New environmentally-friendly antimicrobials and biocides from Andean and Mexican biodiversity.

Persistent application of pesticides often leads to accumulation in the environment and to the development of resistance in various organisms. These chemicals frequently degrade slowly and have the potential to bio-accumulate across the food chain and in top predators. Cancer and neuronal damage at genomic and proteomic levels have been linked to exposure to pesticides in humans. These negative effects encourage search for new sources of biopesticides that are more "environmentally-friendly" to the environment and human health. Many plant or fungal compounds have significant biological activity associated with the presence of secondary metabolites. Plant biotechnology and new molecular methods offer ways to understand regulation and to improve production of secondary metabolites of interest. Naturally occurring crop protection chemicals offer new approaches for pest management by providing new sources of biologically active natural products with biodegradability, low mammalian toxicity and environmentally-friendly qualities. Latin America is one of the world's most biodiverse regions and provide a previously unsuspected reservoir of new and potentially useful molecules. Phytochemicals from a number of families of plants and fungi from the southern Andes and from Mexico have now been evaluated. Andean basidiomycetes are also a great source of scientifically new compounds that are interesting and potentially useful. Use of biopesticides is an important component of integrated pest management (IPM) and can improve the risks and benefits of production of many crops all over the world.

Biopesticides from plants: Calceolaria integrifolia s.l.

The effects of persistent organic pollutants (POPs) on humans and biodiversity are multiple and varied. Nowadays environmentally-friendly pesticides are strongly preferred to POPs. It is noteworthy that the crop protection role of pesticides and other techniques, i.e. biopesticides, plant extracts, prevention methods, organic methods, evaluation of plant resistance to certain pests under an integrated pest management (IPM), could improve the risks and benefits which must be assessed on a sound scientific basis. For this directive it is crucial to bring about a significant reduction in the use of chemical pesticides, not least through the promotion of sustainable alternative solutions such as organic farming and IPM. Biopesticides are derived from natural materials such as animals, plants, bacteria, and certain minerals. Most of them are biodegradable in relatively short periods of time. On this regard, substances from Calceolaria species emerge as a strong alternative to the use of POPs. The American genus Calceolaria species are regarded both as a notorious weeds and popular ornamental garden plants. Some have medicinal applications. Other taxa of Calceolaria are toxic to insects and resistant to microbial attack. These properties are probably associated with the presence of terpenes, iridoids, flavonoids, naphthoquinones and phenylpropanoids previously demonstrated to have interesting biological activities. In this article a comprehensive evaluation of the potential utilization of Calceolaria species as a source of biopesticides is made. The chemical profile of selected members of the Chilean Calceolaria integrifolia sensu lato complex represents a significant addition to previous studies. New secondary metabolites were isolated, identified and tested for their antifeedant, insect growth regulation and insecticidal activities against Spodoptera frugiperda and Drosophila melanogaster. These species serve as a model of insect pests using conventional procedures. Additionally, bactericidal and fungicidal activity were determined. Dunnione mixed with gallic acid was the most active fungistatic and fungicidal combination encountered. Several compounds as isorhamnetin, combined with ferulic and gallic acid quickly reduced cell viability, but cell viability was recovered quickly and did not differ from that of the control. The effect of these mixtures on cultures of Aspergillus niger, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes, was sublethal. However, when fungistatic isorhamnetin and dunnione were combined with sublethal amounts of both ferulic and gallic acid, respectively, strong fungicidal activity against theses strains was observed. Thus, dunnione combined with gallic acid completely restricted the recovery of cell viability. This apparent synergistic effect was probably due to the blockade of the recovery process from induced-stress. The same series of phenolics (iridoids, flavonoids, naphthoquinones and phenylpropanoids) were also tested against the Gram-negative bacteria Escherichia coli, Enterobacter agglomerans, and Salmonella typhi, and against the Gram-positive bacteria Bacillus subtilis, Sarcinia lutea, and Staphylococcus aureus and their effects compared with those that of kanamycin. Mixtures of isorhamnetin/dunnione/kaempferol/ferulic/gallic acid in various combinations were found to have the most potent bactericidal and fungicidal activity with MFC between 10 and 50 µg/ml. Quercetin was found to be the most potent fungistatic single compound with an MIC of 15 µg/ml. A time-kill curve study showed that quercetin was fungicidal against fungi assayed at any growth stage. This antifungal activity was slightly enhanced by combination with gallic acid. The primary antifungal action of the mixtures assayed likely comes from their ability to act as nonionic surfactants that disrupt the function of native membrane-associated proteins. Hence, the antifungal activity of isorhamnetin and other O-methyl flavonols appears to be mediated by biophysical processes. Maximum activity is obtained when the balance between hydrophilic and hydrophobic portions of the molecules of the mixtures becomes the most appropriate. Diterpenes, flavonoids, phenylpropanoids, iridoids and phenolic acids were identified by chromatographic procedures (HPLC-DAD), ESI-MS, and NMR hyphenated techniques.

