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

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

Population genetic data of <i>O. viverrini</i> populations from Khon Kaen Province.

<p>Data analyses of worms from four geographical localities in Khon Kaen Province for each polymorphic microsatellite locus examined at 12 microsatellite loci. <i>H_E</i>: expected heterozygosity; <i>H_O</i>: observed heterozygosity; <i>F_IS</i>: inbreeding coefficient, according to Weir and Cockerham (1984). Tests of deviation from Hardy–Weinberg equilibrium (HWE) were performed using GENEPOP version 3.4. P-values (<0.05) considered significant are italicised. “<i>A</i>” indicates the number of alleles per locus per population. “<i>A_e</i>” indicates the allelic richness per locus per population. “<i>N</i>” indicates the number of individuals successfully typed.</p

Allele frequencies at 12 loci in <i>O. viverrini</i> from Khon Kaen and widely spaced populations.

<p>Sampling localities for the Khon Kaen populations were Ban Sa-ard (KBs), Ban Lerngpluey (KLp), Ban Phai (KBp), Phu Wiang (KPv) and for the widely spaced populations were Lampang (LP), Buri Rum (BR), Chaiya Phum (CP), Nakhon hanom (NP) and Vientiane (VT). See also <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001906#pntd-0001906-g001" target="_blank">Figure 1</a>.</p

Sample populations of <i>O. viverrini</i>.

<p>Sampling localities of the closely spaced populations in Khon Kaen Province in northeast Thailand (left) and expanded map (right) showing the four localities of <i>O. viverrini</i> examined, Ban Sa-ard (KBs), Ban Lerngpluey (KLp), Ban Phai (KBp) and Phu Wiang (KPv). The widely spaced populations (left) include Lampang (LP), Buri Rum (BR), Chaiya Phum (CP), Nakhon Phanom (NP) in Thailand and Vientiane (VT) in Lao PDR.</p