Antônio L. Pinheiro

Chemical composition and antibacterial activities from the essential oils of myrtaceae species planted in Brazil

The essential oils of seven Myrtaceae species were investigated for its chemical composition and antibacterial activity. The volatile oils were characterized by a high content of monoterpenoids of which 1,8-cineole (88.0, 65.0 and 77.0% for Melaleuca hypericifolia, Callistemon viminalis and Callistemon citrinus respectively), terpinen-4-ol (47.0 and 49.8% for Melaleuca thymifolia and Callistemon polandii respectively) and α-pinene (54.5% for Kunzea ericoides) were the major components. The oil from M. linariifolia was characterized by a high concentration of methyleugenol (87.2%). The oil from Melaleuca thymifolia was the most active, exhibiting high antimicrobial activity against all tested bacteria.

Seasonal Variation in the Chemical Composition and Antimicrobial Activity of Volatile Oils of Three Species of Leptospermum (Myrtaceae) Grown in Brazil

This study investigates the seasonal variation of three species of Leptospermum (Myrtaceae) grown in Brazil. The chemical composition of the volatile oils of L. flavescens and L. petersonii did not show any significant seasonal variation in the major components, while for Leptospermum madidum subsp. sativum the levels of major constituents of the volatile oils varied with the harvest season. Major fluctuations in the composition of L. madidum subsp. sativum oil included α-pinene (0–15.2%), β-pinene (0.3–18.5%), α-humulene (0.8–30%), 1,8-cineole (0.4–7.1%) and E-caryophyllene (0.4–11.9%). Levels of β-pinene (0.3–5.6%), terpinen-4-ol (4.7–7.2%) and nerolidol (55.1–67.6%) fluctuated seasonally in the L. flavescens oil. In L. petersonii, changes were noted for geranial (29.8–32.8%), citronellal (26.5–33.9%) and neral (22.7–23.5%). The activity of the volatile oils against the tested bacteria differed, depending on season the oils were obtained. In general, the volatile oils were more active against Gram-positive bacteria.

Norlimonoids from seeds of Toona ciliata

Abstract Further examination of the seeds of Toona ciliata led to the isolation of two new norlimonoids which were identified on the basis of spectroscopic analysis as 5α,6β,8α-trihydroxy-28-norisotoonafolin and 5α,6β,8α,12α-tetrahydroxy-28-norisotoonafolin. In addition, the known limonoids cedrelone and toonacilin and the sterols sitosterol, stigmasterol, campesterol and 3β-O-β- d -glucopyranosylsitosterol were also isolated and characterised. These results show that Toona has a less pronounced relationship to the Swietenioideae.

Limonoids from leaves of Khaya senegalensis

Abstract The leaves of Khaya senegalensis yielded two new limonoids. These compounds were identified on the basis of spectroscopic analysis as methyl 1α-acetoxy-3β,6,8α-trihydroxy-2α-methoxy-2β,14β-epoxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate and methyl 1α-acetoxy-6,8α,14β,30β-tetrahydroxy-3-oxo [3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate. Scopoletin, β-quercitrin and rutin were also isolated.

Sesquiterpenes, triterpenoids, limonoids and flavonoids of Cedrela odorata graft and speculations on the induced resistance against Hypsipyla grandella

Abstract From the stem of Cedrela odorata grafted on Toona ciliata var. australis were isolated calamenene, cycloeucalenol, sitosterol, stigmasterol, campesterol, gedunin, 7-deacetylgedunin, 7-deacetoxy-7-oxogedunin, methylangolensate, febrifugin, azadiradione, 20,21,22,23-tetrahydro-23-oxoazadirone, 3β-deacetylfissinolide and, catechin, together with the new limonoid 1α-methoxy-1,2-dihydrogedunin and the new cycloartane 3β-O-β- d - glucopyranosylcycloeucalenol . The limonoids were of little value to clarify the basis of the induced resistance in the graft against Hypsipyla grandella. The cycloartanes and catechin could have been translocated from Toona stock to the Cedrela graft.

