In vitro evaluation of the antimicrobial activity of fungus-growing termites Macrotermes bellicosus used in traditional medicine in Benin

Background: Insects and insect-derived products have been widely used in folk healing in many parts of the world since ancient times. Among these insects, fungus-growing termites play an important role in nutrition and traditional medicine in various societies in tropical Africa.

Aim of the present study was to explore the traditional therapeutic uses of the fungus-growing termites Macrotermes bellicosus collected from different regions in Benin and subsequently investigate their antimicrobial potential.

An ethnomedicinal survey with active healers in Benin was conducted and the antimicrobial activity of ethanolic extracts of Macrotermes bellicosus against selected pathogenic microorganisms was investigated using the Kirby-Bauer disc diffusion method. Inhibition zone diameter (IZD) and minimum inhibitory concentrations (MIC) were derived to characterize the antimicrobial activity. Amoxicillin was applied as positive control.

The ethnomedicinal survey revealed that fungus-growing termites and its products (termites' mounds and fungus comb) are traditionally used in Benin to treat infectious and inflammatory diseases including digestive disorders, diarrhea and snake bites (Fig 1). Ethanolic extracts (90%V/V) of species from Macrotermes bellicosus collected in Abomey-Calavi (T1S),Sekou (T2S) and Lokossa (T3S) showed antimicrobial activity comparable to amoxicillin (25 µg/disc) against Staphylococcus aureus (T1S:IZD = 15 ± 0.1 mm), Pseudomonas aeruginosa (T2S:IZD = 12 ± 0.1 mm) and Escherichia coli (T3S:IZD = 15 ± 0.1 mm), respectively. Additionally, the termite extract T3S have been showed to inhibite the activity of Klebsiella pneumonia (T3S:IZD = 14 ± 0.1 mm). The MIC values varied between extracts and test organisms used and ranged from 25 to 100 µg/disc with T1S extract being the most effective on S.aureus (MIC = 25 µg/disc). The chemical screening of Macrotermes bellicosus extract revealed the presence of terpenes, steroids, saponins, alkaloids, flavonoids and tannins.

Macrotermes bellicosus used as a traditional medicine is efficient against different bacterial strains and could be a therapeutic option for infectious diseases. The present finding confirmed the efficacy of traditional practices, which could bring new solutions to tackle increasing bacterial resistance to existing antibiotics.

Fig. 1: Traditional therapeutic uses of fungus-growing termites Macrotermes bellicosus and their products in the traditional medicine of Benin. Results from an ethnomedicinal survey with active healers from Benin (n = 30).