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Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae)


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MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 µM, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.
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Quim. Nova, Vol. 35, No. 11, 2229-2232, 2012
#Artigo em homenagem ao Prof. Otto R. Gottlieb (31/8/1920-19/6/2011)
Plectranthus barbatus Andrews (Lamiaceae)#
Roberta T. dos Santos, Liliane L. Hiramoto, João Henrique G. Lago e Patrícia Sartorelli*
Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo. R. Prof. Artur Ridel, 275,
09972-270 Diadema – SP, Brasil
André G. Tempone
Departamento de Parasitologia, Instituto Adolfo Lutz, Av. Dr. Arnaldo, 351, 8o andar, 01246-000 São Paulo – SP, Brasil
Erika G. Pinto
Departamento de Parasitologia, Instituto Adolfo Lutz, Av. Dr. Arnaldo, 351, 01246-000 São Paulo – SP / Instituto de Medicina
Tropical de São Paulo, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 470, 05403-000 São Paulo – SP, Brasil
Harri Lorenzi
Instituto Plantarum de Estudos da Flora, Av. Brasil, 2000, 13460-000 Nova Odessa – SP, Brasil
Recebido em 25/5/12; aceito em 17/9/12; publicado na web em 9/11/12
MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The
bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-b-D-glucose
(PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and
displayed an EC50 value of 67 µM, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence
of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature.
Keywords: Plectranthus barbatus; 1,2,3,4,6-penta-O-galloyl-b-D-glucose; anti-trypanosomal activity.
The genus Plectranthus, synonym Coleus (Lamiaceae), contains
about 350 species with occurrence in Africa, Asia and Australia.1 In
Brazil, it is an introduced genus, whose occurrence has been described
in Northeast and Southeast regions.2 Due to its ethnobotanical uses,
Plectranthus can be classified as an important genus from Lamiaceae,1
affording wide biologically active substances.3-6
P. barbatus, popularly known as “falso boldo”, is one of the most
relevant specie of the Plectranthus genus and has been used in tradi-
tional medicine for the treatment of digestive and respiratory disorders
as well as for heart and central nervous diseases.7-9 Pharmacological
studies have been conducted with extracts of P. barbatus, in which
antioxidant,10 antimicrobial,11 antifungal12 and antiacetylcholineste-
rase potentials were detected.13
Chemically, this specie has been characterized by the presence
of diterpenoids14, especially modified abietanoids.8,9,15 Some typical
abietane derivatives isolated from leaves of P. barbatus, classified
according to their structural characteristics, are barbatusin, ciclobuta-
tusin, plectrinone A, and coleun U.5,16,17 Other described constituents
include the phenolic derivatives rosmarinic acid and 7-O-glucoronide
4’-methyl ether.6
Chagas disease is one of most neglected diseases in several un-
derdeveloped and developing countries and affects approximately ten
million people worldwide, mostly in Latin America.18 It is caused by
the protozoan parasite Trypanosoma cruzi (T. cruzi), which is trans-
mitted to humans by triatomine insects primarily through posterior
transmission from fecal matter during feeding, by blood transfusion,
and even via congenital transmission.19 The therapeutic arsenal is very
limited. At present, there are only two effective drugs for the treatment
of Chagas disease: nifurtimox and benznidazol (nitroheterocycle
derivatives).20 These drugs show high cytotoxicity and the main side
effects for nifurtimox are anorexia, loss of weight, psychological
changes, besides digestive manifestations such as nausea, vomiting
and diarrhoea. Benznidazol is also highly toxic and the symptoms
of adverse reactions are hypersensitivity, dermatitis with cutaneous
eruptions, besides articular and muscular pain.21 Also, these drugs are
ineffective against the chronic phase of the disease demonstrating the
urgent need for new drugs.20 In our continuing search for anti-parasitic
natural products from Brazilian plants,22-24 the crude MeOH extract
from leaves of P. barbatus displayed in vitro anti-trypanosomal ac-
tivity and was subjected to bioactivity-guided fractionation. Using
several chromatographic procedures, the compound 1,2,3,4,6-penta-
-O-galloyl-b-D-glucose (PGG) was isolated for the first time in the
Plectranthus genus, identified after NMR and LRESIMS analysis.
Preliminary testing of crude MeOH extract obtained from leaves
of P. barbatus revealed considerable anti-trypanosomal activity. With
the aim of isolating active compounds, this extract was partitioned
using EtOAc and organic active phase was subjected to several steps
of bioactivity-guided fractionation using SiO2 and Sephadex LH-20.
An amorphous white solid was thus isolated, found to be composed
of a pure substance after TLC and HPLC analysis.
