# The Possibility of Using Bee Drone Brood to Design Novel Dietary Supplements for Apitherapy
## 1 Introduction  
Bee drone brood is a rarely used bee product, which is characterized by a rich chemical composition, which makes it biologically active. It contains approximately 40% protein, 30% reducing sugars, but also hormones, mainly sex hormones: testosterone (0.29-0.31 nmol/100 g), estradiol (431.2-847.90 nmol/100 g), progesterone (42.6-51.3 nmol/100 g), and prolactin (344.6-475.4 nmol/100 g) [1]. Additionally, it is also a good source of vitamins and bioelements, mainly phosphorus, potassium, calcium, iron, and zinc. Freeze-dried drone brood (named Apilarml or Apitstimul) is available for sale mainly in Eastern European countries as a dietary supplement or one of its ingredients. Thanks to preservation by freeze-drying, it can be stored for up to two years [2]. The rich chemical composition and confirmed biological activity of drone brood could indicate its potential use to equalize the hormonal system in people of both sexes [3]. Due to this, drone brood is applied in the treatment and prevention of various diseases, including osteoporosis and male infertility, hypothyroidism, liver diseases, psychiatry, adaptogenic therapies, as well as in malnutrition in the treatment of children [4; 5; 6; 7; 8; 9]. However, there is a lack of scientific data confirming the effectiveness of drone brood in vivo, and the in vitro bioaccessibility of its components is unknown. Osteoporosis is a global problem that affects people of both sexes, more often women than men, and the incidence of its occurrence clearly increases in people over 60 years of age [10; 11]. Sex hormone deficiency has adverse effects on bone growth and modeling,ultimately reducing peak bone mass and setting the stage for osteoporosis in later life. This disorder is characterized by the thinning of bone tissue, which results in low bone mass and a disturbed bone structure, increasing the likelihood of bone fractures [12; 13]. A properly balanced diet plays a very important role in the prevention of osteoporosis and can reduce age-related bone loss and fracture risk. The crucial issue is proper calcium (1000-1200 mg/day) and vitamin D (800-1200 IU/day) supplementation [13; 14]. However, a greater benefit is achieved when calcium is introduced into the diet in small proportions, avoiding oscillator spikes that could lead to cardiovascular complications [15]. Recently, plant-derived phytoestrogens with estrogenic effects (e.g., genistein, daidzein, icarini, dioscin, and _Ginkgo biloba_ extracts) were also proposed as agents for prophylactics of steroid-induced osteoporosis, which could provide a safer alternative to primary pharmacological strategies [16; 17; 18]. Recently, shells of chicken eggs have been proposed as a natural source of calcium in the prevention and treatment of osteoporosis [19; 20; 21]. This natural product, which is bakery waste, is an interesting alternative to the currently used inorganic forms of calcium. Moreover, eggshells are an inexpensive calcium source and are accessible at home. Chicken eggshells contain about 95% calcium carbonate and 3.5% of glycoproteins and proteoglycans; therefore, they could be a valuable natural source of calcium with a higher solubility compared to the oyster shells that are currently used [22]. Additionally, the inner membrane of the eggshell contains glucosamine, chondro sulphate, hyaluronic acid, type I collagen, and a large number of microelements such as magnesium, strontium, zinc, barium, and fluorine, making them an excellent biomaterial for the production of new dietary supplements that positively affect bone metabolism [22; 23; 24; 25]. Furthermore, a better calcium absorption from eggshells was found than from calcium carbonate, due to its porous structure which facilitates digestion [26; 27]. The aim of this study was to combine beneficial compounds of drone brood (hormones, proteins, antioxidants, and bioelements) and hen eggshells to design a new natural dietary supplement with enhanced bioaccessibility tested in vitro.