Antioxidant and anti-inflammatory activities of Pittocaulon species from México.

UNLABELLED: context: Stems and leaves of Pittocaulon spp. (Asteraceae) are used in Mexican traditional medicine as an anti-inflammatory substance and for the treatment of skin injuries. OBJECTIVE: This study evaluated the antioxidant activity of methanol (MeOH) and dichloromethane (DC) extracts of five Pittocaulon species. MATERIALS AND METHODS: DC and MeOH extracts from flowers, roots, and stems of Pittocaulon praecox (Cav.) H. Rob. & Brettell, P. bombycophole (Bullock) H. Rob. & Brettell, P. filare (Mc Vaugh) H. Rob. & Brettell, P. velatum (Greenm.) Rob. & Brettell and P. hintonii H. Rob. & Brettell. RESULT AND DISCUSSION: In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the flower extracts obtained with MeOH were the most active with IC(50) values ranging from 51.83 ± 4.08 to 154.19 ± 8.39 ppm. In the thiobarbituric acid reactive substances (TBARS) model, the best activity was shown by DC extracts of roots with IC(50) values ranging from 55.54 ± 1.28 to 160.82 ± 5.37 ppm. The MeOH extract of flowers of P. bombycophole had the highest IC(50) value in both DPPH (51.83 ± 4.08 ppm) and TBARS (39.78 ± 1.97 ppm). The samples with the best values in the antioxidant activity assays were evaluated in the anti-inflammatory tests. The DC root extract of P. velatum at a dose of 1 mg/ear produced the greatest reduction (84.96%) of the 2-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema. This extract also reduced the activity of the enzyme myeloperoxidase (MPO) (73.65%) at the same dose. In contrast, DC root extract of this species did not show significant inhibition of the increase in paw edema induced by carrageenan at the doses tested (100 mg/kg). CONCLUSION: These results support the traditional use of these plants as anti-inflammatory. DC extracts of P. velatum and MeOH extracts of P. bombycophole may be a potential resource of natural anti-inflammatory and antioxidant compounds, respectively. Additional studies must be done to identify the compounds responsible of the activity on these plants and to establish the mechanism of action.

Antibacterial activity of an oligosaccharide of native Paecilomyces sp. and its aminoglycosylated derivative.

This study reports the antibacterial activity of an oligosaccharide, prepared by partial acid hydrolysis of a native Paecilomyces sp. exopolysaccharide, and of its aminoglycosylated derivative, prepared by reductive alkylation of the oligosaccharide, against E. coli and S. aureus.

Anti-inflammatory and cytotoxic activities of chichipegenin, peniocerol, and macdougallin isolated from Myrtillocactus geometrizans (Mart. ex Pfeiff.) Con.

The oleanane-type triterpene chichipegenin and the sterols peniocerol and macdougallin, isolated from Myrtillocactus geometrizans, showed anti-inflammatory activities in both the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema model and the carrageenan-induced rat paw edema model. All tested compounds inhibited the TPA-induced edema in a dose-dependent manner, with ED50 values less than or equal to that shown by indomethacin. Among them, peniocerol was the most active compound. However, only peniocerol and macdougallin reduced carrageenan-induced rat paw edema. On the other hand, peniocerol and macdougallin showed cytotoxicity against several human cancer cell lines. These results indicate that compounds isolated from M. geometrizans possess antiinflammatory and cytotoxic properties, and the presence of chichipegenin in the aerial parts could justify the medicinal uses attributed to the plant.

