Antimicrobial Triterpenoids and Ingol Diterpenes from Propolis of Semi-Arid Region of Morocco.

The chemical composition and antimicrobial activity of propolis from a semi-arid region of Morocco were investigated. Fifteen compounds, including triterpenoids (1, 2, 7-12), macrocyclic diterpenes of ingol type (3-6) and aromatic derivatives (13-15), were isolated by various chromatographic methods. Their structures were elucidated by a combination of spectroscopic and chiroptical methods. Compounds 1 and 3 are new natural compounds, and 2, 4-6, and 9-11 are newly isolated from propolis. Moreover, the full nuclear magnetic resonance (NMR) assignments of three of the known compounds (2, 4 and 5) were reported for the first time. Most of the compounds tested, especially the diterpenes 3, 4, and 6, exhibited very good activity against different strains of bacteria and fungi. Compound 3 showed the strongest activity with minimum inhibitory concentrations (MICs) in the range of 4-64 µg/mL. The combination of isolated triterpenoids and ingol diterpenes was found to be characteristic for Euphorbia spp., and Euphorbia officinarum subsp. echinus could be suggested as a probable and new plant source of propolis.

Chemical Profile and Antioxidant Capacity of Propolis from Tetragonula, Lepidotrigona, Lisotrigona and Homotrigona Stingless Bee Species in Vietnam.

The present study aimed to analyze and compare the chemical profile and antioxidant capacity of propolis from different bee species and different regions. The chemical profiles of propolis from six stingless bee species (Tetragonula iridipennis, T. laeviceps, Lepidotrigona terminata, L. ventralis, Lisotrigona carpenteri and Homotrigona apicalis) collected from a total of eight locations in Vietnam were investigated by gas chromatography-mass spectrometry (GC-MS). More than 70 compounds were identified, amongst which phenolic lipids (cardanols, resorcinols and anacardic acids), aromatic acids, triterpenes and xanthones. Taxonomic markers for Mangifera indica (phenolic lipids and cycloartane triterpenes) were detected in propolis from bees of the genera Tetragonula and Lepidotrigona, although in different amounts, whereas propolis from H. apicalis was characterized by triterpenes of the amyrine type, typical of dipterocarp trees. A clear discrimination between both groups was observed by principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). Propolis from Tetragonula and Lepidotrigona spp. and from Lisotrigona carpenteri, which is rich in xanthones, possesses higher radical scavenging and ferric-reducing capacity than that from H. apicalis. Propolis produced by all six stingless bee species in Vietnam was analyzed for the first time. In addition, this is the first report on L. carpenteri propolis.

The chemical composition and events related to the cytotoxic effects of propolis on osteosarcoma cells: A comparative assessment of Colombian samples.

Osteosarcoma (OSA) is a type of bone cancer showing an aggressive biological behavior with metastatic progression. Because propolis potential for the development of new antitumoral drugs has been indicated, we evaluated the chemical composition of Colombian propolis samples and the mechanisms involved in their cytotoxic effects on OSA cells. The chemical composition was analyzed by GC-MS and the DPPH free radical scavenging activity was measured. Cluster and principal components analysis were used to establish an association with their inhibitory concentration 50% (IC50 ). Cell viability was analyzed by MTT assay; apoptosis was determined by flow cytometry; mitochondrial membrane permeability and reactive oxygen species were evaluated by rhodamine 123 and DCFH-DA. Transwell assay was used to evaluate the invasiveness of propolis-treated cells. Samples were grouped: Cluster 1 contained diterpenes and benzophenones and showed the highest antiradical activity; Cluster 2 was characterized by triterpenes, fatty acid, and diterpenes. Usm contained diterpenes and triterpenes different of the other samples and Sil contained triterpenes and flavonoids. Apoptosis, mitochondrial membrane alteration, and suppression of cell invasion were the main mechanisms involved in the inhibition of OSA cells in vitro, suggesting the potential of Colombian propolis to discover new antitumor drugs.

Insight into the influence of natural deep eutectic solvents on the extraction of phenolic compounds from poplar type propolis: Composition and in vitro biological activity.

Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.

Chemical Composition and Neuroprotective Properties of Indonesian Stingless Bee (Geniotrigona thoracica) Propolis Extract in an In-Vivo Model of Intracerebral Hemorrhage (ICH).

