Marcos Enoque Leite Lima

Métodos para avaliação da atividade antimicrobiana e determinação da Concentração Mínima Inibitória (CMI) de plantas medicinais

Varias pesquisas vem sendo desenvolvidas e direcionadas no descobrimento de novos agentes antimicrobianos provenientes de extratos de plantas e outros produtos naturais, para serem aplicados em produtos farmaceuticos e cosmeticos. Atualmente, existem varios metodos para avaliar a atividade antibacteriana e antifungica dos extratos vegetais. Os mais conhecidos incluem metodo de difusao em agar, metodo de macrodiluicao e microdiluicao. A proposta dessa revisao e apresentar diferentes metodos comumente utilizados na pesquisa de novos agentes antimicrobianos, provenientes de extratos vegetais, e elucidar os principais fatores interferentes. Dessa maneira, contribuir como fonte de pesquisa para o desenvolvimento de futuros trabalhos relacionado ao estudo de atividade antimicrobiana de produtos naturais.

Screening of Brazilian plants for antimicrobial and dnadamaging activities: I. Atlantic rain forest . Ecological station juréia-itatins

Abstract I. Atlantic Rain For est ΠEcological S tation JurOia-Itatins) Crude extracts from 88 plant species occurring in SaoPaulo State (Brazil), collected in an Atlantic Forest region, have been screened for antimicrobial and DNA-damagingactivities. Of the 114 extracts assayed for antibacterial activity, only the extracts from leaves and stems of Aspidospermaramiflorum (Apocynaceae) showed a slight activity against Escherichia coli . In the antifungal assay with Candida albicans, no active extract was observed, while in the bioautography assay with Cladosporium sphaerospermu m and C. cladosporioides 12% were active. However , only the extract of Psychotria mapour eoides (Rubiaceae) stems showed a strong inhibition ofboth fungi. The DNA-damaging assay with mutant strains of Saccharomyces cerevisiae resulted in 17.5 % of activeextracts. The majority (55 %) of the active extracts showed selectivity for the DNA-repair mechanism of topoisomerase IIand only 20 % showed a selective response for the mechanism of topoisomerase I.

Essential oil composition of fruit colour varieties of Eugenia brasiliensis Lam.

Eugenia brasiliensis Lam. is a variable species concerning fruit colour, with three recognized varieties. However, the definition of varieties is not easy for Myrtaceae species and not widely accepted. Two fruit colour varieties (purple and yellow) of E. brasiliensis had their essential oil composition analysed in order to give support to the existence of varieties for this species. Although, the major components in the leaf oil are the same monoterpenes for both varieties, α-pinene, β-pinene and 1,8-cineol, the purple fruit variety accumulates more oxygenated sesquiterpenes (33.9%) than the one with yellow fruits (3.8%). The major differences occurred in purple fruits that present as major components caryophyllene oxide (22.2%) and α-cadinol (10.4%), not found in the leaf oil, and the yellow fruit oil presented a similar composition as observed for the leaves. These fruit colour varieties of E. brasilensis can be considered as two distinct chemotypes, since the sesquiterpene pathway is more operant in the purple variety than in the yellow one, in which monoterpenes are mainly accumulated.

Anti-inflammatory activity of essential oil from leaves of Myrciaria tenella and Calycorectes sellowianus.

The GC-MS analysis revealed that the leaf essential oils of Myrciaria tenella (DC.) Berg and Calycorectes sellowianus O. Berg (Myrtaceae) were composed of 34 and 37 compounds, respectively. The main constituents of M. tenella oil were β-caryophyllene (25.1%), and spathulenol (9.7%), while for C. sellowianus were guaiol (13.1%) and β-caryophyllene (8.6%). The anti-inflammatory effect of both essential oils was investigated in vitro and in vivo. Both oils reduced significantly (p < 0.005) the treated neutrophils chemotaxis with 93% and 91% inhibition for M. tenella and C. sellowianus, respectively. However, in the systemic treatment with the essential oils (50 mg/kg p.o.) only the M. tenella oil was able to significantly reduce the carrageenan-induced paw edema with a similar effect to that observed for indomethacin (10 mg/kg), the positive control.

Chemical composition and antimicrobial activity of the essential oil from Croton heterocalyx Baill. (Euphorbiaceae s.s.) leaves.

Abstract The chemical composition and the antimicrobial activity of the essential oil from Croton heterocalyx leaves were evaluated. The oil which was analyzed by GC and GC/MS was found to contain germacrene D (12.5%), bicycloger-macrene (11.2%), δ-elemene (9.2%) β-elemene (8.2%), spathulenol (6.9%), linalool (5.4%) and 1,8-cineole (3.7%) as major components. Croton heterocalyx oil displayed a high inhibitory activity against the fungi Aspergillus niger (16404) and Candida albicans (ATCC 10231) as well as the Gram-positive bacterium Staphylococcus aureus (ATCC 6538), but a very weak activity was observed for the Gram-negative bacteria Escherichia coli (ATCC 8739) and Pseudomonas aeruginosa (ATCC 9027).