Anti-inflammatory activity of Penstemon gentianoides and Penstemon campanulatus.

CONTEXT: Penstemon gentianoides (Kunth) Poir. and Penstemon campanulatus (Cav.) Willd. (Plantaginaceae) are important medicinal plants in Mexico used by indigenous people for their anti-inflammatory effects and to also reduce rheumatic pains. OBJECTIVE: In addition to radical scavenging activity, the anti-inflammatory activity of the extracts, fractions and compounds of these plants were investigated and reported here for the first time. MATERIALS AND METHODS: The anti-inflammatory activities of MeOH, CH(2)Cl(2), and ethyl acetate extracts and iridoid, flavonoids, and phenylpropanoids from Penstemon gentianoides and P. campanulatus were studied in the TPA-induced mouse ear edema model. In addition, antioxidant activity against DPPH, crocin and ß-carotene were investigated. RESULTS: All extracts were tested and a selection of known compounds significantly (p <0.05) inhibited mouse ear edema. The results showed that CH(2)Cl(2) extracts of roots and stems from P. gentianoides and ethyl acetate extracts of leaves from P. gentianoides and P. campanulatus, as well as luteolin, diosmetin, penstemide and verbascoside produced the most positive results. Of all substances tested, the CH(2)Cl(2) extract of P. gentianoides roots was the most powerful inhibitor (ED(50)=0.07 mg/ear), with activity comparable to that of indomethacin. These extracts, compounds purified, as well as known compounds, inhibited oxidation of ß-carotene and crocin. DISCUSSION AND CONCLUSION: These findings showed that the iridoid monoterpenes, flavonoids and phenylpropanoids present in these plants species may all contribute to the observed anti-inflammatory activity. Additionally, the observed antioxidant activity is correlated with the anti-inflammatory activity of these plants and the phytochemicals derived from them.

Antioxidant activity of an unusual 3-hydroxyindole derivative isolated from fruits of Aristotelia chilensis (Molina) Stuntz.

3-Hydroxyindole was isolated from the EtOH extract of fruits of Aristotelia chilensis during analyses by HPLC/MS and GC/MS and identified by its mass fragmentation pattern and spectrophotometric data. Additionally, this extract showed an interesting antioxidant activity in DPPH, crocin and TBARS assays. The presence of this type of compound in this fruit species permits us to explain its strong antioxidant activity and its important part in the biosynthetic pathway of phenolic and alkaloid compounds in this plant. Therefore this compound could be useful for the development of future nutraceutical and antioxidant protective agents.

Pyrrolizidine alkaloids of the endemic Mexican genus Pittocaulon and assignment of stereoisomeric 1,2-saturated necine bases.

The endemic Mexican genus Pittocaulon (subtribe Tussilagininae, tribe Senecioneae, Asteraceae) belongs to a monophyletic group of genera distributed in Mexico and North America. The five Pittocaulon species represent shrubs with broom-like succulent branches. All species were found to contain pyrrolizidine alkaloids (PAs). With one exception (i.e., stems of Pittocaulon velatum are devoid of PAs) PAs were found in all plant organs with the highest levels (up to 0.3% of dry weight) in the flower heads. Three structural types of PAs were found: (1) macrocyclic otonecine esters, e.g. senkirkine and acetylpetasitenine; (2) macrocyclic retronecine esters, e.g. senecionine, only found in roots, and (3) monoesters of 1,2-saturated necines with angelic acid. For an unambiguous assignment of the different stereoisomeric 1,2-saturated necine bases a GC-MS method was established that allows the separation and identification of the four stereoisomers as their diacetyl or trimethylsilyl derivatives. All otonecine esters that generally do not form N-oxides and the 1,2-saturated PAs were exclusively found as free bases, while the 1,2-unsaturated 7-angeloylheliotridine occurring in P. velatum was found only as its N-oxide. In a comparative study the 1H and 13C NMR spectra of the four stereoisomeric necine bases were completely assigned by the use of DEPT-135, H,H-COSY, H,C-HSQC and H,H-NOESY experiments and by iterative analysis of the 1H NMR spectra. Based on these methods the PA monoesters occurring in Pittocaulon praecox and P. velatum were assigned as 7-O-angeloyl ester respectively 9-O-angeloyl ester of dihydroxyheliotridane which could be identified for the first time as naturally occurring necine base. Unexpectedly, in the monoesters isolated from the three other Pittocaulon species dihydroxyheliotridane is replaced by the necine base turneforcidine with opposite configuration at C-1 and C-7. The species-specific and organ-typical PA profiles of the five Pittocaulon species are discussed in a biogenetic context.

