Watcharee Khunkitti

Anti-inflammatory, antioxidant and hepatoprotective effects of Thunbergia laurifolia Linn. on experimental opisthorchiasis

Thunbergia laurifolia Linn (Rang Chuet) possesses antioxidant and anti-inflammatory properties as well as anticancer activities. The aim of the present study was to evaluate the efficacy of T. laurifolia in reducing inflammation from pathological changes in Syrian hamsters infected with the human liver fluke Opisthorchis viverrini. Hamster groups were also administered N-nitrosodimethylamine (NDMA) and treated with T. laurifolia. Light microscopic observation of histopathological changes, liver function tests for alanine transaminase (ALT) and alkaline phosphatase (ALP) and kidney function tests for blood urea nitrogen (BUN) and creatinine were performed. Antioxidant effects of both fresh and dried Rang Chuet solutions were observed. Analysis of the histopathological changes showed anti-inflammatory properties, both in the case of O. viverrini infection or with NDMA administration, by reducing the aggregation of inflammatory cells surrounding the hepatic bile ducts as indicated by normal serum ALT, ALP, BUN and creatinine levels in treated Syrian hamsters. The present study found that fresh and dried Rang Chuet solutions clearly reduced the inflammatory cells in both O. viverrini-infected and NDMA-administered groups and was correlated with the total antioxidant capacity. These findings suggest that T. laurifolia possesses antioxidant and anti-inflammatory properties and that its application may be useful for prevention of the inflammatory process, one of the risk factors of O. viverrini-associated cholangiocarcinoma (CCA).

Effect of the derivatives of andrographolide on the morphology of Bacillus subtilis

Andrographis paniculata has been reported to have antiviral, antipyretic and anticancer activities. Andrographolide, an ent-labdane diterpene, is an active constituent in this plant. In this study, andrographolide (1) and its natural derivative 14-deoxy-11,12-didehydroandrographolide (2) and 5 other semisynthetic derivatives were tested for their activity against Grampositive and Gram-negative bacteria and Candida albicans. Only derivatives bearing a 14-acetyl group showed activity, and this activity was only against Gram-positive bacteria. 14-Acetylandrographolide showed the highest potency against Bacillus subtilis; the other 14-acetylandrographolides with additional substitution at the 3- and 19-hydroxyl groups showed lower activity against Gram-positive bacteria. The morphology of B. subtilis after being treated with 14-acetylandrographolide was investigated with TEM. This is the first report on 14-acetylandrographolide’s quantified antibacterial activity, and the crucial functional group of this ent-labdane that plays an important role in perturbing the morphogenesis of B. subtilis leading to cell death.

Effect of Citronella Oil on Time Kill Profile, Leakage and Morphological Changes of Propionibacterium acnes

Abstract The aim of this study was to investigate the effect of citronella oil (Java type) (Cymbopogon winterianus Jowitt) on Propionibacterium acnes DMST 14916. Citronella oil compositions were determined by gas chromatography mass spectrometry (GC/MS). Anti-P. acnes activity of citronella oil and its major components were also investigated. After exposure with P. acnes at various concentrations of citronella oil (0–100 μL/mL), time-kill profiles, pentose leakage and electron microscopic characteristics were determined. The GC/MS results revealed that the major constituents of the oil were citronellal, geraniol and citronellol. At all concentrations above Minimum Bactericidal Concentrations (MBCs; 0.625μL/mL), this essential oil killed P. acnes in a dose-dependent manner. The intracellular materials leakage and electron microscopic characteristics evidenced that the major target sites of antibacterial activity appeared to be cell wall, cytoplasmic membrane and intracellular materials. Citronella oil exerted satisfactory bacteriostatic and bactericidal actions against P. acnes.

Antimicrobial effect of lemongrass oil against oral malodour micro-organisms and the pilot study of safety and efficacy of lemongrass mouthrinse on oral malodour

Lemongrass oil (LG) has been reported as being effective against bacteria embedded within the biofilm. The aims of this study were to investigate antimicrobial activity against common odourigenic micro‐organisms, the safety and efficacy of LG mouthrinse on oral malodour in healthy volunteers.

