|J Nat Prod. 2002 Jul;65(7):1065-8. |
|Constituents of the twigs of Hernandia ovigera that inhibit the transformation of JB6 murine epidermal cells.[Pubmed: 12141878]|
METHODS AND RESULTS:
Activity-guided fractionation of an ethyl acetate extract of the twigs of Hernandia ovigera, using a soft agar assay with JB6 murine epidermal cells, led to the isolation of two new naturally occurring aryltetralin lignans, (7R,8S,7'R,8'R)-(+)-7'-acetyl-5'-methoxypicropodophyllin (1) and (7R,8S,7'R,8'R)-(+)-7'-acetylpicropodophyllin (2), of which 2 was previously identified as a synthetic product, along with eight known compounds, Epiyangambin (3), caruilignan C, diasesartemin, (+)-epimagnolin A, N-methylcorydaldine, (-)-5'-methoxyyatein, (+)-syringaresinol dimethyl ether, and (-)-yatein. The structures and stereochemistry of 1 and 2 were determined using spectroscopic methods.
Compounds 2 and 3 exhibited significant inhibition of the transformation of murine epidermal JB6 cells, with IC50 values of 0.15 and 0.4 microg/mL, respectively, while the other isolates were regarded as inactive (IC50 >4 microg/mL).
|Nat Toxins. 1999;7(1):39-43. |
|Phytotoxic lignans of Leucophyllum frutescens.[Pubmed: 10441036]|
METHODS AND RESULTS:
Bioassay-guided fractionation of the hexane:ethyl acetate (1:1) extract of the leaves of Leucophyllum frutescens (Berl.) I.M.Johnst (Scrophulariaceae) led to the isolation of its phytotoxic constituents diayangambin (1), Epiyangambin (2), diasesartemin (3) and epiashantin (4). Phytotoxicity was demonstrated as inhibition of seed germination of Agrostis stolonifera cv. penncross (Poaceae) and inhibition of development of Lactuca sativa L. (Asteraceae) seedlings in a microassay using 24-well plates. Compound 1 was the most phytotoxic to L. sativa, showing strong inhibitory activity at 110 microM. Compound 1 was more active than 2 and 3 in inhibiting the growth of A. stolonifera with I(50) values of 160, 670 and 930 microM, respectively.
At a concentration of 500 microM, these compounds inhibited all phases of onion root cell division. This is the first demonstration of antimitotic activity of these furofuran lignans, and the first report of their isolation from this species.