Reproductive ecology of Rhodomyrtus tomentosa (Myrtaceae)

Rhodomyrtus tomentosa (Ait.) Hassk. is widely distributed in tropical Asia and is an invasive species in Florida, USA. The purpose of the present study was to investigate the reproductive ecology of the species in order to provide information that may be useful in elucidating factors contributing to its invasiveness. The research was carried out at Heshan Hilly Land Integrated Experimental Station, the Chinese Academy of Sciences, Guangdong Province, China in 2003 and 2004. Rhodomyrtus tomentosa flowers in March or April and the flowering period lasts for about 3 months. Flowers open early in the morning and last 2–3 days. The pollen remain viable for about 12  h and the stigma is only receptive on the blooming day. The breeding system is a mixed mating system (outcrossing and geitonogamy). The species is bee-pollinated with pollen as the floral reward. Almost all pollinators appeared before 12  am. Amegilla florea (Smith) Brooks and Xylocopa nasalis Westwood are the primary pollinators for the species. The results indicate that the reproductive features of R. tomentosa – with the mixed mating system and common generalist pollinators – are not limiting factors when colonization occurs in a new environment.     

A new species of Myrcia (Myrteae, Myrtaceae) from the Atlantic Forest of southern Bahia, Brazil

Myrcia thomasii, a new species from the Atlantic Forest of southern Bahia, is described and illustrated. The new species is similar to M. micropetala, but differs in having the inflorescence and basal bracts puberulent, lanceolate bracts at the base of flowers, longer calyx lobes and petals, and a 3-locular ovary.     

Phytotoxic compounds from Flourensia cernua

Bioassay-directed fractionation of a CH(2)Cl(2)-MeOH (1:1) extract of the aerial parts of Flourensia cernua led to the isolation of three phytotoxic compounds, namely, dehydroflourensic acid (1), flourensadiol (2) and methyl orsellinate (3). Dehydroflourensic acid is a new natural product whose structure was established by spectral means. In addition, the known flavonoid ermanin and seven hitherto unknown gamma-lactones were obtained, these being tetracosan-4-olide, pentacosan-4-olide, hexacosan-4-olide, heptacosan-4-olide, octacosan-4-olide, nonacosan-4-olide, and triacontan-4-olide. Compounds 1-3 caused significant inhibition of radicle growth of Amaranthus hypochondriacus and Echinochloa crus-galli, interacted with bovine-brain calmodulin and inhibited the activation of the calmodulin-dependent enzyme cAMP phosphodiesterase.     

Cytotoxic clerodane diterpenoids from the leaves of Premna tomentosa

Three clerodane diterpenoids, premnones A-C (1-3), were isolated from a chloroform-soluble fraction of Premna tomentosa along with four known flavonoids and three known triterpenoids. Among these isolates, premnones A-C exhibited cytotoxic activity when evaluated against a small panel of tumor cell lines. However, premnone A was found to be inactive when evaluated in a follow-up in vivo hollow fiber assay at the highest dose tested (50mg/kg), using LNCaP, Lu1, and MCF-7 cells.     

A bioactive annuionone from sunflower leaves

From aqueous extract of Helianthus annuus L. cv. Suncross-42 leaves, a annuionone have been isolated. The structural elucidation of the compound is based on 1H and 13C NMR spectral studies. The potential of the compound to be used as natural herbicide template has been evaluated through laboratory bioassays against five weed species. Results proved annuionone H as a potent plant growth inhibitor that can be exploit for the development of a herbicide model.     

Lipid peroxidation inhibitory compounds from daylily (Hemerocallis fulva) leaves

Daylilies (Hemerocallis spp.) have been used as food and in traditional medicine for thousands of years in eastern Asia. The leaves of the plant are used in the treatment of inflammation and jaundice. In studies of the aqueous methanol extracts of fresh Hemerocallis fulva leaves, 1',2',3',4'-tetrahydro-5'-deoxy-pinnatanine (1), pinnatanine (2), roseoside (3), phlomuroside (4), lariciresinol (5), adenosine (6), quercetin 3-O-beta-D-glucoside (7), quercetin 3,7-O-beta-D-diglucopyranoside (8), quercetin 3-O-alpha-L-rhamnopyransol-(1-->6)-beta-D-glucopyranosol-7-O-beta-D-glucopyranoside (9), isorhamnetin-3-O-beta-D-6'-acetylglucopyranoside (10) and isorhamnetin-3-O-beta-D-6'-acetylgalactopyranoside (11) were isolated. All of these compounds were tested for their in vitro lipid peroxidation inhibitory activities. Compounds 3-5 and 7-11 were found to possess strong antioxidant properties, inhibiting lipid oxidation by 86.4, 72.7, 90.1, 79.7, 82.4, 89.3, 82.2, and 93.2%, respectively at 50 microg/mL. Compound 1 is novel and compounds 3-6 and 8-11 described here in are isolated for the first time from daylily leaves.     