Stroke is the world's second-leading cause of death. Current treatments for cerebral edema following intracerebral hemorrhage (ICH) mainly involve hyperosmolar fluids, but this approach is often inadequate. Propolis, known for its various beneficial properties, especially antioxidant and anti-inflammatory properties, could potentially act as an adjunctive therapy and help alleviate stroke-associated injuries. The chemical composition of Geniotrigona thoracica propolis extract was analyzed by GC-MS after derivatization for its total phenolic and total flavonoid content. The total phenolic content and total flavonoid content of the propolis extract were 1037.31 ± 24.10 µg GAE/mL and 374.02 ± 3.36 µg QE/mL, respectively. By GC-MS analysis, its major constituents were found to be triterpenoids (22.4% of TIC). Minor compounds, such as phenolic lipids (6.7% of TIC, GC-MS) and diterpenic acids (2.3% of TIC, GC-MS), were also found. Ninety-six Sprague Dawley rats were divided into six groups; namely, the control group, the ICH group, and four ICH groups that received the following therapies: mannitol, propolis extract (daily oral propolis administration after the ICH induction), propolis-M (propolis and mannitol), and propolis-B+A (daily oral propolis administration 7 days prior to and 72 h after the ICH induction). Neurocognitive functions of the rats were analyzed using the rotarod challenge and Morris water maze. In addition, the expression of NF-κB, SUR1-TRPM4, MMP-9, and Aquaporin-4 was analyzed using immunohistochemical methods. A TUNEL assay was used to assess the percentage of apoptotic cells. Mannitol significantly improved cognitive-motor functions in the ICH group, evidenced by improved rotarod and Morris water maze completion times, and lowered SUR-1 and Aquaporin-4 levels. It also significantly decreased cerebral edema by day 3. Similarly, propolis treatments (propolis-A and propolis-B+A) showed comparable improvements in these tests and reduced edema. Moreover, combining propolis with mannitol (propolis-M) further enhanced these effects, particularly in reducing edema and the Virchow-Robin space. These findings highlight the potential of propolis from the Indonesian stingless bee, Geniotrigona thoracica, from the Central Tapanuli region as a neuroprotective, adjunctive therapy.

The Chemical Composition of Scaptotrigona mexicana Honey and Propolis Collected in Two Locations: Similarities and Differences.

The chemical composition of stingless bee honey and propolis depends on the plant sources they are derived from, and thus reflects the flora available in the vicinity of the hives, the preferences of the bee species, and the climate (altitude and temperature). To understand the relative influence of these factors, we studied the composition of honey and propolis of the stingless bee Scaptotrigona mexicana. Samples from 24 colonies were analyzed: 12 each from two S. mexicana meliponaries located in the state of Chiapas in southern Mexico, approximately 8.5 km apart, Tuxtla Chico and Cacahoatán. The chemical composition of honey and propolis was studied using nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS), respectively. The antioxidant activity of propolis was also studied. Chemometric analyses were applied. The Tuxtla Chico honey samples contained higher concentrations of glucose and fructose, while the Cacahoatán samples displayed a rich composition of di- and trisaccharides. These differences can be attributed to the distinct nectar sources utilized by the bees at each location. Propolis compositions in the two locations also demonstrated qualitative differences, indicating a specific choice of resins by the bees. The observed substantial variations in the chemical composition of propolis and honey of S. mexicana from two locations relatively close to each other supports the assumption that bee species cannot be considered the most important factor in determining their chemistry.

Antimicrobial, Cytotoxic, and α-Glucosidase Inhibitory Activities of Ethanol Extract and Chemical Constituents Isolated from Homotrigona apicalis Propolis-In Vitro and Molecular Docking Studies.

