Activity of acetone and methanol extracts from thirty-one medicinal plant species against herpes simplex virus types 1 and 2.
BACKGROUND
Thirty-one medicinal plant species from Hawaii, Morocco, and the Sonoran Desert, USA have been shown in past studies to be highly inhibitory to pathogenic bacteria, fungi, and certain cancer cell lines. However, none were tested for antiviral activity.


OBJECTIVE
Acetone and methanol extracts from these species were bio-assayed for antiviral activity against herpes simplex virus types 1 and 2, and for cytotoxicity to the Vero C1008 cell line.


METHODS
Extracts from these species were tested in vitro for antiviral activity using an immunoperoxidase mini-plaque reduction assay to detect viral structural protein synthesis. A 50% inhibitory concentration (IC(50)) was computed. Sulforhodamine B and neutral red assays were used to qualitatively and quantitatively assess the cytotoxicity of extracts to C1008 cells, and to compute a 50% cytotoxic concentration (CC(50)) using a dose response curve.


RESULTS
Eight of the 31 plant species assayed showed significant antiviral activity against HSV 1 and HSV 2 viruses. The acetone extract of Kalanchoe pinnata Pers. (Crassulaceae) produced an IC(50) of 0.025 mg/mL and a CC(50) of 1.25 mg/mL yielding a therapeutic index of 50. Additionally, this extract reduced plaque numbers to zero or near zero at a concentration of 0.1 mg/mL when added 30 min before or 30 min after virus infection.


CONCLUSIONS
The mechanism of inhibition against HSV 1 and HSV 2 viruses is now being investigated, along with fractionation of the acetone extract in search of the active compound or compounds.
Jaeger Greer
Mary R
MR
Natural Products Laboratory, Department of Biology, Brigham Young University, Provo, Utah 84602, USA.
Cates
Rex G
RG
Johnson
F Brent
FB
Lamnaouer
Driss
D
Ohai
Levon
L
D000818:Animals; D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity*; D002522:Chlorocebus aethiops; D055808:Drug Discovery; D006254:Hawaii; D006561:Herpes Simplex / Q000188:drug therapy; D018259:Herpesvirus 1, Human / Q000187:drug effects*; D018258:Herpesvirus 2, Human / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D031962:Kalanchoe / Q000737:chemistry; D008519:Medicine, Traditional; D008800:Mexico; D009018:Morocco; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity*; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012997:Solvents; D015206:Southwestern United States; D014709:Vero Cells; D010948:Viral Plaque Assay
D000998:Antiviral Agents; D010936:Plant Extracts; D012997:Solvents