Pensteminoside, an unusual catalpol-type iridoid from Penstemon gentianoides HBK (Plantaginaceae).

From the MeOH and ethyl acetate extracts of aerial parts of Penstemon gentianoides HBK (Plantaginaceae) an unusual iridoid of the catalpol-type, was isolated and characterized as pensteminoside: (8-O-trans-cinnamoyl, 6-hydroxy, 1-[beta-D-glucopyranoside-6'-O-((4''-hydroxy)-cinnamoyl)]-catalpol) was isolated, along with the known iridoids: plantarelanoside and globularisicin, the flavone: luteolin and diosmetin, as well the phenylpropanoids, verbascoside and martynoside. Their structures were established by 1D and 2D NMR spectroscopic analyses.

Antifungal activities of secondary metabolites isolated from liquid fermentations of Stereum hirsutum (Sh134-11) against Botrytis cinerea (grey mould agent).

Extracts obtained from liquid mycelial fermentations of the Chilean fungus Stereum hirsutum (Sh134-11) showed antifungal activity against Botrytis cinerea. Two types of extracts were obtained: EtOAc-extract (liquid phase) and MeOH-extract (mycelial phase). Plate diffusion assay showed that EtOAc-extracts were more active than MeOH-extracts. A large-scale fermentation of Sh134-11 and chromatographic methods allowed to isolated four compounds: MS-3, Vibralactone, Vibralactone B and Sterenin D. Only Sterenin D showed antifungal activity against B. cinerea in the tests performed. Effects on the mycelial growth of B. cinerea showed that Sterenin D showed inhibition at 1000-2000 µg/mL reaching 67% and 76% respectively. Sterenin D was more effective to control the sporogenesis, inhibiting in 96% the sporulation at 500 µg/mL. Assays showed that Sterenin D exhibited a minimal fungicidal concentration (MFC) of 50 µg/mL and minimal inhibitory concentration (MIC) at 20 µg/mL. Our study indicated that submerged fermentations of Chilean S. hirsutum (Sh134-11) produced extracts with antifungal activity and Sterenin D is responsible for this activity, which could be used as possible biofungicides alternative to synthetic fungicides.

The impact of Andean Patagonian mycoflora in the search for new lead molecules.

Secondary metabolites from fungi have become a major source of chemical innovation in programs searching for lead molecules with bioactivities, especially over the last 50 years. In this review, we discuss the fundamental considerations in the discovery of molecules for agricultural and medicinal uses. This group of organisms possesses a strong potential for scientific and industrial communities. Recently, the incorporation of new technologies for the artificial cultivation of fungi and the use of better equipment to isolate and identify active metabolites has allowed the discovery of leading molecules for the design of new and safer drugs and pesticides. The geographical region including the Patagonian Andes mountains harbors a wide diversity of fungi, many of them still unknown and so far associated with Chilean-Argentinian Andean endemic forests. There have been very few chemical studies of the fungi located in this region. However, those few studies have allowed the discovery of new molecules. We argue that the richness of fungal biodiversity in this region offers an interesting source for the discovery of bioactive molecules for the basic and applied sciences.

The chilean superfruit black-berry Aristotelia chilensis (Elaeocarpaceae), Maqui as mediator in inflammation-associated disorders.

