Lucimar B. Motta

Five vicariant genera from Gondwana: the Velloziaceae as shown by molecules and morphology [corrected].

BACKGROUND AND AIMS The amount of data collected previously for Velloziaceae neither clarified relationships within the family nor helped determine an appropriate classification, which has led to huge discordance among treatment by different authors. To achieve an acceptable phylogenetic result and understand the evolution and roles of characters in supporting groups, a total evidence analysis was developed which included approx. 20 % of the species and all recognized genera and sections of Velloziaceae, plus outgroups representatives of related families within Pandanales. METHODS Analyses were undertaken with 48 species of Velloziaceae, representing all ten genera, with DNA sequences from the atpB-rbcL spacer, trnL-trnF spacer, trnL intron, trnH-psbA spacer, ITS ribosomal DNA spacers and morphology. KEY RESULTS Four groups consistently emerge from the analyses. Persistent leaves, two phloem strands, stem cortex divided in three regions and violet tepals support Acanthochlamys as sister to Velloziaceae s.s., which are supported mainly by leaves with marginal bundles, transfusion tracheids and inflorescence without axis. Within Velloziaceae s.s., an African Xerophyta + Talbotia clade is uniquely supported by basal loculicidal capsules; an American clade, Barbacenia s.l. + Barbaceniopsis + Nanuza + Vellozia, is supported by only homoplastic characters. Barbacenia s.l. (= Aylthonia + Barbacenia + Burlemarxia + Pleurostima) is supported by a double sheath in leaf vascular bundles and a corona; Barbaceniopsis + Nanuza + Vellozia is not supported by an unambiguous character, but Barbaceniopsis is supported by five characters, including diclinous flowers, Nanuza + Vellozia is supported mainly by horizontal stigma lobes and stem inner cortex cells with secondary walls, and Vellozia alone is supported mainly by pollen in tetrads. CONCLUSIONS The results imply recognition of five genera (Acanthochlamys (Xerophyta (Barbacenia (Barbaceniopsis, Vellozia)))), solving the long-standing controversies among recent classifications of the family. They also suggest a Gondwanan origin for Velloziaceae, with a vicariant pattern of distribution.

Guava flavonoids and the effects of industrial air pollutants

Abstract Saplings of Psidium guajava (guava, Myrtaceae), a tropical tree species, were exposed to industrial air pollutants at Cubatâo, the largest industrial complex of Latin America, along two periods, each one comprising one-year: period I, July/2000 – June/2001; period II, December/2000 – November/2001. Saplings were exposed in two experimental sites: Piloes River Valley (PV), reference site, with low contamination by air pollutants; and Mogi River Valley (MV), a site severely affected by pollutants from chemical, fertilizer, ceramic, iron and steel industries. At both sites, the main flavonoids found were guaijaverin, quercitrin and two quercetin diglycosides. No interactions among factors were found as well as no significant differences were found among periods and among sites. However, total foliar flavonoid amounts showed the tendency of decrease after 12 months of experimentation. Cubatao industrial air pollution, with high concentrations of NO2, SO2 and particulate matter, plus climatic conditions of the initial months of exposure seem that does not influence flavonoid composition and quantities.

Chemical composition and efficacy of dichloromethane extract of Croton sphaerogynus Baill. (Euphorbiaceae) against the cattle tick Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus microplus is widely distributed in tropical and subtropical regions, causing high economic impact on cattle production. The control of tick infestations is regarded worldwide as critical and has been based on the use of organophosphates, synthetic pyretroids, amitraz and recently ivermectin and fipronil. The present study reports the analysis by gas chromatography/mass spectrometry of the constituents of leaf extracts of Croton sphaerogynus and results of acaricidal activity against the cattle tick R. microplus. The larval package test using the serial dilutions 0.625%, 1.25%, 2.5%, 5.0%, 10.0% and 20.0% (v/v) gave mortality rates 2.25%, 8.26%, 8.81%, 24.80%, 83.66% and 99.32%, respectively. Relevant constituents identified were abietanes, podocarpenes and clerodane type furano diterpenes. The present work may represent a possibility of attainment of natural substances useful for the control of R. microplus.

Antiproliferative activity of methanol extracts of four species of Croton on different human cell lines

Several species of Croton have been described with biological activities, mainly due to diterpenes, alkaloids and/or other secondary metabolites. These activities account for the traditional use of Croton species to treat certain diseases in South America, Asia and Western Africa. The crude methanol extracts obtained from leaves and steam bark of Croton dichrous Mull. Arg., C. erythroxyloides Baill., C. myrianthus Mull. Arg. and C. splendidus Mart. ex Colla were tested for antiproliferative activity against ten human cancer cell lines. Chemical analyses of all extracts were carried out by GC/MS and HPLC/MS/MS. The leaf extract obtained from C. erythroxyloides showed potent activity against PC-3 (prostate) and OVCAR-3 (ovary) cell lines. Lupeol is suggested to be involved in such activity. Tiliroside, an acyl-glycosilated flavonoid ubiquitous in all tested extracts, seems to play an important role in the observed moderate activity of most extracts against the leukemia K562 cell lineage.

Antioxidant activity of flavonoids from Croton sphaerogynus Baill.

Since the early days of medicine, chemical substances derived from animals, plants, and microorganisms have been used for treatment of various diseases. Among these, products derived from plants have dominated the pharmacopoeias for thousands of years, providing an inexhaustible source of medicinal resources. Croton L. is the second largest genus of Euphorbiaceae, comprising about 1300 species of trees, bushes, and herbs. Croton sphaerogynus Baill. belongs to the same clade of Croton cajucara Benth, used in traditional medicine. The aim of this study was to characterize the antioxidant activities of extracts and isolated flavonoids obtained from leaves of C. sphaerogynus. Chemical composition of leaf extracts and its fractions (flavonoid contents) and in vitro antioxidant properties were examined. Two flavonoids were isolated: quercetin 3-O-methyl ether and kaempferol 3-O-methyl ether. Antioxidant activity was higher, especially for fractions composed mainly by quercetin 3-O-methyl ether compared to crude extract and other fractions. For those fractions, EC50 values were found to be close to the ones presented by quercetin when they were analyzed for their radical scavenging activities.

Antiproliferative activity of flavonoids from Croton sphaerogynus Baill. (Euphorbiaceae).

Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. A lyophilized crude EtOH extract from leaves of C. sphaerogynus, obtained by maceration at room temperature (seven days), was suspended in methanol and partitioned with hexane. The purified MeOH phase was fractionated over Sephadex LH-20 yielding five fractions (F1–F5) containing flavonoids, as characterized by HPLC-DAD and HPLC-MS analyses. The antiproliferative activity of the crude EtOH extract, MeOH and hexane phases, and fractions F1–F5 was evaluated on in vitro cell lines NCI-H460 (nonsmall cell lung), MCF-7 (breast cancer), and U251 (glioma). The MeOH phase showed activity (mean log GI50 0.54) higher than the hexane phase and EtOH extract (mean log GI50 1.13 and 1.19, resp.). F1 exhibited activity against NCI-H460 (nonsmall cell lung) (GI50 1.2 μg/mL), which could be accounted for the presence of flavonoids and/or diterpenes. F4 showed moderate activity (mean log GI50 1.05), while F5 showed weak activity (mean log GI50 1.36). It is suggested that the antiproliferative activity of the crude EtOH extract and MeOH phase is accounted for a synergistic combination of flavonoids and diterpenes.