Salidroside and Royal jelly

Salidroside (salidroside) is a tyrosyl glycoside found in the plant Rhodiola rosea.It has been studied along with rosavin as one of the potential compounds responsible for the plant's putative antidepressant and anxiolytic effects.Salidroside may be more active than rosavin although many commercially sold rhodiola extracts are standardized for rosavin content rather than salidroside.

Biological activity

Salidroside was shown to improve glucose homeostasis and alleviate diabetic retinopathy in obese mice.The antioxidant, anti-inflammatory and neuroprotective effects of salidroside have also been reported.

Biosynthesis 

The biosynthetic pathway of salidroside in Rhodiola rosea was described in 2018.Rhodiola contains a pyridoxal phosphate-dependent 4-hydroxyphenylacetaldehyde (4-HPAA) synthase that converts tyrosine to 4-HPAA, which is further reduced by 4-HPAA reductase For tyrosol. Rhodiola contains regioselective tyrosol:UDP-glucose 8-O-glucosyltransferase, which can glycosylate tyrosol to produce salidroside.

Royal jelly

Royal jelly is a bee secretion used to provide nourishment to larvae and adult queen bees.It is secreted by glands in the hypopharynx of nurse bees and feeds all larvae in the colony, regardless of sex or caste.In the process of creating a new queen, worker ants build special queen cells.The larvae in these cells feed on large amounts of royal jelly.This type of feeding triggers the development of queen bee morphology, including fully developed ovaries needed for egg laying.Royal jelly is sometimes used in alternative medicine under the apitherapy category.It is often sold as a dietary supplement for humans, but the European Food Safety Authority has concluded that the current evidence does not support claims that consuming royal jelly has any health benefits in humans.In the United States, the Food and Drug Administration has taken legal action against companies that market royal jelly products with unfounded health benefit claims.

Epigenetic effects

Honeybee queens and workers represent one of the most striking examples of environmental control of phenotypic polymorphism. Even when two larvae have the same DNA and one is raised as a worker ant and the other as a queen, the two adults can differ considerably in a wide range of characteristics, including differences in anatomy and physiology, lifespan and reproductive capacity.Queen bees constitute the female sexual caste and possess a large number of active ovaries, while female worker bees have only rudimentary, inactive ovaries and are functionally sterile.The developmental divide between queen and worker bees is epigenetically controlled by differential feeding of royal jelly; this appears to be due to the protein royalactin.Female larvae destined to become queens are fed copious amounts of royal jelly; this triggers a chain of molecular events that leads to the development of a queen have shown that this phenomenon is mediated by an epigenetic modification of DNA known as CpG methylation.Silencing the expression of an enzyme that methylates DNA in newly hatched larvae had royal jelly-like effects on larval developmental trajectories; most individuals with reduced levels of DNA methylation became queens with fully developed ovaries.This finding suggests that DNA methylation in honeybees allows the expression of epigenetic information to be differentially altered in response to nutrient input.