Used for centuries by humans for its health-promoting qualities, royal jelly is a yellowish, viscous secretion from the hypopharyngeal and mandibular glands of worker bees that nourishes bee larvae of all kinds (i.e., drones, workers, queens) after which it becomes the exclusive nourishment for queens throughout their development.1-3 A wide range of biologic activity has been attributed to royal jelly, including antitumor, antibacterial, anti-inflammatory, antioxidant, collagen production-promoting, immunomodulatory, and wound healing.3-8 Royal jelly is used in cosmetics, health tonics (particularly in Asia), dietary supplements, and beverages.2,9
Produced from pollen, royal jelly contains water, proteins (82%-90% of which are known as the major royal jelly proteins, with five primary members), lipids – including its primary unsaturated fatty acid, 10-hydroxy-2-decenoic acid (10-HDA) – sugars, carbohydrates, free amino acids, vitamins, and minerals.4,7,10 Many of the benefits to human health linked to royal jelly can be partly attributed to the activity of its lipids, particularly 10-HDA, which render the royal jelly emulsion highly acidic and impart antimicrobial properties.10 These and other constituents of royal jelly operate in ways that are thought to yield broad protection against skin aging and cancer development, modulation of the immune system, induction of neurogenesis, and alleviation of menopausal symptoms.1 This column will focus on recent studies pertaining to the topical use of royal jelly.
Dr. Leslie S. Baumann
Wound healing
In 2008, Abdelatif et al. conducted a pilot study to determine the safety and effectiveness of a then-new ointment combining royal jelly and panthenol (Pedyphar) in 60 patients with limb-threatening diabetic foot infections. After 9 weeks of treatment and through 6 months of follow-up, 96% of subjects with full-thickness skin ulcers (Wagner grades 1 and 2) or deep tissue infection and suspected osteomyelitis (grade 3) responded well, with all grade 1 and 2 ulcers healing and 92% of grade 3 ulcers healing. All patients with gangrenous lesions (grades 4 and 5) healed after surgical excision, debridement, and conservative treatment with the royal jelly/panthenol product. The researchers called for more double-blind, randomized controlled studies to confirm their promising findings of the safety and efficacy of the royal jelly/panthenol combination.11
Two years later, Kim et al. treated freshly scratched normal human dermal fibroblasts with different concentrations of royal jelly (0.1 mg/mL, 1.0 mg/mL, or 5 mg/mL) for up to 48 hours. Fibroblast migration was found to have peaked at 24 hours after wound induction, with royal jelly significantly and dose-dependently accelerating the migration at the 8-hour mark. Royal jelly also influenced several fibroblast lipids involved in the wound healing process, with a decrease in cholesterol level and an increase in sphinganines.12
A small study with eight subjects was done in 2011 by Siavash et al. to evaluate the efficacy of topically applied royal jelly for diabetic foot ulcers. Seven of the eight ulcers treated healed, with a mean healing time of 41 days. The eighth ulcer improved, diminishing significantly in size. The researchers concluded that a royal jelly dressing is an effective alternative for treatment of diabetic foot ulcers.13 However, the same team conducted a double-blind, placebo-controlled clinical trial of topical royal jelly on diabetic foot ulcers in 25 patients (6 females, 19 males) and found no significant differences between 5% sterile topical royal jelly or placebo.6
Collagen production
shootthebreeze/thinkstockphotos.com
Queen bee among worker bees on honeycomb frame
A decade ago, Koya-Miyata et al. showed that royal jelly promotes collagen synthesis by skin fibroblasts in the presence of ascorbic acid-2-O-alpha-glucoside. They also showed that its primary fatty acid constituent, 10-HDA, facilitates the collagen production by fibroblasts treated with ascorbic acid-2-O-alpha-glucoside through activation of transforming growth factor-beta 1 production.5
Photoprotection
Park et al. measured the 10-HDA content of royal jelly in 2011 and studied its effects on UVB-induced skin photoaging in normal human dermal fibroblasts. The introduction of royal jelly (0.211% 10-HDA) promoted the production of procollagen type I and transforming growth factor (TGF)-beta-1 without affecting matrix metalloproteinase (MMP)-1 levels. The investigators concluded that the impact of royal jelly on collagen production positioned the bee product as a potential photoprotectant against UVB-induced photoaging.14 The next year, Park et al. observed that the production of type I collagen in the dorsal skin of ovariectomized Sprague-Dawley rats was enhanced by the dietary supplementation of 1% royal jelly extract. Although MMP-1 levels were unaffected, the investigators speculated that the effects on collagen synthesis alone were sufficient for royal jelly to provide anti-aging activity.4
In 2013, Zheng et al. found that 10-HDA significantly protected fibroblasts from UVA-induced cytotoxicity, reactive oxygen species, and cellular senescence. They also noted that 10-HDA inhibited the UVA-generated expression of MMP-1 and -3, and stimulated collagen production. Treatment with 10-HDA also reduced the activation of the c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways. The researchers concluded that this royal jelly fatty acid appears to be a promising agent for the prevention and treatment of cutaneous photoaging.8