The effects of phytochemicals occurred in fractions and extracts of fruits of "Maqui-berry" (Aristotelia chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and the production of proinflammatory mediators were investigated in lipopolysaccharide (LPS)-activated murine macrophage RAW-264 cells, as well as their antioxidant activities. The MeOH extract (A), acetone/methanol extract (B), fractions F3, F4, subfractions (SF4-SF6, SF7, SF8-SF10, SF11-SF15, SF16-SF20), quercetin, gallic acid, luteolin, myricetin, mixtures M1, M2 and M3 exhibited potent anti-inflammatory and antioxidant activities. The results indicated that anthocyanins, flavonoids and its mixtures suppressed the LPS induced production of nitric oxide (NO), through the down-regulation of iNOS and COX-2 protein expressions and showed a potent antioxidant activity against SOD, ABTS, TBARS, ORAC, FRAP and DCFH. The inhibition of enzymes and NO production by selected fractions and compounds was dose-dependent with significant effects seen at concentration as low as 1.0-50.0 (ppm) and 5.0-10.0 µM, for samples (extracts, fractions, subfractions and mixtures) and pure compounds, respectively. Thus, the phenolics (anthocyanins, flavonoids, and organic acids) as the fractions and mixtures may provide a potential therapeutic approach for inflammation associated disorders and therefore might be used as antagonizing agents to ameliorate the effects of oxidative stress.

Inhibition on cholinesterase and tyrosinase by alkaloids and phenolics from Aristotelia chilensis leaves.

It is reported in this study the effect of isolates from leaves of Aristotelia chilensis as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes. The aim of the paper was to evaluate the activity of A. chilensis towards different enzymes. In addition to pure compounds, extracts rich in alkaloids and phenolics were tested. The most active F5 inhibited AChE (79.5% and 89.8% at 10.0 and 20.0 µg/mL) and against BChE (89.5% and 97.8% at 10.0 and 20.0 µg/mL), showing a strong mixed-type inhibition against AChE and BChE. F3 (a mixture of flavonoids and phenolics acids), showed IC50 of 90.7 and 59.6 µg/mL of inhibitory activity against AChE and BChE, inhibiting the acetylcholinesterase competitively. Additionally, F3 showed and high potency as tyrosinase inhibitor with IC50 at 8.4 µg/mL. Sample F4 (anthocyanidins and phenolic composition) presented a complex, mixed-type inhibition of tyrosinase with a IC50 of 39.8 µg/mL. The findings in this investigation show that this natural resource has a strong potential for future research in the search of new phytotherapeutic treatments for cholinergic deterioration ailments avoiding the side effects of synthetic drugs. This is the first report as cholinesterases and tyrosinase inhibitors of alkaloids and phenolics from A. chilensis leaves.

Antifungal and antibacterial activities of Mexican tarragon (Tagetes lucida).

Mexican tarragon (Tagetes lucida Cv. Asteraceae: Campanulatae) is an important, nutritious plant and an effective herbal medicine. Seven coumarins, 7,8-dihydroxycoumarin (4), umbelliferone (7-hydroxycoumarin) (5), scoparone (6,7-dimethoxycoumarin) (7), esculetin (6,7-dihydroxycoumarin) (11), 6-hydroxy-7-methoxycoumarin (12), herniarin (7-methoxycoumarin) (13), and scopoletin (6-methoxy-7-hydroxycoumarin) (14), and three flavonoids, patuletin (18), quercetin (19), and quercetagetin (20), were isolated from CH2Cl2 and MeOH extracts from aerial parts of T. lucida. In addition, 6,7-diacetoxy coumarin (15), 6-methoxy-7-acetylcoumarin (16), and 6-acetoxy-7-methoxycoumarin (17) derivatives were synthesized. 8-Methoxypsoralen (1), 8-acetyl-7-hydroxycoumarin (2), 7,8-dihydroxy-6-meth-oxycoumarin (3), 6,7-dimethoxy-4-methylcoumarin (6), 5,7-dihydroxy-4-methylcoumarin (8), 4-hydroxycoumarin (9), 4-hydroxy-6,7-dimethylcoumarin (10), naringenin (21), glycoside-7-rhamnonaringin (22), and rutin (23) were commercially obtained (Sigma-Aldrich). All of these compounds and extracts (M1 and M2) were assayed against bacteria and fungi. The antibacterial activity was determined on Bacillus subtilis, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Salmonella typhi, Salmonella sp., Shigella boydii, Shigella sp., Enterobacter aerogenes, Enterobacter agglomerans, Sarcina lutea, Staphylococcus epidermidis, Staphylococcus aureus, Yersinia enterolitica, Vibrio cholerae (three El Tor strains, CDC-V12, clinic case, and INDRE-206, were obtained from contaminated water), and V. cholerae (NO-O1). The evaluated fungi were Aspergillus niger, Penicillium notatum, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes. The most active compounds against Gram-positive and -negative bacteria were the dihydroxylated coumarins 3 and 4. In addition, 2-4, 6, 7, and 11 showed an interesting activity against V. cholerae, a key bacterium in the contaminated water; 2-4 were the most active. Coumarins were the most effective compounds against Gram-negative bacteria. The extract MeOH/CH2Cl2 (1: 4) M2 at 0.4 microg/disk inhibited the growth of E. coli and P. mirabilis (40%), K. pneumoniae (31.1%), Salmonella sp. (35.5%), and Shigella sp. (0%) at 72 h of culture. The dimethoxy compounds 6 and 7 showed a strong activity against fungal strains, especially T. mentagrophytes and R. solani (100% of inhibition at 125.0 and 250.0 microg/mL, respectively).

