In-vitro anti rabies virus activity of indian medicinal plants

Of the estimated 55000 cases of Rabies deaths in the world, 20000 occur in India. Even in the second decade of the 21st Century there is no chemotherapeutic available for Rabies, a disease that finds a mention in Ayurveda. The present study was undertaken to assess the in vitro anti rabies virus activity of Mangifera indica (Mango), Aegle marmelos (Bael) and Ricinus communis (Eranda). Methanol extracts of the leaves from these plants were prepared using the Soxhlets apparatus. Total proteins were extracted using commercially available kit. BHK-21 cells infected with the Challenge Virus Standard (CVS) strain of the Rabies Viruswere treated with the methanol and protein extracts from the plants. Anti-Viral activity was assessed using a modified Rapid Fluorescent Foci Inhibition Test (RFFIT) and reduction estimating the reduction in relative viral load using qRT-PCR. Methanol extract from Eranda exhibited the most effective activity with an IC50 value of 19.70 µg/mL (SI=496.95). This was followed by methanol extract of Mango followed by methanol extract of Bael – IC50 of 24.66 µg/mL (SI=286.29) and protein extract of Bael at 39.37 µg/mL (SI=350.27). Methanol extract of Bael also exhibited a promising IC50 at 55.71 µg/mL (SI=203.37). Viral load estimation presented a similar picture with methanol extracts of the 3 plants and the protein extract of Bael exhibiting over 100-fold reduction in the viral RNA copies as compared to controls at 1000 µg/mL. AM, MI and MP exhibited over 30-fold reduction even at 10 µg/mL. In the light of the situation where thousands of people die every year due to rabies and since there is no known anti-viral, the above results present potential leads, which must be explored further for developing anti rabies anti virals.