Ademar A. da Silva Filho

Antiprotozoal, schistosomicidal, and antimicrobial activities of the essential oil from the leaves of Baccharis dracunculifolia.

Baccharis dracunculifolia DC. (Asteraceae), popularly known as ‘alecrim do campo’, is a native plant from Brazil used in folk medicine as febrifuge, anti‐inflammatory, antiseptic, and to treat skin sores. Also, B. dracunculifolia is the most important plant source of the Brazilian green propolis, which is recognized for its antiseptic and antiprotozoal activities. This study aimed at investigating the in vitro antiprotozoal, schistosomicidal, and antimicrobial activities of the essential oil from the leaves of B. dracunculifolia. The essential oil was obtained by hydrodistillation and analyzed by GC and GC/MS, which allowed the identification of 14 compounds, mainly oxygenated sesquiterpenes, such as (E)‐nerolidol (33.51%) and spathulenol (16.24%). The essential oil showed activity against promastigote forms of Leishmania donovani, with IC50 values of 42 μg/ml. The essential oil displayed high activity in the schistosomicidal assay, since all pairs of Schistosoma mansoni adult worms were dead after incubation with the essential oil (10, 50, and 100 μg/ml). B. dracunculifolia essential oil was neither cytotoxic against Vero cells, nor active in the antimicrobial and antiplasmodial assays.

Halogenated indole alkaloids from marine invertebrates.

This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data of these selected natural indole alkaloids is also provided.

Antimicrobial activity of Syzygium cumini (Myrtaceae) leaves extract

The antimicrobial activity of Syzygium cumini leaves extract, known as “jambolao”, was evaluated. The crude hydroalcoholic extract was active against Candida krusei (inhibition zone of 14.7 ± 0.3 mm and MIC = 70 µg/ mL), and against multi-resistant strains of Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus.

Baccharis dracunculifolia, the main botanical source of Brazilian green propolis, displays antiulcer activity

Baccharis dracunculifolia is the most important botanical source of Southeastern Brazilian propolis, known as green propolis for its colour. In a previous study, we described the gastric protective effect of the hydroalcoholic extract of Brazilian green propolis. We therefore wanted to investigate the possibility of using B. dracunculifolia extract for antiulcer treatment. This study was undertaken to evaluate the anti‐ulcerogenic property of hydroalcoholic extract of B. dracunculifolia aerial parts. The HPLC analysis of the chemical composition of B. dracunculifolia extract used in this study revealed the presence mainly of cinnamic acid derivates and flavonoids. Doses of 50, 250 and 500 mg/kg of B. dracunculifolia crude extract and positive controls (omeprazole or cimetidine) significantly diminished the lesion index, the total lesion area and the percentage of lesion compared with negative control groups. The percentage of ulcer inhibition was significantly higher in groups treated with B. dracunculifolia, cimetidine or omeprazole, with all protocols used, compared with negative control groups. Regarding the model of gastric secretion, reductions in the volume of gastric juice and total acidity were observed, as well as an increase in the gastric pH. These results were similar to results from studies carried out with green propolis extract. Although more investigations are required, our results suggest that B. dracunculifolia has potential to be used as a phytotherapic preparation for the treatment of gastric ulcer.

In-vitro trypanocidal activity evaluation of crude extract and isolated compounds from Baccharis dracunculifolia D. C. (Asteraceae)

We have performed a trypanocidal bioactivity‐guided study of Baccharis dracunculifolia (Asteraceae), the main botanical origin of Brazilian green propolis. The leaf rinse extract of B. dracunculifolia, at a concentration of 3.0 mg mL−1, displayed 100% lysis of trypomastigote forms of the Y strain of Trypanosoma cruzi (2 times 106 parasites mL−1). The chromatographic fractionation of the leaf rinse, using several techniques, afforded the isolation of the compounds isosakuranetin (1), aromadendrin‐4′‐methylether (2), baccharis oxide (3), ferulic acid (4), dihydrocinnamic acid (5), 3‐prenyl‐4‐(dihydrocinnamoyloxy)‐cinnamic acid (6), and friedelanol (7). The chemical structures of all compounds were established by UV‐vis, 1H and 13C NMR data analysis in comparison with the literature. Compounds 1 and 3 were the most active in the trypanocidal assay, showing IC50 values (inhibitory concentration required for 50% inhibition) of 247.6 and 249.8 μM, respectively. Compounds 2, 4, and 6 displayed moderate activity, whilst compounds 5 and 7 were inactive.

Effect of Baccharis dracunculifolia D.C. (Asteraceae) extracts and its isolated compounds on macrophage activation

Baccharis dracunculifolia D.C. (Asteraceae), a shrub which grows wild in Brazil, is the main botanical source of Brazilian green propolis. Since Brazilian propolis shows an immunomodulatory activity, the goal of this work was to evaluate the action of B. dracunculifolia extracts and some of its isolated compounds on reactive oxygen intermediate (H2O2) production by macrophages obtained from male BALB/c mice. The results showed that the leaf (Bd‐L) (25, 50, and 100 μg mL−1), leaf rinse (Bd‐LR) (25 μg mL−1), and the root (Bd‐R) (25 μg mL−1) extracts enhanced H2O2 release by macrophages. A phytochemical study of the root and leaves of B. dracunculifolia was carried out. The chromatographic fractionation of Bd‐R, using several techniques, afforded the isolation of baccharis oxide (1), friedelanol (2), viscidone (11), 11‐hydroxy‐10,11‐dihydro‐euparin (12), and 6‐hydroxy‐tremetona (13), while Bd‐LR gave the following isolated compounds: baccharis oxide (1), friedelanol (2), isosakuranetin (3), aromadendrin‐4′‐methyl ether (4), dihydrocumaric acid (5), baccharin (6), hautriwaic acid lactone (7), hautriwaic acid acetate (8), drupanin (9), and cumaric acid (10). Among the isolated compounds, baccharis oxide (1) and friedelanol (2) increased H2O2 production at a concentration of 100μM. This is the first time that the presence of compounds 7, 8, 12, and 13 in B. dracunculifolia has been reported. Based on these results it is suggested that the crude extracts and some isolated compounds from B. dracunculifolia display an immunomodulatory action.