The chemical investigation of Homotrigona apicalis propolis collected in Binh Dinh province, Vietnam, led to the isolation of nine compounds, including four sesquiterpenes: spathulenol (1), 1αH,5ßH-aromandendrane-4ß,10α-diol (2), 1ß,6α-dihydroxy-4(15)-eudesmene (3), and 1ßH,5ßH-aromandendrane-4α,10ß-diol (4); three triterpenes: acetyl oleanolic acid (5), 3α-hydroxytirucalla-8,24-dien-21-oic acid (6), and ursolic acid (7); and two xanthones: cochinchinone A (8) and α-mangostin (9). Sesquiterpens 1-4 and triterpene 6 were isolated for the first time from stingless bee propolis. Plants in the Cratoxylum and Aglaia genus were suggested as resin sources of the propolis sample. In the antibacterial activity evaluation, the EtOH extract only showed moderate activity on S. aureus, while the isolated compounds 7-9 showed good antibacterial activity, with IC50 values of 0.56 to 17.33 µg/mL. The EtOH extract displayed selective cytotoxicity against the A-549 cancer cell line, with IC50 values of 22.82 ± 0.86 µg/mL, and the xanthones 8 and 9 exhibited good activity against the KB, HepG-2, and A-549 cancer cell lines, with IC50 values ranging from 7.55 ± 0.25 µg/mL to 29.27 ± 2.07 µg/mL. The cytotoxic effects of xanthones 8 and 9 were determined by the inhibition of the EGFR and HER2 pathways using a molecular docking study. Compounds 8 and 9 displayed strong binding affinity with EFGR and HER2, with values of -9.3 to -9.9 kcal/mol. Compounds 5, 8, and 9 showed potential α-glucosidase inhibitory activities, which were further confirmed by computational studies. The binding energies of compounds 5, 8, and 9 were lower than that of arcabose.

Chemical Composition and Antioxidant Capacity of the Fruits of European Plum Cultivar "Cacanska Lepotica" Influenced by Different Rootstocks.

We investigated the influence of different rootstocks on the content of sugars, organic acids, and antioxidant phenolic compounds in the whole fruit and fruit skin of the European plum cultivar "Cacanska Lepotica". 1H NMR of the fruit extracts allowed for the identification of sucrose, α- and ß-glucose, sorbitol, fructose, and malic and quinic acids, while LC-DAD-ESIMS showed the presence of neochlorogenic and chlorogenic acids, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, peonidin-3-O-rutinoside, hyperoside, isoquercitrin, rutin, and unidentified quercetin-3-diglycoside. The quantitation of the sugars, malic and quinic acids by 1H NMR and phenolic compounds by HPLC-DAD revealed that the rootstock significantly influenced the content of the individual compounds in the fruit skin and fruit. The fruit grafted on "Wavit" rootstock was characterized by significant amounts of neochlorogenic acid, peonidin-3-O-rutinoside, cyanidin-3-O-rutinoside, and sucrose, while the fruit on "GXN-15" was characterized by high levels of sugars, cyanidin-3-O-glucoside, and malic and chlorogenic acids. The fruit skins of plums grafted on "Wavit" were the richest in sugars, organic acids, and phenolic compounds. A good correlation was observed between the content of total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and individual phenolic compounds in the extracts of the fruit and the fruit skins and their antioxidant capacity (DPPH, ABTS, and FRAP).

Natural Deep Eutectic Extracts of Propolis, Sideritis scardica, and Plantago major Reveal Potential Antiageing Activity during Yeast Chronological Lifespan.

Nowadays, the environmentally friendly approach to everyday life routines including body supplementation with pharma-, nutraceuticals and dietary supplements gains popularity. This trend is implemented in pharmaceutical as well as cosmetic and antiageing industries by adopting a newly developed green chemistry approach. Following this trend, a new type of solvents has been created, called Natural Deep Eutectic Solvents (NADES), which are produced by plant primary metabolites. These solvents are becoming a much better alternative to the already established organic solvents like ethanol and ionic liquids by being nontoxic, biodegradable, and easy to make. An interesting fact about NADES is that they enhance the biological activities of the extracted biological compounds. Here, we present our results that investigate the potential antiageing effect of CiAPD14 as a NADES solvent and three plant extracts with it. The tested NADES extracts are from propolis and two well-known medicinal plants-Sideritis scardica and Plantago major. Together with the solvent, their antiageing properties have been tested during the chronological lifespan of four Saccharomyces cerevisiae yeast strains-a wild type and three chromatin mutants. The chromatin mutants have been previously proven to exhibit characteristics of premature ageing. Our results demonstrate the potential antiageing activity of these NADES extracts, which was exhibited through their ability to confer the premature ageing phenotypes in the mutant cells by ameliorating their cellular growth and cell cycle, as well as by influencing the activity of some stress-responsive genes. Moreover, we have classified their antiageing activity concerning the strength of the observed bioactivities.

Propolis of stingless bees: A phytochemist's guide through the jungle of tropical biodiversity.

