Min-Kyung Jang

Comparison of methods for proanthocyanidin extraction from pine (Pinus densiflora) needles and biological activities of the extracts

Flavonoids are known to be effective scavengers of free radicals. In particular, proanthocyanidins are flavonoids that possess cardiovascular protection, antioxidative activities, and immunomodulatory activities. Here, we evaluated proanthocyanidin contents in the total polyphenolic compounds of pine needle extracts prepared by hot water, ethanol, hexane, hot water-hexane (HWH), and hot water-ethanol (HWE). Analysis of each extract indicated that the ethanol extract contained the highest proanthocyanidin concentration. The HWH and hexane extracts also contained relatively high concentrations of proanthocyanidin. On the other hand, proanthocyanidin content analyses out of the total polyphenolic compounds indicated that the HWH extract contained the highest content. These results suggest that HWH extraction is a suitable method to obtain an extract with a high level of pure proanthocyanidins and a relatively high yield. The HWH extract possessed superior activity in diverse antioxidative analyses such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferrous ion chelating (FIC), and ferric-ion reducing power (FRAP) assays. In addition, upon assessing the effects of the pine needle extracts on macrophages (Raw 264.7 cell), the HWH extract exhibited the highest activity. In this study, we discerned an efficient extraction method to achieve relatively pure proanthocyanidins from pine needles and evaluated the biological functions of the resulting extract, which could potentially be used for its efficacious components in functional food products.

Evaluation of Proanthocyanidin Contents in Total Polyphenolic Compounds of Pine (Pinus densiflora) Needle Extracts and Their Antioxidative Activities

Flavonoids in pine needles are known to be effective scavengers of free radical. Especially, proanthocyanidin, a kind of flavonoids possesses cardiovascular protection and antioxidative activities. Here, we evaluated proanthocyanidin contents in total polyphenolic compounds of pine needle extracts prepared by using hot water, ethanol, hexane or sub-supercritical . Analyses of total polyphenolic compounds and proanthocyanidin in each extracts indicated that hot water extract contained the highest concentrations, but sub-supercritical extract contained the lowest concentrations. On the other hand, evaluation of proanthocyanidin contents in total polyphenolic compounds in each extracts showed that sub-supercritical extract possessed the highest content, but hot water extract possessed the lowest content. These results indicate that extracts containing high concentrations of both total polyphenolic compounds and proanthocyanidin could be obtained by using hot water or ethanol extractions. Furthermore, extract containing high content of proanthocyanidin out of total polyphenolic compounds could be achieved by using sub-supercritical extraction. Measurement of antioxidative activities of extracts showed that hot water extract possessed the highest activity. In this study, we prepared extracts from pine needles by four different methods and evaluated the antioxidative compounds in extracts that could be used for effective components of functional food products.

Isolation and characterization of a marine bacterium Thalassomonas sp. SL-5 producing β-agarase

A novel agar-degrading bacterium SL-5 was isolated from seashore of Homigot at Kyung-Buk province, and cultured in marine broth 2216 media. The bacterium SL-5 was identified as Thalassomonas genus by 16S rDNA sequencing with 96% identity. Growth rate was faster at than at and agarase was produced as growth-related. The optimum pH of the enzyme activity was 7.0 and the optimum temperature for the reaction was . Although the enzyme had no thermostability, the enzyme activity was remained over 80% at . The enzyme hydrolyzed neoagarohexaose to yield neoagarobiose as the main product, indicating that the enzyme is . Thus, the enzyme would be useful for the industrial production of neoagarobiose.

Isolation and Characterization of a Marine Derived Bacterium Glaciecola sp. SL-12 Producing β-agarase

A novel agar-degrading bacterium SL-12 was isolated from seashore of Kijang at Busan, Korea, and cultured in marine broth 2216 media. Isolated bacterium SL-12 was identified as Glaciecola genus by 16S rDNA sequencing with 98% identity. The optimum pH of the enzyme activity was 7.0 and the optimum temperature for the reaction was 30℃. The enzyme hydrolyzed neoagarohexaose to yield neoagarobiose as the main product, indicating that the enzyme is β-agarase. Thus, isolated bacterium and the enzyme would be useful for the industrial production of neoagarobiose.

Verification of Antimicrobial Activities of Various Pine Needle Extracts against Antibiotic Resistant Strains of Staphylococcus aureus

We investigated antimicrobial activities of various pine (Pinus densiflora) needle extracts against antibiotic resistant strains of Staphylococcus aureus. Hot water extract showed the highest antimicrobial activity against normal and methicillin resistant Staphylococcus aureus (MRSA), however, it exhibited no antimicrobial activity against penicillin resistant S. aureus (PRSA). Hot water-hexane (HWH), hot water-ethanol (HWE), hexane, and ethanol extracts showed antimicrobial activity against S. aureus, PRSA and MRSA. Minimum inhibitory concentrations (MIC) of HWH, HWE, hexane, and ethanol extracts were 0.05, 0.05, 0.5 and 5 mg/ml, respectively, and HWH and HWE extracts showed the strongest antimicrobial activity among these extracts. Antimicrobial activities of pine needle extracts were stable after heating at for 20 min. These results suggested that pine needle extracts can be used as an effective natural antimicrobial agent for food and medical industries.

