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.

Constituents of the leaves of Holarrhena pubescens.

The leaves of Holarrhena pubescens yielded a new naringenin glycoside (1), together with naringin, naringenin 7-O-beta-D-glucoside, lupeol, lupeol beta-hydroxyhexadecanoate and ursolic acid. The structure of 1 was determined by spectral analysis.

Bioactive deoxypreussomerins and dimeric naphthoquinones from Diospyros ehretioides fruits: deoxypreussomerins may not be plant metabolites but may be from fungal epiphytes or endophytes.

Deoxypreussomerin derivatives, palmarumycins JC1 (1) and JC2 (2), and two dimeric naphthoquinones, isodiospyrin (3) and its new derivative isodiospyrol A (4), were isolated from dried fruits of Diospyros ehretioides. Structures of the isolated compounds were elucidated by spectroscopic analyses. Palmarumycins were not found in the extract of freshly collected fruits; however, they were present in dried fruit extract.

Antiplasmodial, antimycobacterial, and cytotoxic principles from Camchaya calcarea.

Chemical exploration of Camchaya calcarea (family Compositae) has led to the isolation of nine known sesquiterpene lactones 1 - 9, together with caffeic acid methyl ester 10. Sesquiterpenes 1, 2, 3, 4, 5, 7, and 8 exhibited moderate antiplasmodial activity, but showed potent antimycobacterial activity. Interestingly, the cytotoxicity of sesquiterpene lactones 1, 2, and 4 towards small-cell lung cancer cell line (NCI-H187) is stronger (two orders of magnitude) than towards the Vero cell line.

Combretastatins D-3 and D-4, new macrocyclic lactones from Getonia floribunda.

Chemical investigation of biologically active compounds of Getonia floribunda led to the isolation of two new macrocyclic lactones, combretastatins D-3 (1) and D-4 (2). The structures of these compounds were confirmed by spectroscopic analyses. Combretastatin D-3 (1) exhibited cytotoxicity towards the small-cell lung cancer cell line (NCI-H187, IC50=13.