Antimicrobial activity by Trigona laeviceps (stingless bee) honey from Thailand

ABSTRACT Objective: To determine the key properties of Trigona laeviceps honey from Thailand, including its antimicrobial activity. Methodology: Proline content and the percentage of invert sugar were evaluated as described. Major protein bands were resolved and analyzed by SDS PAGE and MALDI TOF analyses. Antimicrobial activity was assayed by agar well diffusion. Results: The honey was acidic (pH 3.37) but probably undoctored (proline content of 1,723mg/ kg) with a normal sugar content (e.g. invert sugar 15.2% (w/w)) but a higher than expected total protein content (0.28g/100g). From some ten distinct protein bands, six major protein bands were revealed of which the 29 kDa band was likely to be pollen allergen Lol p VA precursor Lolium perenne (Perennial ryegrass). Neat honey is the most effective for use as a contact antimicrobial agent, and Staphylococcus aureus was the most susceptible tested pathogen to honey at all dilutions. Conclusion: The studied honey could perhaps be used as an antimicrobial agent. Since pollen allergen protein was found, it may cause honey intoxication

Characterization of some enzymatic properties of recombinant α-glucosidase III from the Thai honeybee, Apis cerana indica Fabricus

Recombinant α-glucosidase III (rHBGase III) from Apis cerana indica Fabricus (rAciHBGase III) was expressed in the yeast Pichia pastoris GS115, enriched and characterized. The full length cDNA of AciHbgase III (ƒî1.8 kb) was amplified by RT-PCR, cloned into the pPICZαA expression vector and used to transform P. pastoris GS115. The maximum secreted expression level of rAciHBGase III [as an N terminal (His)6 tagged chimera] was found 144 h after induction by 1% (v/v) methanol. Enrichment of the enzyme using histrap affinity purification revealed a single active glucosidase band with a molecular mass of ~68 kDa. The optimal pH and temperature for glucosidase activity of the enriched rAciHBGase III were pH 5.0 and 37¢XC, respectively, whilst the enzyme showed a good pH stability between pH 5.0 to 7.5, but not below pH 5.0, and a poor thermotolerance with < 10% and 0% residual activity at 40 and >50¢XC, respectively. The rAciHBGase showed a relatively high substrate specificity for maltose (Km of 4.5 mM) and p-nitrophenyl α-D-glucoside (Km of 4.4 mM) compared to other reported HBGase enzymes.Key words: α-Glucosidase, Apis cerana indica, expression, kinetics, recombinant enzyme

In vitro antiproliferative activity of partially purified Trigona laeviceps propolis from Thailand on human cancer cell lines

<p>Abstract</p> <p>Background</p> <p>Cancers are some of the leading causes of human deaths worldwide and their relative importance continues to increase. Since an increasing proportion of cancer patients are acquiring resistance to traditional chemotherapeutic agents, it is necessary to search for new compounds that provide suitable specific antiproliferative affects that can be developed as anticancer agents. Propolis from the stingless bee, <it>Trigona laeviceps</it>, is one potential interesting source that is widely available and cultivatable (as bee hives) in Thailand.</p> <p>Methods</p> <p>Propolis (90 g) was initially extracted by 95% (v/v) ethanol and then solvent partitioned by sequential extractions of the crude ethanolic extract with 40% (v/v) MeOH, CH₂Cl₂and hexane. After solvent removal by evaporation, each extract was solvated in DMSO and assayed for antiproliferative activity against five cancer (Chago, KATO-III, SW620, BT474 and Hep-G2) and two normal (HS27 fibroblast and CH-liver) cell lines using the MTT assay. The cell viability (%) and IC₅₀values were calculated.</p> <p>Results</p> <p>The hexane extract provided the highest <it>in vitro </it>antiproliferative activity against the five tested cancer cell lines and the lowest cytotoxicity against the two normal cell lines. Further fractionation of the hexane fraction by quick column chromatography using eight solvents of increasing polarity for elution revealed the two fractions eluted with 30% and 100% (v/v) CH₂Cl₂in hexane (30DCM and 100DCM, respectively) had a higher anti-proliferative activity. Further fractionation by size exclusion chromatography lead to four fractions for each of 30DCM and 100DCM, with the highest antiproliferative activity on cancer but not normal cell lines being observed in fraction# 3 of 30DCM (IC₅₀value of 4.09 - 14.7 μg/ml).</p> <p>Conclusions</p> <p><it>T. laeviceps </it>propolis was found to contain compound(s) with antiproliferative activity <it>in vitro </it>on cancer but not normal cell lines in tissue culture. The more enriched propolis fractions typically revealed a higher antiproliferative activity (lower IC₅₀value). Overall, propolis from Thailand may have the potential to serve as a template for future anticancer-drug development.</p

In vitro antiproliferative/cytotoxic activity on cancer cell lines of a cardanol and a cardol enriched from Thai Apis mellifera propolis