Antifungal and antibacterial activities of Araucaria araucana (Mol.) K. Koch heartwood lignans.

Five lignans (secoisolariciresinol, pinoresinol, eudesmin, lariciresinol, and lariciresinol-4-methyl ether) were isolated from an MeOH extract from Araucaria araucana (Mol.) K. Koch wood for the first time in this species and their structures determined with spectroscopic methods. The antimicrobial activities of these compounds were determined for the bacteria Citrobacter sp., Bacillus subtilis, Escherichia coli, Micrococcus luteus, Staphylococcus aureus, and Pseudomonas aeruginosa, and for the white rooting and staining fungi Mucor miehei, Paecilomyces variotii, Ceratocystis pilifera, Trametes versicolor, and Penicillium notatum, and in addition, the MeOH extract was evaluated against Aspergillus niger, Candida albicans, Fusarium moniliforme, F. sporotrichum and Trichophyton mentagrophytes. The most sensitive bacteria against pinoresinol were the Gram-positive. However, secoisolariciresinol exhibited a significant antifungal activity on fungi of white rooting and wood staining and this compound completely inhibited the mycelial growth of T. versicolor and C. pilifera at 300 and 400 microg per disc, respectively, whereas pinoresinol showed a moderate inhibitory activity. On the other hand, the MeOH extract had the highest activity against rooting and staining and pathogenic fungi as well as T. versicolor, Fusarium spp. and Trichophyton mentagrophytes, inhibiting completely the growth at 400 microg per disc.

Insect growth regulatory effects of some extracts and sterols from Myrtillocactus geometrizans (Cactaceae) against Spodoptera frugiperda and Tenebrio molitor.

A methanol extract from the roots and aerial parts of Myrtillocactus geometrizans (Cactaceae) yielded peniocerol 1, macdougallin 2, and chichipegenin 3. The natural products 1, 2 their mixtures, MeOH and CH(2)Cl(2) extracts showed insecticidal and insect growth regulatory activity against fall armyworm [Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae)], an important insect pest of corn, and [Tenebrio molitor (Coleoptera)], a pest of stored grains in Mexico. The most active compounds were 1, 2, and a mixture (M(2)) of 1 and 2 (6:4). All these extracts, compounds and the mixture had insect growth regulating (IGR) activity between 5.0 and 50.0 ppm and insecticidal effects between 50 and 300 ppm in diets. The extracts were insecticidal to larvae, with lethal doses between 100 and 200 ppm. These compounds appear to have selective effects on the pre-emergence metabolism of Coleoptera, because in all treatments of the larvae of T. molitor, pupation were shortened and this process show precociousness in relation to controls. In contrast to S. frugiperda larvae, onset of pupation was noticeably delayed. Emergence in both cases was drastically diminished. In both pupae and in the few adults that were able to emerge, many deformations were observed. The results of these assays indicated that the compounds were more active than other known natural insect growth inhibitors such as gedunin and methanol extracts of Cedrela salvadorensis and Yucca periculosa. Peniocerol, macdougallin and chichipegenin, as well as mixtures of these substances, may be useful as natural insecticidal agents.