BACKGROUND: Stingless bees (Meliponini), like honeybees Apis mellifera, collect plant resins in order to produce propolis (cerumen, geopropolis). This type of propolis has long been used in traditional medicine in Mexico, Brazil, Argentina, India, and Vietnam, as a remedy for improving health and treating various diseases. The scientific and commercial interest in stingless bee propolis has been steadily increasing over the last few years. The new and growing knowledge in this field requires systematising, as a basis for further work. Recent reviews of Meliponini propolis deal only with the South American and Mesoamerican species, while reviews of the Asian, Australian and African species are missing. Furthermore, the chemical composition has not been thoroughly reviewed since 2007. PURPOSE: This review summarises and discusses the available data about the chemical composition of propolis from the stingless bee species (Meliponinae) of the Americas, Asia and Australia, published after 2007. The published information on the biological action of chemically characterised Meliponini propolis, and of individual constituents, is addressed. The plant sources of this propolis are also considered. CONCLUSION AND PERSPECTIVES: Chemical studies of Meliponini propolis has resulted in the discovery of new natural molecules, some of them with valuable bioactivity. Moreover, finding known molecules in propolis stimulates the study of their pharmacological properties. The enormous chemical variability of stingless bee propolis is a challenge to chemists, entomologists and pharmacologists. It is essential to perform pharmacological studies with only chemically characterised propolis of stingless bees. Further studies are required to chemically characterise and scientifically support the medicinal properties of stingless bee propolis and to clarify the potential for its commercial use. This could lead to increased prices for Meliponinae propolis and provide an additional source of income for farmers in rural communities with most serious social needs.

Pollen Beads: A New Carrier for Propolis Active Compounds.

BACKGROUND: Pollen and propolis are two bee products with highly health promoting properties. But there are some limitations of raw propolis usage not only in daily consumption but also in putting it in food formulations. Propolis should be extracted to convert it into consumable form and ethanol is the first choice as a solvent. But ethanol consumption, either in health-wise or religious aspect, is one of the factors limiting the usage of propolis extract. The strong taste and strong smell of propolis are other factors. The immobilization of propolis active compounds could be a tool for overcoming either all or some of these factors. OBJECTIVE: This study was aimed at the immobilization of propolis active constituents on the surface of whole pollen grains. METHODS: Chemical composition of raw propolis was determined by using GC-MS technique. Total phenolic content and antioxidant activity of the samples were measured spectrophotometrically. The release property of the beads was determined. RESULTS: Immobilization efficiency was 53%. Total phenolic and flavonoid content of pollen, propolis and pollen-propolis beads were measured. It was determined that pollen-propolis beads contain more phenolics than pollen and propolis itself. Ferric reducing activity of the samples was also investigated and pollen-propolis beads showed better activity. Release behavior of pollen and pollen-propolis beads was studied in simulated digestive systems. Better release properties of pollen-propolis beads were achieved in all tested systems as well. These findings support the immobilization of propolis active compounds on the surface of whole pollen grains. CONCLUSION: It could be concluded that the product obtained, pollen-propolis beads, could be considered as a more valuable healthy product since the synergistic action of pollen and propolis.

Mangifera indica as propolis source: what exactly do bees collect?

OBJECTIVE: The mango tree Mangifera indica is known as one of the botanical sources of propolis in Tropical regions. There are two different materials which bees can collect from a mango tree to produce propolis: the resin of the tree bark, and the latex found on the fruits. We performed the study of the chemical profile of mango resin in comparison with propolis in order to clarify its importance as propolis source. RESULTS: We compared the chemical profiles (by GC-MS analysis of ethanol extracts after silylation) of the resin and samples of propolis: of stingless bees (3 Vietnames, 2 Indonesian), and one of Apis mellifera from Thailand. In the resin and all propolis samples, 25 compounds were identified: fatty acids, cardanols (alk(en)yl phenols), cardols, anacardic acids, triterpene alcohols and ketones, cycloartane type triterpenic acids. All samples have the same qualitative composition but there are important quantitative differences. Considering literature data on mango latex, we conclude that bees of different species, make use of the two propolis sources offered by mango: bark resin and fruit latex, in different proportions. We also confirmed for the first time the presence of alk(en)yl phenols and anacardic acids in the tree bark resin of mango.

A Preliminary Study of Chemical Profiles of Honey, Cerumen, and Propolis of the African Stingless Bee Meliponula ferruginea.

Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Meliponula ferruginea from Tanzania. The honey of M. ferruginea was profiled by NMR and indicated different long-term stability from Apis mellifera European (Bulgarian) honey. It differed significantly in sugar and organic acids content and had a very high amount of the disaccharide trehalulose, known for its bioactivities. We suggested trehalulose to be a potential marker for African stingless bee honey analogously to the recent proposal for Meliponini honey from Asia, South America, and Australia and demonstrated its easy discrimination by 13C NMR. Propolis and cerumen were studied by GC-MS (gas chromatography-mass spectometry). The samples contained mainly terpenoids (di-and triterpenes) but demonstrated qualitative and quantitative differences. This fact was an indication that possibly M. ferruginea has no strict preferences for resins used to construct and protect their nests. The antimicrobial and anti-quorum sensing properties of the two materials were also tested. These first results demonstrated that the honey, cerumen, and propolis of African stingless bees were rich in biologically active substances and deserved further research.

New dihydrochromene and xanthone derivatives from Lisotrigona furva propolis.

A new dihydrochromene derivative, named lisofurvin (1) and a xanthone, named dihydrobrasixanthone B (2) together with twenty one known compounds (3-23) were isolated from propolis of the stingless bee Lisotrigona furva. Their chemical structures were determined by means of spectroscopic methods including 1D and 2D NMR, and MS. The chemical constituents are predominantly geranyl(oxy) xanthones and Cratoxylum cochinchinense was suggested as a resin source, besides two other plants Mangifera indica and dammar trees (Dipterocarpaceae). Compound 1 showed significant cytotoxic activity against KB, HepG-2, and Lu-1 cancer cell lines with IC50 values range from 12.63 to 15.17 µg/mL. Several isolated compounds were active against one to four tested cancer cell lines. In addition, among the isolated compounds, α-mangostin (15) displayed the strongest antimicrobial activity against three Gram (+) strains, P. aeruginosa, and C. albicans with MIC values ranging between 1 and 2 µg/mL. Compound 22 showed good activity against three Gram (+) strains and C. albicans.

Preparation and Characterization of UV-Curable Acrylic Membranes Embedding Natural Antioxidants.

We examine the behaviour of acrylic resin-based membranes containing natural anti-oxidants, such as Galla Chinensis tea powder extract (TP) and Taiwanese green propolis (TGP), in different concentrations ranging between 5 and 20 wt %. Membrane morphology was investigated by means of Environmental Scanning Electron Microscopy (ESEM), while the UV-curing reaction was monitored by Fourier-Transform Infra-red (FTIR) spectroscopy. In most cases Thermogravimetric (TG), Differential Scanning Calorimetric (DSC) and Dynamo-mechanical Thermal (DMT) analyses showed that the desirable characteristics of the UV-cured acrylic resin are not substantially altered by the presence of the organic fillers. The release kinetics of polyphenols and flavonoids, determined in water for TP-containing membranes (ETx) and in ethanol/water mixture (7:3 v/v) for TGP-containing ones (EPx), was satisfactory, reaching a plateau after 24 h. Finally, preliminary antibacterial tests against S. Epidermidis were performed on the membranes with higher additive amount and gave positive results for ET-type; on the contrary, no inhibitory effect was observed for the tested EP-type membranes.

Extracts of medicinal plants with natural deep eutectic solvents: enhanced antimicrobial activity and low genotoxicity.

Natural deep eutectic solvents (NADES) are a new alternative to toxic organic solvents. Their constituents are primary metabolites, non-toxic, biocompatible and sustainable. In this study four selected NADES were applied for the extraction of two medicinal plants: Sideritis scardica, and Plantago major as an alternative to water-alcohol mixtures, and the antimicrobial and genotoxic potential of the extracts were studied. The extraction efficiency was evaluated by measuring the extracted total phenolics, and total flavonoids. Best extraction results for total phenolics for the studied plants were obtained with choline chloride-glucose 5:2 plus 30% water; but surprisingly these extracts were inactive against all tested microorganisms. Extracts with citric acid-1,2-propanediol 1:4 and choline chloride-glycerol 1:2 showed good activity against S. pyogenes, E. coli, S. aureus, and C. albicans. Low genotoxicity and cytotoxicity were observed for all four NADES and the extracts with antimicrobial activity. Our results confirm the potential of NADESs for extraction of bioactive constituents of medicinal plants and further suggest that NADES can improve the effects of bioactive extracts. Further studies are needed to clarify the influence of the studied NADES on the bioactivity of dissolved substances, and the possibility to use such extracts in the pharmaceutical and food industry.

