Bio-Active Compounds Composition in Edible Stinkbugs Consumed in South-Eastern Districts of Zimbabwe

Abstract

Encosternum delegorguei Spinola (Hemiptera: Tessaratomidae) are consumed as relish and with traditional claims of having medicinal roles in the South-Eastern districts of Zimbabwe. However, very little has been explored scientifically to validate these claims. The current study was conducted to investigate bio-active compound composition and diversity of stable antibacterial activity from E. delegorguei extracts. Methanol, ethanol and aqueous extractions of E. delegorguei were performed followed by qualitative, quantitative analyses of phytochemical/bioactive compounds and determination of antibacterial activities using disc diffusion method on ten clinically important microbes. Alkaloids, flavonoids, anthraquinones, tannins, phlobatannins, steroids, triterpenoids and cyanogen glycosides were detected in the insect extracts. Flavonoids were detected in significantly higher concentrations in unprocessed compared to processed insects. Mean DPPH free radical scavenging activities were 78% and 88% for traditionally processed and raw insect extracts respectively. Traditional processing resulted in reduction of bioactive compounds (22.2% total phenolics; 68.4% flavonoids) and free radical scavenging activities by 10%. However, it resulted in an increase of cyanogen glycosides by 65.7%. Methanol extracts produced highest mean inhibition zones of 20 mm while aqueous and ethanol extracts had mean inhibition of 0 to 15 mm as compared to control with 20-40 mm. High flavonoids levels could be beneficial to consumers. However, a potential trade-off from elevated levels of cyanogen glycosides after processing needs further investigation. The free radical scavenging activity displayed by E. delegorguei extracts indicate a potential source of natural anti-oxidants that can be formulated into commercial products.

Determination of Nutritional Composition of Encosternum delegorguei Caught in Nerumedzo Community of Bikita, Zimbabwe

“…7, No. 4; such as cyanogens (Musundire et al, 2014). However, further research can be done to elucidate the link between bioactive compounds and protein content.…”

“…The bugs were killed and prepared by methods outlined by (Musundire et al, 2014;Teffo et al, 2007). The bugs (500 g) were killed by immersing in 5 litres of warm water (approximately 37°C) while stirring with a wooden stick for 5 minutes.…”

“…Traditional processing and preparation for consumption of E. delegorguei has been described elsewhere (Teffo, Toms, & Eloff, 2007;Musundire, Zvidzai, & Chidewe, 2014). The traditional processing method employed by the community should be followed accurately in order to obtain a well-prepared or unspoiled bug which imparts desirable flavour and colour.…”

“…This extremely bitter spoiled bug is a result of poor processing method or picking up dead bugs during harvest. The community claims that black chest bugs play an important role in the treatment of hangovers and curing of stomach aches (Musundire et al, 2014;Dzerefos & Witkowski, 2014).These are normally separated from the golden crispy ones before consumption. However, under subsequent quality control, the black chest bug can still be consumed among the golden crispy ones.…”

“…The consumption of golden crispy bug is rapidly increasing due to its acclaimed traditional values that include sensory properties and medicinal such as decreasing hypertension, cure for asthma, heart diseases and as an appetizer (Musundire et al, 2014;Dzerefos & Witkowski, 2014). In Nerumedzo, the insect is consumed in three forms.…”