Tropical Biomedicine

Development of new lateral-flow immunochromatographic strip using colloidal gold and mesoporous silica nanoparticles for rapid diagnosis of active schistosomiasis Manal Kamel, Faten Salah, Zeinab Demerdash, Sara Maher, Shimaa Atta, Abeer Badr, Ahmed Afifi, Hanan El Baz Asian Pacific Journal of Tropical Biomedicine 2019 9(8):315-322 Objective: To develop a new sandwich based lateral flow immunochromatographic strip for rapid detection of circulating Schistosoma mansoni antigen in serum and urine samples of patients with active schistosomiasis. Methods: This lateral flow immunochromatographic strip was prepared by using anti-Schistosoma mansoni soluble egg antigen monoclonal antibody conjugated gold nanoparticles (MAb-AuNPs) as antigen-detecting antibody, while crystalline material (MCM)-41-MAb bioconjugate was immobilized at the test line as antigen-capturing antibody. Both antigen capturing and detecting antibodies formed sandwich complexes with circulating Schistosoma mansoni antigen in the positive samples. Sandwich complexes immobilized at the test line gave distinct red color. The assay reliability was examined by using urine and serum samples of 60 Schistosoma mansoni infected patients, 20 patients infected with parasites other than Schistosoma, and 20 healthy individuals as negative controls. Results were compared with those obtained via sandwich enzyme linked immunosorbent assay (ELISA). Results: The detection limit of circulating Schistosoma mansoni antigen by lateral flow immunochromatographic strip was lower (3 ng/mL) than the detection limit by ELISA (30 ng/mL). The sensitivity and specificity of lateral flow immunochromatographic strip in urine samples were 98.3% and 97.5%, respectively compared to 93.5% and 90.0% by ELISA. In serum samples, they were 100.0% and 97.5%, respectively compared to 97.0% and 95.0% by ELISA. The strip test took approximately 10 min to complete. Conclusions: This new lateral flow immunochromatographic strip offers a sensitive, rapid, and field applicable technique for diagnosis of active schistosomiasis.

Antioxidant, anti-quorum sensing and anti-biofilm potential of ethanolic leaf extract of Phrynium capitatum and Dryptes indica Nagaraju Jalli, KV Santhi Sri, Sairengpuii Hnamte, Subhaswaraj Pattnaik, Parasuraman Paramanantham, Busi Siddhardha Asian Pacific Journal of Tropical Biomedicine 2019 9(8):323-332 Objective: To investigate the antioxidant and anti-infective potential of Phrynium capitatum and Dryptes indica extract. Methods: The antioxidant potentials were determined by DPPH radical scavenging, reducing power, hydroxyl radical scavenging and total antioxidant assays. We further examined anti-quorum sensing activity and inhibition of synthesis of pathogenic factor of Chromobacterium violaceum and Pseudomonas aeruginosa PAO1. Bioactive compounds were determined using gas chromatography–mass spectrometry analysis. In silico analysis was conducted to determine the binding affinity of bioactive compounds of plant extracts for the quorum sensing regulatory receptor LasR. Results: DPPH assay showed that the ethanolic extract of Phrynium capitatum and Dryptes indica at 500 μg/mL showed (86.96 ± 4.07)% and (74.83 ± 3.47)% inhibition, respectively. Hydroxyl radical scavenging assay showed (73.17 ± 3.03)% and (62.63 ± 4.59)% activity, respectively. The ethanolic extract of Phrynium capitatum and Dryptes indica showed high level of attenuation of quorum sensing regulated pyocyanin production. Confocal laser scanning microscopic analysis revealed that the extracts had the potential to effectively inhibit biofilm formation of Pseudomonas aeruginosa. Molecular docking analysis showed a better binding affinity of bioactive compounds from the extracts for the structure of LasR protein of Pseudomonas aeruginosa. Conclusions: The ethanolic extracts of Phrynium capitatum and Dryptes indica possess antioxidant activity and the potential to inhibit the quorum sensing system and its regulatory irulence traits in Pseudomonas aeruginosa PAO1.

Synergistic antioxidant interactions between green tea and Ocimum gratissimum Sumaya Farooq, Amit Sehgal Asian Pacific Journal of Tropical Biomedicine 2019 9(8):333-338 Objective: To evaluate the antioxidant interactions between aqueous infusions of green tea and Ocimum gratissimum at different ratios. Methods: Antioxidant activities of aqueous infusion of green tea and Ocimum gratissimum (leaves) alone or in combination at various proportions (3:1, 2:1, 1:1, 1:2, 1:3) were determined by DPPH, ABTS, NO and ex-vivo assays including lipid peroxidation and haemolysis. Total phenolic content and flavonoid content was calculated by Folin-Ciocalteu reagent and aluminum chloride colorimetry method, respectively. A correlation study was also conducted between the antioxidant activity and total phenolic/flavonoid content of various infusions. The interactions were analyzed by combination index applying CompuSyn software. Results: Green tea exhibited high radical scavenging ability as compared to Ocimum gratissimum infusion. Combination of green tea and Ocimum gratissimum exhibited moderate antagonism to strong synergistic interaction at various ratios. A strong correlation was found between total phenolic content/total flavonoid content and antioxidant activities of individual infusions (green tea and Ocimum gratissimum). For binary mixture at different ratios, a weak to strong correlation was observed between total phenolic content and antioxidant activity and almost no correlation between total flavonoid content and antioxidant potential. Conclusions: Overall, green tea and Ocimum gratissimum combination (1:1) displayed the highest antioxidant potential and maximum synergism.

