Il-Moo Chang

Membrane Filtration Characteristics in Membrane-Coupled Activated Sludge System: The Effect of Floc Structure on Membrane Fouling

The membrane-coupled activated sludge (MCAS) process has many advantages over the conventional activated sludge system, but the inherent membrane fouling problem still remains to be solved. However, it is not yet advanced enough to understand the reliable fouling mechanism. The strength of the MCAS process lies in the almost complete removal of suspended solids from the activated sludge broth. But it has made us overlook the effect of sludge morphology and physiology on membrane flux which is one of the key factors in deciding the economical feasibility of the MCAS system. The aim of this study was to investigate membrane filtration characteristics in the MCAS process, especially to correlate floc structures of the activated sludge with membrane fouling. A series of ultrafiltrations with both hydrophilic and hydrophobic membranes using the stirred batch cell system was performed to assess flux behavior according to the floc structures of the activated sludges (normal, pinpoint, and bulking activated sludg...

Inhibition of the Bacterial Surface Protein Anchoring Transpeptidase Sortase by Medicinal Plants

Inhibition by medicinal plant extracts of a recombinant sortase was evaluated for antibacterial drug discovery. The coding region of sortase, a transpeptidase that cleaves surface proteins of Gram-positive bacteria, was amplified by PCR from the chromosome of Staphylococcus aureus ATCC 6538p with the exception of an N-terminal membrane anchor sequence, expressed in Escherichia coli, and purified by metal chelate affinity chromatography. The purified sortase had maximum activity at pH 7.5 and was stable at 20-45°C for the cleavage of a synthetic fluorophore substrate. The enzyme inhibitory activity in medicinal plants was also evaluated for antibacterial drug discovery. Among 80 medicinal plants tested, Cocculus trilobus, Fritillaria verticillata, Liriope platyphylla, and Rhus verniciflua had strong inhibitory activity. The extract with the greatest activity was the ethyl acetate fraction derived from the rhizome of Cocculus trilobus (IC50=1.52 μg/ml).

Inhibitory Potencies of Several Iridoids on Cyclooxygenase-1, Cyclooxygnase-2 Enzymes Activities, Tumor Necrosis factor-α and Nitric Oxide Production In Vitro

To verify the anti-inflammatory potency of iridoids, seven iridoid glucosides (aucubin, catalpol, gentiopicroside, swertiamarin, geniposide, geniposidic acid and loganin) and an iridoid aglycone (genipin) were investigated with in vitro testing model systems based on inhibition of cyclooxygenase (COX)-1/-2 enzymes, the tumor necrosis factor-α (TNF-α) formation and nitric oxide (NO) production. The hydrolyzed-iridoid products (H-iridoid) with β-gludosidase treatment only showed inhibitory activities, and revealed different potencies, depending on their chemical structures. Without the β-gludosidase treatment, no single iridoid glycoside exhibited any activities. The aglycone form (genipin) also did not show inhibitory activities. To compare anti-inflammatory potency, the inhibitory concentrations (IC50) in each testing system were measured. The hydrolyzed-aucubin product (H-aucubin) with β-gludosidase treatment showed a moderate inhibition on COX-2 with IC50 of 8.83 μM, but much less inhibition (IC50, 68.9 μM) on COX-1 was noted. Of the other H-iridoid products, the H-loganin and the H-geniposide exhibited higher inhibitory effects on COX-1, revealing IC50 values of 3.55 and 5.37 μM, respectively. In the case of TNF-α assay, four H-iridoid products: H-aucubin, H-catalpol, H-geniposide and H-loganin suppressed the TNF-α formation with IC50 values of 11.2, 33.3, 58.2 and 154.6 μM, respectively. But other H-iridoid products manifested no significant activity. Additional experiments on NO production were conducted. We observed that only the H-aucubin exhibited a significant suppression with IC50 value of 14.1 μM. Genipin, an agycone form, showed no inhibitory effects on all testing models, implying the hydrolysis of the glycosidic bond of iridoid glycoside is a pre-requisite step to produce various biological activities.

Elucidation of anti-inflammatory potencies of Eucommia ulmoides bark and Plantago asiatica seeds.

This study elucidated possible mechanisms for the different anti-inflammatory potencies exhibited by the water extracts of Eucommia ulmoides bark and Plantago asiatica seeds, which contain various iridoids. Water extracts of both herbal materials were tested in vitro with a battery of assay models: lipopolysaccharide-induced thromboxane B(2) for cyclooxygenase-1 (COX-1), prostaglandin E(2) for cyclooxygenase-2 (COX-2), the translocation of nuclear factor-kappaB (NF-kappaB), and tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) production in RAW 264.7 cells. The contents of the iridoid glycosides, aucubin (AU), catalpol (CA), and geniposide (GE), were quantified by high-performance liquid chromatography (HPLC). Neither E. ulmoides nor P. asiatica suppressed the COX-1 enzyme. P. asiatica significantly inhibited COX-2 (concentration required for 50% inhibition [IC(50)] = 8.61 (microg/mL), TNFalpha (IC(50) = 9.63 (microg/mL), and NO (IC(50) = 8.65 (microg/mL) production. P. asiatica blocked the translocation of NF-kappaB from the cytosol to the nucleus. E. ulmoides suppressed only the COX-2 enzyme (IC(50) = 9.92 (microg/mL). The results of the HPLC analysis revealed that P. asiatica contained three iridoid glycosides, AU, CA, and GE. E. ulmoides contained CA and GE, but no AU was detected. The difference in the anti-inflammatory potencies of E. ulmoides and P. asiatica appears to be dependent on the presence of AU. Considering the IC(50) values, both herbal extracts exhibit modest and less potent anti-inflammatory activities than common synthetic non-steroidal anti-inflammatory drugs.

