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Two antileukemic daphnane esters, Pimelea factor P2 (I) and the new compound dircin (II), were isolated from the twigs and flowers of Dirca occidentalis A. Gray (Thymelaeaceae). Three lignans, (-)-medioresinol (III), (+)-syringaresinol (IV), and (-)-lariciresinol (V), as well as the coumarin daphnoretin (VI), were found to be additional cytotoxic constitents of this taxon.
The ethnobotany, ethnopharmacology and phytochemistry of the Thymelaeaceae are reviewed. Some members of this family find wide use commercially whilst others are used as deadly poisons or possess extreme irritant properties. The phytochemical evidence thus far available indicates that the daphnane and tigliane diterpene esters are clearly responsible for the toxic reactions observed, but chemotaxonomically it is not possible to predict which additional genera are likely to contain these toxins. Caution should therefore be exercised when studying members of this plant family.
The acetone and methanol extracts of Gnidia kraussiana roots displayed activity against the P-388 lymphocytic leukemia. Bioactivity-directed fractionation led to the isolation of five daphnane orthoesters , all possessing potent antineoplastic activity. Four of these isolates, gnidilatin (1), gnidilatidin (2), Excoecaria toxin (3), and Pimelea factor P2 (4) have been isolated previously from plants in the Thymelaeaceae and Euphorbiaceae. The fifth compound, kraussianin (5), is a new member of the macrocyclic daphnane orthoester series of compounds.
The ethanol extracts of Wikstroemia foetida var. oahuensis and Wikstroemia uva-ursi showed antitumor activity against the P-388 lymphocytic leukemia (3PS) test system One PS-active constituent of both plants was the lignan wikstromol. Several inactive compounds were identified as daphnoretin, pinoresinol, and syringaresinol.
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Haematological and serum biochemical examinations were carried out on 12 high grade bull calves fed Gnidia latifolia (Meisn). This resulted in lymphocytopaenia, increased blood urea nitrogen and lactate dehydrogenase. There were no changes in the red blood cell counts, neutrophil counts, aspartate amino transferase, creatine phosphokinase and alkaline phosphatase. There was also no change in serum protein concentration. Post-mortem changes in the acutely intoxicated calves included petechial haemorrhages of the epicardium and submucosa of the rumen, abomasum and the intestines. The chronic cases showed a generalized emaciation with gelatinous atrophy of the body fat and accumulation of excess fluid in the body cavities. The lymph nodes and spleen showed lymphocytic degeneration with cellular depletion in the follicles. There were extensive liver fibroses in the chronic cases.
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From the leaves of Daphnopsis sellowiana (Thymelaeceae), 2'-hydroxyflavone [1], a rare natural product, has been isolated and characterized through its spectroscopic properties. Confirmation of the structure was achieved through total synthesis, which also afforded adequate material for complete 13C-nmr analysis.
Seventeen mostly new, skin irritant diterpene esters (DTE) of the daphnane and 1 alpha-alkyldaphnane types were isolated from roots of Synaptolepis kirkii and Synaptolepis retusa. The parent alcohols of the daphnane types are shown to be 5 beta-hydroxyresiniferonol-6 alpha,7 alpha-oxide [1] and 5 beta, 12 beta-dihydroxyresiniferonol-6 alpha,7 alpha-oxide [2]. Ten of the daphnane types are 9,13,14-orthoesters and three are conventional esters involving tertiary or secondary hydroxyl groups at C-13 or C-14, respectively. The latter may be considered immediate precursors of corresponding orthoesters. The four 1 alpha-alkyldaphnane types are intramolecular 9,13,14-ortho-(2-hexadecenoic acid)-esters in which, formally, the second to last C atom of the orthoester moiety is linked covalently to C-1 alpha of the diterpene parent alcohols 1 or 2. Thus, in the new structure, a macrocyclic ring bridges the alpha side of the diterpene moiety in an "ansa" type manner. The irritancies on the mouse ear of the DTE obtained cover a wide range (I24 = 0.05-670 nmole-1). Some of them are considerably more irritant than the daphnane type standard simplexin. Structure/activity investigations reveal that an ester group instead of a free hydroxyl group at C-20 ("cryptic types"), or presence of a hydroxy or an acetoxy group in position 12 diminishes the irritancies of the daphnane types isolated, similar to what is known in corresponding tigliane types. In the standardized initiation/promotion protocol on the back skin of mice, some of the irritant DTE exhibit tumor-promoting activities higher than that of simplexin.