This compound showed a molecular formula of C41H32O26 eviden-
ced by a pseudo-molecular ion peak at m/z 938.6 [M-H]- observed in the
LRESIMS (negative mode) spectrum. The 1H NMR spectrum showed
signals attributed to seven protons of the glucopyranosyl unit at d 6.14
(d, 1H, J = 8.4 Hz, H-1), d 5.52 (dd, 1H, J = 8.4; 9.9 Hz, H-2), d 5.81
(t, 1H, J = 9.9, H-3), d 5.49 (t, 1H, J = 9.6 Hz, H-4), d 4.42 (d, 1H, J =
10.5 Hz, H-5), d 4.32 (m, 2H, H-6). This spectrum also showed singlets
at d 7.01, 6.95, 6.88, 6.85, 6.80 which could be assigned to H-2’/H-6’
of five tetrasubstituted aromatic rings (Gal 1-Gal 5), suggesting that
the glucopyranosyl unit could be esterified with five galloyl units. The
dos Santos et al.
2230 Quim. Nova
13C NMR and DEPT 135° spectra showed signals of methynic carbons
at d 93.9 (C-1), d 72.4 (C-2), d 74.2 (C-3), 69.9 (C-4), 74.5 (C-5), and
methylenic carbon at d 63.3 (C-6), characteristic of a glucopyranosyl
unit.25 Additionally, were observed peaks were observed at the d 110-
168 range, assigned to galloyl units.26 The complete structure of the
bioactive compound was determined by analysis of the HMBC spec-
trum, which showed cross peaks between the signals at d 7.01 (H-2´
and H-6´) and d 166.4 (C-7') as well as between the peaks at d 6.14
(H-1) and d 166.4 (C-7'). Finally, the comparison of NMR data with
those described in the literature25-27 (Table 1) allowed the identification
of 1,2,3,4,6-penta-O-galloyl-b-D-glucose (PGG) Figure 1, whose
occurrence has been described for the first time in the Plectranthus
genus. This compound was previously identified in various medici-
nal plants, including species of Rhus, Schinus, Galla and others.27,28
Pharmacologically, this substance showed diverse biological activities,
such as antioxidant,25 anticancer,29 and inhibitory action against the
invasion of mouse melanoma.30 Additionally, an inhibitory effect of
the a-glycosidase of PGG was described, suggested by the presence
of galloyl substituents at the glucose unit26.
Ethnopharmacological studies have revealed anti-parasitic activi-
ty of the Plectranthus species, especially an anti-leishmanial effect.
P. amboinicus has been used in popular medicine to treat cutaneous
leishmaniasis in a rural endemic area of Bahia state, Brazil.31 Its
activity against L. chagasi promastigotes has also been described
from MeOH extract of P. barbatus.32
In our assays, trypomastigotes of T. cruzi showed susceptibility
to the isolated PGG, with an EC50 value of 66.66 µM (Table 2).
Considering the activity against the parasite, it could also be shown
that PGG was 6.6-fold more effective than the standard drug benzni-
dazole, although the cytotoxicity against mammalian cells, resulted in
a CC50 of 39.52 µM (Table 2). In summary, our results demonstrated
that PGG displayed activity against T. cruzi parasites and suggested
the performance of additional studies on reducing its cytotoxicity with
the aim of using this compound as a prototype for the development
of new drugs to treat Chagas disease.
General procedures
1H and 13C NMR spectra were recorded on a Bruker DPX-300
spectrometer operating at 300 and 75 MHz, respectively, using
CD3OD (Tedia Brazil) as the solvent and internal standard (dH 3.21
and dC 49.2). LRESIMS (negative mode) was performed on an Esquire
3000 Plus spectrometer. Analytical HPLC analysis was performed on
a Dionex Ultimate 3000 chromatograph, using a Luna Phenomenex
C18 column (3 µm, 150 × 5 mm) and an UVD-DAD detector. Silica
gel (Merck, 230-400 mesh) and Sephadex LH-20 (Amersham
Biosciences) were used for column chromatographic separation, while
silica gel 60 PF254 (Merck) was used for analytical (0.25 mm) TLC.
Plant material
Leaves of P. barbatus were collected at the Instituto Plantarum de
Estudos da Flora, Brazil, in Nova Odessa/São Paulo state, in October
2010. The studied specie was identified by MSc. H. Lorenzi and a
voucher specimen has been deposited in the Herbarium Plantarum
under number H. Lorenzi 771.
Extraction and isolation
Leaves of P. barbatus (227 g) were dried, milled and extracted
at room temperature with 3 X 1 L of MeOH. Concentration in vacuo
Table 2. Anti-trypanosomal activity and cytotoxicity of PGG and benznidazole
EC50 µM
T. cruzi tripomastigotes
(95% C.I.)
CC50 µM
(95% C.I.)