Antibacterial and antioxidant activities of compounds isolated from the leaves of Symphonia globulifera (Clusiaceae) and their chemophenetic significance

The phytochemical study was done on the methanol extract from of the leaves of Symphonia globulifera. This plant has been used in traditional medicine to treat of different ailments such as malaria, diseases of the skin, diabetes, cough, intestinal worms, pre-hepatic jaundice and fever. Chromatographic fractionation and purification of this extract led to the isolation and characterization of twelve compounds (1–12) including pristriol (1), robustaflavone (2), polycarpol (3), 7''-O-methylrobustaflavone (4), amentoflavone (5), stigmasterol glucoside (6), epicatechin (7), apigenin (8), luteolin (9), 1,5-dihydroxyxanthone (10), β-sitosterol 3-β-D-glucopyranoside (11) and a mixture of stigmasterol and β-sitosterol (12). The structures of compounds 1–12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. All these compounds were isolated for the first time from Symphonia genus. The NMR spectra and structure elucidation of compound 1 were reported for the first in the literature. The antibacterial and antioxidant activities of three of these compounds were evaluated. The chemophenetic significance of these compounds is also discussed.     

<Emphasis Type="Italic">Myrcia incompleta</Emphasis> (Myrtaceae), a new species from Amazonian Brazil

Myrcia incompleta, from the northern Brazilian states of Amazonas and Rondônia, is described and illustrated. This species is apparently related to Calyptranthes paniculata and C. speciosa, from which it is distinguished mainly by its narrower leaves with midvein strongly raised adaxially and shorter, pauciflorous inflorescences. Conservation status for the species is proposed.     

A new species of campomanesia (Myrtaceae) from Brazil

Campomanesia espiritosantensis Landrum is described from the coastal forests of Espírito Santo, Brazil. Its relationship to other species in the genus is discussed.     

A new species of Eugenia (Myrtaceae) from Venezuela

Eugenia mcvaughii is described from a forest remnant of the Jardin Botánico of Caracas, Venezuela. Found also in the hills adjacent to Caracas, it may be considered as an endemic species of the Interior Coastal Cordillera.     

Phytotoxic clerodane diterpenes from Salvia miniata Fernald (Lamiaceae)

Our ongoing research to identify natural growth inhibitors with diterpene and triterpene skeletons exuding from the surface of the aerial parts of Salvia species led us to study Salvia miniata Fernald. Ten clerodane diterpenoids were found, along with three known diterpenes. Most of the isolated compounds from S. miniata inhibited the germination of Papaver rhoeas L. and Avena sativa L. in Petri dish experiments. Parallel results have been obtained in experiments carried out to evaluate the subsequent growth of the seedlings of the target species in the presence of the tested compounds.     

Antifungal effects of Ellagitannin isolated from leaves of Ocotea odorifera (Lauraceae)

Ocotea odorifera is a medicinal plant that is popularly known in Brazil as "canela-sassafrás" and is used to treat dermatosis. This study investigated the antifungal properties of O. odorifera. The methanol extract of O. odorifera was submitted to successive chromatographic separation and yielded Tellimagrandin II (TEL). Candida parapsilosis strain ATCC 22019 was used to determine the minimum inhibitory (MIC) and fungicidal concentrations, and to study the synergistic action with nystatin (NYS), amphotericin (AMP), and fluconazole (FLU). After treatment, the morphology of the yeast was analysed by scanning electron microscopy. Cytotoxicity was assessed in Vero cells, and genotoxicity by the micronucleus test. The TEL structure was proposed based on NMR and comparison with literature data and ESI-MSMS analysis. The compound showed potent inhibitory activity against C. parapsilosis, with a MIC of 1.6 μM. TEL acted synergistically with NYS, AMP, and FLU, and caused morphological alterations in the yeast cells. The methanolic extract showed low cytotoxicity in vitro and in vivo, and was not mutagenic in mice (P < 0.05). The use of O. odorifera in traditional medicine seems to have a valid basis, in view of the antifungal activity of TEL demonstrated in this study, and may contribute to potential drug development.