Biological Properties of the Aggregated Form of Chitosan Magnetic Nanoparticle.

BACKGROUND/AIM: Chitosan-coated iron oxide nanoparticles (Chi-NP) have gained attention because of their biocompatibility, biodegradability, low toxicity and targetability under magnetic field. In this study, we investigated various biological properties of Chi-NP. MATERIALS AND METHODS: Chi-NP was prepared by mixing magnetic NP with chitosan FL-80. Particle size was determined by scanning and transmission electron microscopes, cell viability by MTT assay, cell cycle distribution by cell sorter, synergism with anticancer drugs by combination index, PGE2 production in human gingival fibroblast was assayed by ELISA. RESULTS: The synthetic process of Chi-NP from FL-80 and magnetic NP increased the affinity to cells, up to the level attained by nanofibers. Upon contact with the culture medium, Chi-NP instantly formed aggregates and interfered with intracellular uptake. Aggregated Chi-NP did not show cytotoxicity, synergism with anticancer drugs, induce apoptosis (accumulation of subG1 cell population), protect the cells from X-ray-induced damage, nor affected both basal and IL-1ß-induced PGE2 production. CONCLUSION: Chi-NP is biologically inert and shows high affinity to cells, further confirming its superiority as a scaffold for drug delivery.

Antiviral and Antitumor Activity of Licorice Root Extracts.

BACKGROUND: In the search for anti-viral and antitumor substances from natural resources, antiviral and antitumor activities of licorice root extract and purified ingredients were investigated. MATERIALS AND METHODS: Viability of cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antiviral activity was quantified by the selectivity index, defined as the ratio of the 50% cytotoxic concentration (CC50) to the 50% effective concentration against human immunodeficiency virus (HIV) or herpes simplex virus (HSV)-infected cells (EC50). The tumor specificity was calculated by the ratio of CC50 against human normal oral cells to that against human oral squamous cell carcinoma cell lines. Licorice flavonoids and lower molecular polyphenols were subjected to quantitative structure-activity relationship analysis. RESULTS: Alkaline extract of licorice root had higher anti-HIV activity than did water extracts, confirming our previous reports. On the other hand, water extract, especially the flavonoid-rich fraction, had higher anti-HSV activity than did the alkaline extract. The flavonoid-rich fraction was more cytotoxic against human oral squamous cell carcinoma cell lines compared to normal oral cells, suggesting their tumor-specific cytotoxicity. CONCLUSION: The present study suggests that water and alkaline extracts of licorice root exert different mechanisms of actions against these two viruses. Physicochemical properties, rather than the category of compounds, may be important in determining their anti-HSV activity.

Efficient utilization of licorice root by alkaline extraction.

Compared to studies of water extracts of plants, those utilising alkaline extracts are limited. Both water and alkaline extracts from licorice root were compared regarding their biological activities. Licorice root was successively extracted first with water or alkaline solution (pH 9 or 12), and the alkaline (pH 12.0) extract was further separated into 50% ethanol-soluble and -insoluble fractions. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antibacterial activity against Porphyromonas gingivalis 381 was determined by turbidity assay. Cytochrome P-450 (CYP)3A4 activity was measured by ß-hydroxylation of testosterone using human recombinant CYP3A4. Radical intensity of superoxide and hydroxyl radicals was determined by electron spin resonance spectroscopy. Alkaline extraction yielded slightly higher amounts of dried materials compared to water extraction. Alkaline extract showed higher anti-HIV and antibacterial activities, and similar magnitudes of CYP3A4 inhibitory and superoxide and hydroxyl radical-scavenging activities, compared to water extract. When alkaline extract was fractionated by 50% ethanol, anti-HIV activity was recovered from the insoluble fraction representing approximately 3% of the alkaline extract, whereas antibacterial activity was concentrated in the soluble fraction rich in glycyrrhizid acid, flavanones and chalcones. All extracts and sub-fractions led to bimodal hormetic dose-response (maximum hormetic response=238%) on the bacterial growth. The present study demonstrated the superiority of alkaline extraction over water extraction for preparing anti-HIV and antibacterial agents at higher yield from licorice root.

Evaluation of cytotoxiciy and tumor-specificity of licorice flavonoids based on chemical structure.

