Acetylated triterpene saponins from the Thai medicinal plant, Sapindus emarginatus.
From the pericarps of Sapindus emarginatus (Sapindaceae), three new acetylated triterpene saponins were isolated together with hederagenin and five known triterpene saponins, as well as one known sweet acyclic sesquiterpene glycoside, mukurozioside IIb. The structures of new compounds were elucidated as hederagenin 3-O-(2-O-acetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alp ha-L-arabinopyranoside, 23-O-acetyl-hederagenin 3-O-(4-O-acetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alp ha-L-arabinopyranoside and oleanolic acid 3-O-(4-O-acetyl-beta-D-xylopyranosyl)-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alp ha-L-arabinopyranoside by chemical and spectroscopic data. (+info)
Increased pollen flow counteracts fragmentation in a tropical dry forest: an example from Swietenia humilis Zuccarini.
Habitat destruction and the resultant fragmentation of the remaining forest are a common phenomenon in the tropics. Most investigations emphasize the potential dangers of fragmentation in isolating patches of forest and exposing populations to loss of species diversity through founder effects, genetic drift, inbreeding, and restricted gene flow. However, a limited number of studies have shown that gene flow may be extensive in tropical trees, suggesting that it may occur between forest fragments and also "isolated" remnant trees. There is an urgent need to quantify pollen flow within and between forest fragments to test the veracity of such views and determine the genetic value of such fragments for in situ conservation. Microsatellite markers are used to genotype individuals of Swietenia humilis from a highly fragmented forest mosaic to directly quantify pollen-mediated gene flow. Distances of pollen flow more than 10 times greater than previously reported were detected. Our results show that some tropical angiosperm tree species may be much more adaptable and resilient to habitat destruction and fragmentation than previously considered. The description of many remnant trees as isolated or "living dead" may be more a conditioning of human perception than a true reflection of their potential conservation value. (+info)
Talisia esculenta lectin and larval development of Callosobruchus maculatus and Zabrotes subfasciatus (Coleoptera: Bruchidae).
Bruchid larvae cause major losses in grain legume crops throughout the world. Some bruchid species, such as the cowpea weevil and the Mexican bean weevil, are pests that damage stored seeds. Plant lectins have been implicated as antibiosis factors against insects, particularly the cowpea weevil, Callosobruchus maculatus. Talisia esculenta lectin (TEL) was tested for anti-insect activity against C. maculatus and Zabrotes subfasciatus larvae. TEL produced ca. 90% mortality to these bruchids when incorporated in an artificial diet at a level of 2% (w/w). The LD(50) and ED(50) for TEL was ca. 1% (w/w) for both insects. TEL was not digested by midgut preparations of C. maculatus and Z. subfasciatus. The transformation of the genes coding for this lectin could be useful in the development of insect resistance in important agricultural crops. (+info)
Potent inhibition by star fruit of human cytochrome P450 3A (CYP3A) activity.
There has been very limited information on the capacities of tropical fruits to inhibit human cytochrome P450 3A (CYP3A) activity. Thus, the inhibitory effects of tropical fruits on midazolam 1'-hydroxylase activity of CYP3A in human liver microsomes were evaluated. Eight tropical fruits such as common papaw, dragon fruit, kiwi fruit, mango, passion fruit, pomegranate, rambutan, and star fruit were tested. We also examined the inhibition of CYP3A activity by grapefruit (white) and Valencia orange as controls. The juice of star fruit showed the most potent inhibition of CYP3A. The addition of a star fruit juice (5.0%, v/v) resulted in the almost complete inhibition of midazolam 1'-hydroxylase activity (residual activity of 0.1%). In the case of grape-fruit, the residual activity was 14.7%. The inhibition depended on the amount of fruit juice added to the incubation mixture (0.2-6.0%, v/v). The elongation of the preincubation period of a juice from star fruit (1.25 or 2.5%, v/v) with the microsomal fraction did not alter the CYP3A inhibition, suggesting that the star fruit did not contain a mechanism-based inhibitor. Thus, we discovered filtered extracts of star fruit juice to be inhibitors of human CYP3A activity in vitro. (+info)
Cupaniol, a New branched polyprenol, from Cupania latifolia.
A new branched polyprenol, designated cupaniol, has been isolated from the methanol extract of the leaves of Cupania latifolia (Sapindaceae). The structure was determined to be (2E,6E,12E,16E)-3,7,13,17,21-pentamethyl-10-(1-methylethenyl)-2,6,12,16,20-docosa pentaen-1-ol on the basis of spectral analysis and conversion to a known compound. (+info)
Occurrence of physical dormancy in seeds of Australian Sapindaceae: a survey of 14 species in nine genera.
Toxicity of extract of Magonia pubescens (Sapindales: Sapindaceae) St. Hil. to control the brown dog tick, Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae).
The action of crude ethanol extract of the stem bark of the soapberry Magonia pubescens St. Hil. was studied upon larvae of the Brown Dog tick Rhipicephalus sanguineus (Latreille). Tick larvae were obtained by maintaining gravid females in an incubator, after collecting them from naturally infested kennels. The tick larvae were placed in envelopes of filter paper impregnated with different concentrations of the extract dissolved in dimethylsulfoxide (DMSO) and distilled water. Four tests were repeated with each solution (n > 120). The control was carried out in DMSO and distilled water. The bioassays were performed at 27 +/- 1 degrees C, RH > 80% and 12:12 light cycle. Mortality was observed after 48 h exposure. All motionless larvae were considered to be dead. The extract of M. pubescens showed larvicidal potential against R. sanguineus. The lethal concentrations of 1503 ppm (LC50) and 9991 ppm (LC99) were obtained. There was no mortality in the control group. Based on the results of the current study, M. pubescens should be recognized as an future alternative acaricide for the control of Brown Dog tick. These results reinforce the importance of the preservation of this soapberry in its natural biome. (+info)
Phytochemical and comparative antibacterial studies on the crude ethanol and aqueous extracts of the leaves of Lecaniodiscus cupanoides Planch (Sapindaceae).
Phytochemical investigation was carried out on the leaves of Lecaniodiscus cupanoides Planch (Sapindaceae). The diameter of the zones of inhibition of the 90% ethanol and aqueous extracts of the leaves were compared in order to determine the relative activity of the extracts against the tested microorganisms and also to verify its claimed ethnomedicinal use in the treatment of microbial infections. Phytochemical tests were carried out employing standard procedures. The antimicrobial activity of the extract was tested against standard strains and clinical isolates of some aerobic bacteria using the agar well diffusion method. Commercial antibiotics were used as positive reference standards to determine the sensitivity of the strains. The minimum inhibitory concentration (MIC) values were also determined using the agar well diffusion method. Preliminary phytochemical studies revealed the presence of flavonoids, tannins, saponins and cardiac glycosides as the chemical classes of compounds present in the crude extract. The extracts showed inhibitory activity against clinical isolates of Bacillus subtilis. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa Staphylococcus aureus and a standard strain of Staphylococcus aureus (NCTC 10788). The ethanol extract was more active than the aqueous extract against all the microorganisms tested, except against the clinical isolates of Staphylococcus aureus. The MIC values ranged from 2.5 to 6.25 mg/mL for all the organisms tested. The results showed that the ethanol extract was more potent than the aqueous extract. The broad spectrum of activity displayed by the extracts would appear to provide the scientific basis for the use of the leaves of Lecaniodicus cupanoides for dressing of boils, burns and cuts in ethnomedicine. (+info)