PGG 66.66
Benznidazole 441.15
EC50: 50% Effective Concentration; CC50: 50% Cytotoxic Concentration;
95% C.I. : 95% confidence interval. For EC50 values was determined % T.
cruzi survival: 159.57 mM: 15.5 ± 1.92; 79.79 mM: 27.53 ± 0; 39.89 mM:
95.14 ± 2.85; 19.95 mM: 100 ± 0.42. (Values expressed as mean ± SEM of
two determinations)
Table 1. 1H, 13C and HMBC data of 1,2,3,4,6,-penta-O-galloyl-b-D-glucose
(CD3OD, 300 and 75 MHz)
Position dHdCHMBC (H C)
16.14 (1H, d, 8.4 Hz) 93.4 C2, C3, C7’ (Gal 1),
25.52 (1H, dd J = 8.4,
9.9 Hz)
72.4 C1, C3, C4, C7’ (Gal 2)
35.81 (1H, t, 9.9 Hz) 74.2 C1, C2, C4, C5, C7’ (Gal 3)
45.49 (1H, t, 9.6 Hz) 69.9 C2, C3, C5, C6, C7’ (Gal 4)
54.42, (1H, d, 10.5 Hz) 74.5 C3, C4, C6
6a/6b 4.32 (2H, m)63.3 C4, C5, C7’ (Gal 5)
Gal 1
1’ - 119.8 EC50
2’/6’ 6.95 (2H, s)110.7 C1’,C3’, C4’, C5’, C6’, C7’
3’/5’ - 141.0 -
4’ - 146.7 -
7’ - 166.4 -
Gal 2
1’ - 120.3 -
2’/6’ 6.85 (2H, s)110.5 C1’, C3’, C4’, C5’, C6’, C7’
3’/5’ - 140.5 -
4’ - 146.5 -
7’ - 167.2 -
Gal 3
1’ - 120.5 -
2’/6’ 6.80 (2H, s)110.5 C1’, C3’, C4’, C5’, C6’, C7’
3’/5’ - 140.3 -
4’ - 146.4 -
7’ - 167.4 -
Gal 4
1’ - 120.3 -
2’/6’ 6.88 (2H, s)110.6 C1’, C3’, C4’, C5’, C6’, C7’
3’/5’ - 140.6 -
4’ - 146.6 -
7’ - 167.1 -
Gal 5
1’ - 121.1 -
2’/6’ 7.01 (2H, s)110.4 C1’, C3’, C4’, C5’, C6’, C7
3’/5’ - 140.2 -
4’ - 146.6 -
7’ - 168.1 -
Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-b-D-glucose 2231
Vol. 35, No. 11
yielded 9.1 g of crude extract. Part of this material (9 g) was dissolved
in MeOH:H2O 8:2 and subsequently extracted using hexane, EtOAc
and CHCl3. After evaluation of trypanocidal potential, the active
EtOAc phase (4.0 g) was subjected to silica gel column chromatog-
raphy eluted with increasing amounts of EtOAc in hexane to give 77
fractions (10 mL). After TLC analysis, these fractions were combined
into 23 groups (A1-A23), which displayed activity against T. cruzi
trypomastigote forms. As bioactivity was detected at group A18, part
of this material (700 mg) was introduced to a Sephadex LH-20 column
which was eluted with MeOH. This procedure afforded 40 fractions
(5 mL each) which were pooled into 11 groups (A18/1-A18/11) after
TLC analysis. As the activity was detected at the A18/1 group, this
was analyzed by HPLC (MeOH:H2O 7:3) to afford 48 mg of pure
White amorphous solid. NMR data: see Table 1. LRESIMS m/z
938.6 [M – H].
BALB/c mice and Golden hamsters (Mesocricetus auratus)
were supplied by the animal breeding facility at the Adolfo Lutz
Institute of São Paulo and maintained in sterilized cages under a
controlled environment, receiving water and food ad libitum. Animal
procedures were performed with the approval of the Research Ethics
Anti-trypanosomal activity
Trypomastigotes of T. cruzi (Y strain) were obtained from LLC-
MK2 culture (ATCC CCL 7), counted on a Neubauer hemocytometer
and applied to 1 x 106/wells in 96-well plates. The substance was
dissolved in DMSO and further incubated in various concentrations
ranging from 150 to 0.073 µg/mL for 24 h at 37 °C with 5% CO2 in
a humidified incubator, using benznidazole as the standard drug. The
DMSO concentration did not exceed 0.5% (v/v) of the final volume
of wells to avoid damage to parasites. The viability of parasites was
measured by the trypomastigote cellular conversion of MTT solu-
tion - bromide 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium
bromide) - in insoluble formazan by mitochondrial enzymes.33 The
extraction of formazan was performed with 10% (v/v) SDS for 18
h (100 mL/well) at 24 °C.34 MTT and the test compound (without
parasites) was added to an internal control to investigate possible
oxidative reaction.
Determination of cytotoxicity against mammalian cells
Mouse subcutaneous connective tissue cells, NCTC clone 929,
(ATCC CCL-1™) were seeded at 4 x 104 cells/well in 96-well micro-
plates and incubated with compounds to the highest concentration of
200 µg/mL for 48 h at 37 ºC in a 5% CO2 humidified incubator. The
viability of cells was determined by the MTT assay.35 Benznidazole
was used as the standard drug. Control cells were incubated in the
presence of DMSO and without drugs.
Statistical analysis
Data represent the mean and standard deviation of duplicate
samples from two independent assays. The IC50 values were calcu-
lated using sigmoidal dose-response curves in Graph Pad Prism 5.0
software. The Mann-Whitney t-test (unpaired two-tailed) was used
for significance testing (p < 0.05).
