Data about gross composition of propolis (resins and balsams 50%, wax 30%, pollen 5%, essential oils 10%) have been often quoted in propolis literature. The present paper provides evidence that these ...data are misleading and unsubstantiated.
Propolis is a honey bee product containing chiefly beeswax and resins originated from plant buds or exudates. Propolis resin exerts a diversity of biological activities, such as antitumoral, ...anti-inflammatory, antimicrobial, and defense of the hive against pathogens. Chemical standardization and identification of botanical sources is crucial for characterization of propolis. Types of Brazilian propolis are characteristic of geographical regions and respective biomes, such as savannas (Cerrado), mangroves, dry forest (Caatinga), rain forests (Amazon, Atlantic, and Interior forests), altitudinal fields (“Campos Rupestres”), Pantanal, and
Araucaria
forests. Despite the wide diversity of Brazilian biomes and flora, relatively few types of Brazilian propolis and corresponding resin plant sources have been reported. Factors accounting for the restricted number of known types of Brazilian propolis and plant sources are tentatively pointed out. Among them, the paper discusses constraints that honey bees must overcome to collect plant exudates, including the characteristics of the lapping-chewing mouthpart of honey bee, which limit their possibilities to cut and chew plant tissues, as well as chemical requirements that plant resins must fulfil, involving antimicrobial activity of its constituents and innocuity to the insects. Although much still needs to be done toward a more comprehensive picture of Brazilian propolis types and corresponding plant origins, the prospects indicate that the actual diversity of plant sources of honey bee propolis will remain relatively low.
Croton is a genus of Euphorbiaceae comprising around 1,300 species, widespread in tropical regions of the Old and New Worlds. Several species have a long role in the traditional use of medicinal ...plants in Africa, Asia and South America. Popular uses include treatment of cancer, constipation, diabetes, digestive problems, dysentery, external wounds, fever, hypercholesterolemia, hypertension, inflammation, intestinal worms, malaria, pain, ulcers and weight-loss. Several species of Croton have a red sap, in some species containing proanthocyanidins and/or alkaloids. The latter may be taspine or some of several benzylisoquinoline-like compounds. Diterpenes are very common in Croton, corresponding to clerodanes, cembranoid, halimanes, kauranes, labdanes, phorbol esters, trachylobanes and sarcopetalanes. Some species are aromatic due to the possession of volatile oils. Representatives of new classes of compounds (phenylbutanoids, glutarimide alkaloids, sarcopetalane diterpenes) have been isolated from Croton species. While laticifers have been described in Croton species, so far there are no anatomical studies about secretory structures of volatile oil. Few studies about flavonoids have been carried out with Croton species. Chemical affinities are apparent in the genus, grouping species with (i) kauranes and/or labdanes, (ii) trachylobanes and (iii) alkaloids. Pharmacological assays have frequently corroborated the traditional uses of Croton species. A great part of pharmacological assays with Croton substances dealt with the clerodane trans-dehydrocrotonin, a wide diversity of effects having been noticed, including hypolipidemic, hypoglycaemic, anti-oestrogen and anti-cancer. Cytotoxic effects also have been observed in assays with alkaloids (taspine) and with secokaurene, labdane and cembranoid diterpenes. Several other effects of Croton substances have been registered, including anti-hypertensive, anti-inflammatory, antimalarial, antimicrobial, antispasmodic, antiulcer, antiviral and myorelaxant.
Propolis is a resinous and complex bee product containing resin derived from plants, beeswax, pollen and other minor constituents. The present study aimed to determine the parameters of the gross ...composition of propolis collected by nine stingless bee species from eight different Brazilian localities. The moisture content varied depending on the bee species and localities. Wax content enables us to distinguish between samples of Melipona and Scaptotrigona, samples of the former containing considerably less wax than samples of the latter genus. The ash content has an inverse trend, with samples of Melipona and Scaptotrigona having high and low ash content, respectively. The results indicated that Melipona species produce geopropolis (propolis containing aggregated soil material), while Scaptotrigona produces propolis devoid of soil, with the exception of S. tubiba. Most Melipona species collected sediments with high clay content. The size and color of ash crystals varied, mostly according to the locality of the meliponaries, although differences were observed between samples of the same species, growing in the same meliponary. Mineralogical analysis was relevant to determine that M. flavolineata from North Brazil aggregates river-bed soil sediments to the geopropolis.