Rearranged limonoids from Khaya senegalensis

Abstract The stems of Khaya senegalensis yielded three limonoids which appear to be novel. These compounds were identified on the basis of spectroscopic analysis as methyl 1α,6,8α,14β,30β-pentahydroxy-3-oxo-[3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate; methyl 1α,2β,3α,6,8α,14β-hexahydroxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate and methyl 1α-acetoxy-2β,3α,6,8α,14β-pentahydroxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate. The two latter ones represent a novel group of methyl tricyclomeliac-7-oates. Scopoletin, scoparon, sitosterol, stigmasterol, Campesterol and 3β-O-β- d -glucopyranosylsitosterol were also isolated.

Limonoids from Toona ciliata and speculations on their chemosystematic and ecological significance

Abstract Evolution of limonoids in the Meliaceae appears to be consistent with the resistance of Melioideae against the shoot borer Hypsipyla . The limonoid chemistry of Toona , which has shown absence of attacks of H. grandella , is reminiscent of Melioidease. An investigation of T. ciliata , has led to the identification of two novel meliacin butenolides, 21-hydroxycedrelonelide and 23-hydroxycedrelonelide, two known limonoids, cedrelone and 23-hydroxytoonacilide, and sitosterol, α-amyrin and β-amyrin acylated with fatty acids. Three known coumarins, siderin, scopoletin and isofraxidin were also isolated. All structures were established from spectral data. Some 13 C NMR signals for cedrelone are reassigned.

Limonoids from seeds of Toona ciliata and their chemosystematic significance

Abstract From the seeds of Toona ciliata were isolated, besides toonacilin, two novel limonoids: 12-deacetoxytoonacilin and 6α-acetoxy-14β,15β-epoxyazadirone. These results do not seem to support the affiliation of Toona to the Swietenioideae.

Anatomical characterisation of the foliar colleters in Myrtoideae (Myrtaceae)

Colleters are secretory structures that occur in vegetative or reproductive shoot apices of many botanical families. However, in the order Myrtales, reports of colleters have considered only external morphology. We therefore evaluated apical meristems of 52 species belonging to 17 genera from seven tribes of subfamily Myrtoideae (Myrtaceae), so as to analyse the incidence and morphological types of colleters. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on fresh and methacrylate-embedded material. Proteins of the colleter secretions were analysed by SDS-PAGE. We have classified and described the following three new colleter types: petaloid, conic and euryform. None of the species contained all three colleter types. The petaloid colleters were present in three tribes (Syzygieae, Melaleuceae and Lophostemoneae). The conic colleters were observed in three tribes (Leptospermeae, Myrteae and Melaleuceae) and the euryform type occurred in five tribes (Leptospermeae, Syncarpieae, Myrteae, Syzygieae and Melaleuceae). In the tribe Eucalypteae, we found no evidence of colleters. The presence of mucilaginous secretion that defines colleters was confirmed by histochemical tests, and no proteins were found in the secretion. The colleters in Myrtoideae may help clarify the phylogenetic relationships of the Myrtaceae family.

In vitro genotoxicity of Melaleuca alternifolia essential oil in human lymphocytes

ETHNOPHARMACOLOGICAL RELEVANCE The volatile essential oil derived from the plant Melaleuca alternifolia, also called tea tree oil (TTO), is largely employed for its antimicrobial properties against several human pathogens. It is used in many topical formulations to treat cutaneous infections. AIM OF THE STUDY Since very few studies have been done on the safety and toxicity of the crude Melaleuca alternifolia essential oil, current investigation evaluates the possible genotoxic effects of TTO in human lymphocyte cultures. MATERIAL AND METHODS The composition of current TTO sample was determined by GC/MS and NMR. The level of cytotoxicity in TTO treated cultures was determined by decrease of mitotic index when compared to that in negative control. The genotoxic potential of TTO was assessed by the in vitro mammalian cell micronucleus and the chromosome aberrations (CA) tests. RESULTS Twenty-seven compounds were identified, accounting for 98.9% of the constituents. Terpinen-4-ol (42.8%), γ-terpinene (20.4%), p-cymene (9.6%), α-terpinene (7.9%), 1,8-cineole (3%), α-terpineol (2.8%) and α-pinene (2.4%) were the major compounds of the oil sample. None of the tested TTO concentrations (95μg/ml, 182μg/ml and 365μg/ml) caused a significant increase in the observed frequencies of micronuclei when compared to those in the untreated cultures (negative control). Additionally, no significant differences regarding the frequencies of CA were observed among the tested TTO concentrations and the negative control. CONCLUSIONS Results demonstrate that TTO, in the tested concentrations, is not genotoxic in in vitro mammalian cells.