ABSTRACT
In vitro anti-rotavirus activity of Alpinia katsumadai (AK) extracts were evaluated against bovine G8P[7] and porcine G5P[7] rotaviruses in two different assay strategies, a mixed treatment assay and a post treatment assay. In the mixed treatment assay, six AK extracts [AK-1 (EtOH extract), AK-3 (H(2)O layer), AK-5 (40% methanol fraction), and AK-9-11 (H(2)O extract, polysaccharide fraction, supernatant fraction)] exhibited inhibitory activities against G5P[7] rotavirus with the EC(50) values ranging from 0.7±0.4 to 33.7±6.5 µg/mL. Extracts AK-1, AK-3, and AK-5 inhibited rotavirus infection against G8P[7] rotavirus, the with EC(50) values of 8.4±2.2 µg/mL, 6.5±0.8 µg/mL and 8.4±5.0 µg/mL, respectively. By hemagglutination inhibition (HI) assay, six AK extracts completely inhibited viral adsorption onto human RBCs in both strains of rotaviruses at less than 11 µg/mL. However, in the post treatment assay, there was no anti activity shown against both strains of rotaviruses. As a result, six AK extracts were attributed mainly to having a strong interaction with hemagglutinin protein on the outer surface of rotavirus, resulting to blockage of viral adsorption.
Subject(s)
Alpinia , Phytotherapy/methods , Plant Extracts/therapeutic use , Rotavirus/drug effects , Animals , Cattle , Cattle Diseases/drug therapy , Cattle Diseases/virology , Hemagglutination Inhibition Tests , Macaca mulatta , Rotavirus Infections/drug therapy , Rotavirus Infections/veterinary , Seeds , Swine , Swine Diseases/drug therapy , Swine Diseases/virologyABSTRACT
Toroviruses (ToVs) are a group of emerging viruses that cause gastroenteritis in domestic animals and humans. Currently, methods such as real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) have not yet been developed for the rapid detection and quantitation of bovine (BToV) and porcine (PToV) toroviruses. Using BToV and PToV RNA standards generated by in vitro transcription, the detection limit of the SYBR Green real-time RT-PCR assay was 2.54 x 10(2) BToV and 2.17 x 10(3) PToV copies/reaction (correlation coefficiency=0.99 and 0.97, respectively), whereas those of RT-PCR and nested PCR were 2.54 x 10(5) and 2.54 x 10(4) (BToV) and 2.17 x 10(7) and 2.17 x 10(5) (PToV) cRNA viral copies/reaction, respectively. Archived diarrhea specimens of calves (n=121) and piglets (n=86) were subjected to RT-PCR, nested PCR and SYBR Green real-time RT-PCR. By conventional RT-PCR, 1 (0.8%) bovine and 7 (8.1%) porcine samples tested positive to BToV and PToV, respectively. With nested PCR, 13 (10.7%) bovine and 17 (19.8%) porcine samples tested positive. SYBR Green real-time RT-PCR assay detected BToV and PToV in 22 of 121 (18.2%) bovine and 31 of 86 (36.0%) porcine samples. These results indicate that SYBR Green real-time RT-PCR (P<0.05) is a more sensitive assay, which can be reproduced as a reliable, sensitive, and rapid tool for the detection and quantitation of toroviruses.
