Asian Pacific Journal of Tropical Biomedicine

995–1000

Authors: Aly Younes, Hanaa El-Sherief, Fathia Gawish, Marwa Mahmoud

Objective: To evaluate the predatory potential of the Odonata nymph on freshwater snails that serve as intermediate hosts for Schistosoma species (Bulinus truncatus and Biomphalaria alexandrina). Methods: Observations on the searching, attacking and devouring of the two snail types with series of laboratory-based predation experiments, whose aims were to determine daily predation rate, differential predation, prey preference considering small-, mediumand large-sized snails were conducted. Results: Laboratory evaluation revealed that, the Odonata nymph could kill and consume the two intermediate hosts. The number of snails consumed differed according to the snail type, size and density. The times taken for searching and handling times were dependent on the snail size, type and satiation of the predator. The predation rate varied also with respect to snail type, size and density. This study also evaluated that Odonata nymphs consumed more Bulinus truncatus than Biomphalaria alexandrina per unit time, and that there may be a preference for smaller than larger snails. Conclusions: According to our observation, the predator, Hemianax ephippiger nymph may be a suitable biocontrol agent in connection with Schistosoma intermediate hosts.

1008–1014

Authors: Panan Ratthawongjirakul, Vorraruthai Thongkerd, Wanpen Chaicumpa

Objective: To investigate the impact of the fliD gene on the biofilm formation of Helicobacter pylori (H. pylori). Methods: H. pylori fliD mutant was constructed using inverse PCR mutagenesis. The mobility of the bacteria and its adhesion ability to human epithelial cells were assessed using a motility assay and a fluorescein isothiocyanate staining adhesion assay, respectively. The formation of biofilm was evaluated using a pellicle assay and a crystal violet staining assay. The cyto-architecture of the biofilm was documented with scanning electron microscopy. Results: It was found that there was no significant difference in the levels of bacterial adhesion and the biofilm formation between the wild-type ATCC 43504 and the fliD mutant. Apart from a poor motility, the fliD mutant had a slightly delayed formation of its biofilm and an incomplete cyto-architecture of its biofilm. The bacterial cells residing in the biofilm of the fliD mutant showed a loose accumulation with less apparent crosslinking fibrils. Most of the mutant cells had truncated flagella. Conclusions: This study provides the preliminary evidences that fliD potentially regulates biofilm formation and is required for the motility of H. pylori. Further studies need to be performed in order to develop fliD as a novel target for vaccine or antimicrobial agent in future.

1022–1028

Authors: Doroth
ee Dinangayi Tshilanda, Philippe Bila Babady, Damase Nguwo Vele Onyamboko1, Christian Muamba Tshilolo Tshiongo, Damien Sha-Tshibey Tshibangu, Koto-te-Nyiwa Ngbolua, Philippe Vuka Tsalu, Pius Tshimankinda Mpiana

Objective: To carry out a phyto-chemical characterization of essential oil from Ocimum basilicum L. (O. basilicum) harvested in DR Congo and to assess the antioxidant potential of crude extracts with respect to the polarity for comparison reason. Methods: The phyto-chemical characterization of essential oil produced by hydrodistillation was performed by coupled gas chromatography-mass spectrometer analysis and the antioxidant potential evaluation by in vitro 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity method. Results: A previously weighed amount of fresh leaves of O. basilicum produced 0.65% of essential oil that led to the identification of a set of 84.44% out of 99.98% as major compounds (> 1.5%). The chemo-type of this essential oil was linalool-methyl chavicol. Chemical components of oil were characterized by oxygenated aromatic hydrocarbons (46.00%) and oxygenated monoterpenes (26.75%). With respect to the amount of components, methyl chavicol also known as estragole (35.72%) constituted the very large quantity afterward linalool (21.25%) and then epi-a-cadinol (8.02%), a-bergamotene (6.56%), eugenol (4.60%), 1,8-cineole (4.04%), germacrene D (2.06%), thymol (1.64%), and (E)- citral (1.55%), respectively. Essential oil exhibited antioxidant potential and IC50 = (1.180 ± 0.015)mg/mL. Non-polar crude extracts yieldswere low compared to the one of polar extracts. Only methanol and ethyl acetate had considerably manifested antioxidant potential with IC50 values equal to (0.025 ± 0.013) mg/mL and (0.085 ± 0.012) mg/mL, respectively. As concerns to IC50 values, essential oil was less active than methanol and ethyl acetate extracts. The methanol crude extract exhibited the highest activity. Non-polar extracts showed insignificant radical scavenging ability that did not allow assessing IC50 values. These results highlighted the occurrence of antioxidant potential compounds in polar media. Conclusions: Essential oil and crude extracts of O. basilicum growing in DR Congo can be advocated as natural sources of antioxidant potential compounds not only in food but also in pharmaceutical industries. The high antioxidant potential of polar crude extracts highlights antioxidant character of its composition particularly butyl stearate and rosmarinic acid we isolated and identified, respectively in the methanol crude extract.

