Miliusins; cytotoxic neolignans from the leaves of Miliusa sessilis.

Eight undescribed neolignans and an undescribed propanoid dimer were isolated from the leaves of Miliusa sessilis, together with two known compounds, dehydrodieugenol A and dehydrodieugenol B. All structures were elucidated by extensive spectroscopic data analysis and the structure of (7S,8R)-5'-hydroxy-3,4-dimethoxy-4',7-epoxy-8,3'-neolign-8'-en-9-acetate (miliusin A) was further confirmed by X-ray crystallographic analysis. The absolute configurations were determined using circular dichroism (CD) data analysis and the modified Mosher's method. All isolated compounds were evaluated for their cytotoxic activities against four human cancer cell lines (HeLa, HN22, HepG2, and HCT116), including one normal-type cell line (HaCaT) using MTT assay. (7S,8R)-5'-hydroxy-3,4-dimethoxy-4',7-epoxy-8,3'-neolign-8'-en-9-ol (miliusin B) was found to exhibit the most promising cytotoxic effect against Hela cells with the lowest IC50 value of 0.04 µM and the highest selective index of 187.8, highlighting miliusin B as an attractive candidate for cervical cancer drug development.

SCHISTOSOMICIDAL ACTIVITY OF THE CRUDE EXTRACT OF ARTOCARPUS LAKOOCHA.

Puag-Haad is a traditional anthelmintic drug used to treat taeniasis in Thailand and Lao PDR. It is derived from the aqueous extract of the plant Artocarpus lakoocha. We investigated the in vitro anthelmintic properties of Puag-Haad against Schistosoma mansoni. Adult worms were incubated in M-199 medium containing 250, 500 and 750 µg/ml of Puag-Haad or praziquantel (PZQ) at a concentration of 175 µg/ml for 3, 6, 12 and 24 hours. The relative motility (RM value), survival index (SI) and tegument alterations seen under scanning electron microscope were assessed at each incubation time. The results showed the crude extract of A. lakoocha at a concentration of 250 µg/ml was more effective in causing damage than PZQ at a concentration of 175 µg/ml using RM and SI values. The major target organ affected by Puag-Haad was the tegument. The damage was greater at higher concentrations of the crude extract. It is likely tetrahydroxystilbene (THS), the main compound in Puag-Haad, caused the damage. THS could be a future candidate as a schistosomal drug. Further studies are needed to explore its mechanism, efficiency and safety in vivo.

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.

Chemical constituents of the roots of Piper sarmentosum.

Sixteen compounds were isolated from the fresh roots of Piper sarmentosum. Seven of these have been previously isolated from the fruits and leaves of this plant: the aromatic alkene (1), 1-allyl-2-methoxy-4,5-methylenedioxybenzene (4), beta-sitosterol, pyrrole amide (6), sarmentine (10), sarmentosine (13) and pellitorine (14). (+)-Sesamin (2), horsfieldin (3), two pyrrolidine amides 11 and 12, guineensine (15) and brachystamide B (16) are new for P. sarmentosum. Sarmentamide A, B, and C (7-9) are new natural products. Compounds 1--4 and 6--16 were tested for antiplasmodial, antimycobacterial and antifungal activities.

Chromones from the branches of Harrisonia perforata.

Four new chromones, perforamone A, B, C, and D have been isolated together with six known compounds, peucenin-7-methyl ether, O-methylalloptaeroxylin, perforatic acid, eugenin, saikochromone A and greveichromenol, from the branches of Harrisonia perforata (Simaroubaceae). The structures were identified by spectroscopic data. The compounds were tested for antimycobacterial and antiplasmodial activities.

Cerebrosides and a monoacylmonogalactosylglycerol from Clinacanthus nutans.

A mixture of nine cerebrosides and a monoacylmonogalactosylglycerol were separated from the leaves of Clinacanthus nutans. The structures of the cerebrosides were characterized as 1-O-beta-D-glucosides of phytosphingosines, which comprised a common long-chain base, (2S,3S,4R,8Z)-2-amino-8(Z)-octadecene-1,3,4-triol with nine 2-hydroxy fatty acids of varying chain lengths (C(16), C(18), C(20-26)) linked to the amino group. The glycosylglyceride was characterized as (2S)-1-O-linolenoyl-3-O-beta-D-galactopyranosylglycerol. The structures were established on the basis of the spectroscopic data and chemical reactions.

Sulfur-containing compounds from Clinacanthus siamensis.

Two new sulfur-containing compounds, trans-3-methylsulfonyl-2-propenol (1) and trans-3-methylsulfinyl-2-propenol (2) were isolated together with trans-3-methylthioacrylamide (3), entadamide A (4) and entadamide C (5) from the leaves of Clinacanthus siamensis. The structures were established on the basis of the spectroscopic data. The compounds were tested for antimalarial and antimycobacterial activity.