The pollen of oil palm (Elaeis guineensis Jacq.) is a strong allergen and causes severe pollinosis in Malaysia and Singapore. In the previous study (Biosci. Biotechnol. Biochem., 64, 820-827 (2002)), from the oil palm pollens, we purified an antigenic glycoprotein (Ela g Bd 31 K), which is recognized by IgE from palm pollinosis patients. In this report, we describe the structural analysis of sugar chains linked to palm pollen glycoproteins to confirm the ubiquitous occurrence of antigenic N-glycans in the allergenic pollen. N-Glycans liberated from the pollen glycoprotein mixture by hydrazinolysis were labeled with 2-aminopyridine followed by purification with a combination of size-fractionation HPLC and reversed-phase HPLC. The structures of the PA-sugar chains were analyzed by a combination of two-dimensional sugar chain mapping, electrospray ionization mass spectrometry (ESI-MS), and tandem MS analysis, as well as exoglycosidase digestions. The antigenic N-glycan bearing alpha1-3 fucose and/or beta1-2 xylose residues accounts for 36.9% of total N-glycans: GlcNAc2Man3Xyl1Fuc1GlcNAc2 (24.6%), GlcNAc2Man3Xyl1GlcNAc2 (4.4%), Man3Xyl1Fuc1-GlcNAc2 (1.1%), GlcNAc1Man3Xyl1Fuc1GlcNAc2 (5.6%), and GlcNAc1Man3Xyl1GlcNAc2 (1.2%). The remaining 63.1% of the total N-glycans belong to the high-mannose type structure: Man9GlcNAc2 (5.8%), Man8GlcNAc2 (32.1%), Man7GlcNAc2 (19.9%), Man6GlcNAc2 (5.3%).
Stingless bee-collected pollen (bee bread) is a mixture of bee pollen, bee salivary enzymes, and regurgitated honey, fermented by indigenous microbes during storage in the cerumen pot. Current literature data for bee bread is overshadowed by bee pollen, particularly of honeybee Apis. In regions such as South America, Australia, and Southeast Asia, information on stingless bee bee bread is mainly sought to promote the meliponiculture industry for socioeconomic development. This review aims to highlight the physicochemical properties and health benefits of bee bread from the stingless bee. In addition, it describes the current progress on identification of beneficial microbes associated with bee bread and its relation to the bee gut. This review provides the basis for promoting research on stingless bee bee bread, its nutrients, and microbes for application in the food and pharmaceutical industries.
A basic glycoprotein, which was recognized by IgE from oil palm pollinosis patients, has been purified from oil palm pollen (Elaeis guineensis Jacq.), which is a strong allergen and causes severe pollinosis in Malaysia and Singapore. Soluble proteins were extracted from defatted palm pollen with both Tris-HCl buffer (pH 7.8) and Na-acetate buffer (pH 4.0). The allergenic glycoprotein was purified from the total extract to homogeneity with 0.4% yield by a combination of DEAE- and CM-cellulose, SP-HPLC, and gel filtration. The purified oil palm pollen glycoprotein with molecular mass of 31 kDa was recognized by the beta1-2 xylose specific antibody, suggesting this basic glycoprotein bears plant complex type N-glycan(s). The palm pollen basic glycoprotein, designated Ela g Bd 31 K, was recognized by IgE of palm pollinosis patients, suggesting Ela g Bd 31 K should be one of the palm pollen allergens. The preliminary structural analysis of N-glycans linked to glycoproteins of palm pollens showed that the antigenic N-glycans having alpha1-3 fucose and alpha1-2 xylose residues (GlcNAc(2 to approximately 0)Man3Xyl1Fuc(1 to approximately 0)GlcNAc2) actually occur on the palm pollen glycoproteins, in addition to the high-mannose type structures (Man(9 to approximately 5)GlcNAc2).
Currently, bee-gathered pollen (bee pollen) is commonly used worldwide as a dietary supplement and is recognized for its curative properties. Floral pollen is also important but is less recognized due to a lack of investigation. This study aims to determine the morphological characteristics and nutritional and phytochemical properties of floral maize pollen. Fresh pollen grains harvested from a farm of maize plants are yellow in colour and spheroid in shape. They change to amber and indented prismatic solid shapes when dehydrated. The main composition of floral maize pollen is carbohydrates (44.30±3.73%), followed by moisture (23.38±5.73%), crude proteins (17.16±3.13%), crude fibres (9.56±0.92%), and ash (4.98±0.11%), while the lowest content is observed for crude fats (0.62±0.06%). The predominant mineral is potassium (768.50±11.40 mg 100 g-1), followed by sodium (695.10±9.70 mg 100 g-1), calcium (147.20±12.60 mg 100 g-1), and magnesium (97.30±2.9 mg 100 g-1). The microelements (with average values) consist of iron (49.50±3.30 mg 100 g-1) and zinc (30.00±3.70 mg 100 g-1). Excellent phytochemical properties add value to floral maize pollen. Maize pollen contains a high total phenolic content (TPC) and total flavonoid content (TFC) of 783.02 mg GAE 100 g-1 and 1706.83 mg QE 100 g-1, respectively, and possesses strong antioxidant activity of 10.54 mg mL-1. Maize floral pollen and derived products can serve as future food resources for human consumption and as a source of functional and bioactive compounds in nutraceutical and pharmaceutical industries.