Although in gynodioecious populations male steriles require a fecundity advantage to compensate for their gametic disadvantage, southern Spanish populations of the long-lived shrub Daphne laureola do not show any fecundity advantage over hermaphrodites in terms of seed production and early seedling establishment. By using allozyme markers, we assess the mating system of this species in five populations differing in sex ratio, and infer levels of inbreeding depression over the whole life cycle by comparing the inbreeding coefficients at the seed and adult plant stages. Extremely low outcrossing rates (0.001<t<0.125) were consistently found for hermaphrodites in all populations, whereas, as expected, female progeny were entirely outcrossed. In most populations, offspring were much more inbred than their parents, and heterozygosity of adults was greater than expected from outcrossing rate estimates, with very few selfed progeny appearing to reproduce in the field. The combination of extensive selfing in hermaphrodites and a strong inbreeding depression expressed late in the life cycle (and thus, only estimable by indirect measures based on genetic markers) may explain the persistence and high frequency of D. laureola females in southern Spanish populations.
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In gynodioecious species, male-steriles (termed "females" hereafter) usually exhibit some reproductive advantage over hermaphrodites that allow them to compensate for the loss of male reproductive function. This compensation can result from higher fecundity, vegetative outperformance, and/or lower inbreeding depression. In this study we compared vegetative and reproductive parameters of female and hermaphrodite Daphne laureola individuals in two southeastern Spanish populations and estimated the magnitude of inbreeding depression up to the seedling emergence stage by conducting controlled pollinations and experimental sowings of seed progenies in the field. Reproductive shrubs of both sexes did not differ significantly in size, leaf production, leaf size, leaf growth, nutrient allocation to leaves, and production of flowers and fruits. Seed set and seed size of cross- and self-pollinated flowers of hermaphrodites and cross-pollinated females were also similar. Seedling emergence rates of self- and cross-pollinated seeds from hermaphrodites under natural field conditions were similar, suggesting a minor role of inbreeding depression up to that reproductive stage. Seeds from females produced more seedlings than selfed seeds from hermaphrodites. In 21 populations surveyed in the study region over a broad geographical and elevational gradient, the proportion of females ranged between 20.6 and 56.1% and was inversely related to elevation. The establishment and maintenance of females in southeastern Spanish populations of D. laureola seem to be mainly mediated by ecological factors.
The molluscicidal activity of Gnidia kraussiana Meisn leaf, stem and root was studied. Each morphological part was extracted with cold and boiling water, different organic solvent and successively with organic solvents of increasing polarity. Throughout it was found that the extracts of the root were the most potent followed by the stem. Boiling water extracts were more potent than cold water extracts, while in case of extraction with different organic solvents, the petroleum ether extracts of the root and stem were the most potent, while for the leaf, the ethanolic extract was the most potent. On successive extraction, the petroleum ether extracts of all organs were the most potent. Saponification of the petroleum ether extract of the root was carried out and the activity of the different fractions were tested. Different extract fractions were obtained from the 80 per cent ethanolic percolate of the root. Some of the physical properties and the phytochemical screening of the successive extractives of the three organs were studied.
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A new biflavanone (1) with a C-3/C-3" linkage, a new daphnane-type diterpene (2) acylated by an unsaturated fatty acid, and a new coumarin glycoside (3), along with six lignans, two phenylpropanoids, five flavonoids, two diterpenes, and three coumarins were isolated from the roots of Stellera chamaejasme L. (Thymelaeaceae). Elucidation of these secondary metabolites of S. chamaejasme L. supplied strong chemical verification of the close taxonomic relationships among the genera Stellera, Daphne, and Wikstroemia, all of which belong to the family Thymelaeaceae.