This work was funded by grants provided by FAPESP and CNPq.
J. H. G. Lago and A. G. Tempone are grateful to CNPq to Research
Fellow. R. T. dos Santos and L. L. Hiramoto are indebted to CAPES
and PIBIC/UNIFESP by scholarships.
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... barbatus (previously also known as Coleus forskalaei Briq.) is widely used in traditional medicine in Africa and Latin American to treat a range of human ailments." In addition to reinforcing the endemism of the plant in Asian and African locations, Santos et al. (2012) list the places in Brazil where boldo is widely used by highlighting that "the genus Plectranthus, synonym Coleus (Lamiaceae), contains about 350 species with occurrence in Africa, Asia, and Australia. In Brazil, it is an introduced genus, whose occurrence has been described in the Northeast and Southeast regions." ...
... This explains why a lot of current research focuses on natural molecules and plant-derived products as they can be sourced easily, are locally available and can be selected on the basis of their ethnomedicinal use" (Al-Musayeib et al. 2012). Santos et al. (2012) investigated the antitrypanosomal activity of a gallic acid derivative present in the methanolic extract of Plectranthus barbatus. The researchers found the plants of the Plectranthus genus to be of great ethnobotanical importance, as they provided several bioactive substances, most of which are reported in the scientific literature. ...
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This research envisioned as its main objective the comprehension of the process of knowledge production concerning the Afro-Brazilian boldo (Plectranthus barbatus Andrews), with the contributions from both scientists and the Afro-Brazilian people. As specific objectives, we attempted to reconstruct the research pathways traveled by medicinal plant scientists and by the Afro-Brazilian people and to evaluate the conduct of scientists along this process. The method exploited in this investigation consisted of a systematic literature review followed by content analysis from a bardanian perspective. Within the framework of this investigation (decoloniality of knowledge), the theories of epistemicide, epistemic pillage, and ethics of Ubuntu comprise the main theoretical constructs employed. During content analysis, we formulated a category discussing how the ancestral wisdom was presented in the papers investigated herein. The process of knowledge production always occurs in collaboration with other scientists, which, according to the theory of Ubuntu, can be considered ethical. We analyzed how the ancestral knowledge is presented in the research papers related to boldo in order to understand both its influence on the body of research examined and the possible processes of epistemic injustice. It is possible that, in the process of knowledge production depicted herein, Afro-Brazilian people might have had their epistemes pillaged, which appears to be unethical under the perspective of Ubuntu theory, and this motivated, in this work, the proposal of an ethically oriented process of knowledge production. This research first establishes the approaches between ethical and epistemological aspects with respect to processes of knowledge production, from a decolonial perspective, and reveals the nuances of those processes, the epistemic injustices that have occurred, and the ethical problems due to these injustices.
... Several reports highlighted the in vitro efficacy of some flavonoid compounds against T. brucei [19]. Moreover, penta-O-galloyl-β-D-glucose was revealed to have in vitro anti-trypanosomal activity [48]. Furthermore, gallic acid was cited to exert its effect on T. brucei via iron chelation that caused structural and morphological changes and stopping the cell cycle [49]. ...
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Human African trypanosomiasis is an endemic infectious disease caused by Trypanosoma brucei via the bite of tsetse-fly. Most of the drugs used for the treatment, e.g., Suramin, have shown several problems, including the high level of toxicity. Accordingly, the discovery of anti-trypanosomal drugs from natural sources has become an urgent requirement. In our previous study on the anti-trypanosomal potential of Euphorbia species, Euphorbia abyssinica displayed significant anti-trypanosomal activity. Therefore, a phytochemical investigation of the methanolic extract of E. abyssinica was carried out. Twelve compounds, including two triterpenes (1, 2); one sterol-glucoside (4); three ellagic acid derivatives (3, 9, 11); three gallic acid derivatives (5, 6, 10); and three flavonoids (7, 8, 12), were isolated. The structures of isolated compounds were determined through different spectroscopic techniques. Compound (10) was obtained for the first time from genus Euphorbia while all other compounds except compound (4), were firstly reported in E. abyssinica. Consequently, an in silico study was used to estimate the anti-trypanosomal activity of the isolated compounds. Several compounds displayed interesting activity where 1,6-di-O-galloyl-d-glucose (10) appeared as the most potent inhibitor of trypanosomal phosphofructokinase (PFK). Moreover, molecular dynamics (MD) simulations and ADMET calculations were performed for 1,6-di-O-galloyl-d-glucose. In conclusion, 1,6-di-O-galloyl-d-glucose revealed high binding free energy as well as desirable molecular dynamics and pharmacokinetic properties; therefore, it could be suggested for further in vitro and in vivo studies for trypanosomiasis.
... Compounds 9 (6.2 mg) and 17 (5.2 mg) were obtained from Fr.1 by preparative TLC (EtOAc-MeOH-H 2 O, 5 : 1 : 0.9). 1, 2, 3, 4, 6-Penta-O-galloyl-β-D-glucoside (1): maple powder; 1 H and 13 C NMR data matched literature values [14]. ...