<p>Abstract</p> <p>Background</p> <p>Propolis is a complex resinous honeybee product. It is reported to display diverse bioactivities, such as antimicrobial, anti-inflammatory and anti-tumor properties, which are mainly due to phenolic compounds, and especially flavonoids. The diversity of bioactive compounds depends on the geography and climate, since these factors affect the floral diversity. Here, <it>Apis mellifera </it>propolis from Nan province, Thailand, was evaluated for potential anti-cancer activity.</p> <p>Methods</p> <p>Propolis was sequentially extracted with methanol, dichloromethane and hexane and the cytotoxic activity of each crude extract was assayed for antiproliferative/cytotoxic activity <it>in vitro </it>against five human cell lines derived from duet carcinoma (BT474), undifferentiated lung (Chaco), liver hepatoblastoma (Hep-G₂), gastric carcinoma (KATO-III) and colon adenocarcinoma (SW620) cancers. The human foreskin fibroblast cell line (Hs27) was used as a non-transformed control. Those crude extracts that displayed antiproliferative/cytotoxic activity were then further fractionated by column chromatography using TLC-pattern and MTT-cytotoxicity bioassay guided selection of the fractions. The chemical structure of each enriched bioactive compound was analyzed by nuclear magnetic resonance and mass spectroscopy.</p> <p>Results</p> <p>The crude hexane and dichloromethane extracts of propolis displayed antiproliferative/cytotoxic activities with IC₅₀values across the five cancer cell lines ranging from 41.3 to 52.4 μg/ml and from 43.8 to 53.5 μg/ml, respectively. Two main bioactive components were isolated, one cardanol and one cardol, with broadly similar <it>in vitro </it>antiproliferation/cytotoxicity IC₅₀values across the five cancer cell lines and the control Hs27 cell line, ranging from 10.8 to 29.3 μg/ml for the cardanol and < 3.13 to 5.97 μg/ml (6.82 - 13.0 μM) for the cardol. Moreover, both compounds induced cytotoxicity and cell death without DNA fragmentation in the cancer cells, but only an antiproliferation response in the control Hs27 cells However, these two compounds did not account for the net antiproliferation/cytotoxic activity of the crude extracts suggesting the existence of other potent compounds or synergistic interactions in the propolis extracts_.</p> <p>Conclusion</p> <p>This is the first report that Thai <it>A. mellifera </it>propolis contains at least two potentially new compounds (a cardanol and a cardol) with potential anti-cancer bioactivity. Both could be alternative antiproliferative agents for future development as anti-cancer drugs.</p

Pathogen detection and gut bacteria identification in Apis cerana indica in Thailand

Pathogen infection of honeybees can lead to economic losses in apiculture. The earlier the pathogen contamination can be found the better it will likely be for the treatment of the infected colony and prevention of the spread of the pathogen within and between colonies. A total of 50 colonies of Apis cerana were sampled in Samut Songkhram (five colonies) and Chumphon (45 colonies) provinces in the central and the south of Thailand, respectively. Diagnostic multiplex polymerase chain reaction (PCR) revealed that 20, 6, 4, 20 and 0% of the samples were infected by Paenibacillus larvae, Nosema ceranae, Nosema apis, Ascosphaera apis and Sacbrood virus (Morator aetatulus), respectively. Positive amplified PCR products of target genes were sequenced. A phylogenetic tree was constructed by the neighbor-joining (NJ) distance based, using the Phylogenetic Analysis Using Parsimony (PAUP 4.0b10) program. The phylogenetic relationship of each pathogen, based on the partial sequence of the 16S rRNA of P. larvae, N. ceranae and N. apis, and of the 5.8S rRNA of A. apis, revealed a significant difference from the non-Thai isolates of these pathogens, but no significant geographical isolation between the different Thai apiaries, although it separated some into closely related clusters. In order to reduce the use of antibiotics in an apiary, bacteria in the gut of healthy bees were focused. Interestingly, Bifidobacterium species, Lactobacillus species, Bacillus species, Lactobacillus spp. and other lactic acid bacteria, were isolated from larvae and adult workers, but gave conflicting preliminary identities based on their biochemistry-morphology versus sequence analysis of a partial fragment (1.4 kb) of their 16S rRNA.Keywords: Apis cerana indica, bee pathogens, gut bacteria, multiplex polymerase chain reaction (PCR), 16S rRN

Review of the anticancer activities of bee products

Bee products have long been used in traditional medicine. The raw materials, crude extracts and purified active compounds from them have been found to exhibit interesting bioactivities, such as antimicrobial, anti-inflammatory and antioxidant activities. In addition, they have been widely used in the treatment of many immune-related diseases, as well as in recent times in the treatment of tumors. Bee product peptides induce apoptotic cell death in vitro in several transformed (cancer) human cell lines, including those derived from renal, lung, liver, prostate, bladder and lymphoid cancers. These bioactive natural products may, therefore, prove to be useful as part of a novel targeted therapy for some types of cancer, such as prostate and breast cancer. This review summarizes the current knowledge regarding the in vivo and in vitro potential of selective bee products against tumor cells