New Δ-tocotrienol derivatives from Colombian propolis.

Two new δ-tocotrienol derivatives with oxidized terminal chain: 5,6-dioxo-garcinoic acid (trans-13'-carboxy-5,6-dioxo-δ-tocotrienol) (2) and 5-hydroxy-8b-oxo garcinoic acid (trans-13'-carboxy-5-hydroxy-8b-oxo-δ-tocotrienol) (3), together with one known derivative garcinoic acid (trans-13'-carboxy-δ-tocotrienol) (1) were isolated from a Colombian propolis. Garcinoic acid was found as a propolis constituent for the first time. The isolated compounds and crude ethanolic extract demonstrated high antimicrobial activity against Staphylococcus aureus and Candida albicans (MICs range: 10-39 µg/ml) as well as promising antioxidant potential in DPPH assay. Compound 3 displayed highest radical scavenging activity, even higher than that of dl-α-tocopherol, used as a positive control.

Phytochemical analysis of Vietnamese propolis produced by the stingless bee Lisotrigona cacciae.

Propolis produced by the stingless bee Lisotrigona cacciae was studied for the first time. Using different chromatographic procedures, a total of eighteen constituents (phenols and triterpenes) were isolated, among which flavane 1, homoisoflavanes 2-4, and xanthones 5 and 6 were new for propolis. Propolis extract was also characterized by gas chromatography/mass spectrometry and other fifteen constituents were identified. The xanthone α-mangostin (8) demonstrated significant activity against Staphylococcus aureus with MIC and MBC 0.31 µg/ml, followed by 7,4'-dihydroxy-5-methoxy-8-methylflavane (1) with MIC 78 µg/ml and MBC 156 µg/ml. 10,11- Dihydroxydracaenone C (4), a component bearing ortho-hydroxyl groups, was the only compound displaying radical scavenging ability. Triple botanical origin of the sample was defined, consisting of Dracaena cochinchinensis, Cratoxylum cochinchinense and Mangifera indica. D. cochinchinensis is a new resin source of propolis.

The phytochemistry of the honeybee.

Honeybees rely on plants for everything they need to keep the colony running; plant nectar and pollen are their only carbohydrate and protein food sources. By foraging to satisfy their basic nutritional demand, honeybees inevitably gather specialized plant metabolites as part of the nectar and pollen. In general, these compounds possess biological activity which may become relevant in fighting pests and pathogens in the hive. The third plant derived bee product, besides honey and bee pollen, is propolis (bee glue), which comes from plant resins. It is not a food; it is used as a building material and a defensive substance. Thus, the beehive is rich in specialized plant metabolites, produced by many different plant species and the expression "Phytochemistry of honeybees" is not inappropriate. However, it is virtually impossible to perform a detailed overview of the phytochemical features of honey and pollen in a review article of this nature, for reasons of space. The present review deals with propolis, because it is the bee product with highest concentration of specialized plant metabolites and has valuable pharmacological activities. The most recent developments concerning plant sources of propolis, bees' preferences to particular plants, the application of metabolomic approaches and chemometrics to propolis research and the problems concerning standardization of propolis are summarized. The overview covers the literature published in the last decade, after 2007.

New cycloartane triterpenes from bioactive extract of propolis from Pitcairn Island.

Dichloromethane extract of propolis (DCME) originating from Pitcairn Island demonstrated potent cytotoxicity against triple-negative MDA-MB-231 human breast carcinoma cells. The results from MTT assay showed that DCME inhibits the growth of the cancer cells in a dose- and time-dependent manner and upon the cell growth inhibition propolis extract provoked apoptotic changes in the cell nuclei. A detailed chemical investigation of DCME led to the isolation of four new cycloartane triterpenes (1-4), along with 17 known compounds (5-21). The structures of the new compounds were elucidated by means of extensive analysis of their spectroscopic data and comparison with those reported for their analogues. In vitro antimicrobial activity of new compounds (1-4) along with the DCME against four human pathogens was evaluated. All tested constituents except compound 2 were highly active against Escherichia coli with MIC 64 µg/ml. Compound 1 exhibited high antifungal activity against Candida albicans with potency close to that of the positive control (amphotericin B). The DCME showed very good antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans. This is the first study on propolis from Pitcairn Island.