Acaricidal activity of a 2-methoxy-clovan-9-ol rich fraction from Eugenia copacabanensis (Myrtaceae) extract on Rhipicephalus microplus (Acari: Ixodidae).

Rhipicephalus microplus (Ixodidae, canestrini, 1888) is an invasive ectoparasite of cattle which causes high economic losses in emerging countries such as Brazil. Phytochemical compounds have been tested as an alternative to synthetic acaricides due to potentially lower mammalian toxicity. This study evaluated the acaricidal activity against R. microplus of the 2-methoxy-clovan-9-ol rich fraction obtained from Eugenia copacabanensis Kiaersk.leaves, a little known Myrtaceae species from the Brazilian Atlantic Forest. This fraction was obtained by maceration with methanol, partition with n-hexane and purification by normal-phase column chromatography. GC-MS, 1H and 13C NMR and IR analysis contributed to the identification of a major compound as the sesquiterpene 2-methoxy-clovan-9-ol, reported for the first time for the Myrtaceae family. The fraction was tested against R. microplus unfed larvae and engorged females and a 93% larval mortality was observed at the concentration of 50 mg mL-1. Lower concentrations of the solution tested demonstrated a significant difference in egg mass weight, hatching and control percentage. Experiments with 50.0 mg mL-1 showed significative results, with lower concentration and maximum efficacy for both assays. The IC50 values for unfed larvae and engorged females were 21.76 and 11.13 mg mL-1, respectively. These results were similar to those obtained in other studies with isolated botanical compounds and essential oils. The lower IC50 for engorged females than for unfed R. microplus larvae had also been described for other plant materials, including plants from the same Myrtaceae family. The present result suggested different mechanisms of action of the compound on the reproductive biology of engorged females, improving its effect against egg viability. These results are important for tick control, suggesting that 2-methoxy-clovan-9-ol could be a potential natural acaricidal product against both R. microplus unfed larvae and engorged females.

Myrcia eriopus DC. (Myrtaceae) fruits, a new endemic Brazilian source of bioactive anthocyanins.

Myrcia eriopus DC. (Myrtaceae) is a native and endemic Brazilian species, and there is no information about its chemical composition. In our study, five different anthocyanins and two other phenolic compounds were described for the first time in M. eriopus fruits. Delphinidin 3-O-glucoside (1), cyanidin 3-O-glucoside (2), petunidin 3-O-glucoside (3), peonidin 3-O-glucoside (4), malvidin 3-O-glucoside (5), gallic acid (6) and myricetin (7) were identified by offline system RP-HPLC-DAD/ESI-QTOF-MS and compared to the scientific literature. Furthermore, the lyophilized powder of M. eriopus fruits showed a high anthocyanin content (1878.14 mg cy-3-glu eqv/100 g f.w.), with greater levels of compounds 1 and 3, and an antioxidant potential in DPPH and ABTS assays (EC50 2419 µg/mL and 339 µmol Trolox/g f.w.), results superior to other non-conventional Brazilian fruits. This first report about the chemical composition of M. eriopus fruit reveals the potential of this fruit as a new source of bioactive anthocyanins.

Insect galls of the xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ, Brazil) / Galhas de insetos da vegetacao xerica da Ilha do Cabo Frio (Arraial do Cabo, RJ, Brasil)

The xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ) was investigated for insect galls, in May, June and August of 2012, totalizing 24 hours of field work. Forty-five morphotypes of insect galls were found on 29 species of host plant (25 genera and 18 families). Asteraceae and Myrtaceae were the most galled plant families. Leaves were the most galled plant organ, with ca. 62% of the total, followed by stems (ca. 22%). Globoid and fusiform galls were the most frequent with about 29% and 24%, respectively. The majority was glabrous (ca. 91%), and one-chambered (ca. 84%). Gallers of 30 morphotypes were determined. They belong to Diptera (Cecidomyiidae), and Lepidoptera. The former was the most frequent. Larvae of Muscomorpha (Diptera) (probably inquilines) were found in a single gall morphotype; parasitoids (Hymenoptera) in seven (ca. 15% of the total), and predators (pseudoscorpion) in a single one. As there is no previous data of insect galls of Ilha do Cabo Frio, all records presented here are new. The geographic distribution of nine species of gall midges (Diptera, Cecidomyiidae) is widened. For the first time, eleven plant species are recorded as host of galling insects, and 24 gall morphotypes are described.

A vegetação xérica da Ilha do Cabo Frio (Arraial do Cabo, RJ) foi investigada à procura de galhas de insetos em maio, junho e agosto de 2012, totalizando 24 horas de trabalho de campo. Quarenta e cinco morfotipos de galhas foram encontrados em 29 espécies de plantas hospedeiras (25 gêneros e 18 famílias). Asteraceae e Myrtaceae foram as famílias de planta com maior riqueza de galhas. Os órgãos vegetais mais galhados foram folha (cerca de 62% do total) e caule (cerca de 22%). Galhas globóides e fusiformes foram mais frequentes com cerca de 29% e 24%, respectivamente. A maioria era glabra (cerca de 91%) e unilocular (cerca de 84%). Os galhadores de 30 morfotipos foram determinados. Eles pertencem a Diptera (Cecidomyiidae) e Lepidoptera. Os primeiros foram mais frequentes. Larvas de Muscomorpha (Diptera) (provavelmente inquilinas) foram encontradas em um único morfotipo, parasitóides (Hymenoptera) em sete (cerca de 15% do total) e predadores (pseudoscorpiões) em um. Como não havia informação prévia de galhas de insetos na Ilha do Cabo Frio, todos os registros apresentados aqui são novos. A distribuição geográfica de nove espécies de Cecidomyiidae (Diptera) é ampliada. Pela primeira vez, onze espécies de plantas são assinaladas como hospedeiras de galhas e 24 morfotipos de galhas são descritos.

Secretory cavities and volatiles of Myrrhinium atropurpureum Schott var. atropurpureum (Myrtaceae): an endemic species collected in the restingas of Rio de Janeiro, Brazil.

In this study, we investigated the leaf anatomy and the composition of volatiles in Myrrhinium atropurpureum var. atropurpureum endemic to Rio de Janeiro restingas. Particularly, leaf secretory structures were described using light microscopy, and histochemical tests were performed from fresh leaves to localize the secondary metabolites. To observe secretory cavities, fixed leaf samples were free-hand sectioned. To evaluate lipophilic compounds and terpenoids the following reagents were employed: Sudans III and IV, Red oil O and Nile blue. Leaf volatiles were characterized by gas chromatography after hydrodistillation (HD) or simultaneous distillation-extraction (SDE). Leaf analysis showed several cavities in mesophyll that are the main sites of lipophilic and terpenoid production. Monoterpenes, which represented more than 80% of the major volatiles, were characterized mainly by alpha- and beta-pinene and 1,8-cineole. In order to provide tools for M. atropurpureum identification, the following distinguishing characteristics were revealed by the following data: 1) adaxial face clear and densely punctuated by the presence of round or ellipsoidal secretory cavities randomly distributed in the mesophyll; 2) the presence of cells overlying the upper neck cells of secretory cavities; 3) the presence of numerous paracytic stomata distributed on the abaxial leaf surface, but absent in vein regions and leaf margin; and 4) non-glandular trichomes on both leaf surfaces. Our study of the compounds produced by the secretory cavities of M. atropurpureum led us to conclude that volatile terpenoid class are the main secretory compounds and that they consist of a high concentration of monoterpenes, which may indicate the phytotherapeutic importance of this plant.