Antimicrobial activity of Rosmarinus officinalis against oral pathogens: relevance of carnosic acid and carnosol.

The in vitro inhibitory activity of crude EtOH/H2O extracts from the leaves and stems of Rosmarinus officinalis L. was evaluated against the following microorganisms responsible for initiating dental caries: Streptococcus mutans, S. salivarius, S. sobrinus, S. mitis, S. sanguinis, and Enterococcus faecalis. Minimum inhibitory concentrations (MIC) were determined with the broth microdilution method. The bioassay‐guided fractionation of the leaf extract, which displayed the higher antibacterial activity than the stem extract, led to the identification of carnosic acid (2) and carnosol (3) as the major compounds in the fraction displaying the highest activity, as identified by HPLC analysis. Rosmarinic acid (1), detected in another fraction, did not display any activity against the selected microorganisms. HPLC Analysis revealed the presence of low amounts of ursolic acid (4) and oleanolic acid (5) in the obtained fractions. The results suggest that the antimicrobial activity of the extract from the leaves of R. officinalis may be ascribed mainly to the action of 2 and 3.

In vitro antileishmanial and antimalarial activities of tetrahydrofuran lignans isolated from Nectandra megapotamica (Lauraceae)

Seven tetrahydrofuran lignans, isolated from Nectandra megapotamica (Lauraceae), were evaluated for their in vitro antileishmanial and antimalarial activities. Among the evaluated compounds, machilin‐G (1a) and veraguensin (2a) showed the highest antileishmanial activities, displaying for both compounds an IC50 value of 18 µg/mL and an IC90 value of 36 µg/mL, while galgravin (1b), nectandrin‐A (1c), nectandrin‐B (1d), calopeptin (2b) and ganshisandrine (3) were inactive against Leishmania donovani. In the antimalarial assay against Plasmodium falciparum, it was observed that calopeptin (2b) displayed moderate activity, with IC50 values of 3800 ng/mL (D6 clone) and 3900 ng/mL (W2 clone), while the lignans 1a–1d, 2a and 3 were inactive. In order to compare the effect on the parasites with toxicity to mammalian cells, the cytotoxic activity of the isolated compounds were evaluated against the Vero cells, showing that all evaluated tetrahydrofuran lignans exhibited no cytotoxicity at the maximum dose tested. Copyright

Chemical Composition and in vitro Schistosomicidal Activity of the Essential Oil of Plectranthus neochilus Grown in Southeast Brazil

The chemical composition and the in vitro schistosomicidal effects of the essential oil of Plectranthus neochilus (PN‐EO) grown in Southeast Brazil was studied. β‐Caryophyllene (1; 28.23%), α‐thujene (2; 12.22%), α‐pinene (3; 12.63%), β‐pinene (4; 6.19%), germacrene D (5; 5.36%), and caryophyllene oxide (6; 5.37%) were the major essential oil constituents. This chemical composition differed from that previously reported for specimens harvested in Africa. Concerning the in vitro schistosomicidal activity against adult Schistosoma mansoni worms, PN‐EO was considered to be active, but less effective than the positive control praziquantel (PZQ) in terms of separation of coupled pairs, mortality, decrease in the motor activity, and tegumental alterations. However, PN‐EO caused an interesting dose‐dependent reduction in the number and the percentage of developed S. mansoni eggs. These results suggest that PN‐EO might be very promising for the development of new schistosomicidal agents.

Antimicrobial activity of the extract and isolated compounds from Baccharis dracunculifolia D. C. (Asteraceae).

Baccharis dracunculifolia D.C. (Asteraceae) is the most important plant source of the Brazilian green propolis. Since propolis is known for its antimicrobial activity, the aim of this work was to evaluate the antimicrobial activities of B. dracunculifolia and some of its isolated compounds. The results showed that the leaves extract of B. dracunculifolia (BdE) presents antifungal and antibacterial activities, especially against Candida krusei and Cryptococcus neoformans, for which the BdE showed IC50 values of 65 μg mL −1 and 40 μg mL−1, respectively. In comparison to the BdE, it was observed that the green propolis extract (GPE) showed better antimicrobial activity, displaying an IC50 value of 9 μg mL−1 against C. krusei. Also, a phytochemical study of the BdE was carried out, affording the isolation of ursolic acid (1), 2α-hydroxy-ursolic acid (2), isosakuranetin (3), aromadendrin-4′-methylether (4), baccharin (5), viscidone (6), hautriwaic acid lactone (7), and the clerodane diterpene 8. This is the first time that the presence of compounds 1, 2, and 8 in B. dracunculifolia has been reported. Among the isolated compounds, 1 and 2 showed antibacterial activity against methicillin- resistant Staphylococcus aureus, displaying IC50 values of 5 μg mL−1 and 3 μg mL−1, respectively. 3 was active against C. neoformans, showing an IC50 value of 15 μg mL−1 and a MIC value of 40 μg mL−1, while compounds 4→8 were inactive against all tested microorganisms. The results showed that the BdE, similar to the GPE, displays antimicrobial activity, which may be related to the effect of several compounds present in the crude extract.