Transcriptional auto-regulation of the dopamine receptor regulating factor (DRRF) gene

The murine dopamine receptor regulating factor (DRRF) gene is transcribed from a TATA-less promoter that has several putative Sp1 binding sites. The present investigation identifies functional transcription factors that modulate the expression of this gene. In the D2-dopamine receptor expressing NB41A3 cells, Sp1 potently activates transcription from the DRRF promoter in pCAT-DRRF-1153/+17, while DRRF itself effectively inhibits it. Sp1 also activates this promoter in pCAT-DRRF-310/+17. In competitive co-transfection experiments, DRRF represses the transcriptional activation induced by Sp1, while Sp1 de-represses the inhibitory effect of DRRF. Deletion of the 31 bp fragment between -1153 and -1122 decreased basal transcription down to about 60%. This fragment contains a functional AP1 binding site. In addition, deletion of the 129 bp region between -901 and -772 further decreased transcription. The latter region has a functional AP2 binding site. The present observations suggest that DRRF auto-regulates its own promoter by competing with Sp1 and that both AP1 and AP2 modulate expression of this gene.

Secretory Overexpression of β-Agarase in Bacillus subtilis and Antibacterial Activity of Enzymatic Products

The gene for of an Agarivorans sp. JA-1 was expressed in Bacillus subtilis DB104, 168 and ISW1214 strains for mass-production. Among 3 host strains, B. subtilis ISW1214 secreted the highest amount of recombinant with a specific activity of 201 U/mg and 360 mg of protein into culture broth. This was approximately 130-fold higher than the production in E. coli as an expression host. Recombinant enzyme produced neoagarooligosaccharides such as neoagarohexaose, neoagarotetraose, and neoagarobiose from agar. Produced neoagarooligosaccharides showed antibacterial activities against gram-negative E. coli and gram-positive B. subtilis at a concentration of 1.5%. These data suggest that neoagarooligosaccharides could be an useful preservative for food industry.

Verification of the Fractions with Strong Estrogenic Activities from Brown Algae

In order to evaluate estrogenic compounds in brown algae, an in vitro test system for the verification of estrogenic activity was applied. Fractions from ethanol extracts of each brown alga were prepared by a systematic fractionation procedure with solvents such as , hexane, butanol and methanol. Aqueous fractions of brown algae showed the highest estrogenic activities. Estrogenic activities of aqueous fractions of Undaria pinnatifida and Laminaria japonica showed almost the same strength as that of standard solution (-estradiol). Furthermore, estrogenic activities of aqueous fractions of Ecklonia stolonifera and Porphyra suborbiculate represented higher activities than that of -estradiol. These observations suggest that aqueous fractions of all these brown algae are expected to possess estrogenic compounds and could be developed as estrogenic agents for postmenopausal disorder.

Deodorization of Purified Fish Oil from Squids by Organic Acids

To produce high quality fish oil products, additional deodorization experiments on purified fish oil from squid using columns filled with citric acid or gluconic acid were performed. A deodorization effect on the fish oil was observed on both the citric acid and gluconic acid columns. These effects were more efficient on the columns packed with 3 g of organic acid than those with 1 g or 2 g of organic acid. In addition, a better effect was observed in the column packed with gluconic acid than that with citric acid. Peroxide value (POV) and acid value (AV) of the sample treated with citric acid was the as same as the non-treated sample. However, POV and AV of the sample treated with gluconic acid were about 10% higher than the non-treated sample. Contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of the samples treated with citric acid or gluconic acid columns were about 0.5% higher than the non-treated sample. In conclusion, deodorization of squid fish oil by organic acid could be an efficient method to produce high quality fish oil products.

Establishment of the Extraction Process by Evaluation of Proanthocyanidin Contents and Antioxidative Activities of Pine (Pinus densiflora) Needle Extracts.

We evaluated proanthocyanidin contents out of total polyphenolic compounds in two pine needle extracts prepared by combined extraction methods and compared their antioxidative activities. Amounts of total polyphenolic compounds of sub-supercritical hotwater precipitate (SSHP) and sub-supercritical hotwater supermatant (SSHS) were 225.4 and 116.6 mg/g, respectively. Amounts of proanthocyanidin of SSHP and SSHS were 9.9 and 3.6 mg/g, respectively. Thus, the ratio of proanthocyanidin contents over total polyphenolic compounds of SSHP and SSHS were 4.3 and 3.9%, respectively. Antioxidative activities () of SSHP and SSHS measured by DPPH radical scavenging were 41.5 and , respectively. These results indicates that two combined extracts, SSHP and SSHS showed higher antioxidative activities than extract prepared by hot water or sub-supercritical. In conclusion, extraction procedures for SSHP and SSHS could be useful methods for preparing the effective components of functional food products.