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In the present study, petroleum ether, dichloromethane, ethyl acetate, and n-butanol fractions of mango seed kernel exhibited different degrees of antioxidant and α-glucosidase inhibitory activity. Thus, quantitative and qualitative analysis of the petroleum ether fraction was conducted by GC-MS. Among identified components, four unsaturated fatty acids had never been reported in natural products before, together with 19 known components. In addition, 17 compounds were isolated and elucidated from other active fractions. Compounds 2, 9, 15, and 17 were isolated for the first time from Mangifera genus. Compounds 1 and 2 exhibited prominent DPPH radical scavenging and α-glucosidase inhibitory effects. In order to further explore their mechanism of α-glucosidase inhibition, their enzyme kinetics and in silico modeling experiments were performed. The results indicated that 1 inhibited α-glucosidase in a noncompetitive manner, whereas 2 acted in a competitive manner. In molecular docking, the stability of binding was enhanced by π-π T-shaped, π-alkyl, π-π stacked, hydrogen bond, and electrostatic interactions. Thus, compounds 1 and 2 were determined to be new potent antioxidant and α-glucosidase inhibitors for preventing food oxidation and enhancing hypoglycemic activity.
Belonging to Lamiaceae family, the genus Teucrium L. is a rich source of secondary metabolites used in pharmacology and industrial medicine. This study aimed to investigate the flavonoid contents of methanol extract and the chemical markers of Teucrium at specific and infraspecific levels and identify the chemotypes of its accessions. Nineteen accessions, eight species, and five subspecies were collected from three sections ( Teucris, Polium , and Scordium ) belonging to the natural habitats in the west, southwest, centre, and south of Iran. Total flavonoid extraction was attained by the air-dried leaf of Teucrium species and 90% methanol. HPLC coupled with triple quadrupole mass analyser was applied to screen and identify the chemical constituents. Multivariate analyses were implemented by cluster and principal component analysis. Chemical investigation specified 148 chemical compounds, of which 135 flavonoids were tentatively identified. The most abundant derivatives belonged to flavones (41 derivatives), flavonols (37 derivatives), and isoflavonoids (22 derivatives). Based on the cluster analysis, 13 groups of chemical markers were formed in sections Teucris and Scordium and five groups in section Polium as chemotaxonomic indicators. The specified chemotypes were represented by ten in the sections Teucris and Scordium and by six in the section Polium . A relationship was suggested between type and flavonoid quantity (number), altitude, and geographical location. The present study provided valuable information for pharmacological research, bioactivity assessment, and chemotaxonomic purposes. This is the first report on the presence of chemotypes, chemical markers, and quality assessments for the genus Teucrium .
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Many of Euphorbiaceae species are recognized as traditional medicinal plants and the oils and latex of many species have also economic importance. In fact, Euphorbia heterophylla L., belonging to this family and popularly known in Brazil as “leiteira”, “flor-de-poetas” and wild poinsettia, has been used traditionally in Africa and India to treat many kinds of health disorders. However, the chemical composition of this species has been little studied so far. In the present investigation, the flavonoids quercitrin (quercetin 3-O-α-L-rhamnopyranoside), hyperin (quercetin 3-O-β-D-galactopyranoside), isoquercitrin (quercetin 3-O-β-D-glucopyranoside) and isoquercitrin 6”-malonate (quercetin 3-O-β-D-(6”-malonate)-glucopyranoside) were isolated from an ethyl acetate partition of aqueous ketone extract from E. heterophylla leaves. The dehydroellagitannins geraniin and phyllantusiin D as well as 1,2,3,4,6- penta-O-galloyl- β-D-glucopyranoside, caffeic acid and the coumarin aesculetin (6,7-dihydroxycoumarin) were also isolated. All the compounds were characterized by spectroscopic methods such as 1H and 13C-NMR, COSY, HETCOR, APT and by comparison with literature data. The presence of these substances of relevant bioactivity is reported for the first time in E. heterophylla through our study supporting in this way the medicinal use of this specie.
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Studies in rural communities are important to maintain popular knowledge between generations, as well as to identify new species for pharmaceutical production. Thus, the objectives of this study were to determine which plant species the rural community of Bananal, Mato Grosso, Brazil, uses by calculating the levels of fidelity and concordance regarding species uses among residents and to determine if there is a relationship between the number of known useful plants and levels of education, age, and residence time. Ethnobotanical data was collected from residents of the community through semi-structured interviews in January/December/2016. Species diversity was calculated using Shannon-Wiener, Level of Fidelity (LF), Correction Factor, and the Percentage of Agreement regarding the Main Uses (AMU). Statistical tests were performed using generalized linear models (GLM) in the R environment. The plant use indications were grouped according to the International Classification of Diseases and Related Health Problems (ICD 10). We found 152 species belonging to 130 genera and 67 families. The most frequently used plant parts were leaves, and decoction was the most frequent preparation mode. Strychnos pseudoquina was the species with the highest amount of use indications. The diversity index was 4.5 nats/ind⁻¹. The body system with the most citations was the code XVIII of ICD 10, corresponding to the species: alfavaca, mentraste, terramicina, angelim, fedegoso. Medicinal species with AMU values higher than 25% were: Strychnos pseudoquina, Plectranthus barbatus, Citrus sinensis cv. pera, Cymbopogon citratus. There was a relationship between the number of useful plants and the residence time of the participants. The Bananal community revealed high species richness and the relationship of knowledge showed that the older the residents and the longer their residence time in the community, the more knowledge they acquired.
