Biological screening of rain forest plot trees from Palawan Island (Philippines)

Study plots totaling 0.2 Ha were established in primary forest in the highlands of central Palawan Island, Philippines. Samples of various anatomical parts [typically leaf + twig (If/tw), stem bark (sb), and root (rt)] were collected from all tree species represented within the plots by individuals having a diameter at breast height greater than or equal to 10 cm. In all, 211 distinct samples were obtained from 68 tree species, representing 35 families (not including samples from 4 indeterminate species). Methanol extracts of these samples were tested in in vitro antiplasmodial, brine shrimp toxicity, and cytotoxicity assays. The following samples showed an IC(50) less than or equal to 10 mug/mL against either chloroquine-sensitive or chloroquine-resistant clones of Plasmodium falciparum: Acronychia laurifolia (sb), Agathis celebica (If/tw), Aglaia sp. 1 (sb), Aglaia sp. 2 (If/tw, rt), Bhesa sp. 1 (rt), Cinnamomum griffithii (If/tw), Croton leiophyllus (rt), Dysoxylum cauliflorum (rt), Garcinia macgregorii (sb), Lithocarpus sp. 1 (rt, sb), Meliosma pinnata ssp. macrophylla (If/tw, rt), Myristica guatteriifolia (If/tw), Ochrosia glomerata (rt, sb), Swintonia foxworthyi (If/tw), Syzygium sp. 1 (rt), Turpinia pomifera (rt), and Xanthophyllum flavescens (sb). Secondly, those samples which displayed greater than or equal to 50 % immobilization of brine shrimp at 100 mug/mL were: Acronychia laurifolia (If/tw/fruit, rt, sb), Agathis celebica (If/tw, sb), Aglaia sp. 1 (If/tw), Alphonsea sp. 1 (rt), Ardisia iwahigensis (If/tw), Arthrophyllum aherniannm (If/tw, rt, sb), Castanopsis cf. evansii (rt), Cinnamomum griffithii (If/tw, rt), Croton argyratus (If/tw), C. leiophyllus (If/tw, rt), Dysoxylum cauliflorum (fruit, If/tw, rt), Euonymus javanicus (rt), Glochidion sp. 1 (rt), Polyosma sp. 1 (rt), Symplocos polyandra (rt), Timonius gammillii (sb), and Xanthophyllum flavescens (rt). Lastly, samples which exhibited an IC(50) less than or equal to 20 mug/mL against one or more of the cancer cell lines employed (LUL, KB, KB-V1, P-388, LNCaP, or ZR-75-1) include: Acronychia laurifolia (If/tw/fruit, rt, sb), Aglaia sp. 1 (sb), Aglaia sp. 2 (rt), Alphonsea sp. 1 (rt), Ardisia iwahigensis (If/tw, rt, sb), Astronia cumingiana (sb), Croton argyratus (If/tw, rt, sb), C. leiophyllus (If/tw, rt), Dimorphocalyx murina (If/tw, rt, sb), Lithocarpus caudatifolius (rt, sb), Litsea cf. sibuyanensis (rt), Syzygium cf. attenuatum (rt, sb), S. confertum (sb), Ternstroemia gitingensis (rt), and Ternstroemia sp. 1 (rt, sb).