Melipona subnitida (“jandaíra”) is a species of stingless bee endemic to the Caatinga, a dry forest in the northeastern Brazilian semiarid. Propolis is a product containing beeswax and plant resin. ...It contains compounds that can be able to prevent health problems by protecting cells against damage by oxidative agents. M. subnitida produces geopropolis, a mixture of propolis with soil. Samples of geopropolis of M. subnitida, one of inside and another outside of the nest from a hive in the municipality of Mossoró (northeastern Brazil) were analyzed by HPLC-PDA-ESI-MS/MS and their antioxidant activity evaluated by the DPPH and β-carotene/linoleic acid methods. Both samples exhibited similar chemical profile, characterized by 26 phenolic compounds, however, the compounds detected were more abundant in sample collected from inside of the nest. They were tentatively characterized as galloyl hexoses, coumaroylO-galloyl-hexoses, cinnamoyl-O-galloyl-hexoses, coumaroyl- and cinnamoyl- galloyl hexoses, phenylpropanoyl-O-benzoyl hexoses, flavanones and ellagitannins. Flavonoids, galloyl hexoses, coumaroyl-O-galloyl-hexosides, cinnamoyl-O-galloyl-hexosides and coumaroyl-cinnamoyl-galloyl hexosides were reported previously in this genus, however ellagitannins and phenylpropanoyl-Obenzoyl hexoses are reported for the first time. Comparing the antioxidant activity of the geopropolis samples from inside and outside of the nest, the latter was higher than the former
Acylation of flavonoid glycosides enhances their chemical stability, lipo-solubility and antioxidant activity, improving their medicinal potential. Enzymatic acylation of flavonoid glycosides is ...advantageous compared to chemical procedures, as these reactions proceed at mild conditions and the acyl group is inserted at specific positions. In the present work, enriched leaf protein extracts of
Croton floribundus
Spreng and
C. urucurana
Baillon (Euphorbiaceae) were used as sources of enzymes in approaches to obtain
p-
coumaroyl derivatives of 3-
O
-glycosides of kaempferol and quercetin, as well as 7-
O
-quercetagetin glucoside. Tiliroside (1), helichrysoside (2) and quercetin-3-
O
-(6″-
p
-coumaroyl)-galactoside (3) were detected by HPLC–DAD and UPLC/MS as products of acylation reaction, using protein extracts of
C. urucurana
and either
p
-coumaroyl-CoA or
p
-coumaric acid plus CoA and ATP. Protein extracts of
C. floribundus
Spreng were effective toward the acylation of kaempferol-3-
O
-glucoside. Although acyltransferases seem to be ubiquitous in
Croton
, the ability to acylate different flavonol glycosides might largely depend on the species. Acyltransferases in the protein extracts are versatile at acylating flavonoids with distinct aglycones and distinct sugar substituents. The failure to attain acylated products of quercetagetin-7-
O
-glucoside indicates that
Croton
acyltransferases are regioselective, with a target on 3-
O
-sugars of flavonoids.
Extracts of a sample of brown propolis produced in the district of Itapará (Southern Brazil) were obtained with solvents with increasing polarity. The extracts were analyzed by RPHPLC–DAD–ESI–MS/MS ...and evaluated toward activity against
Mycoplasma bovis
,
M. gallisepticum
,
M. genitalium
,
M. hominis
,
M. hyorinis
,
M. penetrans
and
M. pneumonieae
. Typical components of “alecrim-do-campo” propolis (e.g. prenylated phenylpropanoids and caffeoyl-quinic acids) were characterized in the analyzed extraccts, in addition to several flavonols. Less polar extracts showed higher anti-mycoplasma activity (MIC value commonly 3.9 μg/mL) than alcoholic and aqueous extracts (MIC value often 7.8–250 μg/mL). The results indicate that Itapará propolis is a promising source for the development of therapeutic drugs.
Abstract
We report on the serendipitous discovery of three transient millimeter-wave sources using data from the Atacama Cosmology Telescope. The first, detected at R.A
.
= 273.8138, decl. = −49.4628 ...at ∼50
σ
total, brightened from less than 5 mJy to at least 1100 mJy at 150 GHz with an unknown rise time shorter than 13 days, during which the increase from 250 mJy to 1100 mJy took only 8 minutes. Maximum flux was observed on 2019 November 8. The source’s spectral index in flux between 90–150 GHz was positive,
α
= 1.5 ± 0.2. The second, detected at R.A. = 105.1584, decl
.
= −11.2434 at ∼20
σ
total, brightened from less than 20 mJy to at least 300 mJy at 150 GHz with an unknown rise time shorter than 8 days. Maximum flux was observed on 2019 December 15. Its spectral index was also positive,
α
= 1.8 ± 0.2. The third, detected at R.A
.
= 301.9952, decl. = 16.1652 at ∼40
σ
total, brightened from less than 8 mJy to at least 300 mJy at 150 GHz over a day or less but decayed over a few days. Maximum flux was observed on 2018 September 11. Its spectrum was approximately flat, with a spectral index of
α
= −0.2 ± 0.1. None of the sources were polarized to the limits of these measurements. The two rising-spectrum sources are coincident in position with M and K stars, while the third is coincident with a G star.
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