Over the last 10 years, the maggot has gained a reputation as the 'miraculous medicinal maggot', thanks to its purported anti-inflammatory, anti-microbial, anti-biofilm and wound-healing properties.
In fact, it is the larvae of Lucilia sericata, part of the Calliphoridae family within the order Diptera, which is often used in TCM.
Maggots have long been used to clean wounds by degrading, liquefying and ingesting only devitalised or necrotic tissues — a form of biotherapy dubbed maggot debridement therapy.
There is plenty of clinical evidence of maggots as effective debridement agents, but the science behind the maggot's biochemical and physical actions has been largely overlooked.
As such, researchers at China's Dalian Medical University conducted a review of the latest scientific studies on the maggot, especially with regards to active ingredients found in maggot excretions and secretions.
They reported that maggots could be used for more precise clinical applications at lower cost and with fewer adverse effects than certain conventional therapeutic methods.
Maggots were found to display anti-bacterial properties, and recent studies showed that lucifensin, a defensin peptide from the maggot's excretions and secretions (ES) and body tissues was responsible for this quality, due to its 40 amino acid residues and three intramolecular disulphide bridges.
The maggot has also displayed activity against bacteria in highly resistant biofilm form, which even advanced antibiotics have had problems fighting.
The researchers stated that maggot ES would "act selectively against different bacterial strains" — in some cases, it would disrupt viable biofilm cells, while in others, it would prevent biofilm formation.
One study showed that Chymotrypsin, a component isolated from maggot ES, could digest collagens, which could be "conducive to impede bacterial colonisation and subsequent bioflm formation".
In terms of the maggot's anti-inflammatory properties, one study found that maggot ES decreased pro-inflammatory cytokines, and increased the anti-inflammatory cytokine IL-10.
Another study found that maggot ES altered monocyte-macrophage differentiation, converting it from pro-inflammatory to pro-angiogenic.
Surpassing the maggot
The researchers stated that the diverse properties of the 'medicinal maggot' were the result of active ingredients like lucifensin, Chymotrypsin, and unsaturated fatty acids.
They concluded: "The developments of recombinant and transgenic bioactive molecules from the maggot are both challenges and opportunities for increased treatment acceptance and improved outcome.
"Perhaps one day in the future, these molecules may surpass the use of the maggot itself in the treatment of chronic and refractory wounds.
"Sincerely, we hope to form a more detailed theory foundation from which great efforts towards therapeutic agents of maggots for medical purposes can be made."
Source: Evidence-Based Complementary and Alternative Medicine
"Pharmacological Properties of the Medical Maggot: A Novel Therapy Overview"
Authors: Litao Yan, et al.