BACKGROUND: The mechanism of cytotoxicity induction by flavonoids has been studied by many investigators, but their tumor specificity is not clear. To address this point, 10 licorice flavonoids were subjected to quantitative structure-activity relationship (QASR) analysis with cytotoxicity assay with four human oral carcinoma and three normal cell lines. MATERIALS AND METHODS: Cytotoxicity was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide method. Physico-chemical, structural, and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method. RESULTS: Licurazid and isoliquiritigenin had the highest cytotoxicity against tumor cells, and liquiritin, isoliquiritin and licurazid had the highest tumor specificity, suggesting an antitumor potential for licurazid. Chalcones had slightly higher cytotoxicity and tumor specificity than flavanones. The number of sugar units in the molecule was somewhat negatively-correlated with cytotoxicity, but not with tumor specificity. Parameters that reflect the three-dimensional structure, molecular volume and number of phenolic OH groups were significantly correlated with cytotoxicity, but not with tumor specificity. On the other hand, solvation energy was significantly correlated with tumor specificity, but not with cytotoxicity. CONCLUSION: These physicochemical descriptors may be useful to estimate cytotoxicity or tumor specificity of structurally-related compounds to these licorice flavonoids.

Anti-UV activity of lignin-carbohydrate complex and related compounds.

BACKGROUND: We recently reported that an alkaline extract of the leaves of Sasa senanensis Rehder (SE) and Lentinus edodes mycelia extract (LEM), exhibiting lignin-carbohydrate complex (LCC)-like activity, protected cells from UV-induced injury (referred to as anti-UV activity). We investigated whether LCC is the major active components responsible for anti-UV activity. MATERIALS AND METHODS: Human oral squamous cell carcinoma HSC-2 cells were exposed to short UV irradiation in phosphate-buffered saline, containing different concentrations of LCC. After culturing for 48 h in fresh culture medium, the viable cell number was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. From the dose-response curve, the 50% cytotoxic concentration (CC(50)) and the concentration that increased the viability of the UV-irradiated cells to 50% of the control value (EC(50)) were determined. The selectivity index (SI) was determined by the following equation: SI=CC(50)/EC(50). RESULTS: LCCs (Fr. VI) of pine cones and seed shell, and sulfated LCC exhibited relatively high anti-UV activity (SI=7.1-38), compared with that of SE and LEM. LCCs with lower lignin content (Fr. VII) exhibited anti-UV activity, approximately one half that of Fr. VI. However, polysaccharides (laminarin, pullulan, dextran) introduced with dimethylaminoethyl- or sulfate groups with different substitution ratios were totally inactive (SI<1). The introduction of a sulfate group to LCC did not enhance the anti-UV activity of LCC. Sodium ascorbate and vanillin were the most active (SI=65), whereas gallic acid (SI=5), epigallocatechin gallate (SI=2.6), ar-trumeron (SI<1), and turmeric extract (SI<1) were much less active. CONCLUSION: The prominent anti-UV activity of SE and LEM seems to be generated by LCCs present in the extract.

A clinical pilot study of lignin--ascorbic acid combination treatment of herpes simplex virus.

Antiviral drugs as well as natural remedies have been used to reduce symptoms and the rate of recurrences of herpes simplex virus type 1 (HSV-1) infection, a common disease. To evaluate anti-HSV-1 activity of a pine cone lignin and ascorbic acid treatment, a clinical pilot study was carried out. Forty-eight healthy patients of both genders between 4 and 61 years old (mean: 31+/-16 years), with active lesions of HSV-1, took part in the study. According to the HSV-1 stage at the presentation, the patients were classified into the prodromic (16 patients), erythema (11 patients), papule edema (1 patient), vesicle/pustule (13 patients) and ulcer stages (7 patients). One mg of lignin-ascorbic acid tablet or solution was orally administered three times daily for a month. Clinical evaluations were made daily the first week and at least three times a week during the second week after the onset and every six months during the subsequent year to identify recurrence episodes. The patients who began the lignin-ascorbic acid treatment within the first 48 hours of symptom onset did not develop HSV-1 characteristic lesions, whereas those patients who began the treatment later experienced a shorter duration of cold sore lesions and a decrease in the symptoms compared with previous episodes. The majority of the patients reported the reduction in the severity of symptoms and the reduction in the recurrence episodes after the lignin-ascorbic acid treatment compared with previous episodes, suggesting its possible applicability for the prevention and treatment of HSV-1 infection.

Anti-HIV and vitamin C-synergized radical scavenging activity of cacao husk lignin fractions.

Cacao husk lignin fractions, prepared by acid precipitation and 50% ethanol precipitation showed unexpectedly higher anti-human immunodeficiency virus (HIV) activity, as compared with the corresponding fractions from the cacao mass, amounting to the level comparable with that of popular anti-HIV compounds. The cacao husk lignin fractions also showed anti-influenza virus activity, but did not show antibacterial activity. The cacao husk lignin fractions synergistically enhanced the superoxide anion and hydroxyl radical scavenging activity of vitamin C. The cacao husk lignin fractions stimulated nitric oxide generation by mouse macrophage-like cells, to a level higher than that attained by lipopolysaccharide (LPS). The present study suggests the functionality of cacao husk lignin fractions as complementary alternative medicine.