In vitro activity of some natural honeys against Entamoeba histolytica and Giardia lamblia trophozoites.

Considering the potentiality of honey in combating diseases, the present study was carried out aiming to assess the in vitro antiprotozoal activity of several honeys (Ziziphus spina-christi, Acacia nilotica, Acacia seyal, and Cucurbita maxima) against Entamoeba histolytica and Giardia lamblia by employing the sub-culture method. All the tested honeys inhibited the growth of trophozoites, and the level of inhibition varied according to the assayed concentrations and incubation times. Acacia seyal honey had completely stopped motility of E. histolytica trophozoites at a concentration ≤ 50 µg/ml after incubation for 72 h. Ziziphus spina-christi, Acacia seyal, and Acacia nilotica honeys had completely inhibited the growth of Giardia lamblia trophozoites at concentration ≤ 200 µg/ml after 72 h. These inhibitory activities were similar to that of Metronidazole™ which showed IC50  = 0.27. The mammalian cytotoxicity of these honeys against normal Vero cell line which determined by applying MTT method verified the nontoxicity of the examined honeys. Also the proximate composition of the samples indicated compliance with the natural honey standards. The findings of the study indicate the need for in vivo studies and further investigations to identify active principles with antiprotozoal activities from natural honeys.

Comparison of physicochemical properties and effects of heating regimes on stored Apis mellifera and Apis florea honey.

Many of the components, which render honey its specific aroma, flavor, and biological activity, are unstable over time and thermolabile. This study was aimed to compare the chemical composition, effect of heating as well as the time of heat exposure, and storage period on the quality of honey samples from Apis mellifera (A.m.) and Apis florea (A.f.). Methods of the Association of the Official Analytical Chemists (AOAC) were used in this study. The mean values for both A.m. and A.f. honeys were, respectively: moisture (18.5, 13.7%); glucose (35.2, 36.3%); fructose (33.7, 33.8%); sucrose (7.3, 2.9%); invert sugar (68.9, 70.4%); ash (0.26, 1.1%); acidity (51.8, 98.4 meq/kg); pH (3.6, 4.4) and Hydroxy methyl furfural (HMF) (3.78, 3.17 mg/100 g). Honey from A. florea contained less moisture, have higher acidity and ash contents than A. mellifera honey. Significant alterations (P < 0.05) in glucose, fructose, sucrose, and acidity were noticed after six months. Honeys exposed to heating for 15 and 30 min at 50 and 80 °C have shown increased thermo-generated HMF after 15, 30, and 45 days. HMF reached 16.30 ± 1.1 in A. mellifera and 7.41 ± 1.4 mg/100 g in A. florea honeys that exposed for 30 min at 80 °C. Honey from A. florea showed more heat tolerance to thermo-generation of HMF than honey from A. mellifera.

Nectar secretion dynamics and honey production potentials of some major honey plants in Saudi Arabia.

The contribution of a bee plant species to honey production depends on the plant's nectar secretion quality and quantity, which is mainly governed by biotic and abiotic factors. The aim of the current study, was to investigate the nectar secretion dynamics and honey production potential of 14 major bee plant species of the target area. We examined the quantity and dynamics of nectar sugar per flower five times a day using a nectar sugar washing technique and direct measuring of nectar with calibrated capillary tubes. The average nectar sugar amount of the species varied from 0.41 mg/flower to 7.7 mg/flower (P < 0.0001). The honey sugar per flower was used to extrapolate the honey production potential per plant and per hectare of land. Accordingly the honey production potential of the species observed to vary from 14 kg/hectare in Otostegia fruticosa to 829 kg/hectare in Ziziphus spina-christi. The nectar secretion dynamics of the species generally showed an increasing trend early in the morning, peaking toward midday, followed by a decline but different species observed to have different peak nectar secretion times. Generally, the tree species secreted more nectar sugar/flower than the herbs. The nectar secretion amount of the species was positively correlated with the ambient temperature, indicating the adaptation of the species to hot climatic conditions. However, different species were observed to have a different optimum temperature for peak nectar secretion. Despite the limited rainfall and high temperature of the area, many plants were found to have good potential for honey production. The monetary value of honey per hectare of the studied honeybee plant species can be of equal or greater than the per-hectare monetary value of some cultivated crops that require numerous inputs. In addition, the information generated is believed to be useful in apiary site selection and to estimate the honey bee colony carrying capacity of an area.

Antigiardial activity of glycoproteins and glycopeptides from Ziziphus honey.

Natural honey contains an array of glycoproteins, proteoglycans and glycopeptides. Size-exclusion chromatography fractionated Ziziphus honey proteins into five peaks with molecular masses in the range from 10 to >200 kDa. The fractionated proteins exhibited in vitro activities against Giardia lamblia with IC50 values ≤ 25 µg/mL. Results indicated that honey proteins were more active as antiprotozoal agents than metronidazole. This study indicated the potential of honey proteins and peptides as novel antigiardial agents.