Triterpenoids from Tillandsia fasciculata.

The leaves of Tillandsia fasciculata afforded four tetracyclic triterpenoids of the cycloartane type, two new compounds identified as cyclolaudenyl formate (2) and the (24S)-24-isopropenyl cycloartanone, which we named tillandsinone (1), and the known cyclolaudenone (3) and cyclolaudenol (4).

Cassine, an antimicrobial alkaloid from Senna racemosa.

The leaves of Senna racemosa yielded the piperidine alkaloid cassine and an inositol methyl ether. Antimicrobial screening of the compounds revealed antibacterial activity of cassine with minimum inhibitory concentrations of 2.5 mg/ml for Staphylococcus aureus and Bacillus subtilis and 5.0 mg/ml for Candida albicans.

Antimycobacterial eudesmanolides from Inula helenium and Rudbeckia subtomentosa.

In a bioassay guided search for antimycobacterial compounds from higher plants, the root extracts of Elecampane (Inula helenium L.; Asteraceae) and Sweet Coneflower (Rudbeckia subtomentosa Pursh.; Asteraceae) were chemically investigated for their active constituents. Chromatographic fractions of root extracts of l. helenium, which exhibited significant activity against Mycobacterium tuberculosis, provided the known eudesmanolides alantolactone, isoalantolactone, and 11 alpha H, 13-dihydroisoalantolactone. Peracid epoxidation of alantolactone and isoalantolactone provided 5 alpha-epoxyalantolactone and 4(15) alpha-epoxyisoalantolactone, respectively and oxidation of alantolactone with OsO4 gave 11,13-dihydroxyalantolactone. Active fractions from R subtomentosa contained the known alloalantolactone and 3-oxoalloalantolactone. The structures of the above compounds were established by spectroscopic methods including 1D and 2D NMR techniques as well as spectral comparison with previously reported data. The molecular structure of 5 alpha-epoxyalantolactone was determined by single crystal X-ray diffraction. Eleven natural and semisynthetic eudesmanolides were tested in a radiorespirometric bioassay for activity against M. tuberculosis. 5 alpha-Epoxyalantolactone and encelin from Montanoa speciosa showed minimum inhibitory concentrations (MICs) of 8 and 16 micrograms ml-1, respectively. Alantolactone, isoalantolactone and its 4 alpha, 15-epoxide, 1,2-dehydro-3-epi-isotelekin and alloalantolactone gave MICs of 32 micrograms ml-1. All other compounds showed MIC values of 128 micrograms ml-1 or higher.

Encelin: a fungal growth inhibitor.

A known sesquiterpene lactone, encelin, isolated from the Mexican species Montanoa speciosa (Compositae), was assayed for biocidal activity on fungal cells of Mucor rouxii. The results indicate that encelin has a determining action on growth and the morphogenetic process of fungal cells.

Preliminary results on the protective effect of (-)-edunol, a pterocarpan from Brongniartia podalyrioides (Leguminosae), against Bothrops atrox venom in mice.

(-)-Edunol a prenylated pterocarpan was isolated from the roots of two Mexican 'snakeweeds', Brongniartia podalyrioides and B. intermedia (Leguminosae). Edunol (3.1 mg/kg, i.p.) reduced the expected mortality of mice previously treated by the same route with the LD50 of the venom of the serpent Bothrops atrox. The molecular structure and properties of edunol are similar to those previously reported for cabenegrins A-I and A-II.

Zoapatle. XII. In vitro effect of kaurenoic acid isolated from Montanoa frutescens and two derivatives upon human spermatozoa.

Zoapatle aqueous crude extract (ZACE) from Montanoa tomentosa has been used as an oral contraceptive in traditional Mexican medicine for centuries. Kaurenoic acid, as isolated from Montanoa frutescens, and the methyl esters of 15-hydroxy-dihydro-kaurenoic acid and 15-keto-dihydro-kaurenoic acid were tested in vitro on human sperm motility and viability. The estimated ED50 concentrations immobilization were 374, 126 and 58 micrograms/ml, respectively using 15 X 10(6) sperms/500 microliter. Kaurenoic acid and both of its derivatives displayed only weak to negligible capacity for killing human sperms.

PIP: The effects on human sperm motility and viability of 3 compounds isolated from an aqueous extract of Montanoa frutescens Cerv (Compositae, Heliantheae) were tested. The plant is related to the zoapatle, traditionally used as a contraceptive, and known to have uterotonic and luteolytic activity. Kaurenoic acid, its 15 hydroxy- and its methyl ester were prepared from the polar fraction, and dissolved in 95% ethanol at a concentration of 10 mg/ml. Human sperm, suspended in Bigger's Whitten and Wittingham medium at a final concentration of 15 million sperm per 500 mcl were incubated at 37 degrees C. for 60 seconds. Judging sperm motility under phase contrast microscopy, kaurenoic acid was 0.89 times less effective, and the hydroxy kaurenoic acid 2.6 times more effective than verapamil, while the keto derivative was 5.7 times more potent than verapamil at the same concentration. Sperm viability assessed by vital staining was hampered only about 10% by the keto-kaurenoic acid, 21% by kaurenoic acid, and 33% by hydroxy-kaurenoic acid. Doses required for immobilization of 50% of human sperms ranged from 58 to 374 mcg/ml. This is 225 times lower than that reported for gossypol in vitro, and much lower than the millimolar range needed to inactivate sperm with nonoxynol. Thus these drugs may prompt a search for analogs useful in vaginal contraceptives.