Two new acylated triterpenoid saponins named pendulaosides A and B as well as the known phenolic compounds methyl gallate, gallic acid, 1,2,3,6-tera-O-galloyl-β-D-glucose and 1,2,3,4,6-penta-O-galloyl-β-D-glucose, were isolated from the seeds of Harpullia pendula. The structures of pendulaosides A and B were determined using extensive 1D and 2D NMR analysis and mass spectrometry as well as acid hydrolysis, as 3-O-β-D-glucopyranosyl-(1→2)-[α-L-arabinofuranosyl-(1→3)]-β-D-glucuronopyranosyl-22-O-angeloyl-3β,16α,22α,24β,28-pentahydroxylolean-12-ene and 3-O-β-D-glucopyranosyl-(1→2)-[α-L-arabinofuranosyl-(1→3)]-β-D-glucuronopyranosyl-16-O-(2-methylbutyroyl)-3β,16α,22α,24β,28-pentahydroxylolean-12-ene, respectively. To the best of our knowledge the two triterpene parts 22-O-angeloyl-3β,16α,22α,24β,28-pentahydroxylolean-12-ene and16-O-(2-methylbutyroyl)-3β,16α,22α,24β,28-pentahydroxylolean-12-ene have never been characterized before. The two isolated saponins were assayed for their in-vitro cytotoxic activity against the three human tumor cell lines HepG2, MCF7 and PC3. The results showed that pendulaoside A exhibited moderate activity on PC3 cell line with IC50value equal to 13.0 μM and weak activity on HepG2 cell line with IC50 value equal to 41.0 μM. Pendulaoside B proved to be inactive against the three used cell lines.
Natural products have been used as a valuable source of new lead drugs. The Plectranthus L’Her (Lamiaceae) genus possess a wide diversity of ethnomedicinal uses which indicate the presence of bioactive molecules. Also, innovative methods for natural drug delivery, as phytosome, have showed to be a promising strategy for the improvement of delivery and stability. In this work, three plants from the Plectranthus genus were studied: P. madagascariensis, P. neochilus and P. porcatus. Several extracts were prepared by the combination of extraction methods (infusion, decoction, microwave, ultrasound, maceration and supercritical fluid extraction) with different polarity solvents (water, acetone, methanol and scCO2). Those extracts were profiled by HPLC-DAD and the main components were identified, including polyphenols (caffeic acid, chlorogenic acid and rosmarinic acid), diterpenes (7α-acetoxy,6β-hydroxyroyleanone and coleon U) and flavones (rutina y naringenina). The prepared extracts were screened for their antimicrobial (Gram positive and negative bacteria and yeasts), antioxidant (DPPH radical scavenging activity) and cytotoxic activities (MDA-MB-231 cell line). Extracts from P. madagascariensis (acetone maceration and acetone ultrasound) and P. neochilus (acetone ultrasound) showed antibacterial effects against Gram positive bacteria strains, namely, Bacillus subtilis, Staphylococcus aureus and S. epidermidis and a Gram negative bacteria strain, Klebsiella pneumonia (MIC values 1.95-250 μg/mL). The ultrasound extract of P. madagascariensis prepared with acetone showed potent antibacterial effect against Staphylococcus spp., including a methicillin-resistant strain (MRSA), with MIC values ranging from 1.95 to 7.81 μg/mL. These results validate the traditional uses of such plants as anti-infectious agents. All methanolic extracts showed potent antioxidant effects at 100 ng/mL (60.8- 89.0%). The maceration acetone extract from P. madagascariensis showed moderate cytotoxic effects in the MDA-MB-231 breast cancer cell line with IC50 of 64.52 μg/mL. The organic solvent extracts from P. madagascariensis were the most bioactive and thus characterized (identification and quantification) using HPLC-DAD. Furthermore, the compounds were identified by authentic standard overlay: rosmarinic acid, 7α,6β- dihydroxyroyleanone, 7α-acetoxy-6β-hydroxyroyleanone and coleon U. A diterpenic compound was isolated from the ultrasound acetonic extract of P. madagascariensis and spectroscopically characterized (1H- and 13C-NMR) as 7α-formyloxy-6β- hydroxyroyleanone. This was the first time this compound was isolated from this plant. The cytotoxic effect of the identified compounds was evaluated in a battery of cancer cell lines (MDA-MB-231, MCF-7, HCT116, NCI-H460 and MCR-5). The diterpenic compounds showed moderate to potent cytotoxicity in the majority of tested cell lines. A high selectivity for cancer cell lines was observed for 7α,6β-dihydroxyroyleanone and 7α-acetoxy-6β-hydroxyroyleanone with selectivity index of 4.3 and 3.2, respectively. The combination of the observed results and literature data afforded the establishment of new structure-activity relationships of roylenanone abietanic xi compounds. The relevance of lipophilicity and of the presence of an electron donating group at 6 and/or 7 positions was observed. The antibacterial acetonic ultrasound