Antioxidant Properties and Total Phenolic Content of Selected Traditional Thai Medicinal Plants

Objectives: In accordance with traditional local wisdom, medicinal plants from north-eastern Thailand are used for the treatment of dermatitis-related inflammations. This study aimed to investigate the antioxidant activity and total phenolic content (TPC) of the bark of thirteen medicinal plants. Methods: The study plants included Stephania venosa (Blume) Spreng, Smilax perfoliata Lour., Dolichandrone stipulata, Glochidion coccineum,  Xantolis cambodiana, Dalbergia cultrata, Bauhinia sirindhorniae K., Knema angustifolia, Tristaniopsis burmanica, Ficus hirta Vahl, Capparis zeylanica, Amphineurion marginata (Roxb.) G. Don. and Microsorum pteropus (Blume) Copel. The antioxidant properties were determined by means of three approaches namely 1,1-diphenyl-1-princylhydrazyl (DPPH) radical scavenging assay at 517 nm, ferric-reducing antioxidant power (FRAP) assay at 593 nm and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid  (ABTS) assay at 734 nm. The TPC of the plants was determined via the Folin-Ciocalteu method. The correlation between each of the antioxidant activity value with TPC was tested using the Pearson’s correlation coefficient (r). Results: The antioxidant properties and TPC differed significantly among the plants.  In each of the methods, S. venosa (Blume) Spreng., X. cambodiana, B. sirindhorniae, K. angustifolia and C. zeylanica consistently exhibited the most potent antioxidant property ranging from 70% to 100%. This further suggested their potential rich source of natural antioxidants. Coincidentally, these plants contained the highest TPC (38,113 - 9,989 mg GAE/g). Significant positive correlations were found between antioxidant activity (ABTS·+ and FRAP assays) and the TPC with r = 0.987 and 0.956, respectively. Conclusion: Thirteen medicinal plants contained antioxidant activity which was related to the phenolic content. The active ingredients and other biological activities of these herbal plants merit further investigations. Keywords: Thai medicinal plants, antioxidant activity, total phenolic conten

Population Genetic Structuring in Opisthorchis viverrini over Various Spatial Scales in Thailand and Lao PDR

Khon Kaen Province in northeast Thailand is known as a hot spot for opisthorchiasis in Southeast Asia. Preliminary allozyme and mitochondrial DNA haplotype data from within one endemic district in this Province (Ban Phai), indicated substantial genetic variability within Opisthorchis viverrini. Here, we used microsatellite DNA analyses to examine the genetic diversity and population structure of O. viverrini from four geographically close localities in Khon Kaen Province. Genotyping based on 12 microsatellite loci yielded a mean number of alleles per locus that ranged from 2.83 to 3.7 with an expected heterozygosity in Hardy-Weinberg equilibrium of 0.44-0.56. Assessment of population structure by pairwise F(ST) analysis showed inter-population differentiation (P<0.05) which indicates population substructuring between these localities. Unique alleles were found in three of four localities with the highest number observed per locality being three. Our results highlight the existence of genetic diversity and population substructuring in O. viverrini over a small spatial scale which is similar to that found at a larger scale. This provides the basis for the investigation of the role of parasite genetic diversity and differentiation in transmission dynamics and control of O. viverrini

Preliminary genetic evidence of two different populations of Opisthorchis viverrini in Lao PDR

Opisthorchis viverrini is a major public health concern in Southeast Asia. Various reports have suggested that this parasite may represent a species complex, with genetic structure in the region perhaps being dictated by geographical factors and different species of intermediate hosts. We used four microsatellite loci to analyze O. viverrini adult worms originating from six species of cyprinid fish in Thailand and Lao PDR. Two distinct O. viverrini populations were observed. In Ban Phai, Thailand, only one subgroup occurred, hosted by two different fish species. Both subgroups occurred in fish from That Luang, Lao PDR, but were represented to very different degrees among the fish hosts there. Our data suggest that, although geographical separation is more important than fish host specificity in influencing genetic structure, it is possible that two species of Opisthorchis, with little interbreeding, are present near Vientiane in Lao PDR

Prevalence of gastrointestinal parasites in captive mammals at Khon Kaen Zoo, Thailand

Background and Aim: Captive animals are susceptible to parasitic diseases due to the stress and confinement they experience. In addition, they can serve as reservoirs of zoonotic parasites that have the potential to infect humans. To investigate this possibility, we estimated the prevalence of gastrointestinal (GI) parasites in captive mammals at Khon Kaen Zoo, Thailand. Materials and Methods: One hundred and forty-seven individual mammals (37 primates, 43 carnivores, 62 herbivores, and 5 rodents) were examined for parasitic infections by fecal examination daily for 3 consecutive days using the formalin-ethyl acetate concentration technique (FECT) and the agar plate culture method. Results: According to FECT, the overall prevalence of GI parasites was 62.6% (92/147). Within animal groups, the numbers were as follows: 67.6% (25/37) in primates, 23.3% (10/43) in carnivores, 85.5% (53/62) in herbivores, and 80.0% (4/5) in rodents. Using the agar plate culture method, 21.43% (27/126) were positive for Strongyloides spp. and hookworm infections. The GI parasites identified belonged to three categories: protozoa (including Entamoeba histolytica species complex, Entamoeba coli, Giardia spp., coccidia, and ciliated protozoa), trematodes (minute intestinal flukes and rumen flukes), and nematodes (strongyle/hookworm, Strongyloides spp., Ascarididae, and Trichuris spp.). Conclusion: The findings of this study indicate the prevalence of several GI parasites in zoo animals with the potential for transmission to humans, given the animals’ close proximity to both visitors and animal caretakers

Design of PI Controller for Voltage Controller of Four-Phase Interleaved Boost Converter Using Particle Swarm Optimization

This article introduces voltage feedback controlling using the PI controller tuned gains by metaheuristic optimizations for a four-phase interleaved boost converter. The metaheuristic optimizations, particle swarm optimization (PSO), genetic algorithm (GA), and Tabu search (TS) are applied to find the optimal gains for the proposed control system. In experiment, the designed control system is implemented on the DSP board TMS320F28335 with MATLAB/Simulink. In this paper, there are two conditions of the control system in the test, without load and with load. The response result of the proposed control system tuned gains by PSO is no overshoot and approaches to the steady state better than GA and TS methods. Moreover, it is able to maintain the output voltage feedback at a constant level according to the control signal both without load and with load conditions. As a result, the four-phase interleaved boost converter is regulated by the PI controller tuned gains with PSO which could efficiently maintain the voltage of both levels

Biological variation within opisthorchis viverrini sensu lato in Thailand and Lao PDR

10.1645/GE-2116.1Journal of Parasitology9561307-1313JOPA

Microsatellite loci in the carcinogenic liver fluke, Opisthorchis viverrini and their application as population genetic markers

10.1016/j.meegid.2009.11.005Infection, Genetics and Evolution101146-153IGEN