Water relationships in Phyllantus orbicularis and Punica granatum antiviral extracts and their influence on stability after freezing and freeze-drying.
The effect of freezing, freeze-drying and storage on inhibitory half dose (ID(50)) and on cytotoxic concentration (CC(50)) of Phyllantus orbicularis and Punica granatum extracts was studied. Selective index SI=(CC(50) /ID(50)) was considered as the antiviral criterion. Both frozen and freeze-dried extracts were analyzed by differential scanning calorimetry (DSC). The values of vitreous transition temperatures of P. granatum (Tg' and Tg) were lower than those of P. orbicularis. Sorption isotherms of freeze-dried products showed a typical sigmoidal shape, where GAB model was fitted instead of bet model. Water adsorption in freeze-dried P. prbicularis extract was higher than in the case of P. granatum. No significant changes in SI were induced by freezing or freeze-drying after a 6 months storage at -20 degrees c, but in the case of P. granatum extract, the effectiveness was highly affected after exposure to 37 degrees c or higher.
Pendás
J
J
National Centre For Scientific Research (CNIC), PO Box 6990, Havana, Cuba.
Moreira
T
T
Guerra
O
O
Peña
B R
BR
Fernández
J A
JA
D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002522:Chlorocebus aethiops; D004355:Drug Stability; D004356:Drug Storage; D005612:Freeze Drying; D005615:Freezing; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal; D014709:Vero Cells / Q000187:drug effects; D014780:Viruses / Q000187:drug effects; D014867:Water / Q000032:analysis
D000998:Antiviral Agents; D010936:Plant Extracts; D014867:Water