extract from P. madagascariensis identified in the initial screening was selected for incorporation into a phytosomal formulation and subsequently coated by chitosan. Phytosomes were amorphous, uniform in shape as shown by AFM and SEM, and with an average size of 1082 ± 363 nm and zeta potential of +20.59 ± 12.02 mV. The encapsulation of the antibacterial extract was determined by HPLC (57.7±0.06%) and the chemical interactions between the formulation components was cofirmed by DSC and DRIFTS. Such phytosomes showed a sustained release of the extract 4 and lower skin-like permeation fluxes. An improvement up to a 4-fold factor in the anti-Staphylococci activity (MIC values 0.98-31.25 μg/mL) was observed. The safety of such formulation was verified by in vitro human keratinocytes cytotoxicity assays and by in vivo acute and sub-chronic dermal irritation tests in mice. This study showed the potential of the Plectranthus genus as source of lead antibacterial and antiproliferative agents and validate the ethnomedicinal uses of the studied plants. The isolated abietane diterpenes obtained from P. madagascariensis possess promising selective cytotoxic effects, namely, aginst the lung cancer lines tested. Also, the developed formulation of extract of P. madagascariensis corresponds to a potent topical antibacterial candidate with a broad spectrum of activity.
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Essential oils of ripe fruits from Schinus terebinthifolius (Anacardiaceae), obtained using a pilot extractor and a Clevenger apparatus were chemically characterized. Due the high amount of (-)- α-pinene in both oils, this monoterpene was tested against the protozoan parasite Trypanosoma cruzi, showing a moderate potential (IC50 63.56 µg/mL) when compared to benznidazole (IC50 43.14 µg/mL). Otherwise, (-)- α-pinene oxide did not showed anti-trypanosomal activity (IC50 > 400 µg/mL) while (-)-pinane showed an IC50 of 56.50 µg/mL. The obtained results indicated that the epoxydation of α-pinene results to the loss of the anti-parasitic activity while its hydrogenation product, contributed slightly to the increased activity.
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Neglected diseases are a major global cause of illness, long-term disability and death. Chagas' disease is a parasitic infection widely distributed throughout Latin America, with devastating consequences in terms of human morbidity and mortality. The existing drug therapy suffers from a combination of drawbacks including poor efficacy, resistance and serious side effects. In 2009, we celebrate the 100th anniversary of the discovery of Chagas' disease, facing the challenges of developing new, safe and effective drugs for the treatment of this disease. This brief review attempts to highlight the state of the art, limitations and perspectives of Chagas' disease drug development.
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Leishmaniasis, Chagas disease, and malaria affect the poorest population around the world, with an elevated mortality and morbidity. In addition, the therapeutic alternatives are usually toxic or ineffective drugs especially those against the trypanosomatids. In the course of selection of new anti-protozoal compounds from Brazilian flora, the CH(2)C(l2) phase from MeOH extract obtained from the leaves of Pentacalia desiderabilis (Vell.) Cuatrec. (Asteraceae) showed in vitro anti-leishmanial, anti-malarial, and anti-trypanosomal activities. The chromatographic fractionation of the CH(2)Cl(2) phase led to the isolation of the bioactive compound, which was characterized as jacaranone [methyl (1-hydroxy-4-oxo-2,5-cyclohexandienyl)acetate], by spectroscopic methods. This compound showed activity against promastigotes of Leishmania (L.) chagasi, Leishmania (V.) braziliensis, and Leishmania (L.). amazonensis showing an IC(50) of 17.22, 12.93, and 11.86 μg/mL, respectively. Jacaranone was also tested in vitro against the Trypanosoma cruzi trypomastigotes and Plasmodium falciparum chloroquine-resistant parasites (K1 strain) showing an IC(50) of 13 and 7.82 μg/mL, respectively, and was 3.5-fold more effective than benznidazole in anti-Trypanosoma cruzi assay. However, despite of the potential against promatigotes forms, this compound was not effective against amastigotes of L. (L.) chagasi and T. cruzi. The cytotoxicity study using Kidney Rhesus monkey cells, demonstrated that jacaranone showed selectivity against P. falciparum (21.75 μg/mL) and a selectivity index of 3. The obtained results suggested that jacaranone, as other similar secondary metabolites or synthetic analogs, might be useful tolls for drug design for in vivo studies against protozoan diseases.
