Behind the Therapeutic Effects of Royal Jelly: Recent Advances in the Specific Properties of 10-Hydroxydecanoic Acid

Abstract

Since ancient times, Royal Jelly (RJ) has been known for its remarkable properties in traditional medicine, and it is still widely recommended for mental and physical well-being. RJ consists of a unique and complex mixture of multiple constituents in different concentrations, and some of its biological activities are directly associated with specific components not found elsewhere in nature, such as (E)-10-hydroxy-2-decenoic acid (10-HDA) and its precursor 10-hydroxydecanoic acid (10-HDAA), two medium-chain fatty acids. Together, 10-HAD and 10-HDAA represent the major constituents of the total lipid fraction in RJ, but despite their structural similarity, the former has been extensively investigated over the years, while the latter has been only marginally reported. This review focuses on the promising effects of 10-HDAA that have emerged in a series of recent in vitro, in vivo, and docking simulation studies. Important bioactivities were observed for 10-HDAA, tested both as an individual compound, especially for immunoregulatory, estrogenic, and anti-inflammatory activities, and in synergic combination with other molecules. Specific anti-infective effects against endemic diseases, as well as the structural modification to synthesize biocompatible and biodegradable 10-HDAA-based amphiphiles, are also reported.

Keywords: 10-hydroxydecanoic acid; Royal Jelly; anti-infective activity; bioactive compound; docking simulation; dry eye treatment; hydrogel; medium-chain fatty acid; wound healing.

Figure 1

A comparison of the composition of fresh and dry Royal Jelly. The average percentages of the major constituents are shown. Data are from [5].

Figure 2

Chemical structures of (E)-10-hydroxy-2-decenoic acid (10-HDA) and 10-hydroxydecanoic acid (10-HDAA).

Figure 3

The number of documents obtained for the period 2014–2024 when searching the database Scopus for Royal Jelly, 10-hydroxy-2-decenoic acid, and 10-hydroxydecanoic acid.

Figure 4

IgA response on day 12 against fetuin, poliovirus, and influenza virus with and without 10-HDAA. The % O.D. values are reported as the mean data from three macaques in the investigated conditions. Data are from [36].

Figure 5

Comparison of IL-6, TNF-α, and MCP-1 levels in BV-2 cells after LPS-induced inflammation and 10-HDAA pretreatment at different concentrations. Data are from [40].

Figure 6

Chemical structures and gelation times of 10-HDAA-ILK-NH₂ and 10-HDAA-ILD-NH₂. The moieties of the single constituents are depicted in different colors as follows: black for 10-HDAA; red for isoleucine; blue for leucine; green for lysine; and pink for aspartic acid. Data are from [59].

Figure 7

Percentage contents of the investigated components in ETRJ: 9,10-D2DA (9,10-dihydroxy-2-decenoic acid); 11,12-D2DA (11,12-dihydroxy-2-dodecenoic acid); ACh (Acetylcholine); 12-HAD (12-hydroxydodecanoic acid); SA (sebacic acid); 3,10-DDA (3,10-dydroxydecanoic acid); 8-HOA (8-hydroxyoctanoic acid); 2-DA (2-decenedioic acid); 10-HDAA (10-hydroxydecanoic acid); and 10-HDA (10-hydroxy-2-decenoic acid). Data are from [68].