1037–1043

Authors: Kayini Chigayo, Paul Eanas Lesedi Mojapelo, Simon Mnyakeni-Moleele, Jane Masiiwa Misihairabgwi

Objective: To determine suitable phytochemical extraction solvents, screen for phytochemicals, determine the total phenol and flavonoid contents and the antioxidant activities of different solvent extracts of Kirkia wilmsii (K. wilmsii), an ethnomedicine in South Africa. Methods: Extractionswere performed fromdried tubers of the K. wilmsii plant, using several solvents and varying extraction times. Extract yields were determined and suitable extraction solvents were selected. Total phenol and flavonoid contents of the extracts were determined spectrophotometrically using gallic acid and quercetin as standards. The free radical scavenging activity of the extracts was investigated using 1,1-diphenyl-2-picrylhydrazyl radical. Results: Phytochemical screening confirmed the presence of phenolics, flavonoids, terpenoids, tannins, cardenolide deoxy sugars and reducing sugars.Of the 12 solvent extracts used, six gave yields higher than 5%, while the other six gave yields less than 1%. The highest extract yield of 52.9%was obtained using 80%methanol while the lowest yield of 7.3%was obtained using ethanol at 60 min. The 80% methanol, methanol/chloroform/water (12:5:3) and 60% methanol extracts were significantly higher than those of ethanol, methanol and water (P < 0.05). Total phenolic content recorded extracts ranged from (45.32 ± 0.50) to (122.84 ± 0.31) mg gallic acid equivalent per gram. A maximum total flavonoid content of (917.02 ± 0.10) mg quercetin equivalent per gram and a minimum of (206.26 ± 0.10) mg quercetin equivalent per gram were recorded for methanol and water, respectively. The flavonoid content for methanol was significantly higher than all the other extracts (P < 0.05). The scavenging profiles of K. wilmsii extracts were significantly lower (P < 0.05) than that of ascorbic acid and IC50 values ranged from 129.94 mg/mL for methanol to 225.04 mg/mL for water. An IC50 value of 56.52 mg/mL was obtained with ascorbic acid. Conclusions: Ethanol, methanol, methanol/chloroform/water, 80% methanol, 60% methanol and water can be used as suitable phytochemical extraction solvents for K. wilmsii tubers. Total phenolic content and total flavonoid content analysis proved the presence of high levels of phenolic compounds as well as flavonoids. The presence of phenols and flavonoid could be responsible for the radical scavenging activities observed.

1050–1055

Authors: Patcharawan Tanamatayarat

Objective: To evaluate all parts of Protium serratum (Wall. ex Colebr.) Engl. (P. serratum) for their phytochemistry and biological activities including antityrosinase, antioxidant, and brine shrimp lethality. Methods: Nine ethanolic extracts from different P. serratum parts such as twig, whole fruit, pericarp, and root were investigated for their phytochemical screening and biological activities in terms of tyrosinase inhibition, antioxidant against 1,1-diphenyl-2- picrylhydrazyl and hydroxyl radicals, and lethality to brine shrimp larvae. Results: Phytochemical screening also revealed the presence of flavonoids, condensed tannins, alkaloids, triterpenoids, steroids, and sugars in P. serratum. The root extract was the most effective for antityrosinase activity with IC50 of (21.63 ± 0.31) mg/mL, and the leaf extract exhibited the highest antioxidation activity using 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical scavenging methods, with IC50 of (4.34 ± 0.09) and (119.80 ± 1.01) mg/ mL, respectively. The essential oil extracted from the whole fruit displayed the highest toxicity against brine shrimp, with LC50 of (3.57 ± 1.82) mg/mL. Conclusions: This study indicates that ethanolic extracts from each P. serratum part have differences in phytochemistry and biological activities (antityrosinase, antioxidant, and brine shrimp lethality). Some parts of the plant should be considered in the further study.

1065–1075

Authors: Hassan Nasirian

The brown-banded cockroach, Supella longipalpa (Blattaria: Blattellidae) (S. longipalpa), recently has infested the buildings and hospitals in wide areas of Iran, and this review was prepared to identify current knowledge and knowledge gaps about the brown-banded cockroach. Scientific reports and peer-reviewed papers concerning S. longipalpa and relevant topics were collected and synthesized with the objective of learning more about health-related impacts and possible management of S. longipalpa in Iran. Like the German cockroach, the brown-banded cockroach is a known vector for food-borne diseases and drug resistant bacteria, contaminated by infectious disease agents, involved in human intestinal parasites and is the intermediate host of Trichospirura leptostoma and Moniliformis moniliformis. Because its habitat is widespread, distributed throughout different areas of homes and buildings, it is difficult to control. Considering its possible resistance to insecticides, the control situation may be far more complex. For improved control of S. longipalpa an integrated pest management program is needed. Sanitation, indoor insecticide spraying in the initial cockroach control phase and insecticide formulation baits are recommended simultaneously.