity activity of extract powders from the following natural color resources: Polygonum indigo, Black locust, Cochineal, Catechu, Grape, Tesu flower, Henna, Chrysanthemum, Sandalwood Red, Himalayan Rhubarb, and Madder. Total phenol content was the highest in Catechu extract, at 348.25 mg/g. DPPH, ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) were also higher in Catechu extract. Bleaching inhibition activity in the β-carotene linoleic acid system was the highest in Black locust extract, as was α-Glucosidase inhibition activity. α-Amylase inhibition activity was the highest in Catechu extract. Trypsin inhibition activity of Black locust extract was greater than 60%, and α- chymotrypsin inhibition activity of Catechu extract was greater than 40%. Lipase inhibition activity was the highest Black locust extract, at 52.73%. Viability of 3T3-L1 cells was not affected by treatment with extracts at concentrations of 1.25~25 μg/ml. Lipid accumulation in the 3T3-L1 cells was the lowest following treatment with Catechu extract, at 55.8%, and this extract also inhibited adipocyte differentiation. These results suggest that the Catechu and Black locust extracts have high antioxidant and antiobesity activities and can be useful ingredients in functional foods.

Phenolic Chemical Constituents of the Stem Barks of Robinia pseudoacacia

Robinia pseudoacacia L. (Fabaceae) is commonly known as blacklocust tree and is one of the most well-established exotic plants in South Korea, although it is widely cultivated in temperate regions elsewhere as an ornamental [1]. Flowers of R. pseudoacacia are used as antispasmodics, antitussives, and sedatives. Other parts of this plant, especially the bark and seeds, are poisonous [2]. Previous phytochemical studies on this plant have reported the isolation of compounds such as flavonoids, triterpene glycosides, D-pinitol, and homo-monoterpene (robinlin) [3–8]. These plant compounds and extracts have a number of medicinal uses, including as an antitumor, antibacterial, and antioxidant [7–9]. In a recent report, the extract of R. pseudoacacia was found to have a protect effect against the powdery mildew fungus [10]. In continuation of our studies on chemical constituents from the stem barks of R. pseudoacacia, five compounds were isolated and elucidated as norathyriol (1), urolithin C (2), urolithin M6 (3), catechin lactone A (4), and bis(2-ethylhexyl)phthalate (5). To the best of our knowledge, all these compounds were obtained from the genus Robinia for the first time. Among them, catechin lactone A (4) was isolated for the second time from natural sources. General. NMR spectra were measured on a Bruker Ascend III 700 spectrometer (Bruker, Germany) with tetramethylsilane as an internal standard, and chemical shifts are expressed in values. Electrospray ionization (ESI) mass spectra were obtained on an LTQ Orbitrap XL (Thermo Scientific, USA) mass spectrometer. MPLC (Combi Flash RF, Teledyne ISCO) separations were performed on a RediSep® Rf normal-phase silica column. Preparative HPLC was performed on a Shimadzu (LC-8A pump and SPD-20A UV/VIS detector) column and a YMC-Pack ODS A column (250 20 mm I.D.) using a mixed solvent system of CAN–water at a flow rate of 8 mL/min. All chemicals and solvents were of analytical grade and used without further purification. Plant Material. The stem barks of R. pseudoacacia were provided by the Gyeongbuk Natural Color Industry Institute, Yeongcheon-si, Korea, in August 2014. The origin of the herbal material was identified by the authors (Joa Sub Oh), and a voucher specimen (P6) was deposited at the Natural Product Research Team, Gyeonggi Institute of Science & Technology Promotion, Suwon, Korea.