Proapoptotic activities of Oroxylum indicum leave extract in HeLa cells Nurul Hidayah Wahab, Nur Afina Mohd Din, Yee Ying Lim, Noor Izani Noor Jamil, Nor Fazila Che Mat Asian Pacific Journal of Tropical Biomedicine 2019 9(8):339-345 Objective: To examine the proapoptotic properties of Oroxylum indicum methanol extract on cervical cancer cells. Methods: Methylene blue assay was used to determine the IC50 value of the extract. Western blotting assays were done to analyze the expression of HPV oncoproteins (HPV18 E6 and E7) and apoptotic molecules (caspase-3 and caspase-8). Reverse transcriptase PCR assays were performed to determine genetic alteration of tumor suppressors p53 and pRb and apoptosis markers Fas and FasL. Enzyme-linked immunosorbent assay (ELISA) was done to determine the expression of cytokine levels (IL-6 and IL-12). Results: The determination of IC50 value indicated a higher anti-proliferative activity of the extract compared to cisplatin. After 24 hours of treatment, Western blot analysis showed that treated HeLa cells exhibited a significant down-regulation of HPV18 oncoproteins E6 and E7, and a significant induction of caspase-8 and caspase-3 activation level. Meanwhile, the mRNA expressions of p53, pRb, Fas and FasL were significantly upregulated in treated cells. Moreover, ELISA showed an increased IL-12 and decreased IL-6 production after Oroxylum indicum treatment. Conclusions: The methanol extract of Oroxylum indicum has an anti-proliferative activity and proapoptotic potential. It induces localized-immunity improvements by altering cytokine production in HPV-positive cervical cancer cells.

Cladogynos orientalis Zipp. extracts inhibit cell culture-derived hepatitis C virus genotype 2a replication in Huh-7 cells through NS5B inhibition Piyanoot Thongsri, Khanit Sa-ngiamsuntorn, Pongtip Sithisarn, Mullika T Chomnawang, Krit Thirapanmethee Asian Pacific Journal of Tropical Biomedicine 2019 9(8):346-352 Objective: To evaluate the potential anti-hepatitis C virus (HCV) activities of Cladogynos orientalis Zipp. ex Span and to investigate the molecular mode of action. Methods: Ethanolic and water extracts from various parts of Cladogynos orientalis were examined for cytotoxicity by MTT assay. Sub-cytotoxic concentrations of the extracts were used for further determining anti-HCV activity using cell culture-derived HCV genotype 2a propagated in HepaRG cell line. Immunofluorescence assay was performed to observe the effect on viruses at the pre-entry step. Mode of action at the post-entry step was investigated for the viral RNA and protein expressions by real time RT-PCR and Western blotting assays, respectively. Results: Although Cladogynos orientalis water extracts exhibited lower cytotoxicity than ethanolic extracts, all ethanolic extracts from roots, stems, and leaves of Cladogynos orientalis exhibited higher anti-HCV activities than water extracts. The highest anti-HCV activity was observed in infected cells treated with the extracts 5 h after absorption. No extracts showed pre-viral entry effect. At the post-viral entry step, only leaf ethanolic extracts inhibited NS5B expression, while all extracts did not inhibit HCV NS3 expression. Conclusions: Cladogynos orientalis ethanolic extracts could be further studied and the major active compound needs to be identified as a promising source for anti-HCV agents.

Cytotoxic effect of methanolic extracts of Fritillaria imperialis bulbs and Eryngium caucasicum leaves on hepatoma and colon cancer cells Mostafa Kardan, Zahra Yazdani, Zaher Morsaljahan, Mohammad Ali Ebrahimzadeh, Alireza Rafiei Asian Pacific Journal of Tropical Biomedicine 2019 9(8):353-358 Objective: To evaluate antitumor activities of Fritillaria imperialis and Eryngium caucasicum methanolic extracts on human hepatoma (HepG2) and colon cancer (HCT116) cell lines in comparison to human foreskin fibroblasts as the normal cells. Methods: Methanolic extracts of Fritillaria imperialis and Eryngium caucasicum were prepared by the maceration method. The effect of the extracts at various concentrations (100, 200, 400, 600, and 800 μg/mL) on cell survival was evaluated using the MTT method. Besides, fluorescence staining was used to evaluate death patterns of the cells. Results: MTT assay showed that Fritillaria imperialis significantly decreased the viability of all cell lines after 24 and 48 hours of treatments. However, Eryngium caucasicum extract did not show any significant cytotoxicity effect on the cell lines. Fluorescence staining revealed that Fritillaria imperialis induced apoptosis of HCT116 cells at 550 μg/mL. Conclusions: Fritillaria imperialis extract has antiproliferative and cytotoxic effects on HCT116 and HepG2 cancer cells and therefore, may serve as an anticancer agent.