Evaluation of direct antiviral activity of the Deva-5 herb formulation and extracts of five Asian plants against influenza A virus H3N8

Abstract

BackgroundThe herb formulation Deva-5 is used in traditional medicine to treat acute infectious diseases. Deva-5 is composed of five herbs: Gentiana decumbens L., Momordica cochinchinensis L., Hypecoum erectum L., Polygonum bistorta L., and Terminalia chebula Retz. Deva-5 and its five components were investigated for in vitro antiviral activity against avian influenza A virus subtype H3N8.MethodsThe water extracts of the herbal parts of G. decumbens, H. erectum and P. bistorta, the seeds of T. chebula and M. cochinchinensis and Deva-5 were prepared by boiling and clarified by low-speed centrifugation and filtration. To assess the antiviral properties, avian influenza virus isolate A/Teal/Tunka/7/2010(H3N8) was incubated at 37°C for 30 min in the presence and absence of the extracts of five plants and DEVA-5 in various concentrations. Subsequently, the concentration of infectious virus in each sample was determined by plaque assays. Neutralisation indexes and 90% plaque reduction concentrations were estimated for each extract, and the significance of the data was evaluated using statistical methods.ResultsThe extracts of G. decumbens, H. erectum, P. bistorta and Deva-5 demonstrated no significant toxicity at concentrations up to 2%, whereas extracts of T. chebula and M. cochinchinensis were well-tolerated by Madin-Darby canine kidney cells at concentrations up to 1%. The extracts of H. erectum, M. cochinchinensis and T. chebula reduced the titre of A/Teal/Tunka/7/2010 (H3N8) by approximately five-fold (p ≤ 0.05). The other three extracts did not significantly reduce the infectivity of the virus. The plaque reduction neutralisation tests revealed that none of the extracts tested were able to inhibit formation of plaques by 90%. However, three extracts, H. erectum, T. chebula and M. cochinchinensis, were able to inhibit formation of plaques by more than 50% at low dilutions from 1:3 to 1:14. The T. chebula extract had a concentration-dependent inhibitory effect.ConclusionsFor the first time, the consistent direct antiviral action of the extracts of H. erectum, T. chebula and M. cochinchinensis was detected. These extracts significantly reduced the infectivity of influenza A virus H3N8 in vitro when used at high concentrations (0.5–1%). However, Deva-5 itself and the remainder of its components did not exhibit significant antiviral action. The results suggest that H. erectum, T. chebula and M. cochinchinensis plants contain substances with direct antiviral activity and could be promising sources of new antiviral drugs.

Neurotrophic Effects of Mu Bie Zi (Momordica cochinchinensis) Seed Elucidated by High-Throughput Screening of Natural Products for NGF Mimetic Effects in PC-12 Cells

“…[67, 68] MCS derived cyclic knottins share similar conformational form as noncyclic squash inhibitors such as CPTI [69] and interesting also, NGF [70]. While NGF medicinal applications are limited, natural NGF mimetics such as those found in the MCS extract are generally robust in therapeutic properties previously reported to have anti-viral, [71, 72] anti-angiogenic, anti-tumor [73] anti-inflammatory and anti-oxidant properties [63] and an ability to enhance innate immunity [74, 75], aid in wound healing [76] and heal gastric ulters. [77].…”

Fractionating the Plant Extract in Mini Volumes to Purify the Potential Antivirals from Terminalia Chebula

“…We have previously described that a 2% T. chebula extract completely neutralizes infectious TBEV at a concentration of 1×10 5 PFU, (13) and the antiviral activity of the same extract against the influenza A virus is detectable up to a concentration of 0.01%. (17) Thus, the concentration of the active substance in any of the fractions, even if it is evenly distributed over the entire volume of the column, should be sufficient for detectable neutralization of TBEV.…”

Terminalia chebula Retz. – an important medicinal plant

“…Ajala et al [48] described that chebumeinin A, chebumeinin B and two new hydrolysable tannins together with 8 identified and associated compounds from the dried fruits displayed activity against Hepatitis C virus. T. chebula extracts have been displayed important antiviral activity on influenza A virus H3N8 viral assays when used at higher doses [49]. T. chebula was shown to have significant antiviral action with cytomegalo virus.…”