Part 1: Antiplasmodial, cytotoxic, radical scavenging and antioxidant activities of Thai plants in the family Acanthaceae.

Crude extracts (CH(2)Cl(2) and MeOH) of 20 plants in the family Acanthaceae were screened for their antiplasmodial, cytotoxic, antioxidant, and radical scavenging activities. These plants included Asystasia nemorum, Barleria cristata, B. strigosa, Dicliptera burmanni, Eranthemum tetragonum, Hygrophila ringens, Justicia balansae, J. procumbens, Lepidagathis incurva, Peristrophe lanceolaria, Phaulopsis dorsiflora, Ruellia kerrii, Strobilanthes auriculata, S. corrugata, S. cusia, S. dimorphotricha, S. karensium, S. maxwellii, S. pateriformis, and S. brandisii. CH(2)Cl(2) extracts of A. nemorum, S. corrugata, S. cusia, S. maxwellii, S. pateriformis, and S. brandisii, as well as MeOH extracts of J. balansae and J. procumbens, showed antiplasmodial activity with IC(50) values of 10-100 µg/mL. CH(2)Cl(2) extracts of nine plants including D. burmanni, H. ringens, J. balansae, J. procumbens, L. incurva, P. lanceolaria, P. dorsiflora, S. corrugata, and S. maxwellii showed cytotoxic activity with IC(50) values of 3.5-46.0 µg/mL. MeOH extracts (at 100 µg/mL) of R. kerrii and S. auriculata could effectively scavenge DPPH free radicals (82-83% inhibition) and superoxide anion radicals (79% and 88% inhibition). In the ORAC antioxidant assay, MeOH extracts of B. cristata, J. procumbens, R. kerrii, and S. auriculata exhibited activity with ORAC units of 3.1-3.9.