Plectranthus barbatus is largely used in the Northeast region of Brazil by the local population for treatment of digestive problems As substitute of boldo (Pneumus boldus). Phytochemical analysis of the leaf extracts of Plectranthus barbatus (Labiatae) cultivated in this region yielded two abietane diterpenoids, cyclobubatusin (1) and barbatusin (2) and a new one named 7 beta-acetyl-12-deacetoxycyclobutatusin (3). The structures of the isolated compounds were established by spectral analysis, using mainly mass spectra and H-1 and (CNMR)-C-13 (1D and 2D). These procedures permitted the assignment of all chemical shifts in the diterpenoids.
The structure of three diterpenoids from Coleus barbatus, Bentham (Labiatae) having a spirocyclopropyl side chain have been determined: they are barbatusin (1a), 3β-hydroxy-3-deoxybarbatusin (2) and cyclobutatusin (3a). The structures of 1a and 3a were established by X-ray diffraction analysis, and the latter compound has been shown to have an unusual 4-membered ring produced by a bond across C(1) to C(11). Chemical transformations and interconversions are presented, together with spectroscopic studies.
This study describes the in vitro metabolism, by the gastrointestinal tract, together with the biological activity of the herbal tea obtained from Plectranthus barbatus leaves. The results showed that there was no appreciable degradation and that the activity was kept constant after gastric juice digestion. In the presence of pancreatic juice, degradations varied from negligible, in the case of flavonoid glucuronides, to almost complete, in the case of the abietane diterpenoid. The digested decoction contained only 50% of its initial biological activity, after pancreatic digestion. The action of Caco-2 cells on the extract revealed that neither rosmarinic acid, the main compound of the extract, nor the other components present in minute quantities were metabolised by the intact cells. Rosmarinic acid could be found inside Caco-2 cells although in trace amount. Glucoronidase from Escherichia coli, a gut bacterium, was able to hydrolyse the flavonoid derivatives, thus the aglycones were formed and permeate the Caco-2 cells.
Five distinct organic compounds with protected and unprotected phenolic hydroxyl groups were screened for their α-glucosidase inhibitory potential. Of these compounds, 2,4,6-trihydroxybenzaldehyde (THB) showed the strongest noncompetitive α-glucosidase inhibition (IC50=4.60μM) and the most powerful antioxidant activity (DPPH assay) (IC50=71.4μM) in vitro. In in vivo studies, THB significantly reduced blood glucose levels in normal and diabetic rats after glucose load compared to maltose load. Keywords2,4,6-Trihydroxybenzaldehyde–α-Glucosidase inhibitor–DPPH–Postprandial–Streptozotocin
Leishmaniasis and Chagas' are parasitic protozoan diseases that affect the poorest population in the world, causing a high mortality and morbidity. As a result of highly toxic and long-term treatments, novel, safe and more efficacious drugs are essential. In this work, the CH(2)Cl(2) phase from MeOH extract from the leaves of Baccharis retusa DC. (Asteraceae) was fractioned to afford two flavonoids: naringenin (1) and sakuranetin (2). These compounds were in vitro tested against Leishmania spp. promastigotes and amastigotes and Trypanosoma cruzi trypomastigotes and amastigotes. Compound 2 presented activity against Leishmania (L.) amazonensis, Leishmania (V.) braziliensis, Leishmania (L.) major, and Leishmania (L.) chagasi with IC(50) values in the range between 43 and 52 μg/mL and against T. cruzi trypomastigotes (IC(50)=20.17 μg/mL). Despite of the chemical similarity, compound 1 did not show antiparasitic activity. Additionally, compound 2 was subjected to a methylation procedure to give sakuranetin-4'-methyl ether (3), which resulted in an inactive compound against both Leishmania spp. and T. cruzi. The obtained results indicated that the presence of one hydroxyl group at C-4' associated to one methoxyl group at C-7 is important to the antiparasitic activity. Further drug design studies aiming derivatives could be a promising tool for the development of new therapeutic agents for Leishmaniasis and Chagas' disease.
Plectranthus barbatus Andrews (Lamiaceae) is a popular medicinal plant used to treat gastrointestinal and hepatic ailments. In this work, we assessed the antioxidant activity of the aqueous extract of P. barbatus leaves on Fe2+-citrate-mediated membrane lipid peroxidation in isolated rat liver mitochondria, as well in non-mitochondrial systems: DPPH reduction, OH scavenging activity, and iron chelation by prevention of formation of the Fe2+-bathophenanthroline disulfonic acid (BPS) complex. Within all the tested concentrations (15–75 μg/ml), P. barbatus extract presented significant free radical-scavenging activity (IC50 = 35.8 ± 0.27 μg/ml in the DPPH assay and IC50 = 69.1 ± 0.73 μg/ml in the OH assay) and chelated iron (IC50 = 30.4 ± 3.31 μg/ml). Over the same concentration range, the plant extract protected mitochondria against Fe2+/citrate-mediated swelling and malondialdehyde production, a property that persisted even after simulation of its passage through the digestive tract. These effects could be attributed to the phenolic compounds, nepetoidin – caffeic acid esters, present in the extract. Therefore, P. barbatus extract prevents mitochondrial membrane lipid peroxidation, probably by chelation of iron, revealing potential applicability as a therapeutic source of molecules against diseases involving mitochondrial iron overload.