Influence of Agathi grandiflora active principles inhibit viral multiplication and stimulate immune system in Indian white shrimp Fenneropenaeus indicus against white spot syndrome virus infection

• Published in: Fish & shellfish immunology 2014-12, Vol.41 (2), p.482-492
• Main Authors: Bindhu, Francis, Velmurugan, Subramanian, Donio, Mariathason Birdilla Selva, Michaelbabu, Mariavincent, Citarasu, Thavasimuthu
• Format: Article
• Language: English
• Subjects: Adjuvants, Immunologic - pharmacology; Agathi grandiflora; Agathis; Analysis of Variance; Animals; Antiviral; Coniferophyta - chemistry; DNA Primers - genetics; Fenneropenaeus indicus; Gas Chromatography-Mass Spectrometry; Immunostimulants; Leucas; Methanol; Monophenol Monooxygenase - metabolism; Penaeidae - immunology; Penaeidae - virology; Plant Extracts - pharmacology; Polymerase Chain Reaction; Psoralea; Quantitative real time PCR (qRT-PCR); Quercus; Real-Time Polymerase Chain Reaction; Vibrio - drug effects; Vibrio harveyi; Virus Replication - drug effects; White spot syndrome virus; White spot syndrome virus (WSSV); White spot syndrome virus 1 - immunology
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2014.09.034

Five herbs including Adathoda vasica, Agathi grandiflora, Leucas aspera, Psoralea corylifolia, and Quercus infectoria were selected to screen the antiviral and immunostimulant activity against white spot syndrome virus (WSSV) and Vibrio harveyi respectively using different organic polar and non-polar solvents. Based on the initial screening results, ethyl acetate and methanolic extracts of A. grandiflora had strong antiviral and immunostimulant activities. Those extracts incubated with WSSV injected Fenneropenaeus indicus got only 20% mortality and no PCR positive signals were seen in two step PCR amplification. The methanolic extracts of A. grandiflora were further purified through silica column chromatography and the fractions screened again for antiviral and immunostimulant activity. The secondary screening results revealed that, the fractions of F5 to F7 had effectively controlled the WSSV multiplication and V. harveyi growth. The pooled fractions (F5 to F7) was structurally characterized by gas chromatograph-mass spectrometry (GC-MS) analysis and few compounds were identified including 3,7.11,15-Tetramethyl-2-Hexane-1-ol, pytol and 1,2-Benzenedicarboxylic acid, diisooctyl ester. The pooled fractions were mixed with the basal feed ingredients at the concentration of 100 (D-1), 200 (D-2), 300 (D-3) and 400 (D-4) mg kg−1 and the diets fed to the F. indicus (9.0 ± 0.5 g) for 30 days. After the completion of feeding trail, they were challenged with virulent WSSV and studied the cumulative mortality, molecular diagnosis by quantitative real time PCR (qRT-PCR), biochemical, haematological and immunological parameters. The control diet fed F. indicus succumbed to death 100% within 3 days whereas the D-3 and D-4 helped to reduced the cumulative mortality of 60–80% respectively. The qRT-PCR revealed that, the WSSV copy number was gradually decreased when increasing concentration of A. grandiflora extract active fraction in the diets. The diets D-3 and D-4 helped to reduce the protein and carbohydrate levels significantly (P