Cytotoxic Labdane Diterpenes from Hedychium ellipticum Buch.-Ham. ex Sm.

In order to reveal the constituents and their biological activities, we carried out a phytochemical study on Hedychium ellipticum Buch.-Ham. ex Sm. (Zingiberaceae). Ten labdane diterpenoids (1-10) were isolated from the rhizomes of H. ellipticum for the first time. Their structures were identified on the basis of spectroscopic analyses including two-dimensional NMR and comparison with literature data. All of these compounds were evaluated for their antimycobacterial activity against Mycobacterium tuberculosis and cytotoxicity against KB, MCF7, NCI-H187 and Vero cells. The result showed that compounds 1 and 7 exhibited moderate activity against Mycobacterium tuberculosis and compounds 4, 6 and 7 displayed remarkable cytotoxic activity. This is the first report on the presence of all compounds in H. ellipticum and the first time that their structure activity relationship has been discussed.

Labdane-type diterpenes from Hedychium gardnerianum with potent cytotoxicity against human small cell lung cancer cells.

Seven labdane-type diterpenes, coronarin E, coronarin A, yunnancoronarin A, yunnancoronarin B, hedyforrestin B, villosin, and hedyforrestin C were isolated from the rhizome of Hedychium gardnerianum and evaluated for cytotoxic activity against human small cell lung cancer (NCI-H187) and non-cancerous Vero cells. The results showed that villosin exhibited potent cytotoxic activity with IC(50) of 0.40 microM, which was higher than that of the drug ellipticine (IC(50) 1.79 microM). Moreover, ellipticine was very toxic to Vero cells (IC(50) 7.47 microM) whereas the toxicity of villosin was undetectable at concentration lower than 166.42 microM. The results have indicated that the lactone ring is essential for high cytotoxic activity and that the presence of a hydroxyl group at the 6 or 7 position causes decrease in activity. The very high cytotoxicity against the NCI-H187 cells and the exceptionally high selectivity index (>416) of villosin suggested that this compound may be used as a potential lead molecule for antitumor therapeutic development.

Uncommon secondary metabolites from Etlingera pavieana rhizomes.

From the rhizomes of Etlingera pavieana (Pierre ex Gagnep.) R.M. Sm., four phenylpropens, (E)-3-(4-methoxyphenyl)prop-2-en-1-amine (1), (E)-4-methoxycinamaldehyde (2), (E)-4-methoxycinamic acid (3) and (E)-1-methoxy-4-(3-methoxyprop-1-enyl)benzene (4), together with two other compounds, (E)-((E)-3-(4-methoxyphenyl)allyl)3-(4-hydroxyphenyl)acrylate (5) and 4-methoxybenzoic acid (6) were isolated. This is the first report on the presence of all compounds in Etlingera. Compounds 1 and 5 have been previously synthesised, but this is the first report of their isolation from a natural source. Compound 5 exhibited weak activity against Mycobacterium tuberculosis with MIC 50.00 µg/mL and cytotoxic activity against the KB, MCF7 and NCI-H187 cells with IC50 values of 25.11, 20.16 and 34.83 µg/mL, respectively.

Antimycobacterial and antiplasmodial unsaturated carboxylic acid from the twigs of Scleropyrum wallichianum.

From the twigs of Scleropyrum wallichianum, a new unsaturated carboxylic acid, scleropyric acid (1), two new esters, beta-sitosteryl-3-O-scleropyrate (2) and stigmasteryl-3-O-scleropyrate (3), and two well-known sterols, beta-sitosterol (4) and stigmasterol (5), were isolated and characterized using spectroscopic methods. Compound 1 exhibited antimycobacterial activity with an MIC value of 25 microg/ml and showed antiplasmodial activity with an IC50 value of 7.2 microg/ml. Compounds 2 and 3 were inactive in both assays.