In the search for novel anti-human immunodeficiency virus type I (anti-HIV-
1) agents from natural sources, 49 MeOH extracts of Korean plants were scre
ened for their inhibitory effects against RNA-dependent DNA polymerase (RT)
and ribonuclease H (RNase H) activities of HIV-1 reverse transcriptase and
HIV-1 protease, and anti-HIV-1 activity. Regarding the HIV-1 reverse trans
criptase, Agrimonia pilosa (whole plant), Cornus kousa (stem and leaf), Lim
onium tetragonum (root) and Mallow japonicus (stem) showed significant inhi
bitory activity on RT activity with 50% inhibitory activity (IC50) of 8.9,
6.3, 7.5 and 11.9 mug/mL, respectively, whereas Agrimonia pilosa was also a
ctive against RNase H activity (IC50 = 98.4 mug/mL). Four plants, namely Ag
rimonia pilosa (whole plant), Atractylodes japonica (root), Clematis heracl
eifolia (whole plant) and Syneilesis palmata (whole plant), were appreciabl
y active (< 35%) against recombinant HIV-1 protease at a concentration of 1
00 mug/mL. Crinum asiaticum var. japonicum (root) showed significant anti-H
IV-1 activity (ED50 = 12.5 mug/mL) with a favourable SI value of 16. Copyri
ght (C) 2001 John Wiley & Sons, Ltd.