Two phenylpropanoid conjugated iridoids, deglucosyl gaertneroside (1) and morindoidin (2), were isolated from the leaves of Morinda morindoides (Rubiaceae) by activity-guided fractionation using an anti-malarial activity assay. The known related iridoids molucidin (3) and prismatomerin (4), two lignans, abscisic acid, two megastigmanes, and two avonol glycosides were also identi ed. The structures of isolated compounds were elucidated using spectroscopic analysis. The isolated compounds were evaluated for anti-malarial activity against the chloroquine/me oquine-sensitive strains of Plasmodium falciparum together with cytotoxicity against adult mouse brain cells. Potent anti-malarial activity of and 4 (IC 50 of 0.96 and 0.80 µM, respectively) was shown, while new iridoids 1 and 2 and pinoresinol (5) displayed moderate activity (IC 50 of 40.9, 20.6, and 24.2 µM, respectively). These results indicate that 1-5 may be promising lead compounds for anti-malarial drugs and that extracts of M. morindoides leaves could be effective remedies for malaria infection.

Three phenylpropanoid-conjugated iridoid glucosides, acetylgaertneric acid (1), acetyldehydrogaertneroside (2), and dehydrogaertneric acid (10), together with nine known related iridoid glucosides (3-9, 11, and 12), two coumaroyl alkaloids, one benzenoid, and three flavonoid glucosides were isolated from leaves of Morinda morindoides (Rubiaceae). Structures of these isolated compounds were determined using spectroscopic analysis. Compounds 1-18 and previously isolated compounds (19-29) were evaluated for anti-trypanosomal activity against Trypanosoma cruzi Tulahuen strain (trypomastigote and amastigote) together with cytotoxicity against host cells, new-born mouse heart cells. Among them, molucidin (21) and prismatomerin ( 22) exhibited good anti-trypanosomal activity (IC 50 of 4.67 and 5.70 µM, respectively), together with cytotoxicity (CC 50 of 2.76 and 3.22 μM, respectively). Compounds 1-18 did not show anti-malarial activity against a chloroquine/mefloquine-sensitive strain of Plasmodium falciparum.

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The antinutritional activities of trypsin inhibitors (TIs) were compared between winged beans (Psophocarpus tetragonolobus) and soya beans (Glycine max). The inhibitors of the two beans were isolated by trypsin-bound Sepharose 4B, and 50 mg of lyophilised powders were intubated intragastrically into 24 h fasted rats. The activities of trypsin and chymotrypsin were compared after 30, 60 and 180 min in the washings of the upper, middle and lower parts of the small intestine. The elution pro®les of TI and non-TI compounds in the af®nity chromatography were similar in the two beans, and the antitryptic activities were concentrated 5.5 and 6.2 times (based on speci®c activity) for winged beans and soya beans respectively. Regardless of the TI fed to rats, trypsin activity in the upper intestine was suppressed to almost undetectable levels at 30 and 60 min after intubation. The activities in the middle and lower intestines were also substantially lowered when rats were fed winged bean TI, and signi®cant differences were detected at 30 and 60 min after intubation when compared with rats fed soya bean TI. However, at 180 min after feeding, no differences were found in the trypsin activity in any gut segments. Similar inhibitory properties of isolated TIs were observed in chymotrypsin activities in the small intestine. The results suggest that winged bean TI may have greater inhibitory activity on the intestinal proteinase compared with soya bean TI.

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