Antioxidant activities of extracts from Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae).

Various extracts of the aerial parts of Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae) have been used in folk medicine to treat many ailments, particularly inflammation and migraine. Neither the bioactive components responsible nor the mechanisms involved have been evaluated. Here are reported antioxidant activities of their methanol, dichloromethane, and ethyl acetate extracts. Samples were evaluated for oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, and inhibition of the formation of thiobarbituric acid reactive species (TBARS), a measure of lipid peroxidation. Antioxidant activities were strongly correlated with total polyphenol content. The most active extracts from P. gentianoides in scavenging DPPH radicals and inhibiting TBARS formation were the methanol extract (A) and a further ethyl acetate extract of this (E). Partition E was further divided into eight fractions, and both E and the fractions were compared for activity against butylated hydroxytoluene, quercetin, and tocopherol. Partition E and the most active fractions, 5 and 6, were found to have I(50) values of 14.1, 38.6, and 41.8 ppm, respectively, against DPPH and 18.5, 26.0, and 12.7 ppm, respectively, against TBARS formation. Consistent with this finding, partition E and fractions 4-6 had the greatest ORAC and FRAP values. These results show that these plants could be useful antioxidant sources.

Trypanocidal activity of oleoresin and terpenoids isolated from Pinus oocarpa.

Fractionation with n-hexane/ethyl acetate (1:1 v/v) by open column chromatography of the oleoresin from Pinus oocarpa Schiede yielded two diterpenes, pimaric acid (1) and dehydroabietic acid (5), the sesquiterpene longifolene (3) and a diterpenic mixture containing pimaric acid (1), isopimaric acid (4) and dehydroabietic acid (5). Subsequently, the isolated compounds, the mixture of 1, 4 and 5, the oleoresin and the dehydroabietic acid methyl ester (2), were tested in vitro against epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease. The most active compounds were 1, 3 and the oleoresin, being as active as nifurtimox, a drug effective in the treatment of acute infection by American trypanosomiasis and used in this work as positive control.

Dihydroagarofuranoid Sesquiterpenes as Acetylcholinesterase Inhibitors from Celastraceae Plants: Maytenus disticha and Euonymus japonicus.

Natural cholinesterase inhibitors have been found in many biological sources. Nine compounds with agarofuran (epoxyeudesmane) skeletons were isolated from seeds and aerial parts of Maytenus disticha and Euonymus japonicus. The identification and structural elucidation of compounds were based on spectroscopic data analyses. All compounds had inhibitory acetylcholinesterase (AChE) activity. These natural compounds, which possessed mixed or uncompetitive mechanisms of inhibitory activity against AChE, may be considered as models for the design and development of new naturally occurring drugs for management strategies for neurodegenerative diseases. This is the first report of these chemical structures for seeds of M. disticha.

Antioxidant and insect growth regulatory activities of stilbenes and extracts from Yucca periculosa.

The methanol extract from the bark of Yucca periculosa F. Baker afforded 4,4'-dihydroxstilbene, resveratrol and 3,3',5,5'-tetrahydroxy-4-methoxystilbene and had growth regulatory activity against the Fall Army worm (Spodoptera frugiperda J.E. Smith, Lepidoptera:Noctuidae) an insect pest of corn. The most active compound was 3,3',5,5'-tetrahydroxy-4-methoxystilbene which had significant effects at 3 microg/g in diets. In addition to the inhibitory activity on bleaching of crocin induced by alkoxyl radicals, these compounds also demonstrated scavenging properties toward 2,2-diphenyl-1-picrylhydrazyl in TLC autographic and spectrophotometric assays. Our results indicate that these compounds could be involved in interference of sclerotization and moulting. These compounds appear to have selective effects on the pre-emergence metabolism of the insect. The results were fully comparable to known natural insect growth inhibitors such as gedunin and Cedrela extracts and have had a possible role as natural insecticidal agents.