Novel antioxidant and anti-inflammatory peptides from the Siamese crocodile (Crocodylus siamensis) hemoglobin hydrolysate

Novel antioxidant and anti‐inflammatory peptides were isolated from hydrolysates of Siamese crocodile (Crocodylus siamensis) hemoglobin. C. siamensis hemoglobin hydrolysates (CHHs) were obtained by pepsin digestion at different incubation times (2, 4, 6, and 8 H) at 37 °C and subjected to antioxidant and anti‐inflammatory activity assessment. CHH obtained by 2‐H hydrolysis (2H‐CHH) showed the highest anti‐inflammatory activity with respect to decreasing nitric oxide (NO) production, whereas the strongest antioxidant activity was found for 6‐H hydrolysis (6H‐CHH) against nitric oxide radicals. To evaluate the anti‐inflammatory and antioxidant activity of individual peptide components, 2H‐CHH and 6H‐CHH were purified by semipreparative HPLC. Peptide fraction P57 isolated from 6H‐CHH was found to exhibit the highest nitric oxide radical inhibition activity (32.0%). Moreover, purification of 2H‐CHH yielded peptide fraction P16, which displayed a high efficacy in decreasing NO production of macrophage RAW 264.7 cells (83.2%) and significantly reduced proinflammatory cytokines and inflammatory mediators interleukin‐6 (IL‐6), interleukin‐1 beta (IL‐1β), and prostaglandin‐E2 (PGE2) production to about 2.0, 0.3, and 1.9 ng/mL, respectively. Using LTQ orbitrap XL mass spectrometry, active peptide sequences were identified as antioxidant KIYFPHF (KF7), anti‐inflammatory SAFNPHEKQ (SQ9), and IIHNEKVQAHGKKVL (IL15). Additionally, CHHs simulated gastric and intestinal in vitro digestion positively contributed to antioxidant and anti‐inflammatory activity. Taken collectively, the results of this work demonstrate that CHHs contain several peptides with anti‐inflammatory and antioxidant properties, which may prove valuable as treatment or supplement against diseases associated with inflammation and oxidative stress.

Alginate-caseinate composites: Molecular interactions and characterization of cross-linked beads for the delivery of anticandidals

Polysaccharide-protein composites offer potential utility for the delivery of drugs. The objectives of this work were to investigate the molecular interactions between sodium alginate (SA) and sodium caseinate (SC) in dispersions and films and to characterize calcium alginate (CA) beads mixed with SC for the delivery of fluconazole (FZ) and clotrimazole (CZ). The results demonstrated that SA could interact with SC, which caused a viscosity synergism in the dispersions. Hydrogen bonding between the carboxyl or hydroxyl groups of SA and the amide groups of SC led to the formation of soluble complexes that could reinforce the CA beads prepared by calcium cross-linking. The SC-CA beads provided higher drug entrapment efficiency, lower water uptake and erosion, and slower drug release than for the CA beads. The loaded FZ was an amorphous form, but CZ crystals were embedded in the bead matrix due to the low water solubility of this drug. However, SC micellization could enhance the water solubility and efficacy of CZ against Candida albicans. This finding indicates that SA can interact with SC via hydrogen bonding to form complexes and that the anticandidal-loaded SC-CA beads can be used as drug delivery systems and drug reservoirs in tablets for oral candidiasis.

A novel antibacterial peptide derived from Crocodylus siamensis haemoglobin hydrolysate induces membrane permeabilization causing iron dysregulation, oxidative stress and bacterial death

A novel antibacterial peptide from Crocodylus siamensis haemoglobin hydrolysate (CHH) was characterized for antimicrobial activity.

Some Properties of a Polymeric Surfactant Derived from Alginate

The aim of this study was to prepare a polymeric surfactant from alginate, to evaluate the properties of this surfactant for pharmaceutical application and to study the effect of the surfactant on immune response. The polymeric surfactant was prepared by the method previously reported. Surface tension of its solution was determined by maximum pull force technique. Proliferation of splenocytes was performed by the measurement of 5-bromo-2-deoxyuridine (BrdU) incorporation during DNA synthesis. The proliferative response of splenocyte to the surfactant was compared to quillaja saponin. The surface tension of the surfactant in water was decreased to 30.37 mN/m. Critical concentrations for micelle formation in water, 5% dextrose, phosphate buffered saline and 0.9% NaCl were 2.95 mg/ml, 3.07 mg/ml, 1.55 mg/ml and 1.52 mg/ml, respectively. The surfactant at the concentration higher than 1.5 mg/ml showed significantly reduction of splenocyte proliferation. The highest stimulation was found at a concentration of 0.75 mg/ml. The alginatederived polymeric surfactant seems to form micelles in aqueous solutions and to stimulate immune responses. These results indicated that the polymeric surfactant could be a potential vaccine adjuvant.