Chemical composition and antimicrobial activity of essential oils from Chromolaena laevigata during flowering and fruiting stages.

The chemical compositions and antimicrobial activities of essential oils from the leaves, stems, capitula, and cypselas of Chromolaena laevigata were evaluated at two different phenological stages, flowering and fruiting. Thirty‐eight compounds were identified in the crude oils by GC/MS. The sesquiterpene laevigatin was the major constituent of the leaf, capitulum, and cypsela oils, while the sesquiterpene spathulenol was the main component in the stem oils. The antimicrobial activities of the oils were evaluated against Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Stem oil obtained from Chromolaena laevigata during the fruiting stage generally showed the highest activity with minimum inhibitory concentration (MIC) values of 62.5 μg/ml against Candida albicans and S. aureus, and 500 μg/ml against P. aeruginosa and E. coli. Pure laevigatin exhibited MIC values of 500 and 125 μg/ml against C. albicans and S. aureus, respectively, indicating that this constituent could be responsible, at least in part, for the antimicrobial activities detected in the crude oils. More studies concerning the biological activities of isolated derivatives are required to improve our knowledge of the antimicrobial potential of volatile compounds present in native plants.

Chemical composition and antimicrobial activities of the essential oil of Hypericum cordatum (Vell. Conc.) N. Robson (Hypericaceae).

Abstract The volatile constituents of the fresh materials of Hypericum cordatum were isolated by hydrodistillation and analyzed by GC and GC/MS. The leaves produced 0.04% of a yellowish essential oil and the flowers did not. The main components of the oil were myrcene (40.18%), α-pinene (16.40%), and limonene (12%). The antibacterial activities of the oil against Saccharomyces aureus and Escherichia coli and the anti-fungal activities of the oil against the fungi Cladosporium cladosporioides and C. sphaerospermum were evaluated. The oil showed an antibacterial activity against the bacteria S. aureus and anti-fungal activity against the two fungi.

Chemical composition and antimicrobial activity of the essential oil from Rollinia sericea (R.E.Fr.) R.E.Fr. (Annonaceae) leaves.

Abstract The chemical composition of the essential oil of Rollinia sericea (R.E.Fr.) R.E.Fr. leaves was determined by GC and GC/MS analysis. The analysis revealed the presence mainly of sesquiterpenes: β-elemene (10%), β-caryophyllene (10.0%), bicyclogermacrene (9.1%), germacrene-D (8.2%), bicycloelemene (6.2%) and (Z)-nerolidol (5.3%). Rollinia sericea oil was able to inhibit the growth of both fungi Aspergillus niger (16404) and Candida albicans (ATCC 10231) as well as the Gram-positive bacterium Staphyloccocus aureus (ATCC 6538) but it was inactive against the Gramnegative bacteria Escherichia coli (ATCC 8739) and Pseudomonas aeruginosa (ATCC 9027).

Chemical composition and biological activities of Guatteria elliptica R. E. Fries (Annonaceae) essential oils

Abstract Leaf from two Guatteria elliptica R. E. Fries (Annonaceae) specimens were collected at Paranapiacaba and Caraguatatuba in São Paulo (Brazil). The essential oils presented (GC/GC-MS), as major compound, spathulenol (53.9%) for the Paranapiacaba specimen and caryophyllene oxide (40.9%) for Caraguatatuba. The oils showed low antioxidant activity with EC50 = 7.24 ± 1.03 and 28.68 ± 5.78 mg/mL, respectively, for Paranapiacaba and Caraguatatuba specimens. Both oils did not show a relevant (MIC > 3 mg/mL) antimicrobial activity. However, the Paranapiacaba oil presented an important antitumour activity against breast and prostate cancer cells (IC50 = 7.01 ± 0.23 and 5.35 ± 0.35 μg/mL, respectively) and a low cytotoxicity against normal fibroblast cells (IC50 > 22.27 e IC10 = 18.55 ± 1.89 μg/mL). Isolated major compound, spathulenol, showed good activity against MCF-7 and PC-3 with IC50 = 5.38 ± 0.20 and 2.25 ± 0.28 μg/mL μg/mL, respectively.

Constituents of leaves essential oil of Talauma ovata A. St.-Hil. (Magnoliaceae).

Abstract The volatile constituents of the fresh leaves of Talauma ovata (Magnoliaceae) were extracted by hydrodistillation and analyzed by GC and GC/MS. Twenty-seven compounds were identified representing 98.8% of the total oil. The oil from this species showed to be constituted by monoterpenes and sesquiterpenes in the same ratio. Among the monoterpenes, limonene (34.8%) and α-pinene (11.3%) were the main constituents, and β-bisabolene (10.7%) was the major substance for the sesquiterpene fraction.