Inhibition of sortase, a bacterial surface protein anchoring transpeptidase, by β-sitosterol-3-O-glucopyranoside from Fritillaria verticillata

A glucosylsterol, β-sitosterol-3-O-glucopyranoside, has been isolated as an active principle with sortase inhibitory effect from the bulbs of Fritillaria verticillata by bioassay-guided chromatographic fractionation. The isolate was a potent inhibitor of sortase, with an IC50 value of 18.3 μg/ml and had antibacterial activity against Bacillus subtilis, Staphylococcus aureus, and Micrococcus leuteus with MIC values of 50, 200, and 400 μg/ml, respectively, indicating that this compound is a possible candidate for the development of a bacterial sortase inhibitor. In addition, sitosterol was found to be inactive upon sortase and bacterial cell growth. These results suggest that the inhibitory potency of β-sitosterol-3-O-glucopyranoside is sensitively dependent upon the glucopyranoside side chain moiety.

The practice of Korean medicine: an overview of clinical trials in acupuncture.

Acupuncture, one of the Oriental medical therapeutic techniques that can be traced back at least 2500 years, is growing in popularity all over the world. Korea has continued to develop its own unique tradition of medicine throughout its long history, and has formed different types of acupuncture methods. The purpose of this review is to summarize clinical case studies in acupuncture and related therapies, such as acupressure, electric acupuncture, auricular acupuncture and moxibustion in Korea. A survey of Korean journals revealed that a total of 124 studies were published from 1983 to 2001. Results obtained from the survey showed that most clinical studies using acupuncture, electric acupuncture, moxibustion and other traditional therapies could alleviate a relatively broad range of medical problems. However, it should be emphasized that almost all clinical case studies published in various local journals did not follow the ‘good clinical practice’ with respect to regulatory aspects. Since they were not conducted using the randomized double-blinded controls with a large sample size, all the results should be considered as therapeutic indications. This review is an attempt to show the scope of acupuncture in our country and the kind of diseases, after many years of clinical experience, that were deemed valid targets for clinical trials.

Survey of natural occurrence of trichothecene mycotoxins and zearalenone in Korean cereals harvested in 1992 using gas chromatography/mass spectrometry.

For the survey of the natural occurrence of trichothecene mycotoxins, produced by species of fungi imperfecti such as Fusarium and Trichothecium, a sensitive analytical method was developed for the simultaneous detection and quantitation of the major trichothecene mycotoxins, viz. T-2 toxin (T-2), HT-2 toxin (HT-2), nivalenol (NIV), fusarenon-X (F-X), deoxynivalenol (DON), 3-acetyl deoxynivalenol (3-Ac DON), and zearalenone (ZEN), using gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) mode after trimethyl silyl derivatization. The incidence of NIV and DON in 30 barley samples were 93% and 67%, respectively; the average contents of NIV and DON in positive samples were 390 ng/g (range 40-2038) and 106 ng/g (range 5-361) respectively. In 15 maize samples, the incidences of NIV and DON were 53% and 93% respectively and the average contents were 168 ng/g and 145 ng/g, respectively. These results suggest that NIV and DON were the major contaminating trichothecene mycotoxins in Korean barley and maize samples harvested in 1992.

An Overview of Traditional Chinese Herbal Formulae and a Proposal of a New Code System for Expressing the Formula Titles

Traditional Chinese herbal therapy can be characterized by the use of a large number of multi-herb formulae. To provide modern and Western scientists without knowledge of Chinese literature and cultural background easy access to information, a database with a total of 11 810 traditional Chinese herbal formulae was constructed. All the information was then translated into understandable scientific terms in English. While coining the formula titles in English, we discovered some principles governing the naming of titles by using computer analysis. In addition, we observed that about 92% of the formulae are in the range of single-herb formulae to thirteen-herb formulae. Most large number-herb formulae are formulated by combining pre-existing smaller number-herb formulae. The King herbs () with major therapeutic activity in a multi-herb formula were identified by the formulation concept using two parameters: the herbal dose and the herbal drug property (the degree of toxicity). Based on such analytical data, we established an English code system representing all formula titles written in ideographic Chinese characters: an array of important key words such as ‘Herbal name in Latin + Efficacy (Target organs) + Preparation form + Number of herbs.’ By searching the English version of the database with any of the above key words, a variety of information on the status of traditional Chinese herbal therapy can be accessed.

Detection of antifungal activity in Portulaca oleracea by a single-cell bioassay system

The antifungal activity of Portulaca oleracea extracts against hyphal growth of various fungi was evaluated in real time using an automatic single‐cell bioassay system. Target organisms were the filamentous fungi Aspergillus and Trichophyton and the yeast Candida. A colony of test fungi was in contact with the assay medium, or assay medium containing plant extract, in sequence. The antifungal activity of each fraction of P. oleracea was evaluated based on the dynamic hyphal growth response curves of test fungi. A crude sample obtained by EtOAc extract showed a specific and marked activity against dermatophytes of the genera Trichophyton. Copyright

Antiviral activity of aucubin against hepatitis B virus replication

Aucubin, an iridoid glycoside was found to suppress hepatitis B virus DNA replication in vitro in a 2.2.15 cell culture system. Aucubin itself did not exhibit antiviral activity, but it showed significant activity when preincubated with . Aucubin possesses no cytotoxicity at a broad range of concentrations in vitro.